U.S. patent application number 13/081245 was filed with the patent office on 2011-07-28 for system and method for load control.
This patent application is currently assigned to Hammerhead International, LLC. Invention is credited to Joseph W. Hodges, Richard J. Hodges, Thomas D. Lasky, J. Anthony Sopuch.
Application Number | 20110181114 13/081245 |
Document ID | / |
Family ID | 40562771 |
Filed Date | 2011-07-28 |
United States Patent
Application |
20110181114 |
Kind Code |
A1 |
Hodges; Joseph W. ; et
al. |
July 28, 2011 |
System and Method for Load Control
Abstract
A system is described including a master power saving device
configured for connection with a master load. The master power
saving device is configured to determine when the master load is in
an operating condition and a non-operating condition, and the
master power saving device provides non-continuous power to the
master load when the master load is in a non-operating condition. A
slave power saving device is configured for connection with a slave
load. The slave power saving device is configured to receive a
signal from the master power saving device to turn off said slave
load.
Inventors: |
Hodges; Joseph W.;
(Bloomfield Hills, MI) ; Sopuch; J. Anthony;
(Sylvan Lake, MI) ; Hodges; Richard J.; (Plymouth,
MI) ; Lasky; Thomas D.; (Bloomfield Hills,
MI) |
Assignee: |
Hammerhead International,
LLC
Bloomfield Hills
MI
|
Family ID: |
40562771 |
Appl. No.: |
13/081245 |
Filed: |
April 6, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11875554 |
Oct 19, 2007 |
7800251 |
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13081245 |
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|
12494155 |
Jun 29, 2009 |
7944086 |
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11875554 |
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60980987 |
Oct 18, 2007 |
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Current U.S.
Class: |
307/39 |
Current CPC
Class: |
Y04S 20/20 20130101;
Y02B 70/30 20130101; H02J 9/005 20130101; H02H 3/12 20130101 |
Class at
Publication: |
307/39 |
International
Class: |
H02J 3/14 20060101
H02J003/14 |
Claims
1. A system comprising: a master power saving device configured for
connection with a master load, said master power saving device
configured to determine when said master load is in an operating
condition and a non-operating condition based on said load demand
of the master load, and wherein said master power saving device
provides non-continuous power to said master load when said master
load is in a non-operating condition; and a slave power saving
device configured for connection with a slave load, said slave
power saving device configured to receive a signal from said master
power saving device to turn off said slave load.
2. The system of claim 1, wherein said master power saving device
communicates with said slave power saving device using power line
communication.
3. The system of claim 1, wherein said master power saving device
communicates with said slave power saving device using wireless
communication.
4. The system of claim 1, wherein said slave power saving device is
further configured to receive a signal from said master power
saving device to turn on said slave load.
5. The system of claim 1, wherein said slave power saving device is
further configured to determine when said slave load is in an
operating condition and a non-operating condition, and wherein said
slave power saving device provides non-continuous power to said
slave load when said slave load is in a non-operating
condition.
6. The system of claim 1, wherein said load demand comprises at
least one of electrical current and power.
7. The system of claim 1, wherein said slave power saving device is
paired with said master power saving device to receive said
signal.
8. The system of claim 1, further comprising a plurality of slave
power saving devices configured to receive said signal from said
master power saving device.
9. A system comprising: a sensor configured to determine whether a
human is in the area of the sensor, said sensor providing a signal
when a human is determined to be in the area; and a power saving
device configured to receive said signal, said power saving device
configured for connection with a load, said power saving device
configured to determine when said load is in an operating condition
and a non-operating condition based on a load demand, and wherein
said power saving device provides non-continuous power to said load
when said load is in a non-operating condition, and wherein said
power saving device employs a first power saving strategy when said
signal is received and a second power saving strategy when said
signal is not received.
10. The system of claim 9, wherein said sensor comprises a motion
sensor.
11. The system of claim 9, wherein said first power saving strategy
comprises pulsing power to said load.
12. The system of claim 9, wherein said second power saving
strategy comprises removing power from said load.
13. The system of claim 9, wherein said first power saving strategy
comprises pulsing power having a first period to said load.
14. The system of claim 13, wherein said second power saving
strategy comprises pulsing power having a second period to said
load.
15. The system of claim 14, wherein said second period is longer
than said first period.
16. A method for controlling an electrical load: providing power to
a load for a predetermined time; measuring a load demand;
determining whether the load is turned on by said measured load
demand; and repeating said steps of providing, measuring, and
determining, wherein with each repetition said predetermined time
is extended to a longer predetermined time until said load is
determined to be on.
17. The method of claim 16, wherein said step of determining said
load demand further comprises: comparing said load demand with a
predetermined threshold.
18. The method of claim 16, further comprising: removing power to
said load for a second predetermined time after the step of
measuring.
19. The method of claim 18, further comprising: instructing said
load to turn on during said providing and determining.
20. The method of claim 19, further comprising: storing said
predetermined time used when the load is determined to be on.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a Continuation and claims priority to
U.S. patent application Ser. No. 12/494,155 filed on Jun. 29, 2009.
This application is a Continuation in Part of U.S. patent
application Ser. No. 11/875,554, filed on Oct. 19, 2007, titled
"SYSTEM AND METHOD FOR LOAD CONTROL" which in turn claims priority
to U.S. Provisional Patent Application No. 60/980,987 filed on Oct.
18, 2007, titled "SYSTEM AND METHOD FOR LOAD CONTROL", to Joseph W.
Hodges et al., all of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] The embodiments described herein are generally directed to
control of an electrical load.
BACKGROUND
[0003] Many electrical devices that utilize a plug-in power source
(e.g., household power connection) consume energy while switched
off and not in use. This is primarily due to a transformer or power
supply that remains connected to the power source even during
periods of inactivity. One common method of powering these
electrical devices includes a step-down transformer with a
regulator. Common examples of such devices include mobile phone
chargers, VCRs, televisions, stereos, computers, and kitchen
appliances.
[0004] The devices that remain powered waste energy through their
transformers and/or power supplies that remain connected to the
power source. Such power loss is commonly referred to as a phantom
power load because the power consumption does not serve a purpose.
The electrical device or appliance is typically in a standby state
or otherwise inactive when drawing current and is not serving a
useful function. In aggregate, a large number of phantom loads
contribute to a significant portion of essentially wasted
power.
[0005] One method of preventing a phantom load is to physically
unplug an appliance from the electrical outlet when it is not in
use. This completely disconnects the appliance from the power
source and eliminates phantom loading. However, the user then must
manually plug in the load when load-use is desired and then unplug
the load when use is no longer desired. Such ongoing plugging-in
and unplugging may be a time consuming task as well as increase
wear and tear on the electrical outlet, plug, and wiring to the
load.
[0006] Consequently, there is a need to reduce the amount of power
consumption from loads that are not in use to reduce energy waste.
More generally, there is a need to selectively control a load based
on the behavior of the load itself.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The features and inventive aspects will become more apparent
upon reading the following detailed description, claims, and
drawings, of which the following is a brief description:
[0008] FIG. 1 is a block diagram of an energy saving device.
[0009] FIG. 2 is a schematic of an example of the energy saving
device of FIG. 1.
[0010] FIG. 3 is a state transition diagram for use with the energy
saving device of FIG. 2.
[0011] FIG. 4 is a histogram classification graph for determining
active and inactive states of the load of FIGS. 1 and 2.
[0012] FIG. 5 is a timing diagram for activation of the load of
FIGS. 1 and 2.
[0013] FIG. 6 is a timing diagram for sensing and switching on the
load of FIGS. 1 and 2.
[0014] FIG. 7 is a current vs. time chart of load sensing when the
load is active.
[0015] FIG. 8 is a current vs. time chart of load sensing when the
load is inactive.
[0016] FIG. 9 is an example of a wall outlet alternative energy
saving device.
