U.S. patent application number 14/791440 was filed with the patent office on 2016-03-24 for local metering response to data aggregation in distributed grid node.
The applicant listed for this patent is Clayton Borzini, Fred C. Horton, Frank P. Marrone, Stefan Matan. Invention is credited to Clayton Borzini, Fred C. Horton, Frank P. Marrone, Stefan Matan.
Application Number | 20160087432 14/791440 |
Document ID | / |
Family ID | 55455737 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160087432 |
Kind Code |
A1 |
Matan; Stefan ; et
al. |
March 24, 2016 |
LOCAL METERING RESPONSE TO DATA AGGREGATION IN DISTRIBUTED GRID
NODE
Abstract
Data aggregation enables a local control response at a consumer
node of a distributed grid network. A consumer node includes a
local energy meter. The meter receives multiple inputs indicating
an electrical condition of the grid network and local operating
conditions. The meter can aggregate the grid network and local
operation conditions inputs with power demand for a local load
coupled to the consumer side of the point of common coupling
monitored by the energy meter. The energy meter calculates a mix of
real and reactive power to output from a local energy source, based
on the aggregated data. A local power converter outputs the
calculated power from the local energy source.
Inventors: |
Matan; Stefan; (Novato,
CA) ; Horton; Fred C.; (Santa Rosa, CA) ;
Marrone; Frank P.; (Cloverdale, CA) ; Borzini;
Clayton; (Novato, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Matan; Stefan
Horton; Fred C.
Marrone; Frank P.
Borzini; Clayton |
Novato
Santa Rosa
Cloverdale
Novato |
CA
CA
CA
CA |
US
US
US
US |
|
|
Family ID: |
55455737 |
Appl. No.: |
14/791440 |
Filed: |
July 4, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62021085 |
Jul 4, 2014 |
|
|
|
Current U.S.
Class: |
700/291 ;
700/297 |
Current CPC
Class: |
H02J 3/00 20130101; G06G
7/635 20130101; H02J 13/00034 20200101; Y04S 20/222 20130101; Y04S
20/221 20130101; H02J 3/382 20130101; H02J 3/18 20130101; G01R
11/54 20130101; H02J 3/01 20130101; H02J 13/0006 20130101; H02J
3/383 20130101; H02J 13/00 20130101; H02J 3/381 20130101; Y02B
70/3225 20130101; G05B 15/02 20130101; H02J 13/00004 20200101; H02J
2300/20 20200101; H02J 3/38 20130101; Y02B 70/30 20130101; Y02B
90/20 20130101; Y02E 40/40 20130101; Y02E 10/56 20130101; Y02E
40/70 20130101; Y04S 20/12 20130101; H02J 3/06 20130101; H02J 3/12
20130101; H02J 2310/10 20200101; Y04S 10/123 20130101; H02J 2310/16
20200101; G05B 13/026 20130101; H02M 1/42 20130101; G05F 1/66
20130101; H02J 3/28 20130101 |
International
Class: |
H02J 3/00 20060101
H02J003/00; G05B 15/02 20060101 G05B015/02 |
Claims
1. A method for interfacing with a power grid network, comprising:
receiving multiple inputs at a meter on a consumer side of a point
of common coupling (PCC) to the grid network, the inputs indicating
an electrical condition of the grid network and local operating
conditions at the PCC; identifying power demand for a local load
coupled to the consumer side of the PCC; calculating a mix of real
and reactive power to output from a local energy source, based on
the multiple inputs and the power demand for the local load; and
outputting power from the local energy source based on the
calculated output power.
2. The method of claim 1, wherein the grid network comprises a
utility power grid.
3. The method of claim 1, wherein receiving the external grid
inputs comprises receiving one or more of dispatch information from
a central grid controller, specific control signals from a grid
controller, or grid condition information from other nodes in the
grid network.
4. The method of claim 1, wherein receiving the local sensor inputs
comprises receiving one or more of temperature information, or
information regarding one or more conditions that affect an ability
of a local energy source to generate energy.
5. The method of claim 1, wherein calculating the output power
further comprises calculating the mix of real and reactive power
based at least in part on rate information indicating a value of
power generated.
6. The method of claim 1, wherein calculating the output power
further comprises calculating the mix of real and reactive power
based at least in part on extrapolating from historical information
indicating a history of how local power demand and local power
generation has occurred in the past.
7. The method of claim 1, wherein outputting power comprises
outputting power for consumption by a local load.
8. The method of claim 1, wherein outputting power comprises
outputting power to charge a local energy storage resource.
9. The method of claim 1, wherein outputting power comprises
outputting real power to a power grid market for monetary
credit.
10. The method of claim 1, wherein outputting power comprises
outputting power to one or more ancillary services, including real
and/or reactive power grid support, frequency support for the grid
network, blackstart operation, regulation up operation, regulation
down operation, or a combination.
11. A consumer node in a grid network of a power grid system,
comprising: an energy meter on a consumer side of a point of common
coupling (PCC) to the grid network, the energy meter to receive
multiple inputs indicating an electrical condition of the grid
network and local operating conditions at the PCC, and to identify
power demand for a local load coupled to the consumer side of the
PCC; a local power converter coupled to the consumer side of the
PCC, the power converter to control an interface to the PCC to
control power flow at the PCC; and a gateway controller coupled to
receive information from the energy meter, to calculate a mix of
real and reactive power to output from a local energy source, based
on the multiple inputs and the power demand for the local load, and
to request the power converter to output the calculated output
power.
12. The consumer node of claim 11, wherein the gateway controller
is to calculate the mix of real and reactive power further based at
least in part on rate information indicating a value of power
generated.
13. The consumer node of claim 11, wherein the gateway controller
is to calculate the mix of real and reactive power further based at
least in part on extrapolation of historical information indicating
a history of how local power demand and local power generation has
occurred in the past.
14. The consumer node of claim 11, wherein the power converter is
to output power for local capacity.
15. The consumer node of claim 11, wherein the power converter is
to output power to a power grid market, or to one or more ancillary
services, including real and/or reactive power grid support,
frequency support for the grid network, blackstart operation,
regulation up operation, regulation down operation, or a
combination.
16. A power grid system, comprising: a grid connector to couple a
local consumer node to a utility power grid at a consumer side of a
point of common coupling (PCC); a local energy source coupled on
the consumer side of the PCC; and a control node coupled to the
local energy source at the PCC, the control node including an
energy meter on a consumer side of a point of common coupling (PCC)
to the grid network, the energy meter to receive multiple inputs
indicating an electrical condition of the grid network and local
operating conditions at the PCC, and to identify power demand for a
local load coupled to the consumer side of the PCC; a local power
converter coupled to the consumer side of the PCC, the power
converter to control an interface to the PCC to control power flow
at the PCC; and a gateway controller coupled to receive information
from the energy meter, to calculate a mix of real and reactive
power to output from the local energy source, based on the multiple
inputs and the power demand for the local load, and to request the
power converter to output the calculated output power.
17. The power grid of claim 16, wherein the gateway controller is
to calculate the mix of real and reactive power further based at
least in part on rate information indicating a value of power
generated.
18. The power grid of claim 16, wherein the gateway controller is
to calculate the mix of real and reactive power further based at
least in part on extrapolation of historical information indicating
a history of how local power demand and local power generation has
occurred in the past.
19. The power grid system of claim 16, wherein the power converter
is to output power for local capacity.
20. The power grid system of claim 16, wherein the power converter
is to output power to a power grid market, or to one or more
ancillary services, including real and/or reactive power grid
support, frequency support for the grid network, blackstart
operation, regulation up operation, regulation down operation, or a
combination.
Description
PRIORITY
[0001] The present application is a nonprovisional application
based on U.S. Provisional Application No. 62/021,085, filed Jul. 4,
2014, and claims the benefit of priority of that provisional
application. The provisional application is hereby incorporated by
reference.
[0002] The present application is related to the following U.S.
patent applications filed concurrently herewith, and having common
ownership: U.S. patent application Ser. No. TBD [P016], entitled
"HIERARCHICAL AND DISTRIBUTED POWER GRID CONTROL," U.S. patent
application Ser. No. TBD [P018], entitled "DISTRIBUTED POWER GRID
CONTROL WITH LOCAL VAR CONTROL," U.S. patent application Ser. No.
TBD [P020], entitled "HIERARCHICAL AND DISTRIBUTED POWER GRID
GENERATION," U.S. patent application Ser. No. TBD [P021], entitled
"TOTAL HARMONIC CONTROL," U.S. patent application Ser. No. TBD
[P022], entitled "ENERGY SIGNATURES TO REPRESENT COMPLEX CURRENT
VECTORS," U.S. patent application Ser. No. TBD [P026], entitled
"POWER GRID SATURATION CONTROL WITH DISTRIBUTED GRID INTELLIGENCE,"
U.S. patent application Ser. No. TBD [P027], entitled "VIRTUAL
POWER GRID," U.S. patent application Ser. No. TBD [P028], entitled
"MODULAR POWER GRID."
[0003] The present application is related to the following U.S.
patent applications filed concurrently herewith, and having common
ownership: U.S. patent application Ser. No. TBD [P019], entitled
"GRID NETWORK GATEWAY AGGREGATION," U.S. patent application Ser.
No. TBD [P017], entitled "INTELLIGENT BATTERY BACKUP AT A
DISTRIBUTED GRID NODE," U.S. patent application Ser. No. TBD
[P024], entitled "DATA AGGREGATION WITH OPERATION FORECASTS FOR A
DISTRIBUTED GRID NODE," U.S. patent application Ser. No. TBD
[P025], entitled "DATA AGGREGATION WITH FORWARD PREDICTION FOR A
DISTRIBUTED GRID NODE."
FIELD
[0004] Embodiments of the invention are generally related to an
electrical power grid, and more particularly to a power grid
gateway that generates control decision based on aggregation of
data.
COPYRIGHT NOTICE/PERMISSION
[0005] Portions of the disclosure of this patent document may
contain material that is subject to copyright protection. The
copyright owner has no objection to the reproduction by anyone of
the patent document or the patent disclosure as it appears in the
Patent and Trademark Office patent file or records, but otherwise
reserves all copyright rights whatsoever. The copyright notice
applies to all data as described below, and in the accompanying
drawings hereto, as well as to any software described below:
Copyright .COPYRGT. 2015, Apparent Inc., All Rights Reserved.
BACKGROUND
[0006] Traditional utility power grids include a centralized power
source (such as a coal-powered generator, a nuclear-power
generator, a hydroelectric dam generator, wind farm, or others) and
centralized management. The "grid" may connect to other power
sources as well so that power can be shared across grid
infrastructure from different power sources at a macro-level.
However, traditionally, the grid includes a substantial amount of
infrastructure, such as utility power lines with associated poles
and towers, as well as substations to distribute the power. The
grid is traditionally based on a massive generator that can provide
enough power to satisfy peak demand of interconnected consumers. A
consumer can include a dwelling place, a business, a cellphone
tower or other utility box, or other user of power. The different
consumers can have different peak demands, from the smallest user
of energy to large businesses that have high power demands for
heavy commercial equipment.
[0007] Traditional grid infrastructure is expensive to build and
maintain. Furthermore, it requires the pushing of energy out from
the central power source to the consumers, which can be hundreds of
miles away. The substations and other infrastructure such as
neighborhood transformers are controlled by the centralized
management to keep voltages in-phase with current delivered on the
grid, and keep voltage levels at regulated levels. Typically,
motorized equipment drawing power from the grid will cause a
degradation of power factor of the grid. On a macro scale, the grid
management has attempted to control the power factor disturbance of
the grid due to such motorized equipment. Newer switching power
supply designs in modern electronics further complicate the power
factor and voltage regulation of the grid by requiring reactive
power and introducing noise back onto the grid.
[0008] Power delivered by the grid generally consists of a real
power component and a reactive power component. Real power is power
delivered where the voltage waveform and current waveform are
perfectly aligned in-phase. Reactive power is power delivered where
the voltage waveform and current waveform are not phase-aligned.
Reactive power can be leading or lagging, based on the phase
difference between the current and voltage waveforms.
[0009] Power as seen by a consumer can be understood differently
from energy itself provided to calculate the power. Power is
typically represented by W dot h or Watt-hours. Multiplying the
Watt-hours by the rate charged by the utility provides the dollar
amount owed by the consumer to the utility. But energy can be
represented in different ways, and can be measured in multiple
different ways. Examples include (VA) V dot I (voltage vector
multiplied by current vector for volt-amps), V dot I dot PF
(voltage vector multiplied by current vector times the power factor
for Watts), and the square root of W 2 (square root of Watts
squared for volt-amps-reactive). The consumer typically sees the
power in Watt-hours which gives the cost of the energy delivered to
the premises. Utilities have also started to measure and charge for
reactive power consumption at the user premises.
[0010] There has been a significant increase in grid consumers
adding renewable sources locally at the consumer locale to produce
power. The renewable energy sources tend to be solar power and/or
wind power, with a very significant number of solar systems being
added. One limitation to customer power sources is that they tend
to produce power at the same time, and may produce more power than
can be used on the grid. The grid infrastructure is traditionally a
one-way system, and the real power pushed back from the customer
premises toward the central management and the central power source
can create issues of grid voltage control and reactive power
instability on the grid. These issues have caused grid operators to
limit the amount of renewable energy that can be connected to the
grid. In some cases, additional hardware or grid infrastructure is
required at or near the consumer to control the flow of power back
onto the grid.
[0011] In addition to the issues caused by renewable sources, the
increase in use of air conditioning units and other loads that draw
heavily on reactive power create additional strain for the grid
management to keep voltage levels at needed levels. Recent heat
waves have resulted in rolling brownouts and blackouts. Other times
there are temporary interruptions on the grid as equipment
interfaces are reset to deal with the changes in load when people
return home from work and increase power consumption there.
Traditionally, the central management must maintain compliance of
grid regulations (such as voltage levels). Whenever something
connected to the grid enters an overvoltage scenario, it shuts off
from the grid, which can then create additional load on surrounding
areas, resulting in larger areas of the grid coming down before the
central management can restore grid stability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The following description includes discussion of figures
having illustrations given by way of example of implementations of
embodiments of the invention. The drawings should be understood by
way of example, and not by way of limitation. As used herein,
references to one or more "embodiments" are to be understood as
describing a particular feature, structure, and/or characteristic
included in at least one implementation of the invention. Thus,
phrases such as "in one embodiment" or "in an alternate embodiment"
appearing herein describe various embodiments and implementations
of the invention, and do not necessarily all refer to the same
embodiment. However, they are also not necessarily mutually
exclusive.
[0013] FIG. 1 is a block diagram of an embodiment of a system with
tiered grid control.
[0014] FIG. 2 is a block diagram of an embodiment of a system with
monitoring and control at a point of common coupling within a
neighborhood.
[0015] FIG. 3 is a block diagram of an embodiment of a distributed
grid system.
[0016] FIG. 4 is a graphical representation of an embodiment of
components of a current in a system in which harmonic components of
current have angular offsets with respect to a primary current
component.
[0017] FIG. 5 is a graphical representation of an embodiment of
components of a current in a system in which a current vector is a
composite of a primary current component and harmonic current
components.
[0018] FIG. 6 is a block diagram of an embodiment of a gateway
device in a distributed grid system.
[0019] FIG. 7 is a block diagram of an embodiment of a gateway
aggregator system.
[0020] FIG. 8 is a block diagram of an embodiment of a metering
device that monitors power at a PCC.
[0021] FIG. 9 is a block diagram of an embodiment of a node for a
distributed power grid.
[0022] FIG. 10 is a block diagram of an embodiment of a system that
controls harmonic distortion with a software feedback control
subsystem coupled to a hardware waveform controller.
[0023] FIG. 11 is a block diagram of an embodiment of a system that
transfers power from a local source to a grid-tied load with power
factor conditioning.
[0024] FIG. 12 is a block diagram of an embodiment of a consumer
node having intelligent local energy storage.
[0025] FIG. 13 is a flow diagram of an embodiment of a process for
controlling a grid node with data aggregation.
[0026] FIG. 14 is a flow diagram of an embodiment of a process for
aggregating local and grid-based condition information.
[0027] FIG. 15 is a flow diagram of an embodiment of a process for
generating a grid control operation with an aggregator gateway.
[0028] FIG. 16 is a flow diagram of an embodiment of a process for
intelligent battery backup control.
[0029] Descriptions of certain details and implementations follow,
including a description of the figures, which may depict some or
all of the embodiments described below, as well as discussing other
potential embodiments or implementations of the inventive concepts
presented herein.
DETAILED DESCRIPTION
[0030] As described herein, data aggregation enables a local
control response at a consumer node of a distributed grid network.
A consumer node includes a local energy meter. The meter receives
multiple inputs indicating an electrical condition of the grid
network and local operating conditions. The meter can aggregate the
grid network and local operation conditions inputs with power
demand for a local load coupled to the consumer side of the point
of common coupling monitored by the energy meter. The energy meter
calculates a mix of real and reactive power to output from a local
energy source, based on the aggregated data. A local power
converter outputs the calculated power from the local energy
source.
[0031] As described herein, distributed grid network intelligence
enables data aggregation at a local control node. In a consumer
node, a meter is on a consumer side of a point of common coupling
(PCC). The meter can receive one or more external grid inputs and
one or more local sensor inputs. The grid inputs can come from
sources outside the PCC, and the local sensor inputs monitor
conditions at the PCC and/or within the PCC. The meter can identify
power demand within the PCC and calculate an output power to
generate with a local power converter. The calculation is not
simply based on power demand, but on aggregation information,
including the one or more external grid inputs, the one or more
local sensor inputs, and the power demand for the local load. The
local power converter can then output power in accordance with the
calculated output power.
[0032] In one embodiment, a control node enables distributed grid
control. Multiple independent control nodes can be distributed
throughout the grid. The control nodes can be hierarchically
organized by connecting multiple control nodes to a common control
node of the multiple control nodes. Each control node manages a
point of common coupling (PCC) to the grid. A PCC is an
interconnection point where multiple downstream loads and/or local
power sources connect to the grid. For purposes herein, each
control node couples to multiple loads and/or energy sources, and
is thus associated with a PCC. Because each control node manages
its interface or interconnection to the grid independently of any
other control node, grid control intelligence can be distributed
throughout the grid.
[0033] In one embodiment, each control node operates independently
of other control nodes by monitoring and managing power generation
and power demand at its PCC between a utility power grid and all
devices downstream from the PCC or from the control node. The
downstream devices can include energy sources such as solar and/or
wind power generation, loads such as real and/or reactive power
consumers (e.g., consumer nodes), as well as other PCCs or other
control nodes. In one embodiment, each control node manages its
interface or interconnection to the grid to maintain compliance
with grid regulations. In one embodiment, the control node has any
number of consumer nodes and any number of energy sources connected
downstream. A consumer node can be a customer premises. In one
embodiment, a customer premises can include multiple consumer
nodes. In one embodiment, a consumer node can include multiple
customer premises. In one embodiment, one control node manages
multiple customer premises. Each control node can monitor power
generation and power demand from downstream and ensure that demand
on the grid is within accepted levels. The control node can provide
grid control by adjusting the interface between the control node
and the central grid management via the PCC to maintain compliance
with grid regulations at the PCC.
