U.S. patent application number 17/115117 was filed with the patent office on 2022-06-09 for high-efficiency modular uninterruptible power supply.
The applicant listed for this patent is SCHNEIDER ELECTRIC IT CORPORATION. Invention is credited to Michael J. Ingemi, Luka Petrovic.
Application Number | 20220181904 17/115117 |
Document ID | / |
Family ID | |
Filed Date | 2022-06-09 |
United States Patent
Application |
20220181904 |
Kind Code |
A1 |
Ingemi; Michael J. ; et
al. |
June 9, 2022 |
HIGH-EFFICIENCY MODULAR UNINTERRUPTIBLE POWER SUPPLY
Abstract
Examples of the disclosure include a power system comprising an
input to receive input power, an output to provide power to a load,
a sensor configured to provide load information indicative of power
drawn by the load, a plurality of power modules, each having a
power module input configured to be coupled to the input, and a
power module output configured to be coupled to the output, and a
controller coupled to the power modules and the sensor, and being
configured to control the power modules to provide power to the
output, receive the load information from the sensor, select, based
on the load information, at least one power module to maintain in
an active state to provide power to the output, and deactivate each
power module other than the at least one power module based on
selecting the at least one power module to maintain in the active
state.
Inventors: |
Ingemi; Michael J.;
(Norwood, MA) ; Petrovic; Luka; (North Billerica,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCHNEIDER ELECTRIC IT CORPORATION |
Foxboro |
MA |
US |
|
|
Appl. No.: |
17/115117 |
Filed: |
December 8, 2020 |
International
Class: |
H02J 9/06 20060101
H02J009/06; H02J 1/10 20060101 H02J001/10 |
Claims
1. A power system comprising: an input to receive input power; an
output to provide output power to a load; a sensor configured to
provide load information indicative of power drawn by the load; a
plurality of power modules, each power module of the plurality of
power modules having a power module input configured to be coupled
to the input, a power module output configured to be coupled to the
output, an AC/DC converter coupled to the power module input, a
DC/AC inverter coupled to the power module output, and a power bus
coupled to the AC/DC converter and the DC/AC inverter; and a system
controller coupled to the plurality of power modules and to the
sensor, the system controller being configured to: control the
plurality of power modules to provide power to the output; receive
the load information from the sensor; select, based on the load
information, at least one power module of the plurality of power
modules to maintain in an active state to provide power to the
output; and deactivate each power module of the plurality of power
modules other than the at least one power module based on selecting
the at least one power module to maintain in the active state,
wherein each power module is configured to control a respective
AC/DC converter to maintain the power bus at an active operating
voltage level while the respective power module is deactivated, the
DC/AC inverter being deactivated while the power module is
deactivated.
2. The power system of claim 1, wherein each power module of the
plurality of power modules includes: a module sensor configured to
determine module load information indicative of power provided at a
respective power module output; and a module controller configured
to receive the module load information from the module sensor.
3. The power system of claim 2, wherein each activated module
controller is configured to: detect, based on the module load
information, an overload condition; and provide an activation
signal to at least one other power module of the plurality of power
modules based on detecting the overload condition.
4. The power system of claim 3, wherein each activated module
controller is communicatively coupled to the system controller and
is configured to: receive, from the system controller, a
deactivation signal or an activation signal; control the respective
power module to continue providing module output power responsive
to receiving the activation signal; and control the respective
power module to deactivate and discontinue providing module output
power responsive to receiving the deactivation signal.
5. The power system of claim 4, wherein the system controller is
configured to: select a first group of one or more power modules to
maintain in an active state responsive to the overload condition;
provide the activation signal to each power module in the first
group of one or more power modules; select a second group of one or
more power modules to deactivate responsive to the overload
condition; and provide the deactivation signal to each power module
in the second group of one or more power modules.
6. The power system of claim 5, wherein selecting the first group
of one or more power modules to maintain in the active state
includes identifying a most efficient group of one or more power
modules to satisfy the overload condition.
7. The power system of claim 1, wherein the system controller is
configured to: detect, based on the load information, an overload
condition; and activate each deactivated power module of the
plurality of power modules to provide module output power based on
detecting the overload condition.
8. The power system of claim 7, wherein the system controller is
configured to: select a first group of one or more power modules to
maintain in an active state responsive to the overload condition;
provide the activation signal to each power module in the first
group of one or more power modules; select a second group of one or
more power modules to deactivate responsive to the overload
condition; and provide the deactivation signal to each power module
in the second group of one or more power modules.
9. The power system of claim 8, wherein selecting the first group
of one or more power modules to maintain in the active state
includes identifying a most efficient group of one or more power
modules to satisfy the overload condition.
10. The power system of claim 1, wherein deactivating each power
module includes sending a deactivation signal to each power
module.
11. The power system of claim 10, wherein each power module
includes a respective switch configured to control output
electrical power, and wherein each power module is configured to
deactivate the switch responsive to receiving the deactivation
signal.
12. The power system of claim 11, wherein each power module's DC/AC
inverter includes the respective switch.
13. (canceled)
14. A power module in a power system providing power to a load, the
power module comprising: a module input configured to receive input
power; a module output configured to provide output power to the
load; at least one module sensor configured to provide load
information indicative of the output power provided at the module
output; an AC/DC converter coupled to the module input; a DC/AC
inverter coupled to the module output; a power bus coupled to the
AC/DC converter and the DC/AC inverter; and a module controller
coupled to the at least one module sensor and configured to:
receive the load information from the at least one module sensor;
determine, based on the load information, that an overload
condition exists; provide, responsive to determining that the
overload condition exists, an activation signal to at least one
other power module instructing the at least one other power module
to provide output power to the load; determine that the power
module is to be deactivated; and deactivate the power module to
discontinue providing the output power to the module output,
wherein the power module is configured to control the AC/DC
converter to maintain the power bus at an active operating voltage
level while the power module is deactivated, the DC/AC inverter
being deactivated while the power module is deactivated.
15. The power module of claim 14, wherein determining that the
overload condition exists includes determining, based on the load
information, that a power rating of the load exceeds a power level
of power provided to the load.
16. The power module of claim 14, wherein the module controller is
further configured to: receive an activation signal from the at
least one other power module; and transition from deactive to
active responsive to receiving the activation signal from the at
least one other power module.
17. The power module of claim 14, wherein the module controller is
coupled to a system controller coupled to the at least one other
power module, and wherein determining that the power module is to
be deactivated includes receiving a deactivation signal from the
system controller.
18. The power module of claim 14, wherein the DC/AC inverter
includes at least one switching device to control the output power,
and wherein deactivating the power module includes deactivating the
at least one switch.
19. (canceled)
20. A non-transitory computer-readable medium storing thereon
sequences of computer-executable instructions for controlling a
power module having a module input configured to receive input
power, a module output configured to provide power to a load, at
least one load sensor configured to provide load information, an
AC/DC converter coupled to the module input, a DC/AC inverter
coupled to the module output, and a power bus coupled to the AC/DC
converter and the DC/AC inverter, the sequences of
computer-executable instructions including instructions that
instruct at least one processor to: control the power module to
provide power to the load; receive load information from the at
least one load sensor; determine, based on the load information,
whether an overload condition exists; provide, responsive to
determining that the overload condition exists, an activation
signal to at least one other power module instructing the at least
one other power module to provide output power to the load;
determine that the power module is to be deactivated; deactivate
the power module to discontinue providing the output power to the
module output, wherein deactivating the power module includes
controlling the AC/DC converter to maintain the power bus at an
active operating voltage level while the power module is
deactivated, and wherein the DC/AC inverter is deactivated while
the power module is deactivated.