[0017] FIG. 10 is an example of a power strip including energy
saving features.
[0018] FIG. 11 is an example of a state transition diagram for use
with the energy saving devices described herein.
[0019] FIG. 11A is an example of a timing diagram for an adaptive
power savings system for use with the energy savings devices
described herein.
[0020] FIG. 11B is an example of the power applied to the load in
an energy saving mode and a full power mode.
[0021] FIG. 12 is an example of a state transition diagram for use
with the energy saving devices described herein.
[0022] FIG. 12A is an example of a clipped energy saving mode and a
full power mode.
[0023] FIG. 13 is an example of power pulsing as applied to the
example of FIG. 11.
[0024] FIG. 14 is an example of cycle skipping that may be employed
with the example of FIG. 12.
[0025] FIG. 15 is an example of cycle clipping that may be employed
during a clipped energy saving mode.
[0026] FIG. 15A is an example of a portion of an AC sine wave that
has been clipped.
[0027] FIG. 16 is an example of an energy savings system 1600 that
communicates with and controls other loads.
[0028] FIG. 17 is an example of a timing diagram for the energy
saving device of FIG. 16.
[0029] FIG. 18 is an example of a human-in-area detection system
for use with the energy savings devices described herein.
[0030] FIG. 19A is a partial schematic of a power supply subsystem
for use with the power saving device.
[0031] FIG. 19B is a partial schematic of a load switch subsystem
for use with the power saving device.
[0032] FIG. 19C is a partial schematic of a logic subsystem for use
with the power saving device.
[0033] FIG. 19D is a partial schematic of a load current
measurement subsystem for use with the power saving device.
[0034] FIG. 20 is an example of a power measurement.
[0035] FIG. 21 is an example of an inrush waveform.
[0036] FIG. 22 is an example of a soft start waveform in comparison
with an inrush waveform.
[0037] FIG. 23A is an example of a typical AC power supply
waveform.
[0038] FIG. 23B is an example of gradual clipping of an AC power
supply waveform to achieve a soft start.
DETAILED DESCRIPTION
[0039] Referring now to the drawings, illustrative embodiments are
shown in detail. Although the drawings represent the embodiments,
the drawings are not necessarily to scale and certain features may
be exaggerated to better illustrate and explain novel aspects of an
embodiment. Further, the embodiments described herein are not
intended to be exhaustive or otherwise limit or restrict the claims
to the precise form and configuration shown in the drawings and
disclosed in the following detailed description.
[0040] This application is a Continuation in Part of U.S. patent
application Ser. No. 11/875,554, filed on Oct. 19, 2007, titled
"SYSTEM AND METHOD FOR LOAD CONTROL" which in turn claims priority
to U.S. Provisional Patent Application No. 60/980,987 filed on Oct.
18, 2007, titled "SYSTEM AND METHOD FOR LOAD CONTROL", to Joseph W.
Hodges et al., all of which are incorporated herein by
reference.
[0041] An example of a device including a system and method of load
control may be an energy saving device that removes power to a load
when the load is not performing a useful function. In this way,
phantom load power is reduced. When the load is performing a useful
function, power is supplied normally until a phantom load is
detected, at which time the load is disconnected from the power
source. One example of such a load is a household appliance that
may not serve a useful purpose when a user does not require it to
function, for example a television or a phone charger. When a
television is not turned on, it is still drawing a phantom load
current to power the internal transformer and/or power supply
circuitry. However, the energy saving device discussed herein would
interrupt the television's power input when the television is not
in use. This interruption of the power input substantially
eliminates the phantom load because the transformer or power supply
electronics of the television are substantially un-powered and not
drawing current.
[0042] An example of an energy saving device may include a
measurement means, a switch means, and a logic means. The
measurement means may be configured to detect current or power
flowing to a load from a power source. The switch means may
selectively connect and disconnect the load from the power source.
The logic means determines when to connect and disconnect the load
from the power source. In one example, the logic means determines
whether the load is "active" or "inactive" depending upon the
current or power consumption as read by the measurement means.
[0043] The logic means determines the state of the load by
measuring the current that the load consumes. To make a
determination whether the load is "active" or "inactive", the logic
means compares the current the load is consuming to a threshold.
The threshold may be predetermined value or it may be determined
after the energy saving device is connected to the load (e.g.,
using a learning mode to define and/or characterize the load power
usage). When the energy saving device uses a modifiable threshold,
the value may be tuned for each load connected thereto. Such an
adaptive system may be used where a large number of different loads
could be connected to a single type of energy saving device. For
example, household appliances may consume a wide variety of power
in the "active" and "inactive" states depending upon the particular
appliance (e.g., a television, a radio, a phone charger) and/or
circuit design used therein. The energy saving device may then
adapt to the attached load.
[0044] Each load may have a preferred threshold that the logic
means uses to determine "active" and "inactive" states. This
threshold may be determined by the energy saving device for each
load connected to it and thus, an adaptable system may be used to
allow for a variety of loads to be switched by a single variety of
energy saving devices. One method of adaptive learning of the
threshold includes recording current usage over a predetermined
time (e.g., 24 hours). In the learning mode, the load is maintained
in a fully powered state so that the logic means can record the
power usage. When the predetermined learning time has elapsed, a
threshold can be set between the minimum and maximum currents
recorded during the learning mode. If no variation or minimal
variation is noted in the recoded current measurement data, then a
default threshold may be used.
[0045] Once the threshold is saved, the energy saving device logic
means momentarily turns the load on to measure the current
consumption. The logic means then compares the current consumption
with the threshold. If the current consumption is greater than the
threshold, the logic means deems the load in the "active" state and
maintains power to the load. If the current consumption is less
than the threshold, the logic means deems the load in the
"inactive" state and power to the load is switched off. If the load
is in the inactive state, the logic means occasionally (e.g.,
periodically) powers the load and repeats the above test to
determine the desired power state of the load as a function of the
load's demand behavior.
[0046] By disconnecting the load from the power source when the
load is inactive, the amount of phantom current is reduced. Energy
conservation is realized when the load is disconnected from the
power source during times of inactivity. Power may be supplied to
the load at predetermined intervals (e.g., approximately 400 ms
every 2 seconds) to check the load state. This may be called the
"power duty cycle" which indicates how often and for how long the
load is powered for checking the active/inactive state. The power
duty cycle may be determined at the point of manufacture (e.g.,
stored in non-volatile memory) or it may be adaptable depending
upon the load (and optionally a user input such as a
pushbutton).
[0047] In general, during "power cycling" the energy conservation
device measures current consumption at times when power is applied
to the load. If the current consumed by the load is above the
threshold, the load is deemed in a "power on request" state. In
this case, power cycling stops and power is applied to the load
continuously. This is the normal "on" operating state of the load,
and power is not cycled. During the normal operating state of the
load, supplied current is monitored continuously. If the current is
measured below the threshold, the load is determined to have
changed to the standby state. In this event, the power cycling
condition resumes to conserve energy once again.
[0048] Generally discussed herein is a system that includes a means
for receiving a potential and selectively supplying said potential
to a load. This receiving and supplying means may be configured as
a switching element that receives a voltage from a power source,
such as from a standard power receptacle as is found in a house or
other structures. The receiving and supplying means is also
responsive to a load control signal to supply said potential to the
load when the load control signal is present. The system also
includes a means for measuring a load demand where the load demand
may include a current, voltage, power, or other measurement of load
activity, power demand, or consumption. The system may further
include a means for controlling the receiving and supplying means.
The controlling means continuously providing the load control
signal when the load demand is greater than a predetermined
threshold. The controlling means may also temporarily provide the
load control signal to determine the load demand when the load
demand is less than the predetermined threshold.