[0034] In one embodiment, the control node adjusts downstream
active power consumption. In one embodiment, the control node
adjusts downstream reactive power consumption. In one embodiment,
the control node adjusts downstream reactive power generation. In
one embodiment, the control node adjusts downstream active power
generation. In one embodiment, the control node controls energy at
the PCC to manage the amount and types of power seen at the PCC
from the perspective of the grid (i.e., from the grid side or as
seen from central grid management or the grid infrastructure
looking downstream through the PCC).
[0035] FIG. 1 is a block diagram of an embodiment of a system with
tiered grid control. System 100 represents a power grid with tiered
control. In one embodiment, system 100 includes power plant 110 and
grid backbone 120, although in one embodiment, the tiered grid can
be applied without connection to a central grid management and
central grid power plant. System 100 represents a grid system in
which power consumers are connected to each other and to power
sources.
[0036] Power plant 110 represents a large-scale power plant that
powers grid backbone 120. Power plant 110 is traditionally a
hydroelectric dam generator, a nuclear power plant, a coal-powered
generator plant, or a large wind farm. Recent large-scale solar
farms have also been added. Grid backbone 120 includes towers,
lines, transformers, substations, and other infrastructure to
interconnect consumers to power plant 110. Grid backbone 120
includes grid infrastructure with high voltage power lines that
transport power many miles. In practice, multiple power sources or
power plants can be connected to the same grid backbone 120, but
all are large scale and typically designed to generate as much
power and service as many consumers as possible. Grid backbone 120
is traditionally designed for one-way distribution of power from
power plant 110 to the consumers. Reference to "the grid" or a
"utility grid" can refer to power plant 110 and the infrastructure
of grid backbone 120.
[0037] In one embodiment, the grid can be thought of as a network
that can be hierarchically separated into various different
segments of the grid. Each grid segment can be controlled by a
separate control node. In one embodiment, system 100 includes
control nodes 130, 140, and 150. Each control node can manage a PCC
or point of common coupling point where multiple loads and/or
multiple sub-segments of the grid couple together. The PCCs can
connect each segment and sub-segment to each other and/or to the
grid.
[0038] It will be understood that a PCC can be both an
electrical-equivalency point as well as or instead of a
geographical connection. At the top of the hierarchy illustrated is
PCC[0], which directly connects all downstream segments and
portions to each other. PCC[0] can also connect all downstream
point to grid backbone 120. Reference to "downstream" refers to
devices or items that are farther away along the path of
distribution. Thus, a residence or customer premises can be at one
point on the distribution path of the grid, and a customer premises
further along the distribution path is downstream. It will be
understood that other grid segments with additional structure can
be downstream from PCC[0] by virtue of being farther away from
power plant 110 and thus farther down a distribution path as seen
from central grid management.
[0039] System 100 can be referred to as a grid network, which may
or may not include grid backbone 120 and power plant 110. The grid
network can be hierarchical in that each PCC can aggregate multiple
lower-level PCCs. Each PCC provides a connection point for all
downstream devices. PCC[0] is at the top of the hierarchy of system
100. In one embodiment, multiple additional devices that are not
shown can connect to PCC[0]. Such other devices not shown would be
coupled in parallel with node 130 to PCC[0]. It will be understood
that a lowest level of the grid network hierarchy is a control node
at a customer premises, such as node 162 at customer premises 160,
with PCC[3]. In one embodiment, there are one or more control nodes
at a customer premises. In one embodiment, there are customer
premises with no control nodes in system 100.
[0040] In system 100, two customer premises are illustrated,
customer premises 160 and customer premises 180. The customer
premises can also be referred to as consumers or consumer nodes. In
one embodiment, customer premises can include homes, businesses,
parks, loads, thermostats, pumps, vehicle charging stations, and/or
other consumers of power. Each customer premises includes one or
more loads or devices that rely on electrical power to operate. In
one embodiment, customer premises 160 includes a single control
node, 162. In one embodiment, customer premises 180 includes
multiple control nodes, 182 and 184. There can be zero or more
control nodes at a customer premises. There may be many control
nodes at a single customer premises, depending on the design of the
grid network and the number of loads and power sources at the
customer premises. Other customer premises can be included in
system 100. Zero or more of the customer premises can include
energy generation, which is described in more detail below with
respect to other drawings.
[0041] In one embodiment, each PCC is associated with a control
node. The control node associated with the PCC manages or controls
the electrical operation at that control node. For example, in one
embodiment, in system 100, control node 130 is associated with
PCC[1], and manages load demand and power generation downstream
from PCC[1] as seen at PCC[1] from the grid side. Reference to
looking from the grid side, or seeing from the grid side refers to
what net power demand (either power needed or power produced)
exists at that point. Seeing from the grid side can also refer to
what phase offset or reactive power net exists at that point
looking downstream from that point. The PCCs are aggregation points
for generation and demand. A net power demand can be a difference
in real and reactive power needed based on load demand against real
and reactive power generated within the same segment or area of the
PCC. Within the same segment can be referred to as being "within" a
PCC, meaning within a downstream network connected to the PCC.
[0042] In one embodiment, each control node can independently
control its own PCC. Thus, control node 130 controls PCC[1],
control node 150 controls PCC[2], control node 140 controls PCC[4],
and control node 162 controls PCC[3]. In one embodiment,
independent control refers to the fact that each control node
monitors and controls operation at its PCC to maintain the PCC as
close to compliance with grid rules as possible. It may not always
be possible for each control node to achieve full compliance. In
one embodiment, the control nodes operate based on what neighboring
control nodes output, such as what demand is seen looking toward
the neighboring control node from the present control node.
However, controlling operation by looking at the operation of
another control node does not imply that the operation of each
control node is dependent on each other. To the contrary, in one
embodiment, each control node seeks to make sure that the node as a
whole (everything connected "underneath" or downstream from it)
complies with all requirements, regardless of the operation of
others. Monitoring the performance or operation of neighboring
control nodes or neighboring PCCs can be a consideration to
determine how to operate, and whether to provide support upstream
to the grid. In one embodiment, each control node is capable of
receiving and responding to input from a central data center and/or
from central grid management, but can operate with or without such
input. Thus, each control node operates independently to control
the net power operation as seen at its connection point.
[0043] In one embodiment, each control node includes a converter or
inverter device and a metering device. In one embodiment, the
converter is referred to as a power conversion device or simply
conversion device. Reference to a converter can include one or
multiple converters that can operate together to control operation
and/or an interface at a PCC. In one embodiment, the control node
and converter are separate devices. Thus, converter 132 can be part
of control node 130, or simply connected to it at PCC[1].
Similarly, converter 142 is associated with control node 140,
converter 152 is associated with control node 150, converter 164 is
associated with control node 162, converter 192 is associated with
control node 182, and converter 194 is associated with control node
184. Other network configurations are possible. It will be
understood that the entirety of system 100 is not illustrated.
[0044] As mentioned, each customer premises can be or include a
load. Customer premises 160 includes one or more loads 172. Each
load 172 consumes power. Loads 172 can generate a demand for power
that has a real power component to the demand and a reactive power
component to the demand. Traditionally reactive power has been
provided by the grid, with the exception of heavy equipment (e.g.,
capacitor banks and/or inductive motors) on-site at the customer
premises. Loads 172 can be any form of load, such as lighting,
computer equipment, entertainment devices, motors, HVAC (heating,
ventilation, and air conditioning) equipment, household and kitchen
appliances, or any other type of device that requires electricity
to operate. Such devices can include rechargeable devices that are
charged by plugging to a power outlet. Many of these devices
generate reactive demand. That demand for reactive power will be
seen at the PCC for the load, and can be seen upstream at other
PCCs unless the demand is satisfied. In one embodiment, node 162
and converter 164 can provide reactive power for loads 172.
[0045] It will be understood that there are loads (not specifically
shown) within customer premises 180. In one embodiment, converter
164 is coupled to PCC[3] where loads 172 are coupled. In one
embodiment, converter 192 and converter 194 can be coupled between
the loads and the PCC (PCC[2]). Converter 164 is coupled to PCC[3],
and can be configured to operate to maintain certain performance
parameters at PCC[3]. In one embodiment, in practice, converter 164
is coupled between PCC[3] and a meter of control node 162. The
performance parameters can be associated with controlling real and
reactive power at the PCC. In one embodiment, when a converter is
coupled between the loads and the PCC, the converter is configured
to maintain the particular load or loads coupled to it.
[0046] In one embodiment, each control node includes a metering
device or energy meter built into or associated with or part of the
control node. More details about embodiments of a metering device
are provided below. The metering device measures energy usage at
the PCC and can determine a net power demand or power generation
from downstream. In one embodiment, the metering device enables
monitoring the operation of the grid network at the PCC. In one
embodiment, the metering device can measure energy signatures. Each
converter can control the power usage at the PCC. In one
embodiment, the converter controls the use of real and/or reactive
power at the PCC.
[0047] In one embodiment, the grid hierarchy of system 100 can
include one or more control nodes at a consumer premises, one or
more control nodes within a neighborhood, one or more control nodes
at a substation, or other hierarchy. Each control node in the
hierarchy independently controls operation below it and reports
upstream. Thus, each control node can independently manage
compliance of the grid. If a segment of the grid network
experiences a failure, a node higher up the hierarchy or higher
upstream can attempt to adjust operation to prevent the failure
from being seen or experienced outside the subnetwork below its
PCC. Thus, a distributed grid can recover more quickly and
efficiently from failures, and can reduce the risk that other
segments of the grid will experience failure. For example, each
distributed control node of the grid network can dynamically adjust
reactive and real power consumption to maintain the connection at
its PCC in compliance with connection requirements for the
grid.
[0048] In one embodiment, each distributed control node of system
100 can control how the grid or grid network sees the segment of
the grid via the associated PCC. Thus, control node 130 can control
how the grid sees everything downstream from PCC[1], control node
150 can control how the grid or grid network sees everything
downstream from PCC[3], and so on. The ability to control how the
grid sees a segment of the grid via a PCC can allow more adaptive
behavior within a segment of the grid network. For example, whereas
current regulations would require certain inverters to drop offline
because of the violation of certain conditions (overvoltage,
overcurrent, islanding, and/or other condition(s)), controlling the
connection of the PCC to the grid allows the grid to see the
segment only through the PCC. Thus, each control node can control
its connection to the grid network at the PCC, which can allow
inverters to stay online longer to try to recover. Each inverter
downstream from a PCC could in theory temporarily violate the
passthrough requirements and/or overvoltage requirements for a
period if collectively the devices connected to the PCC comply. In
one embodiment, if the control node and converter at a PCC can
cause support from other converters to be provided, or behavior
changed at those converters to alter the net condition at the PCC,
each inverter could similarly temporarily violate grid conditions
while the control node maintains the PCC within compliance by
changing operation of other devices within the PCC.
[0049] In one embodiment, distributed control or a grid or grid
network includes pushing the point of common coupling out in the
case of a disruption to the grid. Consider a problem at PCC[2] that
would normally cause a failure of the grid at that point. In one
embodiment, control nodes 150 and 130 can detect the condition.
Control node 150 can attempt to change the grid condition at PCC[2]
via operation of converter 152, such as by changing reactive power
control. Control node 150 can also notify control node 130 of the
condition. In one embodiment, control node 130 responds to the
condition by signaling control node 140 to change its operation
(e.g., via converter 142) to balance the net condition seen at
PCC[1]. Control node 130 can also change the operation of converter
132 in response to the condition. Based on the operation of the
control nodes, while PCC[2] may experience a failure condition for
longer than is permissible by standard, the condition at PCC[1] can
be made to comply with standards and regulations. Thus, PCC[2] and
its equipment can stay up to attempt to correct the problem.
[0050] Thus, distribution of control nodes and distribution of
control operations via those nodes can push the point of compliance
as far towards the generator and/or grid backbone as possible to
minimize the impact of a local disturbance. Thus, in one
embodiment, each point in a hierarchy of grid network 100 is a
separate point of control for compliance. In one embodiment, system
100 provides distributed redundant compliance up and down the
hierarchy. In one embodiment, each control node attempts to operate
within compliance. Such operation can normally ensure that each
segment and sub-segment of the grid operates towards compliance,
but if there is a failure at one level, it will not result in the
grid going down if a higher level is able to correct for it. For
example, if control node 130 can adjust operation in response to a
failure at PCC[2], then control node 150 and everything downstream
from it can remain online to attempt to correct the error
condition. With such operation, a segment of the grid will not go
down unless and until there is a last point of control and
compliance that cannot compensate for the condition.
[0051] FIG. 2 is a block diagram of an embodiment of a system with
monitoring and control at a point of common coupling within a
neighborhood. System 200 includes a grid network, and can be one
example of a grid network and/or system in accordance with an
embodiment of system 100 of FIG. 1. Grid 210 represents the grid
infrastructure, which can include a central generator or power
plant and central grid control (not specifically shown).
[0052] Neighborhood 230 represents a segment or sub-segment of the
grid network. Neighborhood 230 couples to grid 210 via PCC 220. PCC
220 has associated control node 222. Control node 222 can be a
control node in accordance with any embodiment described herein,
and can include processing logic to control the performance of the
grid at PCC 220. In one embodiment, control node 222 includes a
converter to control the operation of the PCC. In one embodiment,
neighborhood is one level within a hierarchy of distributed control
for system 200. Other levels of the hierarchy are not specifically
shown. However, PCC 220 can couple to grid 210 via other PCC with
distributed control nodes.
[0053] In one embodiment, neighborhood 230 can be any segment or
sub-segment of the grid. Neighborhood 230 generally represents a
collection or grouping of customer premises of the grid. The
grouping can be any arbitrary grouping controlled by a control
node. In one embodiment, the grouping can be, for example, all
customer premises served by one transformer, one substation, or
some other grouping. In one embodiment, neighborhood can be a large
customer premises with multiple building and/or loads and power
generation that couples to grid 210 via a common point (PCC 220).
In such a scenario, there can be groupings within a single customer
premises. In one embodiment, everything attached to a control meter
or downstream from the same control meter and/or control node can
be a separately controlled by other devices (loads) coupled to a
different control meter. The control meters can control the
connection of all their attached loads to the grid.
[0054] Consider customer premises 240. In one embodiment, customer
premises 240 includes meter 242, converter 244, loads 246, and
energy source 248. Loads 246 can include any type and number of
loads. Converter 244 can be a converter in accordance with any
embodiment described herein. Energy source 248 can include any type
of local source of energy. Solar and wind generation are common
local power sources. Such sources are typically referred to as
"power" sources because they generate power that can be used
locally and/or returned to the grid. However, traditional systems
regulate the output of the sources in terms of power, or voltage
times current (P=VI). Such traditional operation fails to consider
that energy can be more flexibly used if not fixed to a specific
current and/or voltage. Regulation of the power necessarily results
in wasting power.
[0055] In contrast to traditional approaches, converter 244 can
convert the energy generated by source 248 into any type of power
needed by loads 246, whether real, reactive, or a mix. Furthermore,
converter 244 can return energy back to grid 210 via PCC 220 as
real and/or reactive power. Thus, source 248 is more properly
referred to as an "energy" source in the context of system 200,
seeing that it transfers the energy without regulating the output
to specific voltages or currents. More details on such a converter
are provided below.
[0056] Just as power is limiting in the sense of generation, power
metering can be limiting in the sense of monitoring and metering
the operation of customer premises 240. There are multiple ways to
perform measurement of energy. In general, it will be assumed that
it is possible to accurately measure energy without going into
detail about the ways to perform energy measurement. Thus, meter
242 can perform energy measurement. In one embodiment, meter 242 is
a control meter that measures energy instead of Watt-hours (W-h).
In one embodiment, the operation of meter 242 can be used be
controlling energy consumption and energy transfer in system 200.
In one embodiment, meter 242 can track energy signatures of loads
246 to determine how to control a point of common coupling. While
not specifically shown and labeled as such, it will be understood
that the combination of meter 242 and converter 244 can provide a
control node at customer premises 240. Thus, the connection point
of loads 246 to converter 244 and meter 246 can be a PCC. The PCC
of customer premises 240 includes the generation of power via
energy source 248 in addition to the consumption of power or power
demand from loads 246.
[0057] In one embodiment, neighborhood 230 includes an additional
customer premises 250 that similarly includes meter 252, converter
254, loads 256, and energy source 258. There is no requirement that
the amount and type of loads 256 and/or energy source 258 be the
same as loads 246 or energy source 248. Rather, each customer
premises can have any number of loads and/or power generation. In
one embodiment, neighborhood 230 can have any number of customer
premises with energy sources. In one embodiment, neighborhood 230
can include one or more customer premises that do not have energy
sources. In one embodiment, a customer premises without an energy
source can still be fitted with a control node, such as a meter and
a power converter, in accordance with more details below.
[0058] In meters within neighborhood 230 (e.g., meter 242 and meter
252, and others) can talk to each other to share metering and/or
control information. In one embodiment, such sharing of information
between meters or between control nodes can enable the meters
and/or control nodes to control how the point of common coupling
(PCC) for the neighborhood (PCC 220) moves in the network or how
control via different PCCs occurs in the network or grid as a
whole. Any medium can be used for communication between the
metering nodes. The ability to share information with each other
and/or with a central data center can enable the network or grid to
adaptively operate based on what is happening on the grid. Thus, in
one embodiment, system 200 enables distributed realtime data
monitoring and sharing. Other devices that receive the data can
provide reactive power compensation to give voltage support and/or
change real power operation within their control to change net
operation at a PCC.
[0059] As mentioned above, in one embodiment, one or more customer
premises coupled to a PCC includes an energy source, such as a
solar system. As illustrated, both customer premises 240 and
customer premises 250 include respective energy sources 248 and
258. Each customer premises within neighborhood 230 that includes
an energy source can include a respective power converter 246 and
256 to control distribution of the energy from the source. In one
embodiment, each converter enables the customer premises to provide
real and/or reactive power from the energy source to the local
loads (such as 246 and 256). In one embodiment, each converter can
provide real and/or reactive power from the energy source back to
the grid (e.g., to grid 210 via PCC 220 at which neighborhood 230
connects to the grid). In one embodiment, the power provided by one
converter at one consumer premises can affect the power usage as
seen at the PCC. For example, power generated for local consumption
and/or for return to the grid by converter 244 at customer premises
240 can change net power usage seen at PCC 220 by meter 252 and
converter 254. In one embodiment, each converter can support the
power use of a neighboring customer premises within the
neighborhood. Thus, each customer premises 240 and 250 can operate
to first be self-sufficient, and extend out to neighborhood 230,
and then further up the grid hierarchy to other neighborhoods
and/or to grid 210 as a whole.
[0060] As power can be provided up the hierarchy of system 200,
system 200 can also achieve isolation at each different level of
hierarchy or organization of the grid network. In one embodiment,
each meter 242 and 252 monitors local operation within the segment
of the grid downstream from the device itself and to local
operation from neighboring meters. For example, meters within
neighborhood 230 or within each hierarchy level of the grid can
share or distribute monitoring information, which can include power
demand and power generation information. Thus, each meter can
listen to local operation and be aware of what is happening outside
of its local area. In one embodiment, such operation enables system
200 to move the PCC based on what is happening on the grid as a
whole. Similar to what is mentioned above, if something within
neighborhood 230 went down or experienced an error condition,
neighborhood 230 can reroute isolation to shift the reactions of
the grid. Neighborhood 230 can reroute isolations via the
individual operations of control nodes within the neighborhood, and
via control node 222. Such operation will allow the grid to stay up
longer. In one embodiment, neighborhood 230 can effectively control
the reactive needs within its subgroup of the grid while possibly
only taking real power from the grid as a whole. Such operation is
possible via aggregation of information at PCC 220 and other PCCs
within the grid network hierarchy. Thus, in one embodiment,
neighborhood 230 itself responds to grid events at PCC 220 without
needing or waiting for central dispatch or grid management
operation of grid 210. In one embodiment, system 200 can
dynamically redefine the scope of the PCC depending on the event(s)
of the grid.