21. The power system of claim 1, wherein each DC/AC inverter is
configured to: draw bus power from the power bus at the active
operating voltage; convert the bus power to the output power; and
provide the output power to the output.
22. The power module of claim 14, wherein the DC/AC inverter is
configured to: draw bus power from the power bus at the active
operating voltage; convert the bus power to the output power; and
provide the output power to the output.
Description
BACKGROUND
1. Field of the Disclosure
[0001] At least one example in accordance with the present
disclosure relates generally to increasing an efficiency of a power
device.
2. Discussion of Related Art
[0002] The use of power devices, such as Uninterruptible Power
Supplies (UPSs), to provide regulated, uninterrupted power for
sensitive and/or critical loads, such as computer systems and other
data processing systems, is known. Certain UPSs may be "modular,"
in that power modules may be added to or removed from the UPS to
increase or decrease a maximum power output of the UPS,
respectively.
SUMMARY
[0003] According to at least one aspect of the present disclosure,
a power system is provided comprising an input to receive input
power, an output to provide output power to a load, a sensor
configured to provide load information indicative of power drawn by
the load, a plurality of power modules, each power module of the
plurality of power modules having a power module input configured
to be coupled to the input, and a power module output configured to
be coupled to the output, and a system controller coupled to the
plurality of power modules and to the sensor, the system controller
being configured to control the plurality of power modules to
provide power to the output, receive the load information from the
sensor, select, based on the load information, at least one power
module of the plurality of power modules to maintain in an active
state to provide power to the output, and deactivate each power
module of the plurality of power modules other than the at least
one power module based on selecting the at least one power module
to maintain in the active state.
[0004] In various examples, each power module of the plurality of
power modules includes a module sensor configured to determine
module load information indicative of power provided at a
respective power module output, and a module controller configured
to receive the module load information from the module sensor. In
some examples, each activated module controller is configured to
detect, based on the module load information, an overload
condition, and provide an activation signal to at least one other
power module of the plurality of power modules based on detecting
the overload condition. In at least one example, each activated
module controller is communicatively coupled to the system
controller and is configured to receive, from the system
controller, a deactivation signal or an activation signal, control
the respective power module to continue providing module output
power responsive to receiving the activation signal, and control
the respective power module to deactivate and discontinue providing
module output power responsive to receiving the deactivation
signal.
[0005] In various examples, the system controller is configured to
select a first group of one or more power modules to maintain in an
active state responsive to the overload condition, provide the
activation signal to each power module in the first group of one or
more power modules, select a second group of one or more power
modules to deactivate responsive to the overload condition, and
provide the deactivation signal to each power module in the second
group of one or more power modules. In some examples, selecting the
first group of one or more power modules to maintain in the active
state includes identifying a most efficient group of one or more
power modules to satisfy the overload condition. In at least one
example, the system controller is configured to detect, based on
the load information, an overload condition, activate each
deactivated power module of the plurality of power modules to
provide module output power based on detecting the overload
condition.
[0006] In various examples, the system controller is configured to
select a first group of one or more power modules to maintain in an
active state responsive to the overload condition, provide the
activation signal to each power module in the first group of one or
more power modules, select a second group of one or more power
modules to deactivate responsive to the overload condition, and
provide the deactivation signal to each power module in the second
group of one or more power modules. In some examples, selecting the
first group of one or more power modules to maintain in the active
state includes identifying a most efficient group of one or more
power modules to satisfy the overload condition. In at least one
example, deactivating each power module includes sending a
deactivation signal to each power module.
[0007] In various examples, each power module includes a respective
switch configured to control output electrical power, and each
power module is configured to deactivate the switch responsive to
receiving the deactivation signal. In some examples, each power
module includes an inverter including the respective switch. In at
least one example, each power module includes a power bus coupled
to the inverter, and each power module is configured to maintain
the power bus at an active operating voltage level while
deactivated.
[0008] According to at least one example of the disclosure, a power
module in a power system providing power to a load is provided, the
power module comprising a module input configured to receive input
power, a module output configured to provide output power to the
load, at least one module sensor configured to provide load
information indicative of the output power provided at the module
output, and a module controller coupled to the at least one module
sensor and configured to receive the load information from the at
least one module sensor, determine, based on the load information,
that an overload condition exists, provide, responsive to
determining that the overload condition exists, an activation
signal to at least one other power module instructing the at least
one other power module to provide output power to the load,
determine that the power module is to be deactivated, and
deactivate the power module to discontinue providing the output
power to the module output.
[0009] In various examples, determining that the overload condition
includes determining, based on the load information, that a power
rating of the load exceeds a power level of power provided to the
load. In some examples, the module controller is further configured
to receive an activation signal from the at least one other power
module, and transition from deactive to active responsive to
receiving the activation signal from the at least one other power
module. In at least one example, the module controller is coupled
to a system controller coupled to the at least one other power
module, and wherein determining that the power module is to be
deactivated includes receiving a deactivation signal from the
system controller.
[0010] In various examples, the power module further comprises an
inverter including at least one switching device to control the
output power, and deactivating the power module includes
deactivating the at least one switch. In some examples, the power
module further comprises a power bus between the module input and
the inverter, and the power module is configured to maintain the
power bus at an active operating voltage level while
deactivated.
[0011] According to at least one example, a non-transitory
computer-readable medium storing thereon sequences of
computer-executable instructions for controlling a plurality of
power modules is provided, the sequences of computer-executable
instructions including instructions that instruct at least one
processor to control the plurality of power modules to provide
power to the output, receive load information indicative of a power
drawn by a load from a load sensor, select, based on the load
information, at least one power module of the plurality of power
modules to maintain in an active state to provide power to the
output, and deactivate each power module of the plurality of power
modules other than the at least one power module based on selecting
the at least one power module to maintain in the active state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Various aspects of at least one embodiment are discussed
below with reference to the accompanying figures, which are not
intended to be drawn to scale. The figures are included to provide
an illustration and a further understanding of the various aspects
and embodiments, and are incorporated in and constitute a part of
this specification, but are not intended as a definition of the
limits of any particular embodiment. The drawings, together with
the remainder of the specification, serve to explain principles and
operations of the described and claimed aspects and embodiments. In
the figures, each identical or nearly identical component that is
illustrated in various figures is represented by a like numeral.
For purposes of clarity, not every component may be labeled in
every figure. In the figures:
[0013] FIG. 1 illustrates a block diagram of a power system
according to an example;
[0014] FIG. 2 illustrates a block diagram of a power module
according to an example;
[0015] FIG. 3 illustrates a process of controlling a power system
according to an example; and
[0016] FIG. 4 illustrates a process of controlling a power system
according to another example.
DETAILED DESCRIPTION
[0017] Examples of the methods and systems discussed herein are not
limited in application to the details of construction and the
arrangement of components set forth in the following description or
illustrated in the accompanying drawings. The methods and systems
are capable of implementation in other embodiments and of being
practiced or of being carried out in various ways. Examples of
specific implementations are provided herein for illustrative
purposes only and are not intended to be limiting. In particular,
acts, components, elements and features discussed in connection
with any one or more examples are not intended to be excluded from
a similar role in any other examples.
[0018] Also, the phraseology and terminology used herein is for the
purpose of description and should not be regarded as limiting. Any
references to examples, embodiments, components, elements or acts
of the systems and methods herein referred to in the singular may
also embrace embodiments including a plurality, and any references
in plural to any embodiment, component, element or act herein may
also embrace embodiments including only a singularity. References
in the singular or plural form are not intended to limit the
presently disclosed systems or methods, their components, acts, or
elements. The use herein of "including," "comprising," "having,"
"containing," "involving," and variations thereof is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items.