[0049] Another example as discussed herein is an electrical device
that includes a switch responsive to a switching signal. The switch
has a input for receiving power and an output for connection to a
load. A sensor may measure an electrical demand to the load which
may include a current, voltage, power, or other measurement of load
activity, power demand, or consumption. A controller selectively
provides the switching signal. The controller provides the
switching signal to power the load when the electrical demand is
greater than a predetermined threshold. The controller momentarily
providing the switching signal to power the load after a delay to
determine the electrical demand after the delay.
[0050] Also discussed herein is a method for controlling an
electrical load. The method includes determining a load demand. The
load demand may include a current, voltage, power, or other
measurement of load activity, power demand, or consumption. The
method further includes provisioning power to the load when the
load demand is greater than a first threshold. The method also
includes removing power to the load when the load demand is less
than a second threshold.
[0051] FIG. 1 is an example block diagram of an energy saving
device 100. A pair of Inputs 110 are configured for receiving a
voltage from a power source. A load 120 is connected to outputs
that are selectively switched to inputs 110 by a load switch 130. A
controller 140 uses an activation signal to load switch 130 to
selectively supply power to load 120 from inputs 110. Controller
140 may base the activation signal on a number of inputs, including
a load sensor 150 and/or a user switch 170. Additionally,
controller 140 may include a memory 142 that provides for
non-volatile storage of operating parameters of energy saving
device 100.
[0052] In an example, inputs 110 may be configured to interface
with typical power infrastructures that may include standardized
power distribution systems. One example includes the United States'
standard "household power" that operates at around 120 volts AC at
60 Hz. Alternatively, other voltages and frequencies may be used
including typical 220 volts at 50 Hz or 60 Hz. Indeed, energy
saving device 100 should not be limited to household-type
electrical connections, as it may also be employed in a variety of
circumstances including mobile loads, industrial, automotive, etc.
For example, energy saving device 100 may be applied to 120 volts
AC at 60 Hz, 220 volts AC at 60 Hz, 220 volts AC at 50 Hz, 480
volts AC, 660 volts etc. Thus, energy saving device 100 may be
adapted for use with power infrastructures around the world (both
in voltage and in frequency), including but not limited to,
household, industrial, mobile equipment, etc. Other examples may
include applications such as aircraft, motor yachts, mobile homes,
and automobiles, etc., where power for non-essential electrical
systems and devices (e.g., infotainment or communications systems
for passengers) may not require constant powering. Thus, in
power-conscious applications energy saving device 100 may generally
reduce the steady-state load on the power systems which may reduce
operating costs, equipment costs, and/or maintenance costs.
[0053] As shown herein, a power supply 160 provides power for the
operation of controller 140 and the associated electronics such as
load sensor 150 and load switch 130. Power supply 160 may be
configured so that energy is not wasted in the powering of
controller 140. In another example, power supply 160 may include a
battery that is rechargeable and/or user replaceable. Such a
battery configuration would not necessitate power drawn from inputs
110 to provide power to energy saving device 100.
[0054] Load sensor 150 may include a current measurement sensing
topology that may include a high-side resistive differential
amplifier (explained below in detail with respect to FIG. 2). Such
a system typically implements a resistor in series between inputs
110 and load 120 such that the voltage drop across the series
resistor is measured to determine current flowing to load 120. The
measured current to load 120 may be sent to controller 140 at an
analog to digital converter (ADC) input or an analog comparator
input. Alternative implementations may include a hall-effect sensor
to measure current directly flowing from inputs 110 to load 120. In
yet another example, a current measurement system may be integral
with load switch 130 (such as a sense-FET). Moreover, power
measurements or other means may be employed to determine whether
load 120 is in use.
[0055] In operation, controller 140 may occasionally power load 120
to determine whether load 120 is to be activated continuously. If
load 120 demands a relatively large current (e.g., as detected by
load sensor 150), then load 120 is allowed to remain powered by
continued activation of load switch 130. If load 120 demands a
relatively small current, then load 120 is deactivated by turning
off load switch 130. In this way, controller 140 uses load sensor
150 to determine the active or inactive status of load 120. By not
continuously powering load 120, a power savings is realized through
the momentary powering scheme when load 120 is turned off and not
demanding a relatively large current.
[0056] User switch 170 may be used to override the operation of
controller 140 to power the load based on a user request. For
example, if the user believes that energy saving device 100 should
power load 120, user switch 170 may be activated to immediately
power load 120. User switch 170 may also be used by controller 140
as a training input. For example, if the user connects an arbitrary
load to energy saving device 100 with different characteristics
than the previously trained load 120, then the user may press user
switch 170 to activate load 120 and signal to controller 140 that a
training mode should be re-entered (explained below in detail with
respect to FIG. 3).
[0057] Memory 142 may be embodied as a Flash memory, an
Electrically Erasable Programmable Read-Only Memory (EEPROM)
memory, or other non-volatile memory that retains information when
un-powered. Typical information stored in memory 142 may include
statistical information related to the operation of load 120 based
on measurements from load sensor 150. Alternatively, memory 142 may
include general parameter information that defines operational
characteristics of controller 140.
[0058] In general, the block diagram shown herein is not to be
interpreted as the only example of how to configure energy saving
device 100. Indeed, in some circumstances, controller 140 may be
replaced by sequential logic circuitry, analog circuitry, or a
combination of both. Moreover, as is known to those skilled in the
art, measurement of load 120 using load sensor 150 may include
current, voltage, or power measurements depending upon the
configuration. Thus, the current measurement technique for
determining load consumption as discussed herein is not the only
means to measure load activity and load demand. Similarly, load
switch 130 may be configured using variations of components such as
a field-effect transistor (FET), Triode for Alternating Current
(TRIAC), zero-crossing switches, or other switching means to
control load 120.
[0059] FIG. 2 is a schematic of an example of an energy saving
device 200. A power supply block 210 is connected to a power input
260 and a common terminal 262. A sensor block 220 measures the load
current and a load switch block 230 generally controls the flow of
power from power input 260 to a load output 270. Load output 270
may be directly attached to the power input to load 120 (shown in
FIG. 1). While not necessary for operation, user switch 250
provides for immediate activation of a load. Moreover, an infrared
sensor block 240 may be used to determine the operation of a user
remote control, which requests immediate powering the load. This is
used, for example, when a remote control is used to turn on a
television. In this example, infrared sensor block 240 detects use
of the remote and then the logic immediately turns on the
television.
[0060] Power supply block 210 includes a capacitive power supply
topology for low power operation. Power supply block 210 regulates
a dual voltage supply to about 12 volts and about 5 volts. A bridge
rectifier BR1 is used to rectify the alternating current (AC) from
power input 260 and common terminal 262. Zener diodes (D1, D2) and
a capacitor network (C2, C3, C4) generally regulate the voltage. In
addition to supplying power to energy saving device 200, power
supply block 210 also provides a voltage reference (Vref) for use
with the current detection circuitry.
[0061] Sensor block 220 includes a series resistor R6 that is
configured as a low-value resistor with a high power rating. For
example, series resistor R6 may be a one-ohm resistor rated for 200
watts of power. A differential amplifier configuration is used that
includes U2A, U2B, and Vref (from power supply block 210) to
measure the current flowing through series resistor R6 to a load
connected to load output 270. A load signal 280 is provided to
controller U1 that contains control logic for operating load switch
block 230. Controller U1 may be configured to receive load signal
280 at an analog to digital converter (ADC) input to convert the
analog signal to a numeric value. In general, load signal 280
indicates to controller U1 the amount of current or power being
consumed/demanded by the electrical load connected to load output
270. The load consumed by the circuitry described in the schematic
of FIG. 2 does not draw power through sense resistor R6. Thus, any
power consumed by the circuitry shown herein is not included in the
load demand value indicated by load signal 280.