[0061] In one embodiment, in general, two neighborhoods can be
coupled together as part of a distributed grid network.
Neighborhoods can be at the same level of hierarchy within the grid
network, or can be at different levels of hierarchy. In one
embodiment where one neighborhood provides support (e.g., voltage
support) to the other, the neighborhoods will have sufficient
geographic or electrical proximity to allow control at one PCC to
affect the performance at the other PCC as seen from the grid.
[0062] The grid network includes distributed control nodes. In one
embodiment, distributed control nodes first seek compliance at
their respective PCCs, such as within their respective
neighborhoods, and then seek to support compliance of the grid as a
whole. In one embodiment, each control node can be thought of as a
gateway device. The gateway device can control the performance,
power factor, load control, and/or harmonic distortion at its
associated PCC. Each control node has an associated power converter
to control the power output to upstream and the power consumption
downstream.
[0063] In one embodiment, distributed control nodes are
position-aware within the grid network. In one embodiment, each
control node can know where it is in the hierarchy of the grid
network. Furthermore, in one embodiment, each control node can know
where it is relative to the grid from the power plant. In one
embodiment, each node for each neighborhood first tries to manage
the power consumption of its local neighborhood, and can also
support the grid depending on conditions of the grid (e.g., what is
happening at other neighborhoods). The conditions of the grid can
include any performance parameter, such as voltage level, power
factor, harmonic distortion, and/or other electrical parameter.
Position awareness can enable the control node to factor conditions
related to upstream operation of the grid to enable the control
node to provide more specific support. In one embodiment, each
control node can be enabled to provide support to the higher level
PCC based on what is happening within the grid or the grid
conditions. In this way, each control node can seek to ensure local
compliance, and also provide support to achieve overall
compliance.
[0064] In one embodiment, a control node is not associated with a
PCC and/or is not a gateway device if it does not include
disconnection management. For example, in one embodiment, a
neighborhood has only a node associated with a PCC, and there are
no sub-PCCs within the neighborhood. In such an implementation, the
control node associated with the PCC can be considered a gateway
device. In one embodiment, disconnection management executes only
at a gateway device. The gateway device presents all downstream
devices to the grid.
[0065] Position awareness within the grid can be referred to as
string position awareness, referring to a circumstance where a
device knows its position in a string of devices from the grid.
Position awareness can enhance the utility of a microinverter or
other power converter, by allowing it to provide support outside
its own area. For example, microinverters or other power converters
associated with control nodes may be better able to provide grid
support with position awareness. In one embodiment, bulk inverters
can use position awareness to adjust their operation for an overall
desired output. Bulk inverters refer to inverters connected
together in a star or cascade arrangement, or other network
configuration. Bulk inverters refer to a group of multiple
inverters that operate in connection to provide control over a
consumer and/or power generation. Thus, any instance of a control
node can include one or more power converters. In one embodiment,
the head of a string of devices is a gateway device and controls
the coupling for the entire string. Such a head of the string could
represent the entire string to the grid.
[0066] FIG. 3 is a block diagram of an embodiment of a distributed
grid system. System 300 includes a grid network, and can be one
example of a grid network and/or system in accordance with an
embodiment of system 100 of FIG. 1 and/or system 200 of FIG. 2.
System 300 may be only a segment or portion of one of the
previously-described systems. In one embodiment, system 300 can be
an alternative to one of the previously-described systems. In one
embodiment, system 300 is a grid network that operates without
central grid management. In one embodiment, system 300 is a grid
network that operates without a central power plant or other
large-scale power source that provides power to the entire grid. In
one embodiment, system 300 is a virtual grid and/or a modular grid.
In one embodiment, system 300 is a virtual grid that can still
connect to a traditional grid as an independent segment. In one
embodiment, system 300 can connect to other virtual grid and/or
modular grid segments.
[0067] System 300 illustrates neighborhood 340 and neighborhood
360, which can be neighborhoods in accordance with any embodiment
described herein. More specifically, neighborhoods 340 and 360 can
have any number of consumers that do and do not include local
energy sources, and can include any number of consumers that do and
do not include local control nodes. Neighborhood 340 couples to
control node 332. Similarly, neighborhood couples to control node
334. Control odes 332 and 334 can represent control nodes in
accordance with any embodiment described herein. Control nodes 332
and 334 are coupled to each other by some infrastructure, which may
be the same as a grid infrastructure, or may simply be a power line
having sufficient capacity to enable the control nodes to couple to
each other and provide electrical support to each other.
[0068] In one embodiment, the control nodes are the PCCs. Thus,
control node 332 can be PCC 322 and control node 334 can be PCC
324. In one embodiment, control nodes 332 and 334 are coupled to a
central data center 310. Data center 310 can aggregate information
about the operation of multiple distributed nodes within the grid
network of system 300. Data center 310 is central in that control
nodes 332 and 334 provide data to and receive information from the
data center. In one embodiment, data center 310 includes processing
and analysis engines that can determine what operation each node
should take in response to grid conditions. In one embodiment, data
center 310 is similar to central grid management, but it can be
simpler. Whereas central grid management typically controls
interconnection or interface of a central power plant to the grid
and potentially the operation of a substation, data center can
provide information to distributed nodes. The distributed nodes can
independently operate within their segment of the grid network to
respond to grid conditions. In one embodiment, data center 310
provides dispatch information to the distributed control nodes.
[0069] In one embodiment, neighborhood 340 includes one or more
consumers 342 that do not have local energy sources. In one
embodiment, neighborhood 340 includes one or more consumers 350
that include local energy source 352 and local control node 354.
The energy source and local control node can be in accordance with
any embodiment described herein. In general, neighborhood 340 has a
total load that represents the power demand within the
neighborhood, and a total capacity that represents the power
generation within the neighborhood. The load minus the capacity can
represent the net power demand, which can be positive or negative.
A negative power demand can indicate that neighborhood 340
generates more energy than will be consumed by its local consumers.
It will be understood that power demand fluctuates throughout the
day and year as consumers use and generate different amounts of
power. Control node 332 can continuously monitor the net power
demand for its associated neighborhood 340.
[0070] In one embodiment, neighborhood 360 includes one or more
consumers 362 that do not have local energy sources, and one or
more consumers 370 that include local energy source 372 and local
control node 374. The description of neighborhood 340 can apply
equally well to neighborhood 360. Neighborhood 360 also has a total
load that represents the power demand within the neighborhood, and
a total capacity that represents the power generation within the
neighborhood, which can be completely different from those of
neighborhood 340.
[0071] In one embodiment, either or both of the neighborhoods can
include local energy storage. For example, neighborhood 340 is
illustrated with energy store 344, and neighborhood 360 is
illustrated with energy store 364. In one embodiment, at least one
neighborhood does not include energy storage. In one embodiment,
all neighborhoods include energy storage. Energy store 344 and 364
represent any type of energy storage that can exist within the
neighborhoods. Energy store 344 and 364 can represent a sum of all
local energy storage resources of individual consumers within the
neighborhood. In one embodiment, one or more neighborhood includes
a neighborhood energy store. The neighborhood energy store can be
in addition to or as an alternative to local energy storage at the
individual consumers.
[0072] In one embodiment, energy store 344 and 364 can include
battery resources, which can include any type of battery. A battery
is a device that stores energy via chemical and/or electrical means
which can later be accessed. However, energy storage is not limited
to batteries. For example, in one embodiment, an energy store,
either local to one consumer or shared among multiple consumers or
the entire neighborhood, includes a mechanism to perform work to
convert active energy into potential energy, which can then later
be recovered via conversion back from potential energy to active
energy. For example, consider a water storage system as an energy
store. When excess capacity exists within a consume and/or within
the neighborhood, the system can trigger a pump to operate on the
excess power to pump water "uphill," essentially in any manner to
pump against gravity. Recovery of the energy can include allowing
the water to flow back downhill with gravity to turn a generator or
mini-generator to generate energy. Another alternative can be to
use energy to compress air, and then run a generator with the air
as it is decompressed. It will be understood that other examples
could also be used where energy storage is not limited to
traditional battery resources.
[0073] In one embodiment, system 300 is a segment of a grid that
includes distributed control. In such a scenario, each node within
a grid network hierarchy can manage its own conditions at its PCC
for compliance with standards or expectations of performance. In
one embodiment, each node can also provide electrical support to
neighboring segments or PCCs as it sees conditions at the grid
network side (upstream from its segment) fall in performance. In
one embodiment, each node can provide electrical support to
neighboring segments or PCCs in response to receiving information
from data center 310, from other nodes, and/or dispatch or control
information from a central management.
[0074] In one embodiment, system 300 includes one or more power
sources 312 coupled to provide power to the grid network. One or
more power sources 312 can be in addition to local energy sources
at consumers. In one embodiment, no single power source 312 has
sufficient capacity to meet consumer power demands. For example,
rather than an industrial or utility-scale power plant, one or more
power sources 312 can be included local to a segment of the grid.
The segment can be within a neighborhood or shared among multiple
neighborhoods. Power sources 312 can include smaller scale
generators that would be smaller than a full utility
implementation, but larger than what would typically be used at a
consumer or customer premises. Neighborhood-based power sources 312
can be directly associated with a control node (for example, power
source 312 can be coupled to and controlled by control node 332).
The control node can manage the output of the power source.
[0075] Without a large-scale power plant, and instead with
smaller-scale energy generation (e.g., a neighborhood generator, a
neighborhood solar installation, a small-scale hydro-electric
generator, or other power sources), a grid network can be installed
with minimal infrastructure compared to today's grids. Such a
modular grid network can enable the building out of a grid based on
current needs and then interconnecting to other independent grid
network segments. Each segment can continue to operate
independently, but can then benefit from being able to better
distribute power generation and power demand based on availability
to and from neighboring segments. Each interface or interconnection
can include one or more control nodes, which can include one or
more power converters each, to control the use of power and the
presentation of power upstream. Thus, a local grid network can be
built, and then later coupled with another local grid network as
another layer of grid network hierarchy is added to interface the
two independent segments.
[0076] In one embodiment, consider that neighborhood 340 has
multiple customer premises 350 that have local energy sources 352.
Traditionally grids are designed and built to be unidirectional, as
they are designed to deliver power from a single large-scale power
plant to the consumers. With power generation at customer premises
350, neighborhood 340 and up through a connected grid can
effectively become a bidirectional system where power can be
delivered from the central power source to the consumers, but then
the consumers can also generate excess capacity that is placed back
out onto the grid. If the power generation for the neighborhood and
neighboring neighborhoods exceeds instant power demand, the
generated power will be pushed back up the grid toward to the power
plant. Such a condition can challenge the grid infrastructure.
[0077] Grid operators (e.g., utilities) typically set limits on how
much local power generation can be coupled to the grid, to reduce
the risk of a scenario where significant amounts of energy get
pushed back up the grid to the power plant. Such a limit is often
referred to as saturation, where there is a threshold amount of
capacity that is permitted to be attached to the grid. If the
saturation threshold has been reached, a consumer typically has to
pay for additional grid infrastructure (additional equipment) that
will enable the utility to selectively disconnect the consumer's
power generation from the grid. Such scenarios also put consumers
and utilities at odds with each other, as the consumer does not get
to see the same levels of cost reduction because the power
generation cannot be used by the grid, and so the grid operator
does not pay the consumer for it.
[0078] In one embodiment, system 300 can provide an alternative
mechanism to deal with grid saturation. In one embodiment, the
distributed control in system 300 can provide dynamic control over
power demand and power generation as seen at a PCC and/or as seen
at a customer premises or anywhere downstream from a control node.
In one embodiment, the control node includes a power converter to
control real and reactive power demand and real and reactive power
generation. More specifically, the control node can adjust
operation to affect a real power component of power as seen
downstream from the PCC, and a real power component as seen
upstream from the PCC. The control node can adjust operation to
affect a reactive power component of power as seen downstream from
the PCC, and a reactive power component as seen upstream from the
PCC. In one embodiment, the control node can include one or more
inverters or one or more microinverters as power converters to
apply control over demand and generation.
[0079] In one embodiment, node 332 includes a grid connector to
connect upstream in a grid network. The grid connector can include
known connectors and high voltage and low voltage signal lines.
Node 332 is or connects to a PCC (PCC 322) for the grid network
segment of neighborhood 340. Node 332 includes control logic, such
as a controller or microprocessor or other logic to determine how
to operate. In one embodiment, node 332 determines that a
saturation threshold has been reached within neighborhood 340. Such
a determination can be a result of dynamic monitoring to determine
that power generation exceeds power demand. Such a determination
can be in response to a notification from a data center or central
grid management. Such a determination can be in response to data
from other distributed control nodes. In one embodiment, each
energy source 352 in neighborhood 340 is associated with a control
node 354 within the neighborhood. In one embodiment, each control
node 354 is configured with information about the capacity of its
associated energy source 352. In one embodiment, each local control
node 354 registers with control node 332, which can allow node 332
to know a total capacity for neighborhood 340.
[0080] In one embodiment, node 332 knows a total peak real power
demand for neighborhood 340, such as by configuration and/or
dynamic identification via communication with meters or other
equipment distributed at the consumers. In one embodiment, there is
a threshold percentage of the total peak real power demand that
identifies a value of real power, and when real power generation
capacity exceeds the value, neighborhood is considered to be in
saturation. In response to the saturation condition, in one
embodiment, node 332 dynamically adjusts operation of power
converter(s) to adjust an interface between neighborhood 340 and
the grid. In one embodiment, node 332 adjusts a ratio of real power
to reactive power for neighborhood 340 as seen from upstream from
PCC 322 (e.g., as seen from PCC 324 and/or as seen from central
grid management or another part of the grid network).
[0081] In one embodiment, node 332 receives dispatch information
from data center 310 or central grid management indicating a level
of grid saturation for neighborhood 340. In one embodiment, node
332 receives information from downstream such as a via meters
and/or node(s) 354 indicating levels of grid saturation downstream
from PCC 322. In one embodiment, node 332 adjusts at least an
amount of real power generation with neighborhood 340, such as by
communicating to downstream control nodes 354 to adjust their real
power output. In one embodiment, node 332 can communicate
downstream to cause control nodes 354 to change a ratio of reactive
to real power output upstream. In one embodiment, node 332 adjusts
real and/or reactive power generation and/or demand at PCC 322 to
adjust the electrical conditions as seen upstream from PCC 322. In
one embodiment, node 332 and/or node(s) 354 adjust operation to
divert at least a portion of real and/or reactive power to energy
store 344.
[0082] In one embodiment, system 300 represents a virtual grid or
virtual grid segment. As a virtual grid, system 300 does not
require the traditional infrastructure, central power plant, or
central grid management common to traditional utility grids. System
300 can be a virtual grid in that in one embodiment, each
neighborhood 340, 360 can generate local power and satisfy local
demand independent of other areas. Despite being independent,
neighborhoods 340 and 360 can be coupled to each other to enable
each neighborhood to provide support to and/or receive support from
the other neighborhood. The interconnection between neighborhoods
340 and 360 can be minimal compared to requiring significant
infrastructure in a traditional grid.
[0083] In one embodiment, nodes 332 and 334 are coupled together as
a PCC and/or can be considered to couple together via another PCC.
In one embodiment, PCC 322 and PCC 324 will couple together via PCC
326, which will have a separate control node (not explicitly
shown). PCC 326 can be considered higher up a grid network
hierarchy from PCCs 322 and 324. PCC 326 can be managed from the
perspective of a control node seeking to control operation of all
downstream connections and managing upstream connections. In one
embodiment, nodes 332 and 334 are coupled together not via PCC 326,
but are at a highest level of hierarchy of the grid network and can
communicate and provide grid support to each other. In one
embodiment, whatever power generation is available within
neighborhood 340, even if sufficient to meet its own peak power
demand, is not sufficient to meet peak power demands of
neighborhoods 340 and 360. The same could be true with respect to
power generation of neighborhood 360.
[0084] Control nodes 332 and 334 independently manage their local
power sources. From the perspective of each neighborhood, the
neighborhood as a whole appears to have a "power source" in that
power generation resources within the neighborhood can generate
power. Nodes 332 and 334 control distribution of the locally
generated power, each from its respective neighborhood. It will be
understood that while referred to as neighborhoods, the same
principles can apply to two distinct consumers, each having local
power generation and each having a control node. Coupling the two
consumers together can generate a virtual grid. Thus, the virtual
grid can operate at the level of individual consumers or large
groups of consumer and neighborhoods. In one embodiment, each
control node operates based on its local power demand and local
power generation, as well as based on monitoring and/or
communication regarding power demand and power generation from the
coupled neighborhood or consumer.
[0085] In one embodiment, one or more virtual grid network segments
can be connected to a utility power grid. In one embodiment, one or
more additional consumers or neighborhoods can be coupled together
as a virtual grid with consumers or neighborhoods that are coupled
together. In one embodiment, each control node includes
communication and control logic to discover the network structure.
In one embodiment, one control node within system 300 can operate
as a master node, such as node 332. A master control node can have
one or more slave nodes coupled to it. For example, node 334 could
be a slave node to node 332. In a master-slave scenario, control
node 332 can control the operation of node 334 to cause node 334 to
control its local or downstream resources in accordance with one or
more commands or requests generated by master node 332. Thus, node
332 can provide control over its local segment and one or more
sub-segments connected as slave segments. In such a scenario, node
332 can be responsible to ensure compliance of each grid network
segment with regulations or requirements. Node 332 can thus control
distribution of power and power demand throughout system 300.
[0086] In one embodiment, a grid network of system 300 can be
modularly adjusted in size. Seeing that each neighborhood 340, 360,
. . . , in the grid network can independently operate,
neighborhoods, consumers, and/or other segments or groupings of the
network, can be added and/or removed from the grid network
dynamically. For example, in a developing area, a first
neighborhood 340 can be built with its power generation to attempt
to satisfy demand for its consumers. In one embodiment, a power
source 312 can be connected, but it insufficient in itself to
satisfy peak demand for neighborhood 340, but can provide demand
when local energy sources are insufficient to meet demand. In one
embodiment, neighborhood 360 can be further developed, and then
connected to neighborhood 340 (e.g., coupling nodes 332 and 334).
Other neighborhoods could similarly be added, via a higher level
PCC and control node, and/or by coupling neighborhood control
nodes. In one embodiment, power source 312 can then service both
neighborhoods by distribution via the control nodes, and the
neighborhoods would generally rely on local power generation, but
can receive power from power source 312 as a support power source.