[0019] References to "or" may be construed as inclusive so that any
terms described using "or" may indicate any of a single, more than
one, and all of the described terms. In addition, in the event of
inconsistent usages of terms between this document and documents
incorporated herein by reference, the term usage in the
incorporated features is supplementary to that of this document;
for irreconcilable differences, the term usage in this document
controls.
[0020] As discussed above, uninterruptible power supplies (UPSs)
are capable of providing uninterrupted power to certain loads. A
modular UPS may include a configurable number of power modules,
which may be added to or removed from the UPS to increase or
decrease a maximum power output of the UPS, respectively. Each
power module may have a respective power output rating, and a total
power output rating of the modular UPS may be determined based on
the sum of the active power modules' power output ratings. For
example, a modular UPS having two active power modules, each having
a respective power rating of 5 kW, may have an output power rating
of approximately 10 kW, which is the sum of the modules' power
ratings.
[0021] A power module may not operate at maximum capacity at all
times. For example, a power module having a power rating of 5 kW
may provide output power of any magnitude between 0 kW and 5 kW
throughout the power module's lifecycle. In some examples, however,
a power module may be restricted to operate within a certain range
of power, such as within 20% to 95% of the power module's power
rating. In this example, a power module having a power rating of 5
kW would therefore be restricted to outputting power between 1 kW
and 4.75 kW. In other examples, any other range of power output
values may be implemented, including 0% and 100% of a power
module's power rating.
[0022] An efficiency of a power module may vary based on an output
power of the power module compared to the power module's output
power rating. For example, a 5 kW power module providing 1 kW of
output power (thus operating at 20% of a rated output power) may
operate less efficiently than when the power module provides 3.25
kW of output power (thus operating at 65% of a rated output power).
Each power module may be associated with power module efficiency
information indicating a corresponding efficiency for each level of
output power, where a peak efficiency may be achieved at an output
power value between a minimum output power value (for example, 20%
of a rated output power) and a maximum output power value (for
example, 95% of a rated output power) for some power modules. In
some examples, the power module efficiency information may be
stored as computer-readable information such that an electrical
device having access to the information is capable of determining
an efficiency of the power based on a load on the power module.
[0023] In a modular UPS having multiple power modules, it may be
possible to satisfy a load demand with multiple different
combinations of active power modules. For example, consider a
modular UPS having three power modules, each rated at 5 kW, the
modular UPS being connected to a load demanding 3 kW of power. In
one example, all three of the power modules could provide 1 kW of
output power each to satisfy the load's demand for a total of 3 kW
of output power. In another example, two of the power modules could
provide 1.5 kW of output power each to satisfy the load's demand
for a total of 3 kW of output power, and the third power module
could provide no output power. In yet another example, a single one
of the power modules could provide 3 kW of output power to satisfy
the load's demand for 3 kW of output power, and the remaining two
power modules could provide no output power. In other examples,
other combinations of power modules could be implemented with each
power module providing an amount of output power that may be the
same or different than that provided by other modules.
[0024] The efficiencies of the power modules in each of these
examples may differ from one another. For example, a power module
operating at one load (for example, 20% of a rated load) may have
an efficiency that differs from an efficiency of the power module
at a second load (for example, 50% of a rated load). Furthermore,
electrical losses of the power module while the power module is
active (for example, total active and reactive losses) may differ
from electrical losses of the power module while the power module
is not active. Accordingly, it may be advantageous to identify a
most efficient combination of power modules to satisfy a load's
demand such that a total efficiency of a modular UPS system may be
maximized.
[0025] Examples are provided for increasing an efficiency of a
modular UPS by selectively activating power modules in a UPS. Load
information is determined by a system controller, and/or a module
controller in one or more power modules to identify output power
requirements of a load. A determination is made by the system
controller as to which combination of power modules can most
efficiently satisfy the output power requirements. The identified
combination of power modules is instructed by the system controller
to maintain an active state in which output power is provided to
the load. The remaining power modules are instructed to enter a
deactivated state in which the power modules do not provide output
power to a load. For example, a deactivated power module may
deactivate its inverter such that the output of the power module is
disconnected from a power source of the power module.
[0026] The output power requirements of the load may change over
time. The system and/or module controllers may repeatedly
re-evaluate whether a wake-up condition is met, which may be based
on the output power requirements. The wake-up condition may be that
the output power requirements exceed the power rating of the
combination of activated power modules, for example, or that the
output power requirements have changed above a threshold amount. If
the wake-up condition is met, every power module that was not
already active (that is, the deactivated power modules) may be
activated by the system and/or module controllers to provide output
power to the load. The system controller again determines a
combination of power modules that can most efficiently satisfy the
output power requirements of the load, and deactivates the
remaining power modules.
[0027] Current modular power systems, such as modular
uninterruptible power supplies, may maintain all power modules
therein in an active state at all, or substantially all, times that
the modular power system is active. Such modular power systems may
operate inefficiently, because each power module may not be
operating at or near its peak efficiency and one or more power
modules may be unnecessarily active. This is a technical problem.
An exemplary embodiment of a modular power system may comprise an
input to receive input power, an output to provide output power to
a load, a sensor configured to provide load information indicative
of power drawn by the load, a plurality of power modules, each
power module of the plurality of power modules having a power
module input configured to be coupled to the input, and a power
module output configured to be coupled to the output, and a system
controller coupled to the plurality of power modules and to the
sensor. In some examples, the system controller is configured to
control the plurality of power modules to provide power to the
output, receive the load information from the sensor, select, based
on the load information, at least one power module of the plurality
of power modules to maintain in an active state to provide power to
the output, and deactivate each power module of the plurality of
power modules other than the at least one power module based on
selecting the at least one power module to maintain in the active
state. At least this foregoing combination of features comprises a
modular power system that serves as a technical solution to the
foregoing technical problem. This technical solution is not routine
and is unconventional. This technical solution is a practical
application of the power system design that solves the foregoing
technical problem and constitutes an improvement in the technical
field of power supply design at least by increasing an efficiency
of a power supply system.
[0028] FIG. 1 illustrates a block diagram of a power system 100
according to an example. In some examples, the power system 100, or
components thereof, may be or include a UPS, such as a modular UPS.
The power system 100 includes a power input 102, one or more energy
storage devices 104, an arbitrary number of power modules 106, an
output 108, a system controller 110, and one or more system sensors
112. In some examples, the one or more energy storage devices 104
may not be external to, but may be electrically and communicatively
coupled to, the power system 100. In one example, the power system
100 may be coupled to a load 114 via the output 108. The system
controller 110 includes a storage 116 capable of storing
computer-readable information. In some examples, the storage 116
may be internal to the system controller 110, whereas in other
examples, the storage 116 may be partially or entirely external to
the system controller 110, and may further be partially or entirely
internal or external to the power system 100, albeit
communicatively coupled to the system controller 110.
[0029] The power input 102 is coupled to each of the power modules
106, and is configured to be coupled to a power source (not
illustrated). For example, the power input 102 may be coupled to a
utility mains power supply, which may be an AC power supply. In
other examples, the power input 102 may be connected to a DC power
supply. The energy storage devices 104 are coupled to the power
modules 106, and are communicatively coupled to the system
controller 110. As discussed above, the one or more energy storage
devices 104 may be external to the power system 100, but may be
electrically coupled to the power modules 106 and communicatively
coupled to the system controller 110. The power modules 106 are
coupled to the power input 102, the energy storage devices 104, and
the output 108, and are communicatively coupled to the system
controller 110. In some examples, the power modules 106 are
communicatively connected to each other. The output 108 is coupled
to the power modules 106 and is configured to be coupled to the
load 114.