[0062] Although shown herein as a single-range sensing scheme with
a single output of load signal 280, sensor block 220 may also
include multiple ranges of sensed current. For example, a second
load signal (not shown) may be measured by controller U1 provided
by a signal at the output of amplifier U2A. Thus, controller U1
would then be able to detect current over two ranges provided by
the outputs of both U2A and U2B, which would be connected to
separate ADC inputs of U1. Alternative examples may also include a
low-side measurement scheme or a Hall-effect load measurement
scheme.
[0063] Controller U1, in an example, may be configured as a
micro-controller capable of performing the actions detailed in FIG.
3. Examples of micro-controllers known to those skilled in the art
may include, for example, PIC (TM) micro-controllers from Microchip
(TM), or AVR (TM) micro-controllers from Atmel (TM). For compact
designs, the example shown herein includes a relatively small
device that may have eight pins. However, energy saving device 200
may include other features not detailed herein, including radio
frequency reception for further intelligent control of a load.
Moreover, micro-controller U1 may control more than one load based
on a single sensor block 220, or more than one sensor block 220.
Thus, controller U1 may be scaled up or down in capabilities
depending upon the measurement and control requirements for a
particular application.
[0064] Load switch block 230 includes a FET driver circuit for
controlling power to a load connected to load output 270. The load
(as shown in FIG. 1 as load 120) is electrically connected to load
output 270 and common terminal 262. A load control signal 286 is
provided by controller U1 to control load switch block 230. Load
switch block 230 activates (powers) or deactivates (disconnects) a
load (e.g., a device or appliance) connected to load output 270.
Load switch block 230 generally includes a charge pump, including
U3A and U3B, that drives a bridge rectifier BR2 that in turn drives
FETs Q4 and Q5. A Metal Oxide Varistor (MOV) is included to protect
the relatively sensitive FETs Q4 and Q5 when the load connected at
load output 270 is switched off. The MOV may also perform a
secondary function as a surge suppressor for potentially damaging
signals present at power input 260.
[0065] An additional feature may include a user output signal 288
from controller U1 that switches a LED D7. Output signal 288 may be
used to indicate an operating status (e.g., load on or off) of
energy saving device 200 to the user. Alternatively, output signal
288 may indicate that energy saving device 200 is in a learning
mode (discussed below in detail with respect to FIG. 3) or whether
an abnormal load condition exists that may require turning off the
load to preserve the electronics.
[0066] Other examples of inputs that may trigger controller 140 to
turn on load 120 (similar to infrared sensor block 240 and user
switch 250) may include a general radio frequency input, a network
input (such as a LAN or WiFi), digital information transmitted over
the power line at power input 260, and/or signals designed for
intelligent control of electrical devices, etc.
[0067] FIG. 3 is a state transition diagram 300 for use with energy
saving device 200 of FIG. 2. Initial entry point 310 leads to an
activate load transition 312. A typical event for energy saving
device 100 to enter initial entry point 310 is when the unit is
plugged into a power source. A power up mode 314 is then entered
where the load is powered for a predetermined delay time.
Typically, a timer/counter is used in conjunction with controller
140 (see FIG. 1). When the delay has elapsed, a power up timer
expired transition 316 transfers to a teach/learn state 320.
[0068] Initial entry to teach/learn state 320 transitions to a
learn state 322 where controller 140 measures the current
(electrical demand) used by the load over a predetermined amount of
time. Here, controller 140 determines the behavior of the load over
a number of on and off cycles. By examining the load behavior, the
controller may determine when the load is in use by the pattern of
"load active" current consumption and "load inactive" current
consumption (explained in detail below with respect to FIG. 4).
[0069] Controller 140 remains in learn state 322 until a learn
timer expired transition 324 transfers control to a set threshold
state 326. Controller 140 then calculates an appropriate threshold
to distinguish the load "active" and "inactive" states. When the
threshold has been determined, a threshold stored/activate load
transition 288 transfers control to a sleep check load status state
330. Threshold stored/activate load transition 288 generally
indicates that the threshold has been stored in memory (which may
include a non-volatile memory such as memory 142 of FIG. 1).
[0070] Alternatively, the threshold may be a hard-coded value
placed in non-volatile memory during manufacturing. Another
alternative may provide a table of hard-coded threshold values. If
the threshold does not suit the particular load connected, the user
may push user switch 170 (shown in FIG. 1) to indicate to the
controller that the current threshold is not functioning as
desired. The controller may then select another threshold value
from the table using, for example, a bisection algorithm to locate
the appropriate threshold value for the load to reduce required
user interaction.
[0071] Sleep check load status state 330 has an initial entry point
332 which immediately transfers control to a pulse activate load
state 334. Pulse activate load state 334 activates the load and
waits for a predetermined time for the current signal to stabilize.
A current stabilized transition 336 transfers control to a current
compare state 338 where the current measured through the load is
compared to the threshold determined in set threshold state 326. If
the current measured through the load is greater than the
threshold, a current high activate load transition 346 transfers
control to an activate load state 350.
[0072] Alternatively, if the current measured through the load is
less than the threshold, a current low deactivate load transition
340 transfers control to a sleep deactivate load state 342 where
the load is deactivated. In sleep deactivate load state 342, a
timer may be monitored to determine when a predetermined sleep time
has elapsed. When the predetermined sleep time has elapsed, a sleep
timer expired activate load transition 344 transfers control back
to pulse activate load state 334. As can be determined from sleep
check load status state 330, the controller may repeat a cycle
where the load is measured for significant use or insignificant
use. When a current is measured that is greater than the threshold,
the load is turned on. Similarly, when a current is measured that
is less than the threshold, the load is turned off. Also noted is
that controller 140 may include hysteresis for the threshold value
in the on-to-off and off-to-on transitions to avoid oscillation
and/or undesirable activation and deactivation.
[0073] In activate load state 350, the controller monitors the
current for a transition to a low current consumption state of the
load. When a current is measured less than the threshold determined
in set threshold state 326, then current is turned off to the load.
A current low transition 352 is then triggered and control proceeds
to entry point 332 and pulse activate load state 334.
[0074] FIG. 4 is an example of a histogram classification graph 400
for determining active and inactive states of load 120 of FIGS. 1
and 2. During learn state 322 of teach/learn state 320 (described
in detail with respect to FIG. 3), the controller monitors the
usage of the load to collect information. As shown in the chart,
current magnitude is measured over time to develop two distinct
regions. On the right hand side of the chart, an active state 420
is indicated by a large number of samples. Similarly, a large
number of samples on the left hand side of the chart indicate an
inactive state 410. When the controller has collected enough
information, or a timer has expired, then the microcontroller
transfers control to set threshold state 326.
[0075] A threshold 430 may be determined in a number of manners.
However, many loads exhibit dramatic differences in load demand
behavior when inactive and active. Thus, for many applications the
simple classification problem of the active and inactive states is
solved by determining the average difference between clusters of
measurements. These clusters of measured current, in this example,
are shown by the two distinct measured current regions for inactive
state 410 and active state 420. Although not shown, threshold 430
may include hysteresis that would substantially prevent undesirable
switching of the load.
[0076] FIG. 5 is a timing diagram 500 for activation of load 120 of
FIGS. 1 and 2. Timing diagram 500 generally refers to the sequence
of applying power and removing power during sleep check load status
state 330 of FIG. 3. At an activation time 510, load 120 (of FIG.
1) is provided power based on sleep timer expired activate load
transition 344 to pulse activate load state 334 of FIG. 3.