In one embodiment, power is used from source 312 when local power
generation including converting power from energy stores does not
satisfy demand. In one embodiment, one control node supports the
other control node by adjusting reactive power output to change
voltages and power flow at the interconnection of the
neighborhoods. Changing the reactive power or the phase offset of
power generated and/or consumed locally at the neighborhood can
cause an electrical condition that will cause power to flow a
different direction, depending on whether the other neighborhood
needs to receive additional power or offload it.
[0087] FIG. 4 is a graphical representation of an embodiment of
components of a current in a system in which harmonic components of
current have angular offsets with respect to a primary current
component. Diagram 410 provides a complex vector representation of
current. A vector has a magnitude and a direction. Instead of
simply measuring power as traditionally done, in one embodiment, a
meter and/or a control node can monitor power as an energy
signature including a representation of a complex power vector. In
one embodiment, each signature identifies characteristics to define
and/or "name" the signature. Each signature includes a complex
vector representation that provides a vector for primary current
and a vector for one or more harmonics.
[0088] Vector 420 is the vector for primary current. In typical
representation, the x-coordinate is the vector component that
extends from left to right across the page. The y-component goes
from bottom to top of the page. It will be understood that while
not represented here for purposes of simplicity, a vector could
have a negative y-component. The x-y coordinates define the end of
the vector. Now assume that the x and y coordinates of primary
current vector 420 define a plane. The most correct way to envision
the harmonics, in accordance with research and work done by the
inventors, is to represent the harmonics as a three-dimensional
vector. Thus, if the x-y coordinates of vector 420 define a
reference plane, one or more of the harmonics can have an angular
offset relative to the plane of the primary current vector.
[0089] For example, consider the example of diagram 410. The first
harmonic is illustrated as having vector 430, which includes an x
component and a y component, where the magnitudes of the components
can be any magnitude with respect to the primary current
components. In addition to the x and y coordinates, first harmonic
vector 430 includes a z coordinate component, which defines angular
offset 452 of the vector with respect to the reference plane of
primary current vector 420. It will be understood that the starting
points of the primary current and the harmonics are the same. Thus,
the third dimension of the harmonic vectors or the complex vectors
is not necessarily an absolute z coordinate component, but an
angular offset relative to the primary current.
[0090] As illustrated, third harmonic vector 440 also has an x
component and a y component, and angular offset 454, which can be
different (greater or less than) angular offset 452 of first
harmonic vector 430. The angular shift of the angular offsets
represents a magnetic effect on the current. The inventors have
measured noticeable effects on power consumption up to the fortieth
harmonic. Thus, the contribution of harmonic offsets should not be
understated. The harmonics shift with respect to the angular offset
due to the differing resonant effects of magnetic flux when trying
to move a current. Primary current vector 420 is the current the
consumer expects to see. However, the harmonic components can add
significant (measurable) power consumption. The offsets of the
harmonics can shift the simple expected two-dimensional current
vector into a three-dimensional current vector (complex current
vector). The traditional power triangle does not fully address the
power usage by the consumer, as additional power will be required
to overcome the magnetic components represented by the shifted or
offset harmonic components.
[0091] FIG. 5 is a graphical representation of an embodiment of
components of a current in a system in which a current vector is a
composite of a primary current component and harmonic current
components. Diagrams 510, 520, 530, and 540 illustrate component
parts of a complex current vector in accordance with an embodiment
of diagram 410 of FIG. 4. As illustrated, diagram 510 represents
the primary current vector 512. The primary current includes x and
y components, and defines a reference frame for the harmonics.
[0092] Diagram 520 represents first harmonic vector 522, which
includes x and y components and angular offset 524. Diagram 530
represents third harmonic vector 532, which includes x and y
components and angular offset 534. Diagram 540 represents fifth
harmonic vector 542, which includes x and y components and angular
offset 544. Each of the primary current 512 and various harmonics
(522, 532, 542) are shown as two-dimensional "power triangle"
representations, which is what is traditionally expected for each
one. However, as mentioned already, the harmonics are frequently at
an angular offset with respect to the primary current component
vector, and thus the resulting composite current vector will not be
in the same plane as primary current vector 512.
[0093] Rather, consider the power triangle of the composite current
vector as a triangle in a three dimensional box. Diagram 550
provides a simple illustration of this concept. It will be observed
that primary current vector 512 is on a face of the three
dimensional box of diagram 550. The harmonics push the triangle for
the composite current "into" the box in some way. Composite current
vector 552 is both larger in magnitude, and offset angularly with
respect to primary current vector 512. Offset 554 represents the
angular offset. It will be understood that primary current vector
512 and composite current vector 552 define the "shape" of the box.
Depending on the amount of harmonic contribution, the box shape
will be different. The composite current vector 552 can be a
signature stored by the metering device. The reference plane of
primary current 512 can be defined as a plane of the grid power
(referring to the power condition as seen at the grid via the
PCC.
[0094] With respect to the noise and harmonics generated, it will
be understood that there are regulations on switching power
supplies and magnetic resonance in general. Each device is tested
for compliance (e.g., UL certification). When each device or load
works individually as designed and tested, each one will comply as
required per regulations. However, when there are multiple loads
and/or devices coupled together, they tend to create unanticipated
resonance. The inventors have measured contributions to the energy
triangle from the first up to the 40th harmonic. Thus, there is
typically a significant amount of harmonic noise happening on the
power lines. Harmonic suppression traditionally includes filters
that target specific noise components. However, the noise
components can continue to vary as different devices come online
and offline, and the electrical resonance structure of the network
continually changes. In one embodiment, a meter detects the
characteristics of each load or group of loads. The characteristics
can be referred to as a signature of the harmonics.
[0095] In one embodiment, the power meter or energy meter can
detect such shifts as the angular offsets of the harmonic current
vectors, by measuring energy contributions. The power converter can
compensate for the actual composite current by providing the
reactive power needed to match the load and/or PCC to the grid.
Thus, the current at the load can be adjusted by the converter to
bring the composite current into alignment with the grid, not
simply in power factor, but in complex vector. Such operation will
naturally eliminate or at least reduce harmonic distortion caused
by loading on the grid.
[0096] In one embodiment, what is described in reference to loading
can also be performed with reference to energy generation. In one
embodiment, the meter can determine an energy signature at the PCC
and compute what current would be needed to offset the grid to a
desired offset (if some power factor other than unity is desired)
and/or to match to the grid in a case where unity power factor is
desired. The converter can adjust operation to adjust the power
output to not only match reactive power needs, but complex current
vector shift as well to more efficiently match the interface of the
grid with the downstream from the PCC.
[0097] It will be understood that the energy triangle represented
in diagram 550 can be represented as a mathematical representation
of the effect seen when looking at the current component of power
drawn by a load or consumer. The effect is wasted energy, which
usually manifests itself as heat. The problem traditionally is that
systems do not match well, and there are significant noise
components. In one embodiment, a control node matches not just
impedance, but matches noise or harmonic correction to provide a
specific energy signature connection to the grid. Thus, the control
node can provide a "cleaner" connection to the grid network with
respect to the power interface, whether outputting power onto the
grid or receiving power from the grid.
[0098] FIG. 6 is a block diagram of an embodiment of a gateway
device in a distributed grid system. System 600 represents one
embodiment of a grid system, and can be a grid system in accordance
with any embodiment described herein. For example, system 600 can
be one example of a system in accordance with system 100, system
200, and/or system 300. Grid 610 represents a grid network, and can
be any type of grid described herein, whether utility power grid,
virtual grid, distributed hierarchical grid network, or a
combination. Meter 620 represents a grid meter, or a meter used
within the grid to measure and charge for power delivered by the
grid. In one embodiment, meter 620 can be considered part of the
grid infrastructure and can be referred to as an entrance meter.
Meter 634 of gateway 630 is understood to be separate from meter
620. In one embodiment, meter 620 monitors power delivered by grid
610 to PCC 622, which represents a PCC in accordance with any
embodiment described herein.
[0099] In one embodiment, system 600 includes gateway that can be
and/or be part of a control node in accordance with any embodiment
herein. In one embodiment, gateway 630 represents "the brains" of a
control node. In one embodiment, gateway includes router 632 to
enable gateway 630 to communicate with other devices, such as
devices outside of the PCC. In one embodiment, router 632 enables
gateway 630 to communicate with data center 680. Data center 680
can represent a central data location for a distributed grid
network. In one embodiment, data center 680 represents central grid
management. Thus, data center 680 represents a source of grid-based
information, such as control, dispatch information, or other data
about grid operation. Router 632 can include Ethernet connections
or other connections that use Internet protocols. Router 632 can
include grid interconnections. Router 632 can include proprietary
connectors. Router 632 can represent a stack or protocol engine
within gateway 630 to generate and process communication in
addition to the hardware connectors that provide an interface or
connection to the grid.
[0100] In one embodiment, gateway 630 includes meter 634, which
represents a metering device in accordance with device 800 of FIG.
8. Meter 634 enables gateway 630 to monitor power demand and/or
power generation on the consumer side of PCC 622. The consumer side
of PCC 622 is the side opposite the grid. The consumer side is the
electrical point of contact to the loads and/or load control for
the consumer. Typically the PCC includes some type of fuse system
and/or other disconnection mechanism. The fuse system can be soft
fuses (e.g., switches or other mechanisms that can be electrically
opened and closed) or hard fuses that must be mechanically or
physically reset or replaced. In one embodiment, meter 634 stores
and manages energy signatures. In one embodiment, meter 634
performs aggregation.
[0101] Gateway 630 includes controller 636, which represents
hardware processing resources to control the operation of the
gateway. Controller 636 can also represent software or firmware
logic to control the operations of gateway 630. In one embodiment,
controller 636 can be implemented by more than one hardware
component. In one embodiment, controller 636 includes or is an
embedded computer system. For example, controller 636 can include
an embedded PC (personal computer) board and/or other hardware
logic. Controller 636 generally controls the operation of gateway
630, such as controlling router 632 and/or meter 634. In one
embodiment, if gateway 630 is said to do something, controller 636
can be considered to execute operations to perform what is said to
be done.
[0102] In one embodiment, system 600 includes one or more loads 640
on the consumer side of PCC 622. In one embodiment, system 600
includes one or more energy sources 660. Energy source 660
represents a power generation resource at the consumer or on the
consumer side of PCC 622. In one embodiment, energy source 660 is a
renewable energy source, such as wind or solar power systems. In
one embodiment, energy source 660 generates real power. In one
embodiment, system 600 includes battery backup 670. Battery backup
can be any form of energy store or energy storage described
herein.
[0103] In one embodiment, the consumer includes local power
converter 650. Converter 650 can be in accordance with any
embodiment of a converter described herein. Converter 650 performs
one or more operations to manage or control an interface. In one
embodiment, the interface represents the interconnection of a
device to PCC 622. In one embodiment, the interface represents the
electrical interconnection or electrical coupling of a device to
another point. For example, converter 650 can operate to adjust an
interface between PCC 622 and loads 640, such as by changing how
power or energy is transferred between the grid and the load. In
one embodiment, converter 650 can operate to adjust an interface
between energy source 660 and load 640, for example, to deliver
power to the load from a local energy source. In one embodiment,
converter 650 can operate to adjust an interface between energy
source 660 and PCC 622, for example, to deliver power from the
energy source to the grid. In one embodiment, converter 650 can
operate to adjust an interface between battery backup 670 and PCC
622 and/or energy source 660, for example, to charge the energy
store and/or provide power from the energy store to use for the
load and/or the grid.
[0104] FIG. 7 is a block diagram of an embodiment of a gateway
aggregator system. System 700 is one embodiment of a gateway
device, and can be or be included in a control node in accordance
with any embodiment described herein. Aggregator 710 represents
hardware and software logic to perform aggregation of data.
Aggregator 710 can compute a determination of how to control an
interface based on the aggregated information.
[0105] Aggregation logic 720 represents logic that enables
aggregator 710 to gather multiple elements of data related to
electrical grid conditions. External I/O 722 represents sources
external to a PCC that can provide grid condition information.
Typically such information is provided in light of conditions of
the grid as a whole or of specific segments or sections of the grid
that are larger than the consumer or neighborhood or portion
managed by a control node associated with aggregator 710. Examples
of external I/O 722 can include, but are not limited to, dispatch
information and grid control signals. Dispatch information can be
broadcast to a grid network or can be sent to specific areas in a
grid network. Grid control represents specific signals indicating
at least one electrical condition the PCC is supposed to comply
with and/or address. For example, the PCC can be requested to
provide specific output from the PCC. As another example, the PCC
can be specifically requested to comply with a regulation based on
conditions at another location of the grid network.
[0106] Sensors 724 represent sources of data within the PCC, for
example, one or more sensors local to a control node or other
gateway device or aggregation device. Examples of sensor data can
include, but are not limited to, load information, local
temperature, light conditions, and/or other information. In one
embodiment, load information is gathered or monitored by a meter
that determines what loads are drawing power, such as by energy
signatures that indicate complex current vectors for the load. In
one embodiment, load information can be configured into aggregator
710, which can be maximum load capacities allowed for specific load
connections (e.g., breakers, outlets, or other connection). In one
embodiment, the operation of a local energy source can be affected
by temperature, or the temperature can be an indication of expected
efficiency and/or demand for certain loads and/or energy sources.
Light condition is specific to solar systems, but other sensors
such as wind sensors could alternatively or additionally be
used.
[0107] Each sensor can provide information to be considered when
determining how to output power or otherwise control interfaces
within the PCC and/or external to the PCC. In one embodiment, each
sensor registers with aggregation logic 720. Aggregation logic 720
can include a sensor control hub to gather and aggregate
information from the various sensors. In one embodiment, aggregator
710 stores aggregation data and/or raw data in memory 742. Memory
742 can be local to aggregator 710 and store sensor and/or grid
control information.
[0108] In one embodiment, aggregation logic 720 includes weights to
provide greater weight to certain data over other data. The weights
can change based on time and/or based on other data received. For
example, temperature data can be considered in determining what
operations to perform, but can be weighted very low or ignored
completely when grid control is received. Countless other examples
are possible. In one embodiment, aggregation logic 720 operates as
a type of complex state machine. In one embodiment, each condition
output generated by aggregation logic 720 identifies a state as
determined based on the various inputs. For example, aggregation
logic 720 can make determinations based on ranges of data, such as
when light conditions are within a given range and the temperature
is within a specific range, and when the grid conditions are within
certain ranges, then a particular condition output is generated.
Other ranges will produce other condition outputs. The condition
outputs can indicate what the state of aggregator 710 is to
determine how to control a power converter to operate.
[0109] In one embodiment, aggregation logic 720 generates one or
more conditions for execution by execution logic 750. In one
embodiment, aggregator 710 can include zero or more other logic
elements to make changes to the determined conditions. In one
embodiment, aggregator 710 includes one or more of forecast logic
730 and/or forward prediction 740. In one embodiment, all logic
blocks within aggregator 710 can be considered control logic for
the aggregator. Thus, reference to the aggregator performing
computations or calculations can include operations of aggregation
logic 720, forecast logic 730, forward prediction logic 740,
execution logic 750, and/or other logic not shown.
[0110] In one embodiment, forecast logic 730 can receive rate
source information 732. Rate source information 732 can include
consumer rate or price information and/or market rate or market
price information. In one embodiment, consumer rates will include
different rates for real and reactive power. In one embodiment,
market rates will include different rates for real and reactive
power. Reactive power can generally be delivered to the grid for an
"ancillary market" or to provide ancillary services. Thus, reactive
power rates can actually include many different rates depending on
market conditions and the ancillary market selected. It will be
understood that rate information can change throughout the day,
and/or through the season or year. Thus, time of day and time of
year can be information considered in computing operations to
perform based on rate information. In one embodiment, rate source
732 is a realtime rate information source, and can provide data
related to a deregulated energy market, such as rate contract
information, instantaneous rates, and/or other information. In one
embodiment, aggregator 710 couples to rate source 732 via external
I/O 722.
[0111] In one embodiment, forecast logic 730 makes a determination
or calculates an operation to perform based on the condition(s)
identified by aggregation logic 720 and rate information. Forecast
logic 730 can determine one or more actions to take based on
combining rate information with condition information. For example,
a determined condition as calculated by aggregation logic 720 can
identify a specific state or zone of operation for an interface
managed by aggregator 710. Aggregator 710 is associated with a
control node that can provide power to local loads and to the grid.
Thus, forecast logic 730 can determine the best use of locally
generated energy, for example. Forecast logic 730 can determine how
to best control interfaces based on where the maximum financial
reward is for the consumer.
[0112] For example, in a given day market price might fluctuate
between real power and ancillary services, depending on the
conditions of the grid network. When real power rates are higher,
forecast logic 730 can determine to cause an associated power
converter to generate real power to transmit to the grid. If one or
more ancillary market prices then goes higher than real power
market rates, forecast logic 730 can determine to cause the power
converter to generate reactive power to transmit to the grid. In
another example, consider that the consumer has loads that have
load demand. However, because market rates are currently higher
than the value of consuming the energy locally, forecast logic 730
determines to transmit the energy to the grid, and draw power from
the grid to power the loads. Similarly, when market rates drop,
forecast logic 730 can determine to redirect more energy to the
local load demand. Thus, aggregator 710 can dynamically monitor and
control the interface to the grid from the local PCC to maximize
the value of energy for the local consumer and for the grid.
[0113] In one embodiment, forward prediction 740 accesses
historical information from memory 742. The historical information
can include one or more conditions with associated operations
performed, historical trend information for rates, electrical
conditions, power demand, and/or other information. The history or
historical information can enable aggregator 710 to identify trends
or patterns based on previous operation. Thus, the longer a control
node is operational, the more its historical data can inform
operation. In one embodiment, aggregator 710 includes a period of
data gathering prior to using history information. The time of data
gathering can be variable for the different uses of an aggregator,
but can be a matter of hours, days, weeks, or even months. In one
embodiment, such information can be gradually "phased in" by
gradually giving more weight to historical data analysis or
evaluation or calculation of what operations to perform.
[0114] In one embodiment, historical data can identify particular
states of operation and subsequent states of operation and how long
elapsed between them. Thus, for example, forward prediction can
determine whether or not to perform a determined action based on
historical information indicating whether such a condition or state
is likely to persist for long enough for economic benefit. In one
embodiment, forward prediction 740 determines from selected actions
or state and historical data what operations should be executed by
a control node. In one embodiment, each prediction represents an
estimate of what decision to make based on present conditions in
light of past data of energy loads, energy prices, weather
conditions, rates, and/or other information. In one embodiment, the
historical data can be referred to as operating history or
operational data, referring to operations within the
monitored/controlled grid node.
[0115] In one embodiment, execution logic 750 receives one or more
conditions, one or more actions, and/or one or more predictions,
respectively, from aggregation logic 720, forecast logic 730, and
forward prediction logic 740. Execution logic 750 can analyze the
input data and compute or calculate one or more operations to
perform based on the received data. In one embodiment,
collectively, aggregator 710 can have knowledge of connected local
energy sources, entrance meter information, energy store or energy
backup system, local or onsite loads, and other information. In one
embodiment, all the information gathered within a gateway device
such as aggregator 710 is gathered by a local meter. Logic within
aggregator 710 can receive the data from the multiple sources and
make decisions based on the data. The aggregation of data itself is
different from previous control nodes. Forecasting and/or
prediction can be added to the aggregator. In one embodiment,
execution logic 750 selectively generates an operation based on
computed conditions, actions, and predictions.