[0030] The system controller 110 is communicatively coupled to the
energy storage devices 104, the power modules 106, and the system
sensors 112. The system sensors 112 are communicatively coupled to
the system controller 110, and may be coupled to one or more
additional components. For example, the system sensors 112 may
include one or more temperature, voltage, current, and/or power
sensors configured to sense temperature, voltage, current, and/or
power information at any of the components 102-108, including load
information at the output 108 indicative of output power drawn by
the load 114 and/or power requirements of the load 114. The load
114 is configured to be coupled to the power system 100 via the
output 108. The storage 116 is configured to be communicatively
coupled to the system controller 110, and may store
computer-readable information such as load information, power
module efficiency information, and so forth.
[0031] The system controller 110 may control the power system 100
to operate in one of at least two modes of operation, including a
normal mode of operation and a backup mode of operation, based on
information received from the system sensors 112. For example, the
system sensors 112 may sense input power information (for example,
voltage and/or current information) indicative of input power
received at the power input 102 and provide the input power
information to the system controller 110, and/or may sense a
temperature value indicative of an ambient temperature in or near
one or more components of the power system 100 and provide the
temperature information to the system controller 110. If the system
controller 110 determines that the input power is acceptable (for
example, by having a voltage level within a range of acceptable
voltage levels), then the system controller 110 may control the
power system 100 to be in the normal mode of operation. Otherwise,
if the system controller 110 determines that the input power is not
acceptable, then the system controller 110 may control the power
system 100 to be in the backup mode of operation.
[0032] In the normal mode of operation, power received at the power
input 102 is distributed to the power modules 106. As discussed in
greater detail below, some or all of the power modules 106 may be
in an active mode of operation. In the active mode of operation, a
power module conditions the power received from the power input 102
and provides output power to the output 108. A power module may
also provide power to the energy storage devices 104 to charge the
energy storage devices 104 during the normal mode of operation.
[0033] In the backup mode of operation, power stored in the energy
storage devices 104 is distributed to the power modules 106. Power
modules in the active mode of operation may condition the power
received from the energy storage devices 104 and provide output
power to the output 108.
[0034] In both the normal and backup mode of operation, the output
108 may receive power from the power modules 106 and provide the
power to the load 114. In some examples, the output 108 may include
or be connected to one or more power distribution units (PDUs) to
distribute power to one or more loads. For example, the load 114
may include multiple different loads, or the load 114 may be one of
several loads receiving power from the output 108.
[0035] As discussed above, in some examples, some of the power
modules 106 may be active and some of the power modules 106 may be
inactive. In the active mode, a power module provides output power
to the output 108. For example, the output power may be derived
from input power received from one or both of the power input 102
or the energy storage devices 104. In the inactive mode, a power
module does not provide output power to the output 108. As used
herein, a "deactivated power module," "inactive power module," or a
power module that has been "deactivated" or "inactivated" refers to
a power module that is not providing output power to the output
108. However, even in the inactive mode, a power module may still
receive power from the power input 102 and/or may provide or
receive power to or from the energy storage devices 104.
Furthermore, certain components of a deactivated power module may
remain operational including, for example, a module controller of
the power module, a rectifier of the module, and/or a DC/DC
converter of the module, as discussed in greater detail below.
[0036] FIG. 2 illustrates a block diagram of a power module 106
according to an example. The power module 106 may be an example of
any of the power modules 106 of FIG. 1. The power module 106
includes a module input 202, a rectifier 204, a DC bus 206, an
inverter 208, a module output 210, a DC/DC converter 212, an energy
storage device power interface 214, a module controller 216, and
one or more module sensors 218. The rectifier 204 includes one or
more rectifier switches 220, the inverter 208 includes one or more
inverter switches 222, and the DC/DC converter 212 includes one or
more converter switches 224. The DC bus 206 includes one or more
bus capacitors 226.
[0037] The module input 202 is coupled to the rectifier 204, and is
configured to be coupled to the power input 102. The rectifier 204
is coupled to the module input 202 and the DC bus 206. The DC bus
206 is coupled to the rectifier 204, the inverter 208, and the
DC/DC converter 212. The inverter 208 is coupled to the DC bus 206
and to the module output 210. The module output 210 is coupled to
the inverter 208 and the output 108. The DC/DC converter 212 is
coupled to the DC bus 206 and to the energy storage device power
interface 214. The energy storage device power interface 214 is
coupled to the DC/DC converter 212, and is configured to be coupled
to the energy storage devices 104. The module controller 216 is
communicatively coupled to the module sensors 218 and to the
switches 220-224. In some examples, the module controller 216 may
further be communicatively coupled to the system controller 110
and/or to one or more other module controllers of one or more other
power modules 106. The module sensors 218 are communicatively
coupled to the module controller 216, and may be coupled to one or
more additional components. For example, the module sensors 218 may
include one or more temperature, voltage, current, and/or power
sensors configured to sense temperature, voltage, current, and/or
power information at any of the components 202-214, including load
information at the module output 210 indicative of output power
provided at the module output 210, power requirements of the load
114, and/or a voltage at the module output 210. The rectifier
switches 204 are communicatively coupled to the module controller
216. The inverter switches 222 are communicatively coupled to the
module controller 216. The converter switches 224 are
communicatively coupled to the module controller 216.
[0038] In the normal mode of operation of the power system 100, the
power module 106 is configured to receive input power from the
power input 102 at the module input 202. In one example, the input
power is AC power. The rectifier 204 is configured to rectify the
AC power to DC power. For example, the module controller 216 may
control the rectifier switches 220 to rectify the AC power to DC
power. The DC power is provided to the DC bus 206.
[0039] The DC bus 206 conducts DC power to the inverter 208 and/or
DC/DC converter 212, and to the bus capacitors 226. The bus
capacitors 226 receive the DC power to maintain the DC bus 206 at a
desired voltage level, which may be referred to herein as an
"active operating voltage level." As understood by those of
ordinary skill, it may be advantageous to maintain a DC bus from
which an inverter receives electrical power at a certain voltage
level for the inverter to convert power received therefrom to AC
power.
[0040] DC power received from the rectifier 204 may be provided to
the inverter 208 and/or the DC/DC converter 212. For example, if
the power module 106 is in an active mode of operation in which the
inverter 208 inverts DC power to AC power and provides the AC power
to the module output 210, then the module controller 216 may
control the inverter switches 222 such that the inverter 208
receives and inverts DC power stored by the bus capacitors 226 from
the DC bus 206. However, in examples in which the bus capacitors
226 are maintained at the active operating voltage level even when
the inverter 208 is not inverting power, the power module 106 may
be able to quickly respond to a change in operation in which the
inverter 208 does begin inverting power, because the voltage level
on the DC bus 206 is already maintained at the active operating
voltage level by the bus capacitors 226. Thus, the bus capacitors
226 need not be recharged from a discharged state, where such
recharging may otherwise take a longer amount of time than if the
bus capacitors 226 are already charged. The module controller 216
may therefore control the inverter 208 to provide output power to
the output 108 via the module output 210 when the power module 106
is in the active mode of operation, where the power module 106 is
able to quickly respond to a transition from a deactive to active
mode of operation.