[0077] A load activation time 520 allows controller 140 to
determine whether load 120 is desired to be fully powered. In
general, load activation time 520 includes the logic processes of
current stabilized transition 336 and current compare state 338 of
FIG. 3. A decision time 530 indicates that controller 140 is
testing the current measured by load sensor 150 (of FIG. 1) against
threshold 430 (of FIG. 4). At decision time 530, load 120 is
deactivated because the current measured is less than threshold
430. Load 120 is then deactivated during an inactive time 540.
Further repetitions of activation time 510 and inactive time 540
demonstrate that load 120 is continuously demanding current less
than threshold 430. Although timing diagram 500 shows a periodic
interval for activation time 510 and inactive time 540, it is also
possible to configure each timing sequence with a non-periodic time
such that some activations and/or deactivations are not equally
spaced in time. For example, if the current measured is close to
threshold 430, controller 140 may reduce the time between checking
for activation and deactivation in an attempt to more closely
monitor load demand.
[0078] FIG. 6 is a timing diagram 600 for sensing and switching
load 120 of FIGS. 1 and 2. In this example, activation time 510
powers load 120 for a load activation time 520. Then, at decision
time 530 it is determined that load 120 is consuming a current
greater than threshold 430. After the determination (corresponding
to current high activate load transition 346 of FIG. 3), load 120
remains active for a load active time 610 that includes activate
load state 350. Load 120 will remain active until a current low
transition 352 is triggered by the current to load 120 dropping
below threshold 430 (not shown in FIG. 6).
[0079] FIG. 7 is a current vs. time chart 800 of load sensing when
load 120 is active. In this example, the current as measured by
load sensor 150 (shown in FIG. 1) is shown in an analog chart form.
At inactive time 540 (shown in FIG. 5) substantially no current is
flowing to load 120. However, at activation time 510, a ramp up of
current 812 indicates that load 120 is demanding current flow.
During a stabilization period 820, the current flow may oscillate
or otherwise behave unpredictably due to the unknown nature of load
120. It is during stabilization period 820 that load 120 receives
full power to initialize the systems (if logic based) or otherwise
transition to a fully powered state. At a stabilization end time
830, a sampling window 840 is used to sample the load current. At
this time, one or more samples are taken from load sensor 150 to
determine whether load 120 is drawing more current than threshold
430. As shown at decision time 530, load 120 remains active because
the current to load 120 is greater than threshold 430. Therefore,
load 120 remains active for load active time 610.
[0080] FIG. 8 is a current vs. time chart 880 of load sensing when
load 120 is inactive. Here, the current as measured by load sensor
150 (shown in FIG. 1) is shown in an analog chart form with a
slightly higher zoom factor when compared with FIG. 7 (although the
figures are not to scale). At inactive time 540 (shown in FIG. 5),
substantially no current is flowing to load 120. At activation time
510, a ramp up of current 812 indicates that load 120 is demanding
current flow. During a stabilization period 820, the current flow
oscillates but does not oscillate to the extent as shown in FIG. 7.
At a stabilization end time 830, sampling window 840 is used to
sample the load current. At decision time 530, load 120 is
deactivated because the current demand is less than threshold 430.
Load 120 will remain inactive for inactive time 540 until the next
activation time 510 or a user activation.
[0081] FIG. 9 is an example of a wall outlet alternative energy
saving device 900. The example here shows a stylized packaging
alternative for the energy saving device 100 of FIG. 1. In use, a
user may plug device 900 into a standard dual outlet where power
pins 920, 930 connect with the receptacle and hold device 900 in
place. Device 900 may be encased in a housing 910 and includes two
receptacles 922, 932 for the user to plug in loads. Here, energy
saving device 100 is employed as a user installable device for
retro-fitting existing receptacles. In this example, power pins 920
map to inputs 110 (see FIG. 1) and receptacle 932 maps to where
load 120 (see FIG. 1) is plugged in.
[0082] FIG. 10 is an example of a power strip 1000 that includes an
alternative energy saving device. A configuration similar to a
"power strip" 1010 is shown having a power source plug 1020 as an
input. Outputs include a master outlet 1030 and multi-slave outlets
1040, 1042, 1044 controlled by an energy saving device that
monitors master outlet 1030. However, energy saving device 1000
does not simply switch slaves 1040, 1042, 1044 based on the power
consumption of master 1030. Rather, energy saving device 1000
switches all of master 1030 and slaves 1040, 1042, 1044 based on
the power consumption of master 1030. The user has a manual input
(e.g., user switch 170) to override the operation of energy saving
device 1000 to manually switch the outlets on or off.
[0083] Moreover, as discussed herein, the energy saving device may
also be built into a product for saving power. In an example, the
energy saving device may be designed into the circuitry of a
television to reduce power consumption. In another example, the
energy saving device may be designed into a phone charger. In yet
another example, the energy saving device may be designed into a
standard transformer for use generally with electronics and
electrical devices. Moreover, the systems and methods described
herein may be used to provision power to sub-systems within larger
designs and need not be located at the main power input.
[0084] By employing the examples of energy saving devices as
described herein, energy loss from phantom loads may be reduced
significantly. For example, a television that includes a cathode
ray tube (CRT) with a transformer-based power supply may consume
around 120 Watts when active. When inactive (e.g., in a standby
mode) the idle power consumption may be around 8 Watts of phantom
load. When using the energy saving devices as described herein,
power savings from phantom loads may be around 66% which is a
direct function of the active duty cycle percentage as described
above with respect to FIGS. 3 and 4. Thus, the power consumed by
the television when an energy saving device is employed may be
around 2.6 Watts at idle. The difference from an always-connected
idle condition (8 Watts) is about 5.4 Watts of saved power. Other
devices may include, for example a laptop computer power supply
which at standby consumes about 3 Watts of phantom load. Another
example is a desktop computer that consumes about 8 Watts at
idle.
[0085] Examples of the threshold as discussed herein to determine
the load is "active" or "inactive" state are discussed in detail
above and in particular with FIGS. 3, 4, 7, and 8. In the example
of a CRT television, the inactive state demands about 8 Watts and
the active state demands about 120 Watts. The threshold may then be
safely set anywhere between 8 Watts and 120 Watts. However, a
margin of error may be factored in to allow the threshold to be
used with a multitude of CRT televisions or to account for
manufacturing variations that could shift the inactive and active
power demand. Thus, a safe threshold value may be set at 64 Watts,
which is the midpoint between the active and inactive power demand
values. In another example, a laptop computer power supply demands
around 3 Watts while inactive and about 26 Watts when active. Thus,
a safe threshold value may be set at 14.5 Watts. In another
example, a desktop computer power supply demands around 8 Watts
while inactive and about 120 Watts when active. Thus, a safe
threshold value may be set at 64 Watts. Of note is that while the
power demand values are discussed in watts, as well as the
threshold in the instant case, the actual threshold value used
depends upon the methodology used to determine the load demand
which may include current measurement, power measurement, or
voltage measurement. One of ordinary skill in the art will
recognize that the threshold value may be adapted to the particular
load demand measurement employed.
[0086] It is noted that the above examples are not indicative of
any particular load and should not be used in any way to limit this
disclosure. Indeed, televisions, laptop computer power supplies,
and desktop computers, are only some examples of load types that
may be employed using the load control method including an energy
saving device. Moreover, each load discussed herein is used as an
example of how to employ an energy saving device. The loads may
have wide ranges of active demands and inactive demands based on
their technology, manufacture, intended use, and other conditions.
Thus, the loads, and in particular, threshold values discussed do
not translate to limiting values and are only exemplary.
[0087] FIG. 11 is an example of a state transition diagram 1100 for
use with the energy saving devices described herein. From a reset
state the system enters a learn state 1110 where the power saving
device adapts to an arbitrary load. This adaptation may include
applying power to a load and determining the "on" and "off"
currents as well as determining the thresholds for the power saving
device to use when determining the power state of "on" and "off"
for the load. Learn state 1110 is described in detail below with
respect to FIG. 11A. After learn state 1110 is complete, control
proceeds to a measure current state 1120.