[0116] Consider an example that a meter detects that a
refrigeration load has turned on and more reactive power is needed.
The meter could make such a determination, for example, by
computing or processing different load energy signatures of the
loads. For example, consider a composite current that is already
present in the system. The addition of another load coming online
will change the overall composite current. In one embodiment, the
meter can compute a difference between the new composite current
and the previous composite current to determine the energy
signature of the new load(s). As such, the meter can identify the
specific load and determine to effect a change in operation via
aggregator 710 to respond to the power demands of the specific
load. It will be understood that such computations could require
vector analysis and/or calculations to distinguish specific loads.
In one embodiment, aggregator 710 can keep historical data for one
or more energy signatures, and can thus determine how long a given
load is expected to be on, based on historical averages. Thus,
energy signatures can be used with historical data and/or other
determination data computed in aggregator to determine what
operation(s) to execute.
[0117] Continuing with the example of the refrigeration load coming
online, in one embodiment, the meter detects the increased demand
for reactive power in the system. In one embodiment, the meter
detects the energy signature of the refrigeration load. The gateway
can have an attached solar system (local energy source) adjust its
phase angle (e.g., via a converter and/or inverter coupled to the
solar system) to produce more reactive power to address the
refrigeration load. Once the refrigeration load turns off, the
gateway can then tell the solar system to use the extra power to
charge a battery backup system, or provide support to the grid.
Again, the different possible examples are too numerous to
address.
[0118] In one embodiment, execution logic 750 generates an
operation and executes the operation. In one embodiment, execution
logic 750 can generate an operation for local output 752 and/or for
market output 754. Example local outputs can include, but are not
limited to, providing real and/or reactive power to a load,
providing real and/or reactive power to charge an energy storage
device, and/or providing power to local "capacity," which can
represent one or more load and one or more energy storage devices.
Examples of market outputs can include, but are not limited to,
providing real power to the grid, and/or providing ancillary
services.
[0119] The ancillary services can include many different services,
which are represented generically, even though not all possible
services are illustrated. Ancillary services can include grid
support, frequency support, regulation up, regulation down, and/or
blackstart services, and/or other services. Grid support represents
any type of voltage support services to boost or reduce the grid
voltage condition at the PCC. Regulation up and regulation down
refer to specific frequency support services. Regulation up and
regulation down can refer to controlling load interfaces to change
a load seen at the PCC. Frequency support represents other types of
frequency service, and can include changing an interface to change
a flow of energy onto the grid to adjust a frequency of the AC
power as seen at the PCC. Blackstart service represents operations
performed to ramp a grid up to enable a disconnected portion of the
grid to reconnect to the grid network. All ancillary services can
include providing capacity that responds to a need by the grid as
seen from the PCC.
[0120] In general, in one embodiment, a consumer node can include a
control node. Typically a control node includes an energy meter and
a controller. The controller can be in accordance with aggregator
710 and/or other gateway device. The energy meter and the
controller are located on the consumer side of the PCC, and perform
operations within the PCC to change an interface as seen from the
grid via the PCC. The consumer node includes one or more power
converters that change their operation in response to commands or
controls from the controller and/or meter. The power converter
operation changes the interfaces to the PCC in accordance with
decisions made by the controller. Operation by the power
converter(s) can change the flow of energy within a grid network at
the local node.
[0121] Thus, the power converter can respond to aggregation
information by changing operation in response to a decision by a
controller that determines how to operate based on the aggregation
information. The aggregation information can include information
from one or more sensors, one or more grid-side controllers or data
center, and local power demand and local conditions. The
decision-making by the controller can include computing based on
the gathered local and grid condition information. In one
embodiment, the decision-making includes computing based on rate
information. In one embodiment, the decision-making includes
computing based on historical information. In one embodiment, the
decision-making includes computing by execution logic to generate
one or more controls for one or more power converters. The power
converters change the flow of energy within the PCC and/or between
the PCC and the grid, in accordance with any embodiment described
herein. The power converters can control a mix of real and reactive
power from a local energy source and/or from the grid, in
accordance with any embodiment described herein.
[0122] FIG. 8 is a block diagram of an embodiment of a metering
device that monitors power at a PCC. Metering device 800 can be a
power meter or an energy meter in accordance with any embodiment
described herein. In one embodiment, metering device 800 is or is
part of a control node in accordance with any embodiment described
herein. Device 800 includes hardware components to interconnect to
a grid network, connecting upstream and/or connecting to
neighboring grid network nodes. In one embodiment, device 800
includes hardware components to interconnect to one or more loads
and/or other devices or nodes coupled downstream from the power
metering. It will be understood that device 800 can be separate
from a meter used by the grid to measure and charge for power
delivered from the grid. There can be multiple devices 800 that
couple to a single grid meter.
[0123] Device 800 includes load interface 820. Load interface 820
provides hardware to interconnect to downstream devices. Device 800
monitors the energy usage of downstream devices. In one embodiment,
device 800 includes voltage sense hardware 824 and current sense
hardware 822. Current sense hardware 822 can measure current drawn
by the loads, and can include hardware capable to measure harmonic
components of power demand. Current sense 822 can include
magnitude, phase offset (e.g., power factor), frequency, and/or
other electrical properties of a current drawn by a load or group
of loads. In one embodiment, device 800 can generate energy
signatures and compare such energy signature computations to stored
energy signatures. Device 800 can also store new energy signatures
computed. Voltage sense hardware 824 can measure a voltage
including phase, frequency, magnitude, and/or other electrical
property of the voltage waveform.
[0124] Processor 810 represents control logic or a controller for
device 800. Processor 810 can be configured or programmed to
perform the energy monitoring. Processor 810 can be configured to
perform computations to compute energy signatures and/or compare
current and voltage readings to energy signatures. In one
embodiment, processor 810 determines how current can be adjusted to
compensate for harmonics, a grid condition, or other condition to
bring the PCC into compliance, and/or to provide support to
compensate for a failure at another control node. Processor 810 can
perform operations and include hardware and/or control logic to
track energy consumption of the grid network segment below device
800, and determines how to compensate to bring the local grid
network segment below it into compliance. While not shown, metering
device 800 operates in conjunction with a power converter to
provide the needed reactive power indicated by the monitoring.
[0125] Device 800 includes external I/O 840 to enable device 800 to
connect to other metering devices or control nodes, and to connect
to a data center or other central data device. In one embodiment,
external I/O 840 enables device 800 to connect to grid management
of a traditional utility power grid. In one embodiment, external
I/O 840 enables device 800 to send data to and/or to receive data
from a central data center. External I/O 840 can receive dispatch
information for device 800. External I/O 840 can include any type
of communication interfaces, including known wired and/or wireless
communication mechanisms. In one embodiment, external I/O 840
includes proprietary and/or customer communication mechanisms,
which can include wireline and/or wireless communication platforms,
including hardware and software stacks or other processing logic to
send and receive communication.
[0126] Grid interface 850 represents hardware to enable device 800
to couple to the grid network. In one embodiment, grid interface
850 enables device 800 to determine a condition of a grid at a PCC
associated with device 800. In one embodiment, grid interface 850
represents hardware to enable device 800 to couple to a local
energy source. In one embodiment grid interface 850 and/or other
interface within device 800 enables device 800 to determine what
type (how much) energy support can be provided from its downstream
devices. For example, device 800 can determine how much energy is
being produced by local energy source(s). The power converter
adjusts the interface to the grid at the PCC by adjusting its
operation, including what current waveform appears at the PCC.
[0127] In one embodiment, device 800 includes storage resources,
such as memory and/or hard drives or solid state storage. Storage
830 represents memory resources for device 800. In one embodiment,
device 800 stores multiple signatures 832 to be used in monitoring
and controlling loads. In one embodiment, each signature 832 is a
complex current vector representing a condition of a current
waveform drawn under various loads. In one embodiment, processor
810 can generate and store signature 832. In one embodiment,
signatures 832 are preloaded on device 800. In one embodiment,
processor 810 computes composite current waveform information to
compare to signatures 832. Depending on matching to the signatures,
processor 810 can calculate a current waveform phase and shape that
is desired for a given load scenario (power demand) and/or power
generation scenario.
[0128] In one embodiment, processor 810 accesses one or more items
of compliance information 834. In one embodiment, compliance
information 834 is stored in storage 830. In one embodiment,
compliance information 834 is received via external I/O 840. In one
embodiment, processor 810 computes a current waveform phase and
shape desired for a given power demand scenario and/or power
generation scenario based on compliance information 834. Thus,
compliance information 834 can affect how device 800 operates. In
one embodiment, external I/O 840 enables device 800 to couple to an
associated converter or converters. Based on calculations made by
processor 810, device can signal a converter how to operate to
achieve the desired current. In one embodiment, device 800 simply
indicates the desired current to the converter, which can then
separately compute how to generate the current. In one embodiment,
device 800 computes specific parameters as input to a converter
device to cause it to adjust its operation for the desired current
waveform at the PCC.
[0129] In one embodiment, metering device 800 is capable of
location awareness, in accordance with location awareness mentioned
previously. With location awareness, processor 810 can, in one
embodiment, determine its location. Thus, based on conditions
measured or received for grid interface 850, processor 810 can
compute a reactive power needed based on location detection.
External I/O 840 can then signal the associated converter(s) to
generate the power. Device 800 can detect and determine to provide
voltage support upstream towards the generator or central grid
network management by causing the control node at the PCC to give
negative or lagging-phase reactive support. Device 800 can detect
and determine to provide voltage support downstream away from the
generator or central grid network management by causing the control
node at the PCC to positive or leading-phase reactive support. It
will be understood that leading support refers to a current
waveform that leads an AC voltage of the grid in phase. Similarly,
lagging support refers to a current waveform that lags the AC
voltage of the grid in phase.
[0130] Signatures 832 represent complex current vectors for one or
more loads. The complex current vectors are composite currents that
a drawn when a load is active. In one embodiment, each signature
has an associated complex current vector, with an apparent power
component, and harmonic components that shift the actual power used
by the load. In one embodiment, device 800 can track the signatures
and cause an associated power converter to operate differently
based on detecting specific loads coming online and/or going
offline.
[0131] In one embodiment, processor 810 includes can perform vector
calculations and/or vector analysis of monitored currents. Thus,
device 800 can identify and track various energy signatures or
current signatures. Signatures 832 can be referred to as current
signatures, referring to the fact that when the various loads are
active or operational, there will be a specific, identifiable
current vector associated with the load coming online. Signatures
832 can be referred to as energy signatures, referring to the fact
that the complex vectors themselves are representations of the
complex energy usage of the loads when they are active.
[0132] Signatures 832 can represent not just the measurable power
component of energy for a load, but also include information about
the harmonics or harmonic noise as well. Thus, in one embodiment,
device 800 can aggregate harmonic information as well as measurable
energy usage. The resulting representation of signatures 832 is not
a traditional power vector, but includes information about
harmonics. In one embodiment, knowledge of harmonics can inform the
operation of a converter to adjust an interface to power supply to
suppress harmonics.
[0133] In one embodiment, an energy signature 832 is unique to one
or more loads or load conditions based on measuring and computing a
composite current for the loads. In one embodiment, each energy
signature 832 represents a load condition (a scenario when various
loads are concurrently on), as opposed to identifying a specific
device. Device 800 can identify a complex current vector for a load
including identifying a real power component and a reactive power
component for the primary current, and a real power component, a
reactive power component, and an angular displacement relative to
the primary current for the harmonics.
[0134] FIG. 9 is a block diagram of an embodiment of a node for a
distributed power grid. Node 900 represents a control node, and can
be an example of a control node in accordance with any embodiment
described herein. Node 900 includes various hardware elements to
enable its operation. In general, the hardware can be described as
processor 910, power distribution hardware 920, and power
monitoring hardware 930. Each of these elements can include
specific types and functionality of hardware, some of which can be
represented by other elements of FIG. 9.
[0135] Processor 910 represents one or more controllers or
processors within node 900. In one embodiment, node 900 includes a
power meter, a power converter, and control hardware to interface
the two elements and couple to the grid. In one embodiment, each
separate item includes a controller, such as a controller within
the metering device, and a controller within the power converter.
The power converter can include a power extractor controller, an
inverter controller, and another controller to manage them. Thus,
controller 910 can represent multiple controllers or elements of
control logic that enables node 900 to monitor and distribute
power.
[0136] Processor 910 manages and controls the operation of hardware
within node 900, including any hardware mentioned above. Processor
910 can execute to provide MGI (modern grid intelligence) for node
900. In one embodiment, processor 910 executes logic to provide at
least some of the functions described with respect to node 910. To
the extent that functions described are provided by hardware,
processor 910 can be considered a controller to control the
operation of the hardware. In one embodiment, processor 910
executes a control node operating system for node 900. In one
embodiment, the operating system is MGIOS (Modern Grid Intelligent
Operating System). MGIOS can provide capabilities and benefits
including at least some of the following.
[0137] The MGIOS can provide computing, and general control over
the operation of node 900. In one embodiment, the MGIOS enables the
node to collect data and make decisions to send data outside the
node. In one embodiment, the MGIOS can use the data to control the
local system, such as the local elements coupled to a same side of
a PCC. In one embodiment, the MGIOS also sends data for use by
external entities, such as a utility manager and/or other nodes in
the grid network.
[0138] In one embodiment, the MGIOS controls dispatch functionality
for node 900. The dispatching can include providing and receiving
data and especially alerts used to determine how to distribute
power. In one embodiment, the MGIOS can enable autonomous
dispatching, which allows the nodes of the grid network to share
information among themselves that control the operation of the
grid. The autonomous dispatching refers to the fact that a central
grid operator does not need to be involved in generating or
distributing the dispatch information.
[0139] In one embodiment, the MGIOS enables control functionality.
The control can be by human, cloud, and/or automated control logic.
In one embodiment, the MGIOS enables node 900 to work independently
as an individual node and/or work in aggregate with other control
nodes in a grid network. The independent operation of each can
enable the distributed network to function without a central power
plant, and/or with minimal central grid management.
[0140] In one embodiment, the MGIOS can enable blackstart
operation. Blackstart operation is where node 900 can bring its
segment of the grid back up online from an offline state. Such
operation can occur autonomously from central grid management, such
as by each node 900 of a grid network independently monitoring
conditions upstream and downstream in the grid network. Thus, node
900 can come online when conditions permit, without having to wait
for a grid operator to control distribution of power down to the
node. Node 900 can thus intelligently bring its node segment back
up online by controlling flow of power to and from the grid, and
can thus, prevent startup issues.
[0141] In one embodiment, the MGI enables node 900 to offer
multiple line voltages. In one embodiment, grid interface 980,
which may be through control logic of processor 910, can be
configured for multiple different trip point voltages. Each trip
point voltage can provide a different control event. Each control
event can cause processor 910 to perform control operations to
adjust an interface of the control node. The interface can be an
interface to a load and/or an interface to the grid network.
[0142] In one embodiment, the MGI can economize interconnects
within the grid network. In one embodiment, node 900 controls
backflow onto the grid network by limiting the backflow, and/or
adjusting output to change a type of power presented to the grid.
In one embodiment, node 900 provides utility control functions that
are traditionally performed by utility grid management that
controls flow of power from a central power plant. Node 900 can
provide the grid control functions to enable a distributed power
grid.
[0143] Power distribution hardware 920 includes power lines,
connectors, phase locked loops, error correction loops, interface
protection or isolation such as transformers, and/or other hardware
that enables the control node to transfer energy from one point to
another, to control interfaces to control how power flows
throughout the grid, or other operations. In one embodiment, a
power converter can be included within the power distribution
hardware. A power converter can be a smart inverter or
microinverter, and can be in accordance with what is described with
respect to systems 1500 and 1600.
[0144] Power monitoring hardware 930 includes connectors, signal
lines, sampling hardware, feedback loops, computation hardware,
and/or other hardware that enables the control node to monitor one
or more grid conditions and/or load conditions. The grid conditions
can be or include voltage levels, phases, frequencies, and other
parameters of the grid operation. The load conditions can be or
include voltage, current, phase, frequency, and other parameters of
power demand from loads.
[0145] In one embodiment, node 900 includes grid control 940. Grid
control represents hardware and logic (e.g., such as
software/firmware logic, configurations) to control an interface to
the grid network. In one embodiment, grid interface 980 represents
grid network interfaces. Grid control 940 can include real power
control 942 and reactive power control 944. The real and reactive
control can be in accordance with any embodiment described herein.
In one embodiment, real power control 942 includes logic (hardware
and/or software) to provide real power to the grid. In one
embodiment, reactive power control 944 includes logic to provide
reactive power to the grid. Providing power to the grid can include
changing an interface to cause power of the type and mix desired to
flow to the grid.
[0146] In one embodiment, node 900 includes local control 950.
Local control represents hardware and logic (e.g., such as
software/firmware logic, configurations) to control an interface to
the load or to items downstream from a PCC coupled to a grid
network. Local control 950 can include real power control 952 and
reactive power control 954. The real and reactive control can be in
accordance with any embodiment described herein. In one embodiment,
real power control 952 includes logic (hardware and/or software) to
provide real power to a load. In one embodiment, reactive power
control 954 includes logic to provide reactive power to a load.
Providing power to the load can include changing an interface to
cause power of the type and mix desired to flow to the load from a
local energy source and/or from the grid.
[0147] It will be understood that a utility power grid has rate
structures that are based on not just the amount of use, but the
time of use. For example, a utility grid can have tiered rates. In
one embodiment, processor 910 includes rate structure information
that enables it to factor in rate structure information when making
calculations about how to change an interface with grid control 940
and/or with local control 950. Factoring in rate structure
information can include determining what type of power (real or
reactive) has more value in a given circumstance. Thus, processor
910 can maximize value of energy production and/or minimize the
cost of energy consumption. In an implementation where tiered rate
structures exist, processor 910 can instruct grid control 940
and/or local control 950 based on how to keep consumption to the
lowest tier possible, and how to provide power at a highest rate
possible. In one embodiment, processor 910 takes into account
utility or grid network requirements when controlling the operation
of grid control 940 and/or local control 950. For example, the grid
may have curtailments or other conditions that affect how power
should be provided and/or consumed. In one embodiment, node 900 can
adjust power output as loads dynamically come online and offline.
For example, local control 950 can reduce output when loads go
offline, and can increase output when load come online.
[0148] Metering 960 represents metering capability of node 900, and
can include a meter in accordance with any embodiment described
herein. In one embodiment, metering 960 can include load control
metering 962. Load control 962 can include logic to monitor load
power demand. In one embodiment, metering 960 can include signature
manager 964. Signature manager 964 includes logic to create, store,
and use energy signatures in monitoring what is happening with
loads. More specifically, signature manager 964 can manage energy
signatures including complex current vectors in accordance with any
embodiment described herein.
[0149] Traditionally, a net energy meter was required to connect to
the grid. However, newer regulations may prevent connecting to the
grid at all unless certain capabilities are met. Metering 960 can
enable node 900 to control an inverter or converter to respond to
specific loads and/or to specific energy signatures identified on
the line. Based on what metering 960 detects, node 900 can provide
realtime control over energy production and load consumption.
[0150] In one embodiment, node 900 includes data interface 970. In
one embodiment, data interface 970 includes data manager 972 to
control data that will be sent to a data center or data management,
and data that is received from the data center or data management.