[0041] The module controller 216 may alternately or additionally
control the converter switches 224 such that the DC/DC converter
212 receives and converts DC power from the DC bus 206, and
provides the converted power to the energy storage device power
interface 214. For example, the DC/DC converter 212 may provide DC
power to the energy storage device power interface 214 to charge
one or more of the energy storage devices 104 connected thereto. In
some examples, the DC/DC converter 212 may charge the energy
storage devices 104 when the power module 106 is in either the
active or inactive mode of operation. For example, the energy
storage devices 104 may include one or more batteries, capacitors,
flywheels, or other rechargeable energy storage devices capable of
being recharged via the DC/DC converter 212.
[0042] In the backup mode of operation of the power system 100, the
power module 106 does not receive power at the module input 202.
The power module 106 may receive DC power from the energy storage
devices 104 at the energy storage device power interface 214. Power
received from the energy storage device power interface 214 is
provided to the DC/DC converter 212. The module controller 216 may
control the converter switches 224 to convert power received from
the energy storage device power interface 214 to DC power of a
different voltage level, and provide the converted power to the DC
bus 206. The DC bus 206 may conduct the received power to the
inverter 208 and/or the bus capacitors 226. As discussed above, if
the power module 106 is in an active mode of operation, then the
module controller 216 may control the inverter switches 222 to draw
power via the DC bus 206 and provide inverted output power to the
module output 210. Otherwise, the inverter 208 may not draw any
appreciable power from the DC bus 206 if the power module 106 is in
the deactive mode of operation.
[0043] Accordingly, the power system 100 may operate at least in a
normal mode of operation or a backup mode of operation. In the
normal and/or the backup modes of operation, each power module 106
may be in either an active mode or a deactive mode. For power
modules in an active mode, power received from the power input 102
and/or the energy storage devices 104 (depending on whether the
power system 100 is in a normal or backup mode of operation) may be
provided to the output 108 via the module output 210 of a
respective power module 106. Otherwise, if a power module 106 is in
an inactive mode, the power module 106 may not provide power to the
module output 210 and, consequently, the output 108. However, even
in the inactive mode, components of the power module 106 may remain
operational, including one or more of the rectifier 204, the DCDC
converter 212, the module controller 216, and/or the module sensors
218. The module controller 216 may control the power module 106 to
draw power from the power input 102 and/or the energy storage
devices 104 to maintain the bus capacitors 226 at an active
operating voltage level, such that the power module 106 is able to
quickly respond to an instruction to provide output power. For
example, the module controller 216 may control the rectifier 204 to
draw power from the module input 202 and/or may control the DC/DC
converter 212 to draw power from, or provide power to, the energy
storage device power interface 214. Furthermore, a deactivated
power module may monitor load information at a respective module
output 210.
[0044] Operation of the power system 100 will now be discussed with
respect to FIGS. 3 and 4. FIG. 3 illustrates a process 300 of
operating the power system 100 according to an example. The process
300 may be executed in connection with one or more components of
the power system 100, including the system controller 110. FIG. 4
illustrates a process 400 of operating the power system 100
according to another example. The process 400 may be executed in
connection with one or more components of the power system 100,
including a respective module controller 216 of one or more of the
power modules 106. In some examples, the processes 300, 400 may
both be executed by the power system 100, including by executing
the processes 300, 400 simultaneously.
[0045] At act 302, the process 300 begins. For example, the process
300 may begin at a system start-up of the power system 100, or at
another time thereafter. As discussed in greater detail below, acts
of the process 300 may be executed repeatedly and, in some
examples, indefinitely.
[0046] At act 304, the system controller 110 controls one or more
of the power modules 106 to provide power to the output 108. The
system controller 110 may control fewer than all of the power
modules 106 to provide power to the output 108, or may control all
of the power modules 106 to provide power to the output 108. For
example, the system controller 110 may control all of the power
modules 106 to provide power to the output 108 when the process 300
and act 304 are first executed before a more efficient subset of
the power modules 106 is identified, in examples in which such a
subset is identified, as discussed in greater detail below.
[0047] Controlling the one or more of the power modules 106 to
provide power to the output 108 may include sending an activation
signal from the system controller 110 to each of the one or more
power modules 106 to provide power (also referred to herein as
"activating" the one or more power modules 106). The activation
signal may be sent from the system controller 110 to a respective
module controller 216. The module controller 216, in turn, may
control the respective components of the power module 106 to
provide power to the module output 210, such as by controlling the
switches 220-224 to provide power to the module output 210.
Controlling the switches 220-224 to provide power to the module
output 210 may include controlling the inverter switches 222 to
draw DC power from the bus capacitors 226, invert the DC power to
AC power, and provide the AC power to the module output 210. In
other examples, act 304 may include the system controller 110
directly controlling the components of the power module 106,
including the inverter switches 222, to provide power to the module
output 210.
[0048] At act 306, the system controller 110 monitors the load 114.
For example, the system controller 110 may monitor the load 114 to
determine load information indicative of a power drawn by the load
114 at the output 108, and power requirements of the load 114. The
system controller 110 may determine the load information based on
information sensed by the system sensors 112, including information
sensed at the output 108. For example, the system sensors 112 may
include one or more current or voltage sensors configured to sense
a current and/or voltage at the output 108, and/or at an output of
each of the power modules 106. The system sensors 112 may provide
the load information to the system controller 110. In other
examples, the power module 106 may provide the load information to
the system controller 110, where a respective module controller 216
of a power module 106 may obtain module load information by polling
the module sensors 218, and send the module load information to the
system controller 110.
[0049] At act 308, the system controller 110 determines whether
additional power modules should be activated. For example, the
system controller 110 may determine that additional power modules
should be activated where an "overload condition" is detected. An
overload condition may be detected where the output power
requirements of the load 114 increase beyond the output power
capacity of the power modules 106 that are controlled to provide
output power at act 304. Such an overload condition may be
indicated by certain electrical parameters (for example, an output
current, voltage, and/or power) falling outside of an acceptable
range or ranges of values, such as a sub-cycle disturbance in
output power provided to the load 114, or an amount of current
provided to the load 114 being greater than a rated maximum output
current of the power modules 106, or another example of a
disturbance in electrical parameters. It may be desirable to
activate additional power modules to meet the output power
requirements if an overload condition is detected. In other
examples, the system controller 110 may determine that an overload
condition exists even if the power modules 106 that are controlled
to provide output power at act 304 are capable of meeting the
increased output power requirements of the load 114. For example,
the system controller 110 may detect an overload condition in such
a scenario where the system controller 110 determines that
activating additional power modules would nonetheless be desirable
because activating additional power modules would increase an
efficiency of the power system 100.
[0050] If the system controller 110 determines that additional
power modules 106 should not be activated (308 NO), then the
process 300 returns to act 306. The system controller 110 resumes
monitoring the load 114, and acts 306 and 308 are repeated until a
determination is made that additional power modules 106 should be
activated. For example, if the system controller 110 detects an
overload condition and determines that additional power modules 106
should be activated (308 YES), then the process 300 continues to
act 310.
[0051] At act 310, the system controller 110 activates any of the
power modules 106 that are deactivated. Deactivated power modules
may include those of the power modules 106 that are not controlled
to provide output power to the output 108 at act 304. Activating
the power modules 106 at act 310 may be similar to act 304. For
example, the system controller 110 may send an activation signal to
each of the power modules 106 that is deactivated, and a
corresponding module controller 216 may control the power module
106 to provide output power to the output 108 responsive to
receiving the activation signal. Once each of the power modules 106
has been activated, the power modules 106 collectively provide
power to the output 108 at a first efficiency.