[0088] In measure current state 1120, power is applied to the load
and the power saving device determines whether a load demands power
equal to or more than the "on" threshold determined in learn state
1110, or whether the load demands power less than or equal to the
"off" threshold determined in learn state 1110. To provide
hysteresis, if the initial power demanded by the load when entering
measure current state 1120 meets the "on" threshold, then the power
is determined to be "high" and control remains at measure current
state 1120 with full power applied to the load. If the power
demanded by the load meets the "off" threshold, then the power is
determined to be "low" and control proceeds to power down load
state 1130.
[0089] In power down load state 1130, power is turned off to the
load and a power saving is achieved. Control then proceeds to off
wait state 1140.
[0090] In off wait state 1140, a time delay is measured for a
predetermined time with the power turned off to the load. When the
predetermined time elapses, control proceeds to apply power to load
state 1150. Note that the predetermined time may be adjustable for
various power saving mode schemes. For example, as discussed below
with respect to FIG. 18, the delay may be adjustable to
predetermined times to allow for increased power savings, or
alternatively, increased response time of the load turn-on.
[0091] In apply power to load state 1150, full power is applied to
the load. Control then proceeds to an on wait state 1160.
[0092] In on wait state 1160, a time delay is measured for a
predetermined time with the power turned on to the load. This
predetermined time allows for the load power to stabilize after
initial turn on so that measurements may proceed later in the
process to determine the operating power of the load, rather than
the inrush load on initial turn on. When the predetermined time
elapses, control proceeds to measure current mode 1120 and the
process repeats.
[0093] FIG. 11A is an example of a timing diagram 1170 for an
adaptive power savings system for use with the energy savings
devices described herein. A first timing diagram 1172 shows the
power to the load as "on" or "off". A second timing diagram 1180
shows the status of the load power button as triggered by a user. A
third timing diagram 1190 shows the load current demand.
[0094] To determine the whether a load is turned "on", (e.g., for a
television or other appliance) the minimum length of time with full
power applied to the load for testing the power demand thresholds
may be a fixed time, or it may be adjustable (e.g., as discussed
above with respect to measure current state 1120 of FIG. 11). This
minimum "on" time allows the load to turn on and the power
consumption to stabilize. If, for example, the "on" time is too
short, the load may not have enough time to achieve a fully "on"
state and the power demand measurement may be inaccurate, or may be
premature, resulting in an incorrect determination of the load's
power state. To allow for arbitrary loads being connected to the
power saving device, the power "on" time may be adaptive for
various loads in a learning mode.
[0095] In an example, the user may turn the load "on" 1182 by
holding the load's power button or remote button and hold the power
"on" during a testing period 1184. After testing period 1184 is
complete, the user may release the power button 1186. In
coordination with learn mode 1110 of FIG. 11, the learn mode may be
triggered by the power saving device, for example, by a user button
or when the power saving device is initially connected to the power
source and the load connected to the power saving device. When
learn mode 1110 is active, the power saving device may sweep the
"on" time from a short time to a longer time to determine the
threshold at which the load demands power above the "on" threshold.
For example, the initial "on" time 1173 may be a short on time
(e.g., 50 ms) and if the load does not demand power above the "on"
threshold then the power saving device may increase the "on" time
1175, 1177, 1179 until the load crosses the "on" power demand
threshold 1194. Between the full power "on" times, an "off" time
1174, 1176, 1178 is provided so that the load has an opportunity to
power "off" to avoid a false positive indication of the load status
and/or load demand. Note that although FIG. 11A as discussed herein
provides three examples of pulse widths for the "on" time (e.g.,
"on" times 1175, 1177, 1179) the adjustable process may be provided
with only two pulse widths, or may continue with an infinite number
of increasing duration pulse widths.
[0096] As shown in timing diagram 1170, the load is determined to
be "off" during a test period 1192, and then when full power is
applied to the load for a long enough time 1179, the load demands
power above the on/off threshold 1193. At this time, learn mode
1110 may determine that the load needs a minimum full power on time
described by time period 1179 before a determination can be made as
to the load status of on or off. In this way, the power saving
device may optimize the "on" time for testing load demand to
further reduce power consumption when the load is "off".
[0097] The variable times for each "on" time 1173, 1175, 1177, 1179
may be related back to FIGS. 7 and 8 as the time from activation
time 510 to stabilization end time 830 and/or decision time 530
(see FIGS. 7 and 8). Alternatively, the Each "on" time 1173, 1175,
1177, 1179 may have an increasing time providing for more time the
load during stabilization period 820 and prior to sampling window
840. Moreover, when used in conjunction with a soft start feature
(disclosed below with respect to FIG. 23B) the inrush may be
reduced which may substantially reduce false-positive
determinations that a load is "on".
[0098] FIG. 11B is an example of the power applied to the load in
an energy saving mode 1195 (e.g., non-continuous power when the
load is in a non-operating condition) and a full power mode 1198
(e.g., continuous power when the load is in an operating
condition). When a load is "off", the power saving device may turn
the load "on" 1196 to test the load power demand, such as is
performed in measure current state 1120. If the load power demand
is determined to be in the "off" state, power is turned off for a
predetermined time 1197 to save power. Alternatively, if the load
power demand is determined to be in the "on" state, full power is
turned on 1198 to the load allowing normal use of the load. If load
demand reduces to below the "off" threshold, the power saving
device reverts back to energy saving mode 1195.
[0099] FIG. 12 is an example of a state transition diagram 1200 for
use with the energy saving devices described herein. As discussed
above with respect to FIGS. 11 and 11A, a learn state 1110 may be
included to allow for optimization and/or adjustment of the load
on/off times to determine the load status, and a measure current
mode 1120 to allow for the determination of load power demand and
load status. Diagram 1200 shows an alternative power saving mode
that allows for cycle skipping and/or cycle clipping. In measure
current state 1120, if the load power demand meets the "off"
criteria, control proceeds to the cycle skip/clip state 1210. In
cycle skip/clip state 1210, the power to the load may be modified
to include cycle skipping and/or cycle clipping to provide energy
savings. For example, cycle skipping allows for a single cycle of
"on" and a predetermined number of cycles of "off" to be sent to
the load. This power saving strategy may allow some power to be
applied to keep the load "alive" during the off periods to
preserve, for example, volatile memory in the load. Alternatively,
cycle clipping may be employed to send power to the load, but
certain portions of the cycles may be clipped to conserve power.
After cycle skip/clip state 1210 is initiated, control transfers to
a wait state 1220. When a predetermined wait time has elapsed, the
control proceeds to measure current state 1120 where the load may
be tested for power demand.
[0100] FIG. 12A is an example of a clipped energy saving mode 1210
and a full power mode 1120. When clipping is employed for power
saving, only a portion of the power is provided to the load. As
shown in FIG. 15, cycle clipping may be employed during clipped
energy saving mode 1210. The clipping may provide only a portion of
an AC power signal to the load to conserve power. For example, FIG.
15A shows a portion of an AC sine wave that has been clipped. An on
portion 1510 is provided where power flows to the load. An off
portion 1520 is where the AC cycle has been clipped. An ideal AC
signal would have the full partial cycle 1530. However, the
clipping turns power off at clipping point 1540.
[0101] FIG. 13 is an example of power pulsing as applied to the
example of FIG. 11. Power is applied 1310 for a predetermined time
(e.g., corresponding to full power mode 1120) and power is turned
off for a predetermined time (e.g., corresponding to power down
load state 1130). The predetermined on and off times may be
adjusted using various techniques as described herein, including
response to a human-in-area detection system (see FIG. 18).
[0102] FIG. 14 is an example of cycle skipping, that may be
employed with the example of FIG. 12. When cycle skipping (e.g.,
during cycle skip/clip state 1210), a full cycle may be provided to
the load followed by an off period. In this way, the load may be
provided with some power during the energy saving period rather
than having power fully off.