Data manager 972 can gather data by making a request to a data
center or comparable source of data. In one embodiment, data
interface 970 includes external manager 974, which can manage the
interface with a data center, central grid management, other nodes
in the grid network, and/or other data sources. In one embodiment,
data manager 972 receives data in response to data sent from a data
source. In one embodiment, external manager 974 makes a request for
data from a data source. The request can be in accordance with any
of a number of standard communication protocols and/or proprietary
protocols. The medium for communication can be any medium that
communicatively couple node 900 and the data source. In one
embodiment, external manager 974 communicates with a data source at
regular intervals. In one embodiment, external manager 974
communicates with the data source in response to an event, such as
more data becoming available, whether receiving indication of
external data becoming available, or whether data manager 972
indicates that local data is ready to send. Data interface 970 can
enable realtime data for market use. In one embodiment, data
interface 970 provides data collection, which can be used in one
embodiment to identify currents for energy signatures.
[0151] In one embodiment, node 900 includes grid interface 980. In
one embodiment, grid interface 980 includes utility interface 982
to interface with a utility grid. In one embodiment, grid interface
980 includes virtual interface 984 to interface with a distributed
grid network. The operation of the grid interface can be referred
to as MGI (modern grid intelligence), referring to execution of an
MGIOS by processor 910. Grid interface 980 can include any type of
interface that couples node 900 to grid infrastructure, whether
traditional utility grid infrastructure and/or distributed grid
networks. In one embodiment, grid interface 980 can enable node 900
to know a power direction. In one embodiment, the grid network
provides dispatch information, such as provide a signal from a
feeder to indicate a power direction. Node 900 can manage its
operation based on the direction of power flow in the grid network.
Grid interface 980 can also dynamically monitor changes in
direction of power flow.
[0152] In one embodiment, the MGIOS enables node 900 to adjust
operation of one or more elements connected downstream from a PCC,
to scale back operation of the grid. Consider an example of air
conditioners coupled downstream from a PCC. In one embodiment, the
MGIOS can detect that the grid network is experiencing heavy load,
and can determine to slow down all air conditioners to relieve the
grid for 5 to 10 minutes. Thus, the devices do not need to be
stopped, and the grid does not need to shut off power to any
segment. Instead, the power can be reduced for a period of time to
selected loads to allow the grid can recover itself. Thus, the
MGIOS can control the load and/or the sources. Such operation can
reduce or prevent brownouts or rolling blackouts, for example, by
scaling power demand back instead of completely shutting supply
down.
[0153] It will be understood that node 900 requires a certain
amount of power to operate. The power consumed by node 900 can be
referred to as tare loss, which indicates how much power the
controlling devices consume when the node is not generating power.
In one embodiment, node 900 includes a sleep feature to reduce tare
loss. For example, a node that controls a metastable energy source
such as solar can sleep when there is no sun, and can wake up when
the sun comes up. In one embodiment, the node can default to a low
power state and awake in response to a signal from a solar
detector, power over Ethernet, or some other external signal
trigger to wake it up. In one embodiment, a node can wake up during
a sleep cycle at night to perform upgrades or perform other
ancillary services.
[0154] FIG. 10 is a block diagram of an embodiment of a system that
controls harmonic distortion with a software feedback control
subsystem coupled to a hardware waveform controller. System 1000
includes power source 1004, load 1006, and converter 1002 to
generate output and control of an interface between the source and
the load. In one embodiment, converter 1002 is in accordance with
what is described in U.S. patent application Ser. No. 12/708,514,
entitled "POWER TRANSFER MANAGEMENT FOR LOCAL POWER SOURCES OF A
GRID-TIED LOAD," and filed Feb. 18, 2010. In one embodiment, the
power conversion can be in accordance with U.S. patent application
Ser. No. 11/849,242, entitled "MULTI-SOURCE, MULTI-LOAD SYSTEMS
WITH A POWER EXTRACTOR," and filed Aug. 31, 2007. System 1000 can
be one example of a system includes a converter for a control node
in accordance with any embodiment described herein.
[0155] Power path 1010 represents the path of electrical power from
source 1004 to load 1006, as controlled by converter 1002.
Converter 1002 includes input power converter 1020 to receive input
power from source 1004 and convert it to another form (e.g., DC to
AC). Input power converter 1020 includes hardware components for
receiving a power signal to convert, and may include appropriate
power components. In one embodiment, input power converter 1020
implements dynamic impedance matching, which enables the input
electronics to transfer maximum power from source 1004. Dynamic
impedance matching includes constantly tracking a maximum power
point, as well as driving an input power coupler (e.g., a
transformer) to maintain as flat a power slope as possible (e.g.,
slope of zero). Input power converter 1020 may receive control
signals or information from controller 1030, as well as providing
input to indicate operation of the converter. In one embodiment,
dynamic impedance matching includes high-frequency switching of the
input power through a transformer or inductor to charge an internal
node within converter 1002. The internal node can then act as an
energy reservoir for high-frequency switching of an output through
another transformer or inductor to allow a load to draw whatever
power is needed. Thus, input power converter 1020 can provide
unregulated energy transfer from an input to an output.
[0156] Input feedforward 1012 provides information (e.g., maximum
power value, frequency as appropriate, or other information to
control the input power converter hardware) about the source power
to controller 1030. Controller 1030 controls input power converter
1020 based on the input information about the input power.
Controller 1030 represents any type of processor controller that
may be embedded in converter 1002. Controller 1030 may be or
include any type of microcontroller, digital signal processor
(DSP), logic array, or other control logic. Additionally,
controller 1030 may include appropriate memory or storage
components (e.g., random access memory, read only memory (ROM),
registers, and/or Flash) to store code or values generated or
obtained during runtime operation or pre-computed.
[0157] Controller 1030 drives programmable waveform generator 1040
to generate the desired output waveform. Generator 1040 also lies
on power path 1010, and receives input power from input power
converter 1020 to output. While the power may be transferred, it is
not necessarily output with the same waveform as it is received.
For example, a DC signal may be output as a sinusoidal signal.
Other power conversions can similarly be accomplished. In one
embodiment, generator 1040 includes a PWM (pulse wave modulator) to
generate an output waveform. Generator 1040 receives control
signals and information from controller 1030, and may provide
status or operations information or feedback to controller 1030.
The output waveform may be either current or voltage. In one
embodiment, the output is a current having a phase offset and an
angular offset with respect to a load voltage waveform to enable
harmonic-free output.
[0158] Converter 1002 is able to incorporate specific timing,
phasing, or other frequency information, into generating the output
waveform. Such timing, phasing, or other frequency information may
be referred to as "input synchronization data." In one embodiment,
such input synchronization data arrives from real-time load
information, in which case it may be referred to as "load
synchronization input." The load synchronization input or input
synchronization data indicates information necessary to determine
the synchronization signal discussed above. Such information is
indicated in converter 1002 as output sync 1014. In a system where
the output is anticipated (e.g., connecting to an electrical grid),
certain voltage, timing, or other information may be expected
(e.g., 120V at 60 Hz), and an initial estimate programmed in or
made by the system at startup. Based on load synchronization data,
the initial estimate may be adjusted.
[0159] Controller 1030 also measures output feedback 1016 off power
path 1010, to determine the actual output generated by generator
1040. The actual output is compared to an ideal reference to
determine if the desired output is being generated. In one
embodiment, output feedback 1016 is an abstraction to represent
output measurement by controller 1030, and does not include
separate components in itself. In one embodiment, output feedback
1016 includes a sampling mechanism or other data selection
mechanism to compare to the ideal reference signal. The ideal
reference signal can be an idealized representation of a desired
output waveform. The output converges on the idealized waveform
rather than on the target waveform of the load or grid itself. If
output feedback 1016 includes components separate from controller
1030, it may be driven by controller 1030, and receive comparison
data from controller 1030 and provide error or feedback
information. In one embodiment, output feedback 1016 is understood
to include at least hardware components necessary for a feedback
control process to interface with the output lines. Additionally,
output feedback 1016 may include other hardware for performing
measurements, computations, and/or performing processing.
[0160] Both output sync 1014 and output feedback 1016 may be
considered feedback loops. It will be understood that output sync
1014 and output feedback 1016 are not the same thing, and serve
different purposes. Output sync 1014 indicates what the ideal
reference signal should look like, as stored in reference waveform
table 1032. Output feedback 1016 indicates how the actual output
varies from the reference signal. Update table 1034 represents data
generated in response to output feedback 1016. In one embodiment,
output sync 1014 is based on voltage information on the output of
power path 1010, while output feedback 1016 is based on output
current generated at the output of power path 1010.
[0161] Based on output sync 1014 (or based on an initial estimate
of the output sync), converter 1002 stores and/or generates
reference waveform table 1032, which represents an ideal form of
the output waveform desired to be generated by generator 1040.
Reference waveform table 1032 may be stored as a table or other set
of points (or setpoints) that reflect what the output waveform
"should" look like. The reference waveform can be any periodic
waveform. In one embodiment, the reference waveform is represented
as a series of points that have an amplitude and a position. Thus,
converging on the reference waveform can include driving an output
waveform generator to match sampled output points to the setpoints
representing the reference waveform. Reference waveform table 1032
may alternatively be referred to as a reference waveform
source.
[0162] Based on output feedback 1016, converter 1002 generates
update table 1034. Update table 1034 includes entries or points to
indicate how to modify the operation of generator 1040 to provide
an output more closely matching the waveform of reference waveform
table 1032. While indicated as a table, update table 1034 may be a
stored table that is modified at certain intervals (e.g., each
entry is updated as necessary to reflect measured error data), or
may be generated newly at each update interval. Update table 1034
may alternatively be referred to as an update data source. The
"updates" may be modifications of old values, the replacement of
values, or may be stored in different locations within a memory
accessed by controller 1030. In one embodiment, each value of
update table 1034 indicates an "up," "down," or no change for each
of a set of points. Such values are applied to the hardware that
controls the output of generator 1040 to cause the output signal to
converge on the desired ideal waveform.
[0163] From one perspective, converter 1002 can be viewed as having
five features or components. While these features are depicted in
system 1000 via certain block diagrams, it will be understood that
different configurations and a variety of different components can
be used to implement one or more of these features. For purposes of
discussion, and not by way of limitation, these features are
described following with references such as "Feature 1," "Feature
2," and so forth. It will be understood that such a convention is
merely shorthand to refer to the subject matter of the described
feature or component, and does not necessarily indicate anything
with respect to order or significance.
[0164] Feature 1 may include means for incorporating specific
timing, phasing or other frequency information. The means includes
hardware and/or software to generate and receive the input
synchronization data or load synchronization input referred to
above, which is based on output sync 1014. Feature 2 includes
reference waveform table 1032, which may include a table of data or
an equation within software that represents the ideal form of
output waveform 1008. Feature 3 includes controller 1030, which may
be or include a software algorithm that compares the actual output
waveform generated by generator 1040 with the ideal tabular
representation as represented by reference waveform table 1032.
Feature 4 includes an algorithm within controller 1030 that
computes or otherwise selects and generates update data represented
by update table 1034. Feature 5 includes generator 1040 that uses
the update data from update table 1034 to generate output waveform
1008 of the desired shape, proportion, timing, and phase.
[0165] With regard to Feature 1, the specific timing, phasing, or
other frequency information provides synchronization information to
the comparison and update algorithms in controller 1030. The
information may come by way of a table, equation, sampling of
real-time hardware monitored signals, or other source.
[0166] With regard to Feature 2, the data representing the
reference waveform, can be of any length and of any format, integer
or non-integer, if within a table. Such a table may be generated
dynamically at runtime or be hard-coded at compile time. The ideal
form of the waveform represented may be sinusoidal or
non-sinusoidal. The waveform may be represented by data values
evenly spaced in the time domain or non-evenly spaced, forward in
time or backward in time or any mix thereof. The waveform could
alternatively be represented by data values in the frequency
domain, and organized in any fashion. The data may be compressed or
non-compressed. The data may be represented by an equation rather
than computed data setpoints, or part by an equation and part by a
table. In one embodiment, the stored setpoints in a table are the
computed results of an equation. The data may be altered during
processing at runtime to change the form of the ideal waveform to a
different ideal. The values in reference waveform table 1032 can be
modified or replaced with different values if altered at runtime.
The data may be aligned to be in exact phase with the input
waveform or it may be shifted in phase.
[0167] With regard to Feature 3, controller 1030 may include any
traditional or standard comparison algorithm. A control algorithm
compares data values representing the output waveform, sampled by
hardware, and transformed into software data values through
standard or non-standard sampling techniques. In one embodiment,
the controller compares the ideal setpoints of the table or
equation computations with the synchronization information, point
by point, and generates error data, point by point. In one
embodiment, the controller can process multiple points at once
instead of point-by-point.
[0168] With regard to Feature 4, controller 1030 includes a
selection algorithm which creates or generates new data using any
standard or non-standard technique. In one embodiment, the
selection algorithm involves performing calculations.
Alternatively, the selection algorithm may simply select data
without performing processing or performing calculations. The
selection algorithm may replace data values in a table of
setpoints, or leave the data values in the table preferring to use
another storage area. The selection algorithm may transform the
data from the time domain to the frequency domain and vice-versa as
part of its selection process. The algorithm provides an error
update mechanism (e.g., algorithm) in that it identifies data
values that will correct the output waveform when applied. Thus,
the output waveform after application of the data values appears
more like the preferred ideal waveform.
[0169] With regard to Feature 5, the new data values represented by
update table 1034 are applied to hardware in generator 1040 through
standard processes to drive the generation of the output waveform.
In one embodiment, the new data values are applied via a PWM
mechanism or any other mechanism that transforms discrete data
values into an analog output form.
[0170] FIG. 11 is a block diagram of an embodiment of a system that
transfers power from a local source to a grid-tied load with power
factor conditioning. System 1100 illustrates a grid-tied converter
that couples to an energy source, a load, and a grid. Converter
1120 of system 1100 represents a converter for a control node,
which can be in accordance with any embodiment described herein.
System 1100 represents a power system that includes metastable
energy source 1110, converter 1120, load 1102, and utility power
grid 1130. Load 1102 represents a consumer tied to grid 1130. Grid
1130 can be any embodiment of a grid network described herein.
Metastable source 1110 (e.g., solar cells/array, wind power
generator, or other time-varying or green power source) and
converter 1120 are local to load 1102, as being on a same side of a
PCC, and provide power to the load. In one embodiment, metastable
source 1110 produces a variable/unstable source of DC power. The
source may be time-varying and/or change in available power due to
environmental conditions. Converter 1120 represents a dynamic power
extractor and inverter apparatus.
[0171] Source 1110 is a variable or unstable power source. System
1100 includes converter 1120, which includes DC/DC converter 1122,
coupled to DC/AC inverter 1124, both of which are coupled to and
controlled by controller (CPU) 1140. Additionally, switching device
S1126 (e.g., a relay) selectively connects the inverter to load
1102 and grid 1130. Under normal operation, DC power is drawn from
source 1110, and extracted, inverted, and dynamically treated by
converter 1120, to dynamically produce maximum AC current
relatively free of harmonic distortion and variability, and at a
desired phase with respect an AC voltage signal from grid 1130.
Putting the generated AC current in phase with the grid AC voltage
produces AC power with a power factor at or near unity to load
1102, meaning that all reactive power drawn by the load comes from
grid 1130. If source 1110 produces enough energy to satisfy the
real power requirements of load 1102, converter can cause the only
AC power drawn from grid 1130 by the load to be exclusively or
nearly exclusively reactive power. When source 1110 is unable to
produce DC power sufficient to completely satisfy the power demand
from load 1102, converter 1120 can adjust an interface to allow
real power to flow from grid 1130 to load 1102.
[0172] In one embodiment, converter 1120 can generate AC current
intentionally out of phase to a certain extent with respect to the
AC voltage signal of the grid. Thus, the single converter 1120 can
deliver power at any desired power factor to compensate for
conditions of power on power grid 1130. In one embodiment, multiple
converters 1120 can operate in parallel at the same interface, and
each can generate power with the same power factor, or each can be
dynamically configured to produce different mixes of real and
reactive power.
[0173] When energy source 1110 generates sufficient power to
satisfy load 1102, the inverter current and the grid current will
flow towards grid 1130. In general, power can be given back
generally to the grid, and the consumer can be appropriately
compensated for power provided to the grid. In one embodiment, a
give back scenario can involve providing power to a neighbor
consumer, in accordance with any embodiment described herein.
[0174] In one embodiment, power meter 1132 represents a meter to
measure real power consumed by load 1102. In one embodiment, VAR
meter 1134 represents a meter to measure the reactive power
consumed by load 1102. In one embodiment, power meter 1132 and VAR
meter 1134 can be combined physically and/or functionally by a
meter. The meter can be on the side of grid 1130. In one
embodiment, the meter (combining meters 1132 and 1134) is located
with a PCC to connect to the grid, and is part of a control node
with converter 1120. Such a meter can be in accordance with any
embodiment described herein. In one embodiment, typically meter
1132 measures the voltage and current and computes power from those
measurements. It will be understood that in the case only reactive
power is drawn from grid 1130, power meter 1132 will not measure
any power usage by load 1102. VAR meter 1134 can measure and
compute the reactive power drawn, such as by measuring the phase of
the current and voltage of the grid power at the load, and
performing calculations based on the measured values.
[0175] As discussed, in one embodiment, the power factor delivered
by converter 1120 to load 1102 is at or near 1.0 relative to grid
1130. Thus, converter 1120 can perform power factor correction. In
one embodiment, converter 1120 can provide harmonic distortion
correction. In one embodiment, converter 1120 provides table-based
harmonic distortion correction. Previous harmonic distortion
techniques use a hardware-based method or Fast Fourier Transform
(FFT). The table-based method implemented on a processor or
controller reduces cost per inverter and scales better than typical
hardware implementations, and can be in accordance with what is
described with reference to system 800.
[0176] Inverter 1124 of converter 1120 generates output in
accordance with a desired power factor (unity or otherwise). In one
embodiment, inverter 1134 monitors the operating conditions at the
point of connection to load 1102, and provides maximum power from
source 1110 dynamically and in real time with changes in the energy
source and current load. Thus, if the amount of energy generated by
source 1110 changes, converter 1120 can modify the output based on
that source in real time. Additionally, if the resistive conditions
of load 1102 (e.g., an inductive motor such as a vacuum is turned
on), converter can automatically generate changes to power output
to track the needs of the load. All such changes can occur in
realtime as conditions vary. In one embodiment, converter 1120 can
provides output adjustments that provide total harmonic distortion
control for harmonic distortion more efficiently than what is
required by standards, thus complying with standards and improving
performance of the system by dynamically adjusting to variable and
unstable power sources, and to a changing load.
[0177] It will be understood that if the output voltage and current
of converter 1120 are matched in phase with each other and with the
voltage on the grid (e.g., through a phase lock loop, or through a
power generation sampling and feedback mechanism), any reactive
power necessary will be absorbed from the grid. The more real power
provided by source 1110, the further out of phase the grid voltage
and the grid current will be locally at load 1102. If all real
power is provided locally, the current and voltage of the grid will
be 90 degrees out of phase locally at load 1102, causing the grid
real power contribution to fall to 0 (recall that
Preal=(Vmax*Imax/2)cos(Vphase-Iphase)).