[0052] At act 312, the system controller 110 selects at least one
power module of the power modules 106 to maintain in an active
state based on the load information received at act 306. The at
least one power module will provide power to the output 108 at a
second efficiency, which may be different than the first efficiency
if the at least one power module includes fewer than all of the
power modules 106. In various examples, the system controller 110
may select the at least one module such that the at least one
module is capable of meeting the output power requirements of the
load, and such that the second efficiency is greater than the first
efficiency. In some examples, therefore, the system controller 110
determines a most efficient group of the power modules 106 capable
of meeting output power requirements, or at least determines a
group of power modules 106 capable of meeting the output power
requirements with a greater efficiency than if all of the power
modules 106 were maintained in an active state.
[0053] In some examples, the system controller 110 may access
stored efficiency information indicative of an efficiency of each
of the power modules 106. For example, the efficiency information
may be accessibly stored in the storage 116. The efficiency
information may indicate a power efficiency of the power module 106
against a load on the power module 106. For example, the efficiency
information may indicate a first efficiency where the power module
106 is providing 25% of a rated load, a second efficiency where the
power module 106 is providing 50% of a rated load, a third
efficiency where the power module 106 is providing 75% of a rated
load, and so forth. Act 312 may include using the efficiency
information to determine a most efficient group of the power
modules 106 that is capable of satisfying the output load
requirements. For example, the system controller 110 may determine
that the output power requirements of the load 114 could be
satisfied by four of the power modules 106 operating at 45% of a
rated load, three of the power modules 106 operating at 60% of a
rated load, or two of the power modules 106 operating at 90% of a
rated load. The system controller 110 may then use the efficiency
information to determine which number and combination of the power
modules 106 is most appropriate, and select these power modules to
remain active at act 312.
[0054] At act 314, the system controller 110 deactivates those of
the power modules 106 that are not remaining active. Deactivating
the power modules 106 may include sending, by the system controller
110, a deactivation signal to each of the power modules 106 not
remaining active, or may include de-asserting an activation signal
that the system controller 110 previously sent to the power modules
106. The power modules 106 discontinue providing output power to
the output 108 responsive to receiving the deactivation signal. A
respective module controller 216 may receive the deactivation
signal and, in response thereto, control components thereof, such
as the switches 220-224, to discontinue providing power to the
module output 210. For example, the module controller 216 may
control the inverter switches 222 to discontinue providing output
power at the module output 210 (also referred to herein as
"deactivating the inverter 208"), which may include controlling one
or more of the inverter switches 222 to be in an open and
non-conducting position, such that the DC bus 206 is electrically
disconnected form the module output 210. In other examples,
deactivating the power modules 106 may include the system
controller 110 directly controlling components of the power modules
106, such as one or more of the switches 220-224, to discontinue
providing output power at the module output 210. In various
examples, certain components of the power module 106, including the
module controller 216 and the sensors 218, remain operational even
where the power module 106 is in a deactive mode.
[0055] The process 300 then returns to act 304. At act 304, the
system controller 110 controls those of the power modules 106
selected to remain active at act 312 to provide output power at the
output 108. Those of the power modules 106 that are deactivated may
not be controlled to provide output power at the output 108, such
as by deactivating the inverter 208 thereof. However, those of the
power modules 106 that are deactivated may be controlled to perform
certain operations, such as monitoring module load information at
the module output 210 using the module sensors 218. A respective
module controller 216 of a deactivated power module may also
control the power module to draw power from the module input 202 or
the energy storage device power interface 214 to maintain the bus
capacitors 226 at an active operating voltage level, as discussed
above.
[0056] A respective module controller 216 of a deactivated power
module may also control the power module to provide a charging
current to the energy storage devices 104 via the energy storage
device power interface 214. For example, the module controller 216
may control the switches 220, 224 to draw AC power from the module
input 202, rectify the AC power to DC power, provide the DC power
to the DC bus 206, draw the DC power from the DC bus, convert the
DC power to converted DC power, and provide the converted DC power
to the energy storage device 104 via the energy storage device
power interface 214. In other examples, a deactivated power module
may not provide output power via the energy storage device power
interface 214.
[0057] Turning to FIG. 4, at act 402, the process 400 begins. For
example, the process 400 may begin at a system start-up of the
power system 100, or at another time thereafter. As discussed in
greater detail below, acts of the process 400 may be executed
repeatedly and, in some examples, indefinitely.
[0058] At act 404, the system controller 110 controls one or more
of the power modules 106 to provide power to the output 108. Act
404 may be substantially similar to act 304. The system controller
110 may control fewer than all of the power modules 106 to provide
power to the output 108, or may control all of the power modules
106 to provide power to the output 108. For example, the system
controller 110 may control all of the power modules 106 to provide
power to the output 108 when the process 400 and act 404 are first
executed before a more efficient subset of the power modules 106 is
identified, if such a subset is so identified, as discussed in
greater detail below. Controlling the one or more of the power
modules 106 to provide power to the output 108 may include the
system controller 110 sending an activation signal to each of the
one or more power modules 106 (also referred to herein as
"activating" the one or more power modules 106), similar to act
304.
[0059] At act 406, one or more module controllers 216 of respective
power modules 106 monitor a respective module output 210, and the
system controller 110 monitors the load 114. The system controller
110 may monitor the load 114 in a manner similar to the manner
discussed above with respect to act 306. A module controller 216
may similarly monitor the load 114 by determining module load
information indicative of output power provided at the module
output 210 (including, for example, voltage and/or current
information), and determining power requirements of the load 114.
In another example, module load information may include information
indicative of power drawn by the load 114 where power may or may
not be provided at the module output 210. The module controller 216
may determine the module load information based on information
sensed by the module sensors 218, including information sensed at
the module output 210. For example, the module sensors 218 may
include one or more current or voltage sensors configured to sense
a current and/or voltage at the module output 210. The module
sensors 218 provide the module load information to the module
controller 216. In some examples, each module controller 216 may be
communicatively coupled to one or more sensors, such as the system
sensors 112, configured to determine load information indicative of
a power drawn at the output 108 in addition to the module sensors
218. Accordingly, each module controller 216 may determine load
information indicative of a power drawn at a respective module
output 210 and/or at the output 108 of the power system 100.
[0060] In some examples, a respective module controller 216 of each
of the power modules 106 monitors a respective module output 210 at
act 406. In other examples, only module controllers 216
corresponding to active power modules 106 monitor a respective
module output 210. In other examples, only module controllers 216
corresponding to deactivated power modules 106 monitor a respective
module output 210. In other examples, a combination of module
controllers 216 corresponding to active and deactivated power
modules 106 monitor a respective module output 210. In various
examples, load information determined by a module controller 216
may vary based on whether the module controller 216 corresponds to
an active power module 106. For example, if the module controller
216 corresponds to an inactive power module 106 having an inactive
inverter 208, the module sensors 218 may provide voltage
information indicative of a voltage at the module output 210 to the
module controller 216, but the module sensors 218 may not provide
output current information to the module controller 216. In another
example, if the module controller 216 corresponds to an active
power module 106 having an active inverter 208, the module sensors
218 may provide voltage information indicative of a voltage at the
module output 210 and current information indicative of a current
provided by the inverter 208 to the module controller 216. In other
examples, the module controller 216 may determine other load
information or no load information based on a mode of
operation.