[0103] FIG. 16 is an example of an energy savings system 1600 that
communicates with and controls other loads. A master load 1630
(e.g., such as a television) may be controlled from a master energy
saving device 1620. Master energy saving device 1620 may
communicate (e.g., digital and/or analog communication) with slave
power savings devices 1622, 1624, 1626 using the power lines (e.g.,
power wiring). Slave power savings devices 1622, 1624, 1626 may
control slave loads such as a receiver 1632, a game station 1634,
and a DVD player 1636, respectively. The slave loads 1632, 1634,
1636 may be configured with the slave power saving devices such
that when the master load 1630 is not in use, the power is turned
off to slave loads 1632, 1634, 1636. This system configuration
allows master power saving device 1620 to determine the on/off
status of master load 1630 and control slave loads 1632, 1634, 1636
to a full off status when master load 1630 is determined to be off,
and a full on status when master load 1630 is determined to be on.
In this way, additional power savings may be achieved for slave
loads 1632, 1634, 1636 when master load 1630 is off.
[0104] Communication from master energy saving device 1620 and
slave power savings devices 1622, 1624, 1626 may be through the
power wiring, such as is described by the X10 standard for home
automation, or other protocols (e.g., power line communication).
Alternatively, the communication may be wireless (e.g., Bluetooth
or 802.11-type communications). Moreover, to facilitate
communications, master energy saving device 1620 may be keyed to
slave power savings devices 1622, 1624, 1626 using a code that may
be programmed by a user, or pre-programmed. Such a keying system
allows for multiple masters and slaves to operate independently
using the same communication medium (e.g., wiring or wireless).
[0105] FIG. 17 is an example of a timing diagram 1700 for the
energy saving device of FIG. 16. During a power saving mode 1710
when master load 1630 is determined to be off, all slaves 1632,
1634, 1636 are turned off. For master load 1630, master power
saving device 1620 may periodically determine the power status to
determine whether the load is on or off. When master load 1630 is
turned on 1730, master power saving device 1620 turns the master
load to full power 1720 and sends a signal to slave power savings
devices 1622, 1624, 1626 to turn all slaves on 1742 (e.g., see
slaves 1632, 1634, 1636 of FIG. 16). When master load 1630 is
turned off 1732, master power saving device 1620 reverts to power
saving mode 1710 and sends a signal to slave power savings devices
1622, 1624, 1626 to turn all slaves off 1740 (e.g., see slaves
1632, 1634, 1636 of FIG. 16).
[0106] FIG. 18 is an example of a human-in-area detection system
1800 for use with the energy savings devices described herein. In
an example, a sensor or detector 1810 may be configured for use
with power saving devices 1812, 1814, 1816. Sensor 1810 may be
configured as a motion sensor, a thermal sensor, a sound sensor, or
other type of sensor to detect persons, for example without
limitation. Sensor 1810 may detect a person 1802 within a
predetermined proximity and communicate the presence of the person
1820 to power saving devices 1812, 1814, 1816 as a "human-in-area"
("HIA") signal. Alternatively, when person 1802 is not detected or
in range of sensor 1810, a "no-human-in-area" ("NHIA") signal may
communicate to power saving devices 1812, 1814, 1816.
[0107] Power saving devices 1812, 1814, 1816 may then use the HIA
or NHIA signals to alter their power saving strategies to provide
for increased power savings when the NHIA signal is present, or to
increase response time when the HIA signal is present. For example,
power saving device 1812 may be connected to a television load
1820. When the HIA signal is present, a decreased response time
strategy 1840 may be employed where the duration between testing
the load status is reduced. Alternatively, when the NHIA signal is
present, an increased power saving strategy 1842 may be employed
that increases the duration between testing the load status. In and
example, the period of the pulses of power for the increased power
saving strategy 1842 (e.g., a second power saving strategy) is
longer than the period of the pulses of power for the increased
response time strategy 1840.
[0108] In another example, a personal computer 1822 may be
connected to a power saving device 1814. In this example, when the
HIA signal is present, the power saving mode may be unchanged from
a normal power saving mode. However, when the NHIA signal is
present, the load may be switched completely off 1852 to achieve
greater power savings.
[0109] Other loads 1824 may be controlled by power saving device
1816 that may or may not change power saving strategies upon the
present of the HIA or NHIA signals.
[0110] When discussing the HIA and NHIA power saving strategies as
it relates to the power saving devices as discuss herein, sensor
1810 does not directly control the on/off status of the load.
However, where the power saving devices are configured to use the
HIA and NHIA signals, they may alter their power strategies.
[0111] Communication from sensor 1810 and power saving devices
1812, 1814, 1816 may use wired, including power wiring, or wireless
communications. Also, note that while motion sensor 1810 is shown
as a separate unit in FIG. 18, it may also be integrated with a
power saving device.
[0112] FIG. 19A is a partial schematic of a power supply subsystem
for use with the power saving device. In general, the power supply
subsystem converts the AC mains power to 5V DC used for power the
load switch subsystem (see FIG. 19B), the logic subsystem (see FIG.
19C), load current measurement subsystems (see FIG. 19D), and user
input/output.
[0113] The power supply subsystem is generally divided into an AC
and DC section that is divided by diode D2. The AC section includes
inrush protection resistors R24, R25 to prevent excessive current
spikes. Capacitor C6 functions as an isolation capacitor that
couples energy from AC mains into regulator DC section. Diodes D5,
D6 provide over voltage protection. Diodes D2, D3 are half wave
rectifiers for AC to DC conversion.
[0114] In the DC section, capacitor C8 functions as a preregulator
holding capacitor to smooth AC signal into DC. Capacitor C1
functions as a high frequency filter capacitor. Diode D11 (a Zener
diode) functions as a preregulator to prevent over voltage to
remaining circuit elements. Resistors R7, R10 function as a Zener
shunt regulator resistor which in combination with diode D4 (a
zener diode) forms basis of 5V DC regulator. Capacitor C7 functions
as a power supply low frequency smoothing capacitor. Capacitor C2
functions as a high frequency filter capacitor. Resistors R14, R15
function as a voltage divider (generally 2:1) to supply a 1/2 Vcc
reference voltage to the load current measurement subsystem.
[0115] FIG. 19B is a partial schematic of a load switch subsystem
for use with the power saving device. The load switch subsystem
functions to apply or cut power to the load under instruction from
the logic subsystem.
[0116] Optoisolator U2 and resistor R3 permit AC power to be
applied/cut to the load by a low voltage DC microcontroller (see U1
of FIG. 19C). Resistors R19, capacitor C10, and resistors R2, R6
function as a triac biasing circuit, capable of handling reactive
loads. Resistor R18 functions as a zero cross detector resistor
used to inform the logic subsystem when AC signal is generally at
zero volts. The zero cross detector is generally used to apply/cut
power synchronous to the AC mains voltage signal. Resistor R20 and
capacitor C9 function as a TRIAC snubber circuit which prevents
inadvertent turn-on of TRIAC with reactive loads. TRIAC Q1 is used
as a switching element to apply/cut power to load. Fuse F1
functions as a safety fuse to prevent undesirable failure modes in
case of circuit failure or user connecting an excessive current
demand load beyond the rated use. MOV RV1 (a Metal Oxide Varistor)
functions for output protection. Connectors J1, J2 are male and
female AC connections.
[0117] FIG. 19C is a partial schematic of a logic subsystem for use
with the power saving device. The logic subsystem performs command
and control of the power saving device and controls energy savings
functions by instructing modulation of power to load based on load
state and load on/off demand as sensed by the load current
measurement block (shown in FIG. 19D).
[0118] Microcontroller U1 is a microcontroller with internal ND
(analog to digital converter) and EEProm (non-volatile storage)
that executes software capable of controlling the load as discussed
herein based on various scenarios that include evaluation of load
current demand. Crystal Y1 and capacitors C11, C12 function as an
oscillator for the microcontroller U1. Diode D9, capacitor C5 and
resistors R13, R4 function as a reset circuit for microcontroller
U1. Resistors R21, 22 and diode D10 function as an AC mains voltage
monitor used for data collection device to calculate true power.