[0178] In one embodiment, DC to DC converter 1122 of power
converter 1120 includes input and output portions, as represented
by the dashed line separating the device into two portions. The
portion coupled to source 1110 can be referred to as an input
portion, and the portion coupled to DC to AC inverter 1124 can be
referred to as the output portion. In one embodiment, the operation
of converter 1122 is to vary input impedance and output impedance
to transfer energy from source 1110 to inverter 1124. In one
embodiment, converter 1122 can be referred to as a power
extractor.
[0179] Converter 1122 can impedance match to change an interface on
the input to maximize energy transfer from source 1110 without
fixing the voltage or current to specific values. Rather, the input
can allow the power to float to whatever voltage is produced by
source 1110, and the current will match based on whatever total
power is produced. Similarly, on the output, converter 1122
impedance matches to change an output interface to allow the load
(in this case, inverter 1124) to draw whatever power is needed at
whatever voltage the inverter operates at. Thus, the output of
converter 1122 can float to match the voltage of inverter 1124, and
generate current to match the total power. Converter 1122 can
generate an output current waveform, where the magnitude is
determined by how much energy is available, and whatever voltage
inverter 1124 is at. Thus, the output floats to match the load, and
is not fixed at current or voltage. An internal node within
converter 1122 can act as an energy reservoir, where the input
impedance matching enables the efficient charging of the internal
node, and the output impedance matching enables the load to draw
energy from the internal node. The input and output both couple to
the internal node via inductors and/or transformers to isolate the
input and output from each other and from the internal node.
[0180] Controller 1140 can monitor the AC current, which moves out
of DC/AC inverter 1124, and the generated voltage of grid 1130,
which appears across load 1102. Controller 1140 controls at least
one electrical parameter of the interfaces of converter 1122 to
control its operation. Parameters 1142 and/or 1144 represent
control from controller 1140 to control the operation of converter
1122 within converter 1120. In one embodiment parameters 1142
and/or 1624 may be a duty cycle of a switching signal of the power
extraction, which changes input and/or output impedance matching,
which in turn controls the charging and drawing from the internal
node. The modification of each parameter can be dependent on the
quality of the monitored current and voltage. Controller 1140
further controls switching device S1626 to couple the load to power
produced (by converter 1122 and inverter 1124 from source 1110),
when suitably conditioned power is available for use by load
1102.
[0181] In one embodiment, converter 1120 includes tables 1150,
which provides a table-based method for controlling power factor,
to adjust the operation of converter 1120 to generate reactive
power as desired. The tables may include entries that are obtained
based on input conditions measured from the system, to achieve a
desired mix of real and reactive power. Feedback from the grid-tied
node may include voltage zero crossing, voltage amplitude, and
current waveform information. With such information, controller
1140 uses tables 1150 to adjust the operation of converter 1122
and/or inverter 1124. The tables may include setpoints that provide
idealized output signals the system attempts to create. By matching
output performance to an idealized representation of the input
power, better system performance is possible than simply attempting
to filter and adjust the output in traditional ways.
[0182] In one embodiment, system 1100 can be applied without a
specific energy source 1110. For example, converter 1120 can be
coupled to receive power from grid 1130, and generate an output to
load 1102 that provides whatever mix of real and reactive power is
needed by load 1102. In one embodiment, converter 1122 can be
adjusted to receive AC input. In one embodiment, a connection to
converter 1122 can be configured with hardware to generate DC power
from the grid, such as an AC to DC converter. However, it will be
understood that such conversion cause some inefficiency. In one
embodiment, converter 1122 can be implemented with an input
transformer that will enable connection between grid power and the
internal node.
[0183] FIG. 12 is a block diagram of an embodiment of a consumer
node having intelligent local energy storage. System 1200
represents a consumer node or an area within a PCC in accordance
with any embodiment described herein. System 1200 specifically
shows a configuration where local energy storage is combined with
local energy generation at a consumer node. System 1200 can be or
include a control node in accordance with any embodiment described
herein.
[0184] PCC 1210 represents an interconnection point to a grid
network. Grid power represents power drawn from the grid. In one
embodiment, system 1200 includes gateway 1220 to aggregate
information and control operation within system 1200 based on the
aggregation information. Gateway 1220 can manage the capacity and
the demand for system 1200. The capacity refers to the ability of
system 1200 to generate power locally. The demand refers to the
load demand locally for system 1200, which comes from loads (not
specifically shown).
[0185] In one embodiment, system 1200 generates capacity with one
or more local energy sources 1260. Local energy source 1260 can be
any type of energy generation system. In one embodiment, the energy
generation mechanisms of local energy source 1260 generate real
power. In one embodiment, local energy source 1260 represents an
energy generation mechanism with an associated power converter
and/or inverter. When source 1260 includes a power
converter/inverter, it can be referred to as an energy generation
system. Solar power systems are commonly used at customer premises,
and source 1260 can be or include a solar power system.
[0186] System 1200 includes one or more energy conversion or power
converter devices to control the flow of energy within the PCC. In
one embodiment, converter 1252 and inverter 1254 represent power
converter devices for system 1200. In one embodiment, each inverter
includes a power converter. In one embodiment, a power converter
represents an energy conversion device that enables efficient
coupling between a source and a load, such as what is described in
reference to system 1000 and system 1100. Devices 1252 and/or 1254
provide control of the interchange of energy within system 1200. In
one embodiment, each energy source includes an inverter and/or
converter. Thus, the devices represented in the dashed box
represent devices that can be spread throughout system 1200. Each
consumer node can include multiple converter devices for the
control of energy flow. In one embodiment, each energy storage
resource includes an inverter and/or converter.
[0187] System 1200 includes one or more energy storage resources.
As illustrated, battery backup system 1230 represents a system of
commercial batteries to store energy. Energy store 1240 represents
a non-battery backup or energy storage device or system, but
battery backup will be understood as a specific example of energy
store. Examples of non-battery backup can include systems that
include a pump or other motorized device that convert active power
within system 1200 into kinetic energy. For example, energy store
1240 can pump water or other liquid against gravity, can compress
air or other gas, can lift counterweights again gravity, or perform
some other function to convert energy into work to store in a
system. The stored energy can be retrieved later by using a reverse
force (e.g., gravity or decompression) to operate a generator.
Thus, the energy storage system can convert the kinetic energy back
into active power for system 1200.
[0188] In one embodiment, converter 1252 can be used to charge an
energy store (e.g., 1230, 1240) when it is depleted or partially
depleted. In one embodiment, inverter 1254 can be used to convert
energy from the energy store into active power. Gateway 1220 can
intelligently control the use of energy storage 1230, 1240. For
example, gateway 1220 can monitor grid conditions to know when the
least "expensive" time to charge the energy storage is. Sometimes
grid power is less expensive and can be converted into stored
energy for later use. Sometimes there is excess capacity from
energy source 1260 that can be stored locally in energy storage
1230, 1240.
[0189] In general, in one embodiment, system 1200 includes local
energy source 1260, and local energy store 1230, 1240 on a consumer
side of PCC 1210. System 1200 also includes a local energy
conversion device such as converter 1252 and/or inverter 1254 to
control the flow of energy to and from the energy storage in system
1200. The energy conversion enables system 1200 to access energy
from the energy store and/or to charge the energy store. In one
embodiment, system 1200 charges energy store 1230, 1240 from grid
power. In one embodiment, system 1200 charges energy store 1230,
1240 from energy source 1260. In one embodiment, system 1200 powers
a local load to meet local power demand from energy in energy store
1230, 1240. In one embodiment, system 1200 transfers power to the
grid from energy store 1230, 1240. The use of stored energy can
include the conversion of the energy to any mix of real and
reactive power needed for the local load and/or the grid, depending
on where the energy is being transferred.
[0190] FIG. 13 is a flow diagram of an embodiment of a process for
controlling a grid node with data aggregation. Process 1300 for
controlling a grid node with aggregation information can be
performed by elements of a control node. In one embodiment, the
control node includes a gateway device, which can be or include an
aggregator. For simplicity, and not by way of limitation, the
description of process 1300 refers to operations by an aggregator.
The aggregator can be in accordance with any embodiment of an
aggregator described herein. In one embodiment, the aggregation
information includes information gathered by a local meter that
measures local and/or external grid conditions.
[0191] In one embodiment, the aggregator interfaces with one or
more sensors and can receive data measurements from the sensors,
1302. In one embodiment, the aggregator can receive one or more
forms of external information about the grid. The external
information is grid condition information that the aggregator can
receive, 1304. In one embodiment, the aggregator aggregates sensor
information about local equipment with grid-based information to
determine one or more conditions to address with power converter
operation, 1306. Thus, the aggregator can generate one or more
items of grid condition information based on the aggregated data,
1308. In one embodiment, the grid condition information represents
a state in a state machine, where the state is determined based on
relationships between the condition information, which can include
the grid information and the sensor information. In one embodiment,
the aggregator includes an aggregation engine that implements a
relational database of condition information. For example, the
relational database can include tables for conditions and rows that
represent specific ranges within the condition, which can then be
condition keys for states. In one embodiment, the aggregator
generates a state as a "condition" for execution by a power
converter or as input for other decision logic.
[0192] In one embodiment, the aggregator receives or accesses rate
information that indicates a value or price of power, 1310. In one
embodiment, the aggregator uses the rate information to forecast a
best operation based on the value of power in light of the
aggregated condition information, or state previously determined,
1312. In one embodiment, the aggregator access prior history
information about the operation or operating conditions of the
consumer node or operation of the local control node, 1314. In one
embodiment, the aggregator computes a forward looking prediction
based on the aggregation information and/or the forecast
information in light of the historical information, 1316.
[0193] In one embodiment, the aggregator generates one or more
controls for interface hardware based on the computed action(s),
and/or predictions, 1318. Thus, the aggregator can evaluate grid
condition information and local load and operating conditions
together, and can modify the evaluation by rate information and/or
historical information. The aggregator can control an interface
with converter/inverter hardware to provide power to local capacity
and/or to the grid in accordance with the operation computed based
on the information, 1320. In accordance with the operation, one or
more power converters control the flow of power within a node
and/or between the node and the grid.
[0194] FIG. 14 is a flow diagram of an embodiment of a process for
aggregating local and grid-based condition information. Process
1400 for aggregating local and grid-based information to make a
decision based on the aggregation of information can be performed
by elements of a control node. In one embodiment, the control node
includes a gateway device, which can be or include an aggregator.
For simplicity, and not by way of limitation, the description of
process 1400 refers to operations by an aggregator. The aggregator
can be in accordance with any embodiment of an aggregator described
herein. In one embodiment, the aggregation information includes
information gathered by a local meter that measures local and/or
external grid conditions.
[0195] In one embodiment, process 1400 includes monitoring for
local sensors and monitoring for grid condition information. In one
embodiment, local sensors register with the aggregator, 1402. In
one embodiment, the aggregator registers the sensors to configure
monitoring the data from the sensors, such as frequency of
obtaining data from the sensor, and parameters for interconnecting
with the sensor. The aggregator can monitor local conditions by
data from the sensors, 1404. In one embodiment, the aggregator
monitors the sensor until updated information is available. If
there is not updated data, 1406 NO branch, the aggregator can
continue to monitor the sensor for local conditions, 1404. If there
is updated data, 1406 YES branch, in one embodiment, the aggregator
records the condition, 1408.
[0196] In one embodiment, the aggregator also configures itself for
interfacing with grid I/O (input/output), 1410. The grid I/O can
enable the aggregator to receive information about grid conditions
from outside the local node of which the aggregator is a part. The
aggregator can monitor the grid conditions indicated by the grid
I/O, 1412. If there is not updated data, 1414 NO branch, the
aggregator continues to monitor the grid I/O, 1412. If there is
updated data available, 1414 YES branch, in one embodiment, the
aggregator determines whether the grid I/O indicates a condition
that needs to be addressed immediately. If there is not an
immediate need for action, 1416 NO branch, the aggregator can
record the grid conditions indicated from the external I/O,
1408.
[0197] After recording conditions from the grid and from local
sensors, the aggregator can determine to adjust operation at the
local control node, 1418. In one embodiment, the aggregator makes a
determination based on a schedule. In one embodiment, the
aggregator makes a determination of what action to take on each
data event, where a data event can be when updated data is
available. In one embodiment, if data received from the grid needs
immediate attention, 1416 YES branch, the aggregator can determine
to adjust the operation of a converter of the control node,
1418.
[0198] In one embodiment, the aggregator applies weights to
aggregated data and calculates a state or condition, 1420. In one
embodiment, the weights can be applied to factor one item of data
more than another. In one embodiment where grid information is
received requiring immediate attention, the "weight" on that data
can be to cause the control node to immediately comply with the
request. In one embodiment, the aggregator generates one or more
operations to be executed at the consumer node, 1422. In one
embodiment, the calculation of state and/or the generation of an
operation to execute can include the execution of a heuristics
decision algorithm that searches a best match output scenario based
on the input conditions.
[0199] The operations can be executed by a power converter of the
control node, which can be a device of the control node itself,
and/or of equipment within the consumer node. In one embodiment,
the operations can include one or more of transferring energy to a
local load, 1424, transferring energy between a local energy store
and the PCC, 1426, transferring energy between the local energy
source and the PCC, 1428, and/or transferring energy between the
PCC and the grid, 1430. In one embodiment, energy transfer to the
local load can include real power, reactive power, and/or a mix of
real and reactive power. In one embodiment, the power is generated
to offset the complex vector of a load's energy signature. In one
embodiment, transferring energy between the energy store and the
PCC can include charging the battery or powering a load from the
energy store. In one embodiment, the energy transfer between the
local energy source and the PCC can include real power, reactive
power, or a mix. In one embodiment, the control node can deliver
power to the grid via the PCC, which can be real power or ancillary
services.
[0200] FIG. 15 is a flow diagram of an embodiment of a process for
generating a grid control operation with an aggregator gateway.
Process 1500 for generating control operations with a gateway
aggregator can be performed by elements of a control node. In one
embodiment, the control node includes a gateway device, which can
be or include an aggregator. For simplicity, and not by way of
limitation, the description of process 1500 refers to operations by
an aggregator. The aggregator can be in accordance with any
embodiment of an aggregator described herein. In one embodiment,
the aggregation information includes information gathered by a
local meter that measures local and/or external grid
conditions.
[0201] In one embodiment, a controller or control logic of an
aggregator receives aggregation data, which can include local
conditions and grid conditions, 1502. The aggregation data can
include or can accompany local load demand. In one embodiment, the
aggregator identifies local power demand, 1504. The local power
demand can be measured by a local meter in accordance with any
embodiment described herein. In one embodiment, the aggregator can
also identify local power generation capacity, 1506. Certain local
conditions identified by local sensors can include conditions that
affect how much power can be generated by the local energy source.
For example, solar intensity can determine whether a solar system
can provide peak output, or something less based on the
conditions.
[0202] In one embodiment, the aggregator accesses rate information,
1508. The rate information can include consumer and market pricing
information. Based on rate information, the aggregator can forecast
a best operation from the perspective of best monetary benefit to
the consumer. In one embodiment, the aggregator accesses historical
information, 1510. The historical information can indicate previous
conditions, which can allow the aggregator to predict what
conditions will come next. Based on the historical data, the
aggregator can generate an operation that reflects a prediction of
what will happen with conditions, rate, or other circumstance, or a
combination of these.
[0203] In one embodiment the aggregator calculates an ability of
local energy generation to meet the power demand of local loads,
1512. In one embodiment, the power from the local energy source can
fully satisfy the local power demand, 1514 YES branch. If there is
not enough local power to satisfy local demand, 1514 NO branch, in
one embodiment, the system can determine if there is local energy
storage. Local energy storage can be determined in one embodiment
with local sensor data, and part of aggregation data. In one
embodiment, if there is not a local energy store, 1516 NO branch,
the system draws power from the grid, 1518. In one embodiment, if
there is a local energy store, 1516 YES branch, the system can draw
energy from the local energy store, assuming there is capacity in
the energy store, 1520. The energy drawn from the energy store or
the grid can be converted by a power converter to a mix of real and
reactive power to meet the local demand, 1524.
[0204] If there is enough local energy to satisfy demand, 1514 YES
branch, and there is not excess local power, 1522 NO branch, the
local power is converted by a power converter to a mix of real and
reactive power needed by the load(s), 1524. In one embodiment, if
there is excess local power after satisfying the demand of local
load(s), 1522 YES branch, the system can determine whether to store
the excess energy in a local energy store. In one embodiment,
depending on local conditions and grid conditions determined by the
aggregator, the system can charge the local energy store without
fully satisfying the local power demand. Thus, in one embodiment,
determining whether the demand is fully satisfied, 1514, can
include determining whether the full demand should be satisfied, or
whether the local energy is better used in other ways (e.g., charge
a local energy store with local power while drawing grid power for
a load.
[0205] If the system determines to charge a local energy store with
the local power, 1528 YES branch, the system charges the local
energy store, 1532. In one embodiment, if the system determines not
to charge the local energy store with the local power, 1528 NO
branch, the system can apply excess local power to the grid, 1530.
Applying the local power to the grid can include determining how to
provide the energy to the grid. In one embodiment, the system
applies the energy as real power. In one embodiment, the system
provides ancillary services to the grid.
[0206] FIG. 16 is a flow diagram of an embodiment of a process for
intelligent battery backup control. Process 1600 for intelligent
backup control can be performed by elements of a control node. In
one embodiment, the control node includes a gateway device, which
can be or include an aggregator, which can provide aggregation
data. The control node and the gateway device can be devices in
accordance with any embodiments described herein.
[0207] In one embodiment, a control node monitors one or more grid
conditions at a PCC, 1602. The grid conditions can include voltage
levels, phases, frequencies, or other conditions, or a combination.
In one embodiment, the control node monitors downstream power
demand and downstream power generation 1604. The downstream power
demand represents demand for power by one or more loads, which can
include other grid nodes further down a hierarchical grid network.
In one embodiment, the downstream power generation represents one
or more sources that generate energy. In one embodiment,
determining demand can include computing and/or identifying one or
more energy signatures.
[0208] In one embodiment, the control node computes aggregation
information via an aggregator associated with the control node,
1606. In one embodiment, the aggregator and control node can
identify local conditions, including a state of a battery or other
energy backup system, 1608. While battery is specifically
identified, it will be understood that the same descriptions will
apply equally well to another energy storage, which can include a
non-battery system. In one embodiment, if the state of the battery
is that its energy reserves are at least partially depleted, 1610,
in one embodiment, the control node can determine if there is local
energy supply to charge the battery. If there is local supply to
charge the battery, 1612 YES branch, in one embodiment, the control
node adjusts an interface within the PCC to apply the local energy
to charge the battery, 1614. If the battery is depleted and there
is no local energy supply, 1612 NO branch, in one embodiment, the
control node can determine to adjust an interface to charge the
battery from the grid, 1616. In one embodiment, if there is no
local supply of energy available, the control node will not charge
the battery unless certain conditions are met, such as time of day,
or if the battery is below a predetermined threshold of depletion,
or the cost of power from the grid is within a threshold cost, or
other condition, or a combination.