[0061] At act 408, each module controller 216 monitoring the load
114 determines whether additional power modules should be
activated. If an overload condition is determined to exist by a
respective module controller 216, then the module controller 216
may determine that additional power modules should be activated. As
discussed above, an overload condition may be detected where the
output power requirements of the load 114 increase beyond the
output power capacity of the power modules 106 that are providing
output power, for example, or where activating additional power
modules 106 would be desirable even if the increased output power
requirements are capable of being met by the currently active power
modules 106. In one example, detecting an overload condition may
include the module controller 216 determining, based on current
information received from the module sensors 218, that an output
current provided by the inverter 208 is outside of a range of
acceptable current values (for example, indicating an overcurrent
condition). In another example, detecting the overload condition
may include the module controller 216 determining, based on voltage
information received from the module sensors 218, that an output
voltage provided at the output 108 is outside of a range of
acceptable voltage values (for example, indicating a voltage sag
condition). In another example, detecting the overload condition
may include the module controller 216 determining, based on power
information received from the module sensors 218 (including, for
example, current and/or voltage information), that an output
voltage provided at the output 108 is outside of a range of
acceptable voltage values (for example, indicating a voltage sag
condition).
[0062] If the module controller 216 monitoring the load 114
determines that additional power modules 106 should not be
activated (408 NO), then the process 400 returns to act 406. The
module controller 216 continues monitoring the load 114, and acts
406 and 408 are repeated until a determination is made that
additional power modules 106 should be activated. For example, if
the module controller 216 detects an overload condition and
determines that additional power modules 106 should be activated
(408 YES), then the process 400 continues to act 410.
[0063] At act 410, each active module controller 216 that
determines that additional power modules 106 should be activated
(408 YES) activates any of the power modules 106 that are
deactivated. Deactivated power modules may include those of the
power modules 106 that are not controlled to provide output power
at the output 108 at act 404. In some examples, activating the
deactivated power modules 106 may include sending, by each active
module controller 216, an activation signal to all other power
modules 106, or a subset of the power modules 106, such as those of
the power modules 106 that are deactivated. For example, the signal
sent to the system controller 110 may include a request or
instruction for the system controller 110 to send an activation
signal to all of the power modules 106, or those of the power
modules 106 that are deactivated. In other examples, each module
controller 216 of a deactivated power module 106 may activate
itself at act 410, and may or may not send an activation signal to
the other power modules 106. Once each of the power modules 106 has
been activated, the power modules 106 collectively provide power to
the output 108 at a first efficiency.
[0064] At act 412, the system controller 110 selects at least one
power module of the power modules 106 to maintain in an active
state based on the load information received at act 406. Act 412
may be substantially similar to act 312. As discussed above,
selecting the at least one power module may include selecting fewer
than all of the power modules 106 to provide output power to the
output 108 at an efficiency greater than if all of the power
modules 106 were to provide output power to the output 108.
[0065] At act 414, the system controller 110 deactivates those of
the power modules 106 that are not remaining active. Deactivating
the power modules 106 may include sending, by the system controller
110, a deactivation signal to each of the power modules 106 not
remaining active, or may include de-asserting an activation signal
that the system controller 110 sent to the power modules 106 at act
310. The power modules 106 discontinue providing output power to
the output 108 responsive to receiving the deactivation signal. A
respective module controller 216 may receive the deactivation
signal and, in response thereto, control components thereof, such
as the switches 220-224, to discontinue providing power to the
module output 210. For example, the module controller 216 may
control the inverter switches 222 to discontinue providing output
power at the module output 210 (also referred to herein as
"deactivating the inverter 208"), which may include controlling one
or more of the inverter switches 222 to be in an open and
non-conducting position such that the DC bus 206 is electrically
disconnected from the module output 210. In other examples,
deactivating the power modules 106 may include the system
controller 110 directly controlling components of the power modules
106, such as one or more of the switches 220-224, to discontinue
providing output power at the module output 210.
[0066] The process 400 then returns to act 404. At act 404, the
system controller 110 controls those of the power modules 106
selected to remain active at act 412 to provide output power at the
output 108. Act 404 is substantially similar to act 304.
[0067] Accordingly, the processes 300, 400 may be executed to
select a group of one or more of the power modules 106 to maintain
in an active state in which power is provided to the output 108.
Remaining power modules may be deactivated such that power is not
provided to the output 108. Providing power to the output 108 with
fewer than all of the power modules 106 may increase an efficiency
of the power system 100 as compared to providing power to the
output 108 with all of the power modules 106.
[0068] If power requirements of the load 114 change after selecting
the group of one or more of the power modules 106 to maintain in an
active state (for example, increase), additional power modules may
be activated. In the process 300, the system controller 110
monitors power information (including, for example, current and
voltage information) with the system sensors 112 to determine if
additional power modules should be activated. In the process 400, a
respective module controller 216 of one or more of the power
modules 106 monitors load information with the module sensors 218
and/or the system sensors 112 to determine if additional power
modules should be activated. In some examples, the power system 100
may execute only one of the processes 300, 400 at one time. In
other examples, the power system 100 may execute both of the
processes 300, 400 simultaneously, alternately, or some combination
thereof.
[0069] As discussed above in connection with acts 308 and 408, a
determination may be made by the system controller 110 and/or a
module controller 216 as to whether to activate additional power
modules. In some examples, including examples provided above,
additional power modules may be activated responsive to determining
that the output power requirements of the load 114 exceed an output
power capacity of the currently active power modules 106. In other
examples, additional power modules may be activated responsive to
other conditions in addition to, or in lieu of, determining that
the output power requirements of the load 114 exceed an output
power capacity of the currently active power modules 106. Such
conditions may be referred to herein as "wake-up conditions," and
may include the output power requirements of the load 114 exceeding
an output power capacity of the currently active power modules
106.
[0070] Other wake-up conditions may include the output power
requirements of the load 114 changing by more than a threshold
amount after the group of the power modules 106 to provide power to
the load 114 is selected. The threshold amount may be a relative
value (for example, a 10% change in output power requirements) or
an absolute value (for example, a 500 W change in output power
requirements). Multiple thresholds may be implemented. For example,
a wake-up condition may be satisfied if the output power
requirements of the load 114 increase by more than a first
threshold amount or decrease more than a second threshold amount,
which may be different than the first threshold amount.
[0071] Other wake-up conditions may include a threshold amount of
time having elapsed since the group of the power modules 106 to
provide power to the load 114 was selected. The threshold amount of
time may vary based on a number of the power modules 106 that are
active.
[0072] Other wake-up conditions may be based in part on power
received at the power input 102. For example, if power at the power
input 102 becomes acceptable after being unacceptable, or becomes
unacceptable after being acceptable, the wake-up condition may be
satisfied. In another example, a wake-up condition may be based on
anomalies in the power received at the power input 102 including,
for example, certain power transient conditions.
[0073] Other wake-up conditions may be based in part on power
stored in the energy storage devices 104. For example, a wake-up
condition may be satisfied if the power system 100 is operating in
a back-up mode of operation and one or more of the energy storage
devices 104 becomes depleted of stored energy. In another example,
a wake-up condition may be satisfied if the power system 100 is
operating in a normal mode of operation and is charging the energy
storage devices 104, and one or more of the energy storage devices
104 becomes fully charged.
[0074] Other wake-up conditions may be based on a status condition
of the power system 100. For example, a wake-up condition may be
satisfied if any anomalies or error conditions are detected. Such
error conditions may include, for example, a component failure, a
parameter (for example, temperature) falling outside or inside a
range of values, and so forth.
[0075] In various examples, other wake-up conditions may be
implemented. Furthermore, one or more of the foregoing wake-up
conditions may be implemented in combination with one another.