Switch U4 (shown here as a Hall Effect sensor) and resistor R27
function to read a user command for entering learning modes and
other user-input related features. Switch S1 and resistor R28 are
an alternative user input configuration having a standard push
button switch. Resistor R12 and diode D8 function as a status LED
to indicate system status to user. Capacitors C3, 13 function as
high frequency bypass capacitors. Jack J4 and resistor R17 provide
for flash programming of microcontroller U1.
[0119] FIG. 19D is a partial schematic of a load current
measurement subsystem for use with the power saving device. The
load current measurement subsystem measures load current demands
and present it to the logic subsystem in a usable form (e.g., 0-5V
for analog to digital conversion). In general, the topology of the
load current measurement subsystem includes a ground reference
resistive 2 stage differential amplifier.
[0120] Operational amplifier U3 is a low current, low offset
voltage rail to rail CMOS OP amp. Resistor R1 is a sense resistor
to convert load current into a low voltage (for later
amplification). Resistors R5, R8, R9, R11, R16, and R26 are
resistors chosen to provide a two stage differential amplifier with
82 counts per amp for stage 1 and 820 counts per amp for stage 2
with R1 as the sense resistor. Paired diodes D7 function as
microcontroller input protection diodes. Capacitor C4 functions as
a high frequency bypass capacitor.
[0121] FIG. 20 is an example of a power measurement including time
and ADC counts as references. For reference a standard AC mains
signal 2010 is overlaid for context. The ADC counts correspond to a
current measurement generally provided by the load current
measurement subsystem shown in FIG. 19D and as converted by the ADC
of microcontroller U1 (shown in FIG. 19C). As shown the lower the
ADC count, the higher the power consumption. At the peak of the
sine wave 2020, many loads exhibit a spike in power consumption
2030 (shown as the downwardly extending power spike). This may be
due to switching regulators at the load that pull power in short
bursts to increase efficiency. An example of a burst current is
about 5A which corresponds to about 550W, where the average power
of the load shown may be about 67W. This short burst of power
consumption at the peak of the AC sine wave 2020 may be caused by
the inductive nature of the power supply transformer and capacitor
reactances in the load. However, each load may perform differently,
and may not include a power spike 2030 at all depending on the load
configuration.
[0122] FIGS. 21-23B discuss a soft start system that may reduce
wear-and-tear on electrical components in the load that may include
derating of the components. In general, the soft start system
reduces the inrush current and voltage to avoid derating of
components. For example, many common capacitors derate over their
life based on current spikes. For capacitors, such as electrolytic
capacitors in a load power supply, the inrush current may
momentarily present as a short-circuit condition to the component
which stresses the component. Alternatively, if the current spikes
are reduced to a smoother voltage profile they may derate slower
and last longer.
[0123] FIG. 21 is an example of an inrush waveform 2100. When power
is applied to the load an inrush 2110 typically occurs (e.g., see
also inrush current 812 of FIG. 8) where the load demand greater
power than when operating in a normal stable operating condition.
This inrush at the initial connection of power may draw excessive
power (thus wasting power) and may derate the electrical components
of the load. Moreover, by controlling high inrush demands via the
soft start feature, energy may be saved.
[0124] FIG. 22 is an example of a soft start waveform in comparison
with an inrush waveform. Soft start waveform 2210 shows a gradual
application of power to the load that reduces the inrush spike
(shown in FIG. 22 as a dashed line and shown in FIG. 21 as inrush
2110). The soft start waveform 2210 shows a gradual application of
power to the load (shown in FIG. 23B) that generally reduces the
over-voltage and/or over-current conditions generally associated
with application of power to certain loads. Because the maximum
power applied using soft start waveform 2210 is less than the
inrush power 2110, the electrical components of the load would
derate slower and the overall lifetime of the electrical components
may be extended.
[0125] FIG. 23A is an example of a typical AC power supply waveform
2300 where power is applied at activation time 2310 (also
corresponding to activation time 510 of FIGS. 5 and 7).
[0126] FIG. 23B is an example of gradual clipping of an AC power
supply waveform to achieve a soft start that reduces inrush. At
activation time 2310, power is applied for a first portion 2330 of
a first AC cycle. A the second half of the first AC cycle, power is
applied for a second larger portion 2340 of the AC waveform In a
first half of a second AC cycle, power is applied for a third
larger portion 2350. In a second half of a second AC cycle, power
is applied for a fourth larger portion 2360. In a first portion of
a third AC cycle, power is applied for a fifth larger portion 2370.
Thereafter, full power may be applied to the load.
[0127] In general, the gradual application of power achieves the
soft-start system. Although only five increasing applications of
power are show, the soft start feature may provide for gradual
application of power over many AC cycles. Moreover, the application
of power may be on the high side or the low side, or both (as
shown), of the AC cycle. Thus, the soft start system as shown
herein is an example of a soft start system and is not
limiting.
[0128] Relating the gradual application of power from a small
portion of full power to full power relates back to the
stabilization period 820 shown in FIGS. 7 and 8. For example, the
application of power at activation time 2310 may also relate with
activation time 510 of FIGS. 5-8. Moreover, the various times of
partial application of power (e.g., first portion 2330, second
larger portion 2340, third larger portion 2350, fourth larger
portion 2360, and fifth larger portion 2370) may be performed in
the window of time shown in FIGS. 7 and 8 during the timer period
defined by activation time 510 and stabilization end time 830.
Application of full power may be before or at stabilization end
time 830 (see FIGS. 7 and 8). Moreover, full power may be applied
during sampling window 840 to avoid varying current consumption
while sampling power demand.
[0129] The present invention has been particularly shown and
described with reference to the foregoing embodiments, which are
merely illustrative of the best modes for carrying out the
invention. It should be understood by those skilled in the art that
various alternatives to the embodiments of the invention described
herein may be employed in practicing the invention without
departing from the spirit and scope of the invention as defined in
the following claims. The embodiments should be understood to
include all novel and non-obvious combinations of elements
described herein, and claims may be presented in this or a later
application to any novel and non-obvious combination of these
elements. Moreover, the foregoing embodiments are illustrative, and
no single feature or element is essential to all possible
combinations that may be claimed in this or a later
application.
[0130] With regard to the processes, methods, heuristics, etc.
described herein, it should be understood that although the steps
of such processes, etc. have been described as occurring according
to a certain ordered sequence, such processes could be practiced
with the described steps performed in an order other than the order
described herein. It further should be understood that certain
steps could be performed simultaneously, that other steps could be
added, or that certain steps described herein could be omitted. In
other words, the descriptions of processes described herein are
provided for illustrating certain embodiments and should in no way
be construed to limit the claimed invention.
[0131] Accordingly, it is to be understood that the above
description is intended to be illustrative and not restrictive.
Many embodiments and applications other than the examples provided
would be apparent to those of skill in the art upon reading the
above description. The scope of the invention should be determined,
not with reference to the above description, but should instead be
determined with reference to the appended claims, along with the
full scope of equivalents to which such claims are entitled. It is
anticipated and intended that future developments will occur in the
arts discussed herein, and that the disclosed systems and methods
will be incorporated into such future embodiments. In sum, it
should be understood that the invention is capable of modification
and variation and is limited only by the following claims.
[0132] All terms used in the claims are intended to be given their
broadest reasonable constructions and their ordinary meanings as
understood by those skilled in the art unless an explicit
indication to the contrary is made herein. In particular, use of
the singular articles such as "a," "the," "said," etc. should be
read to recite one or more of the indicated elements unless a claim
recites an explicit limitation to the contrary.
* * * * *