[0209] In one embodiment, the state of the battery is that there is
battery power available, 1618. In one embodiment, the control node
can determine how to use the battery power. If there is a local
demand for power, 1620 YES branch, in one embodiment, the control
node can adjust an interface to power the local load(s) from
available battery power, 1622. In one embodiment, if there is no
local demand, 1620 NO branch, but there is demand for power or
services at the control node, the control node can adjust an
interface to apply battery power to the grid, 1624. In one
embodiment, a state of the battery can be other than depleted to be
charged, and available to be used, such as depleted but not to be
charged yet, or available energy to be stored and not used yet,
then another condition can exist, and the control node can control
operation consistent with the other condition, 1626.
[0210] In one aspect, a method for interfacing with a power grid
network includes: receiving one or more external grid inputs and
one or more local sensor inputs at a meter on a consumer side of a
point of common coupling (PCC) to the grid network; identifying
power demand for a local load coupled to the consumer side of the
PCC; calculating an output power to generate with a local power
converter coupled to the consumer side of the PCC, based on the one
or more external grid inputs, the one or more local sensor inputs,
and the power demand for the local load; and outputting power from
the local power converter based on the calculated output power.
[0211] In one aspect, a consumer node in a grid network of a power
grid system includes: an energy meter on a consumer side of a point
of common coupling (PCC) to the grid network, the energy meter to
receive one or more external grid inputs and one or more local
sensor inputs, and to identify power demand for a local load
coupled to the consumer side of the PCC; a local power converter
coupled to the consumer side of the PCC, the power converter to
control an interface to the PCC to control power flow at the PCC;
and a gateway controller coupled to receive information from the
energy meter, to calculate a local output power to generate, based
on the one or more external grid inputs, the one or more local
sensor inputs, and the power demand for the local load, and to
request the power converter to output the calculated output
power.
[0212] In one aspect, a power grid system includes: a local energy
source coupled to a consumer side of a point of common coupling
(PCC) to a grid network of the power grid system, the local energy
source to generate real power; and a control node coupled to the
local energy source at the PCC, the control node including an
energy meter on a consumer side of a point of common coupling (PCC)
to the grid network, the energy meter to receive one or more
external grid inputs and one or more local sensor inputs, and to
identify power demand for a local load coupled to the consumer side
of the PCC; a local power converter coupled to the consumer side of
the PCC, the power converter to control an interface to the PCC to
control power flow at the PCC; and a gateway controller coupled to
receive information from the energy meter, to calculate a local
output power to generate, based on the one or more external grid
inputs, the one or more local sensor inputs, and the power demand
for the local load, and to request the power converter to output
the calculated output power, including generating power from the
local energy source.
[0213] For the method, the consumer node, and/or the power grid
system of the preceding three paragraphs, the following embodiments
provide examples of embodiments that can apply, and are
illustrative, but not limiting. In one embodiment, the grid network
comprises a utility power grid. In one embodiment, receiving the
external grid inputs comprises receiving one or more of dispatch
information from a central grid controller, specific control
signals from a grid controller, or grid condition information from
other nodes in the grid network. In one embodiment, receiving the
local sensor inputs comprises receiving one or more of temperature
information, or information regarding one or more conditions that
affect an ability of a local energy source to generate energy. In
one embodiment, calculating the output power comprises applying a
decision algorithm that applies weights to the inputs based on time
of day or time of year or both. In one embodiment, calculating the
output power comprises applying a heuristics decision algorithm to
search a best match output scenario. In one embodiment, outputting
power comprises outputting power for consumption by a local load.
In one embodiment, outputting power comprises outputting power to
charge a local energy storage resource. In one embodiment,
outputting power comprises outputting real power to a power grid
market for monetary credit. In one embodiment, outputting power
comprises outputting power to one or more ancillary services,
including real and/or reactive power grid support, frequency
support for the grid network, blackstart operation, regulation up
operation, regulation down operation, or a combination.
[0214] In one aspect, a method for interfacing with a power grid
network includes: monitoring local power demand and local energy
generation on a consumer side of a point of common coupling (PCC)
to the grid network; calculating an interface operation for a local
energy storage on the consumer side of the PCC, wherein the
interface operation includes accessing energy from the local energy
storage or charging the local energy storage, based on the local
power demand, and the local energy generation; and triggering a
local power converter coupled to the consumer side of the PCC to
execute the interface operation with the local energy storage.
[0215] In one aspect, a consumer node within a power grid system
includes: a local energy source on a consumer side of a point of
common coupling (PCC) to the grid network; a local energy store on
the consumer side of the PCC; an energy conversion device on the
consumer side of the PCC to execute an interface operation,
including accessing energy from the local energy store or charging
the local energy store, to transfer energy between the local energy
store and the PCC.
[0216] In one aspect, a power grid system includes: a local energy
source coupled to a consumer side of a point of common coupling
(PCC) to a grid network of a utility power grid, the local energy
source to generate real power; and a local energy store on the
consumer side of the PCC; a control node coupled to the local
energy source and the local energy store at the PCC, the control
node including a metering device to monitor a grid condition on the
consumer side of the PCC, wherein the grid condition indicates an
electrical condition of the grid network; an energy conversion
device to execute an interface operation, including accessing
energy from the local energy store or charging the local energy
store, to transfer energy between the local energy store and the
PCC in response to a condition of the utility power grid.
[0217] For the method, the consumer node, and/or the power grid
system of the preceding three paragraphs, the following embodiments
provide examples of embodiments that can apply, and are
illustrative, but not limiting. In one embodiment, the local energy
storage comprises a battery. In one embodiment, the local energy
storage comprises a non-battery energy storage system. In one
embodiment, further comprising monitoring a grid condition on the
consumer side of the PCC, wherein the grid condition indicates an
electrical condition of the grid network; and wherein calculating
the interface operation comprises generating an operation to charge
the local energy storage from the grid network. In one embodiment,
monitoring the grid condition comprises monitoring one or more of
voltage levels, phases, or frequencies, as seen at the PCC. In one
embodiment, monitoring the local energy generation comprises
monitoring an amount of power generated by a local source coupled
to the consumer side of the PCC that generates real power. In one
embodiment, calculating the interface operation comprises
generating an operation to charge the local energy storage from the
grid network. In one embodiment, calculating the interface
operation comprises generating an operation to charge the local
energy storage from a local energy source. In one embodiment,
calculating the interface operation comprises generating an
operation to power a local load from the local energy storage. In
one embodiment, triggering the power converter to execute the
interface operation comprises triggering the power converter to
generate a mix of real and reactive power. In one embodiment,
calculating the interface operation comprises generating an
operation to provide grid support from the local energy storage. In
one embodiment, calculating an interface operation further
comprises performing calculations based at least in part on
aggregation data, the aggregation data including one or more of
dispatch information from a central grid controller, specific
control signals from a grid controller, grid condition information
from other nodes in the grid network, local temperature
information, or information regarding one or more local conditions
that affect an amount of local energy generation.
[0218] In one aspect, a method for interfacing with a power grid
network includes: receiving multiple inputs at a meter on a
consumer side of a point of common coupling (PCC) to the grid
network, the inputs indicating an electrical condition of the grid
network and local operating conditions at the PCC; identifying
power demand for a local load coupled to the consumer side of the
PCC; calculating a mix of real and reactive power to output from a
local energy source, based on the multiple inputs and the power
demand for the local load; and outputting power from the local
energy source based on the calculated output power.
[0219] In one aspect, a consumer node in a grid network of a power
grid system includes: an energy meter on a consumer side of a point
of common coupling (PCC) to the grid network, the energy meter to
receive multiple inputs indicating an electrical condition of the
grid network and local operating conditions at the PCC, and to
identify power demand for a local load coupled to the consumer side
of the PCC; a local power converter coupled to the consumer side of
the PCC, the power converter to control an interface to the PCC to
control power flow at the PCC; and a gateway controller coupled to
receive information from the energy meter, to calculate a mix of
real and reactive power to output from a local energy source, based
on the multiple inputs and the power demand for the local load, and
to request the power converter to output the calculated output
power.
[0220] In one aspect, a power grid system includes: a grid
connector to couple a local consumer node to a utility power grid
at a consumer side of a point of common coupling (PCC); a local
energy source coupled on the consumer side of the PCC; and a
control node coupled to the local energy source at the PCC, the
control node including an energy meter on a consumer side of a
point of common coupling (PCC) to the grid network, the energy
meter to receive multiple inputs indicating an electrical condition
of the grid network and local operating conditions at the PCC, and
to identify power demand for a local load coupled to the consumer
side of the PCC; a local power converter coupled to the consumer
side of the PCC, the power converter to control an interface to the
PCC to control power flow at the PCC; and a gateway controller
coupled to receive information from the energy meter, to calculate
a mix of real and reactive power to output from the local energy
source, based on the multiple inputs and the power demand for the
local load, and to request the power converter to output the
calculated output power.
[0221] For the method, the consumer node, and/or the power grid
system of the preceding three paragraphs, the following embodiments
provide examples of embodiments that can apply, and are
illustrative, but not limiting. In one embodiment, the grid network
comprises a utility power grid. In one embodiment, receiving the
external grid inputs comprises receiving one or more of dispatch
information from a central grid controller, specific control
signals from a grid controller, or grid condition information from
other nodes in the grid network. In one embodiment, receiving the
local sensor inputs comprises receiving one or more of temperature
information, or information regarding one or more conditions that
affect an ability of a local energy source to generate energy. In
one embodiment, calculating the output power further comprises
calculating the mix of real and reactive power based at least in
part on rate information indicating a value of power generated. In
one embodiment, calculating the output power further comprises
calculating the mix of real and reactive power based at least in
part on extrapolating from historical information indicating a
history of how local power demand and local power generation has
occurred in the past. In one embodiment, outputting power comprises
outputting power for consumption by a local load. In one
embodiment, outputting power comprises outputting power to charge a
local energy storage resource. In one embodiment, outputting power
comprises outputting real power to a power grid market for monetary
credit. In one embodiment, outputting power comprises outputting
power to one or more ancillary services, including real and/or
reactive power grid support, frequency support for the grid
network, blackstart operation, regulation up operation, regulation
down operation, or a combination.
[0222] In one aspect, a method for interfacing with a power grid
network includes: receiving grid condition information at a meter
on a consumer side of a point of common coupling (PCC) to the grid
network, wherein the grid condition information includes an
aggregation of multiple inputs indicating an electrical condition
of the grid network and local operating conditions at the PCC,
including local power demand; accessing rate information for the
grid network, the rate information indicating a consumer power
price and a market power price; calculating an output power to
generate with a local power converter coupled to the consumer side
of the PCC, based on the multiple inputs, the local power demand,
and the rate information; and outputting power from the local power
converter based on the calculated output power.
[0223] In one aspect, a consumer node in a grid network of a power
grid system includes: an energy meter on a consumer side of a point
of common coupling (PCC) to the grid network, the energy meter to
receive grid condition information including an aggregation of
multiple inputs indicating an electrical condition of the grid
network and local operating conditions at the PCC, including local
power demand; a local power converter coupled to the consumer side
of the PCC, the power converter to control an interface to the PCC
to control power flow at the PCC; and a gateway controller coupled
to receive information from the energy meter, to calculate an
output power to generate with the local power converter, based on
the multiple inputs, the local power demand, and the rate
information, and to request the power converter to output the
calculated output power.
[0224] In one aspect, a power grid system includes: a grid
connector to couple a local consumer node to a utility power grid
at a consumer side of a point of common coupling (PCC) a local
energy source coupled on the consumer side of the PCC; and a
control node coupled to the local energy source at the PCC, the
control node including an energy meter on a consumer side of a
point of common coupling (PCC) to the grid network, the energy
meter to receive grid condition information including an
aggregation of multiple inputs indicating an electrical condition
of the grid network and local operating conditions at the PCC,
including local power demand; a local power converter coupled to
the consumer side of the PCC, the power converter to control an
interface to the PCC to control power flow at the PCC; and a
gateway controller coupled to receive information from the energy
meter, to calculate an output power to generate with the local
power converter including power from the local energy source, based
on the multiple inputs, the local power demand, and the rate
information, and to request the power converter to output the
calculated output power.
[0225] For the method, the consumer node, and/or the power grid
system of the preceding three paragraphs, the following embodiments
provide examples of embodiments that can apply, and are
illustrative, but not limiting. In one embodiment, receiving the
external grid inputs comprises receiving one or more of dispatch
information from a central grid controller, specific control
signals from a grid controller, or grid condition information from
other nodes in the grid network. In one embodiment, receiving the
local sensor inputs comprises receiving one or more of temperature
information, or information regarding one or more conditions that
affect an ability of a local energy source to generate energy. In
one embodiment, accessing the rate information comprises obtaining
rate information from a realtime market rate source. In one
embodiment, accessing the rate information comprises accessing rate
information indicating prices for consumer real power and for
market real power. In one embodiment, accessing the rate
information comprises accessing rate information indicating prices
for consumer reactive power and for ancillary markets. In one
embodiment, calculating the output power further comprises
performing forward prediction based on historical data monitored at
the meter. In one embodiment, calculating the output power
comprises determining operations to be performed by multiple power
converters coupled to the consumer side of the PCC. In one
embodiment, outputting power further comprises activating a local
energy storage for the calculated output power. In one embodiment,
outputting power comprises outputting power for consumption by a
local capacity. In one embodiment, outputting power comprises
outputting to a power grid market or to one or more ancillary
services, including real and/or reactive power grid support,
frequency support for the grid network, blackstart operation,
regulation up operation, regulation down operation, or a
combination.
[0226] In one aspect, a method for interfacing with a power grid
network includes: receiving grid condition information at a meter
on a consumer side of a point of common coupling (PCC) to the grid
network, wherein the grid condition information includes an
aggregation of multiple inputs indicating an electrical condition
of the grid network and local operating conditions at the PCC,
including local power demand; accessing operating history for a
local control node, the operating history including records of
previous power output for various grid conditions and operating
conditions at the PCC; calculating an output power to generate with
a local power converter coupled to the consumer side of the PCC,
based on the multiple inputs, the local power demand, and the
operating history; and outputting power from the local power
converter based on the calculated output power.
[0227] In one aspect, a consumer node in a grid network of a power
grid system includes: an energy meter on a consumer side of a point
of common coupling (PCC) to the grid network, the energy meter to
receive grid condition information including an aggregation of
multiple inputs indicating an electrical condition of the grid
network and local operating conditions at the PCC, including local
power demand; a local power converter coupled to the consumer side
of the PCC, the power converter to control an interface to the PCC
to control power flow at the PCC; a memory device to store
operating history for the consumer node including records of
previous power output for various grid conditions and operating
conditions at the PCC; and a gateway controller coupled to receive
information from the energy meter, to calculate an output power to
generate with the local power converter, based on the multiple
inputs, the local power demand, and the operating history, and to
request the power converter to output the calculated output
power.
[0228] In one aspect, a power grid system includes: a grid
connector to couple a local consumer node to a utility power grid
at a consumer side of a point of common coupling (PCC); a local
energy source coupled on the consumer side of the PCC; and a
control node coupled to the local energy source at the PCC, the
control node including an energy meter on a consumer side of a
point of common coupling (PCC) to the grid network, the energy
meter to receive grid condition information including an
aggregation of multiple inputs indicating an electrical condition
of the grid network and local operating conditions at the PCC,
including local power demand; a local power converter coupled to
the consumer side of the PCC, the power converter to control an
interface to the PCC to control power flow at the PCC; a memory
device to store operating history for the consumer node including
records of previous power output for various grid conditions and
operating conditions at the PCC; and a gateway controller coupled
to receive information from the energy meter, to calculate an
output power to generate with the local power converter including
from the local energy source, based on the multiple inputs, the
local power demand, and the operating history, and to request the
power converter to output the calculated output power.
[0229] For the method, the consumer node, and/or the power grid
system of the preceding three paragraphs, the following embodiments
provide examples of embodiments that can apply, and are
illustrative, but not limiting. In one embodiment, receiving the
external grid inputs comprises receiving one or more of dispatch
information from a central grid controller, specific control
signals from a grid controller, or grid condition information from
other nodes in the grid network. In one embodiment, receiving the
local sensor inputs comprises receiving one or more of temperature
information, or information regarding one or more conditions that
affect an ability of a local energy source to generate energy. In
one embodiment, accessing the operating history comprises accessing
operating conditions based on time of day. In one embodiment,
accessing the operating history comprises accessing operating
conditions based on time of year. In one embodiment, calculating
the output power further comprises accessing rate information
indicating prices for consumer real power, market real power,
consumer reactive power, and ancillary markets. In one embodiment,
accessing the operating history comprises accessing historical rate
information. In one embodiment, calculating the output power
comprises determining operations to be performed by multiple power
converters coupled to the consumer side of the PCC. In one
embodiment, outputting power further comprises activating a local
energy storage for the calculated output power. In one embodiment,
outputting power comprises outputting power for consumption by a
local capacity. In one embodiment, outputting power comprises
outputting to a power grid market or to one or more ancillary
services, including real and/or reactive power grid support,
frequency support for the grid network, blackstart operation,
regulation up operation, regulation down operation, or a
combination.
[0230] Flow diagrams as illustrated herein provide examples of
sequences of various process actions. The flow diagrams can
indicate operations to be executed by a software or firmware
routine, as well as physical operations. In one embodiment, a flow
diagram can illustrate the state of a finite state machine (FSM),
which can be implemented in hardware and/or software. Although
shown in a particular sequence or order, unless otherwise
specified, the order of the actions can be modified. Thus, the
illustrated embodiments should be understood only as an example,
and the process can be performed in a different order, and some
actions can be performed in parallel. Additionally, one or more
actions can be omitted in various embodiments; thus, not all
actions are required in every embodiment. Other process flows are
possible.
[0231] To the extent various operations or functions are described
herein, they can be described or defined as software code,
instructions, configuration, and/or data. The content can be
directly executable ("object" or "executable" form), source code,
or difference code ("delta" or "patch" code). The software content
of the embodiments described herein can be provided via an article
of manufacture with the content stored thereon, or via a method of
operating a communication interface to send data via the
communication interface. A machine readable storage medium can
cause a machine to perform the functions or operations described,
and includes any mechanism that stores information in a form
accessible by a machine (e.g., computing device, electronic system,
etc.), such as recordable/non-recordable media (e.g., read only
memory (ROM), random access memory (RAM), magnetic disk storage
media, optical storage media, flash memory devices, etc.). A
communication interface includes any mechanism that interfaces to
any of a hardwired, wireless, optical, etc., medium to communicate
to another device, such as a memory bus interface, a processor bus
interface, an Internet connection, a disk controller, etc. The
communication interface can be configured by providing
configuration parameters and/or sending signals to prepare the
communication interface to provide a data signal describing the
software content. The communication interface can be accessed via
one or more commands or signals sent to the communication
interface.
[0232] Various components described herein can be a means for
performing the operations or functions described. Each component
described herein includes software, hardware, or a combination of
these. The components can be implemented as software modules,
hardware modules, special-purpose hardware (e.g., application
specific hardware, application specific integrated circuits
(ASICs), digital signal processors (DSPs), etc.), embedded
controllers, hardwired circuitry, etc.
[0233] Besides what is described herein, various modifications can
be made to the disclosed embodiments and implementations of the
invention without departing from their scope. Therefore, the
illustrations and examples herein should be construed in an
illustrative, and not a restrictive sense. The scope of the
invention should be measured solely by reference to the claims that
follow.
* * * * *