Accordingly, no limitation is implied by the example wake-up
conditions identified above.
[0076] As discussed above, the system controller 110 may identify a
group of one or more of the power modules 106 to maintain in an
active mode of operation. In some examples, the system controller
110 identifies a group of one or more of the power modules 106 that
provides power to the output 108 at a highest efficiency. For
example, the system controller 110 may determine, based on stored
efficiency information, an efficiency of the power system 100 for
every combination of the power modules 106 being in an active state
and select the most efficient group of the power modules 106.
[0077] In other examples, the system controller 110 may select the
group of the power modules 106 to maintain in an active state based
on one or more additional or alternate parameters. For example, the
system controller 110 may consider a temperature of one or more
components of the power system 100 in selecting the group of the
power modules 106 to maintain in an active state. In one example,
the system controller 110 may select a highest-efficiency group of
the power modules 106 where components of the power system 100 are
within a first range of temperature values, but may select a
different group of the power modules 106 that does not provide a
highest efficiency where components of the power system 100 are
within a second range of temperature values. If the power system
100 is too hot, for example, it may be undesirable to prioritize
efficiency over other concerns. Furthermore, in various examples,
the system controller 110 may have access to stored efficiency
information for the power modules 106 indicating an
efficiency-versus-load for various temperature values (for example,
stored in the storage 116), such that the system controller 110 may
determine an efficiency of each of the power modules 106 operating
at a certain load and at a certain temperature.
[0078] In another example, the system controller 110 may select a
group of the power modules 106 to maintain in an active state based
on additional parameters. For example, the system controller 110
may determine that maintaining a first group of the power modules
106 in an active state is more efficient than maintaining a second
group of the power modules 106 in an active state. The system
controller 110 may nonetheless maintain the second group of the
power modules 106 in the active state rather than the first group
based on considerations other than, or in addition to, efficiency.
For example, the first and second group may each include two power
modules, but the modules of the first group of power modules may
have consumed more of their operating lifetimes than those of the
second group. The system controller 110 may select the second group
to maintain in an active state, such that the operating lifetimes
of the first and second groups are balanced. In this example,
however, if the efficiency of the first group exceeds the
efficiency of the second group by more than a certain amount, the
system controller 110 may nonetheless select the first group to
maintain in an active state if efficiency concerns outweigh an
interest in balancing operating lifetimes. It is to be appreciated
that other examples are within the scope of the disclosure, and
that efficiency-increasing concerns or interests may be balanced
with other benefits.
[0079] In some examples, the power system 100 may be configured to
receive AC power from the power input 102. However, in other
examples, the power system 100 may be configured to receive DC
power. One or more of the power modules 106 may be configured to
receive DC power at a respective module input 202 in addition to,
or in lieu of, AC power. In these examples, the rectifier 204 may
be replaced by a component configured to receive and/or filter DC
power from the module input 202 (for example, a DC/DC converter),
and provide output power to the DC bus 206. In other examples, the
rectifier 204 may be removed without being replaced, such that the
module input 202 is coupled directly to the DC bus 206. Similarly,
the inverter 208 may be removed and may be replaced by a different
component, such as a DC/DC converter, a switching device, or a
similar component. In still other examples, the rectifier 204
and/or the inverter 208 may be replaced or supplemented by
components configured to operate in connection with either DC or AC
power, such that the power module 106 is capable of receiving
either AC or DC power at the module input 202, and is capable of
outputting either AC or DC power at the module output 210. In some
examples, the power system 100 may be configured to receive AC
power at the power input 102, but may be configured to provide DC
power, rather than AC power, at the module output 210. In these
examples, the inverter 208 may be replaced by an alternate
component configured to output DC power. Accordingly, it is to be
appreciated that the principles of the disclosure are not limited
to any particular type of input or output power.
[0080] In some examples, a range of permissible loads for each of
the power modules 106 may vary based on the load 114. For example,
the power modules 106 may be capable of operating between 20% and
95% of a rated load where the load 114 is a first type of load (for
example, a non-critical load). However, the power modules 106 may
be capable of operating only between 20% and 75% of a rated load
where the load 114 is a second type of load (for example, a
critical load). Different loads may be categorized into various
categories, each of which may be restricted to a specified range of
a rated load. In some examples, each of the power modules 106 may
have a different permissible range. For example, one or more of the
power modules 106 may be of a different type, or have a different
rating, than others of the power modules 106.
[0081] As discussed above, deactivating a power module 106 may
include controlling, by a respective module controller 216,
respective inverter switches 222 to be in an open and
non-conducting position such that the DC bus 206 and the bus
capacitors 226 are electrically disconnected from the module output
210. In various examples, the rectifier 204 and/or the DC/DC
converter 212 may remain operational while the power module 106 is
deactivated such that the bus capacitors 226 remain at an active
operating voltage. In some examples, the rectifier 204 and/or the
DC/DC converter 212 may not remain operational while the power
module 106 is deactivated. Whether the rectifier 204 and/or the
DC/DC converter 212 remain operational may depend on a type or
operating requirements of the load 114. For example, if the load
114 is less sensitive to interruptions in power provision, the
rectifier 204 and/or the DC/DC converter 212 may not maintain the
bus capacitors 226 at an active operating voltage in some examples.
Conversely, if the load 114 is sensitive to interruptions in power
provision, the bus capacitors 226 may be maintained at an active
operating voltage such that the power module 106 is capable of
quickly transitioning to providing output power via the inverter
208.
[0082] Although certain examples may be implemented in connection
with modular uninterruptible power supplies, it is to be
appreciated that other examples may be implemented in connection
with other devices. In some examples, principles of the disclosure
may be practiced in connection with a non-modular power device
having a fixed number of power-conditioning components in lieu of
the power modules 106. In another example, principles of the
disclosure may be implemented to select a most efficient group of
components other than power modules to maintain in an active state,
such as one or more energy storage devices capable of being
selectively activated or deactivated to discharge stored energy. In
some examples, principles of the disclosure may be implemented in
connection with a device other than an uninterruptible power
supply.
[0083] Accordingly, examples discussed herein enable an efficiency
of a modular UPS to be increased by selectively activating power
modules in a UPS. Load information is determined by a system
controller and/or a module controller in one or more power modules
to identify output power requirements of a load. A determination
may be made by the system controller as to which combination of
power modules can most efficiently satisfy the output power
requirements. The identified combination of power modules may be
instructed by the system controller to maintain an active state in
which output power is provided to the load. The remaining power
modules may be instructed to enter a deactivated state in which the
power modules do not provide output power to a load. For example, a
deactivated power module may deactivate its inverter such that the
output of the power module is disconnected from a power source of
the power module.
[0084] The output power requirements of the load may change over
time. The system and/or module controllers may repeatedly
re-evaluate whether a wake-up condition is met, which may be based
on the output power requirements. The wake-up condition may be that
the output power requirements exceed the power rating of the
combination of activated power modules, for example, or that the
output power requirements have changed above a threshold amount. If
the wake-up condition is met, power modules that were not already
active (that is, the deactivated power modules) may be activated by
the system and/or module controllers to provide output power to the
load. The system controller again determines a combination of power
modules that can most efficiently satisfy the output power
requirements of the load, and deactivates the remaining power
modules.
[0085] Having thus described several aspects of at least one
embodiment, it is to be appreciated various alterations,
modifications, and improvements will readily occur to those skilled
in the art. Such alterations, modifications, and improvements are
intended to be part of, and within the spirit and scope of, this
disclosure. Accordingly, the foregoing description and drawings are
by way of example only.
* * * * *