Field of the Invention
The present invention relates to a power control
system and an electric device, the power control system
controlling the electric device to consume a power generated
by a self-generated electrical power facility using a
natural energy.
Background of the Invention
Previously, a self-generated electrical power facility
using a natural energy, such as a photovoltaic power system,
a wind power system or the like has been configured such
that a generated surplus power is reversely supplied (sold)
to an electric power system, or is accumulated in a storage
battery to be discharged from the storage battery when the
demand for power becomes greater than the amount of power
generated (for example, see Japanese Patent Application
Publication No. 2006-311676).
However, when a surplus power from a self-generated
electrical power facility, such as a photovoltaic power
system or the like, exceeds even the demand for power
selling and the charge capacity of the storage battery, the
relevant surplus power has to be inevitably discarded and
then wasted.

Summary of the Invention
Therefore, the present invention provides a power
control system and an electric device capable of efficiently
consuming a surplus portion of a power from a self-generated
electrical power facility, such as a photovoltaic power
system and the like.
In accordance with an aspect of the present invention,
there is provided a power control system configured to
control electric devices to consume a power generated by a
self-generated electrical power facility using a natural
energy. The power control system includes: a surplus power
detection unit for detecting a surplus power generated by
the self-generated electrical power facility; and an
appliance control unit for controlling operations of the
electric devices. The appliance control unit performs a
control such that when the surplus power detection unit
detects the surplus power, one or more of the electric
devices respectively execute predetermined operations and
consume the surplus power.
In accordance with this configuration, there can be
provided a power control system in which surplus power is
consumed by causing one or more electric devices to execute
predetermined operations, thus enabling a surplus portion of
power from a self-generated electrical power facility, such

as a photovoltaic power system, to be efficiently consumed.
The electric devices may include one or more
chargeable electric devices, each having a secondary cell as
a power source, and, when the surplus power detection unit
detects the surplus power, the appliance control unit may
perform a control such that the surplus power is supplied to
the chargeable electric devices and each of the chargeable
electric devices executes a charging operation.
In accordance with this configuration, the secondary
cell of a chargeable electric device is charged using
surplus power, thus enabling the surplus power to be
efficiently consumed.
The power control system may further include an
appliance information storage unit for storing information
on predetermined operations that are executed by electric
devices in power usage candidates for the surplus power.
When the surplus power detection unit detects the surplus
power, the appliance control unit may perform a control such
that a combination of electric devices which efficiently
consumes the surplus power is selected among the power usage
candidates on the basis of the information on the
predetermined operations stored in the appliance information
storage unit, and the selected electric devices may consume
the surplus power by executing the respective predetermined
operations.
In accordance with this configuration, even if the

amount of surplus power is greater than the amount of power
consumed by each individual electric device, a combination
of electric devices having power consumption, the sum of
which does not exceed the amount of surplus power, is
selected from the power usage candidates, and the selected
electric devices execute predetermined operations, thus more
efficiently using the surplus power without any waste of
power.
The power control system further includes a surplus
power prediction unit for predicting a time at which the
surplus power is -generated and an amount of the surplus
power, based on an amount of a power generated by the self-
generated electrical power facility and a demand for the
power.
The appliance information storage unit stores
information on times taken to activate the electric devices
in the power usage candidates for the surplus power,
together with the information on the predetermined
operations. The appliance control unit the surplus power
among the power usage candidates, based on the amount of the
surplus power predicted by the surplus power prediction
unit, the information on the predetermined operations stored
in the appliance information storage unit, and the
information on the times taken to activate the electric
devices, thus activating the selected electric devices
before the surplus power generation time predicted by the

surplus power prediction unit, and enables the surplus power
to be supplied to the selected electric devices when the
surplus power detection unit detects the surplus power to
allow the electric devices to execute the predetermined
operations.
In accordance with this configuration, the time of the
generation of surplus power and the amount of the surplus
power are predicted, so that electric devices are previously
activated correspondingly to the timing at which the surplus
power is generated, thus more efficiently using the surplus
power.
In accordance with another aspect of the present
invention, there is provided an electric device configured
to consume a power generated by a self-generated electrical
power facility using a natural energy. The electric device
includes: an execution unit for executing a predetermined
operation upon power supply; a control unit for controlling
the execution unit; and a surplus power detection unit for
detecting a surplus power from the self-generated electrical
power facility. When the surplus power detection unit
detects the surplus power, the control unit controls the
execution unit to consume the surplus power by executing the
predetermined operation.
In accordance with this configuration, there can be
provided an electric device that consumes surplus power by
causing the execution unit to execute predetermined

operations, thereby enabling a surplus portion of power from
a self-generated electrical power facility, such as a
photovoltaic power system, to be efficiently consumed.
The execution unit may be a secondary cell, and, when
the surplus power detection unit detects the surplus power,
the control unit preferably controls the surplus power to be
supplied to charge- the secondary cell.
In accordance with this configuration, the secondary
cell is charged using surplus power, thus enabling the
surplus power to be efficiently consumed.
Brief Description of the Drawings
The objects and features of the present invention will
be apparent from the following description of preferred
embodiments which is given in conjunction with the
accompanying drawings.
Fig. 1 is a system configuration diagram showing a
power control system in accordance with a first embodiment
of the present invention.
Fig. 2 is a sequence diagram showing an operation of
the above power control system.
Fig. 3 is a block diagram showing an appliance control
device in a power control system in accordance with a second
embodiment of the present invention.
Fig. 4 is a block diagram showing an appliance control

device in a power control system in accordance with a third
embodiment of the present invention.
Fig. 5 is a system configuration diagram showing the
above power control system.
Fig. 6 is a block diagram showing an appliance control
device in a power control system in accordance with a fourth
embodiment of the present invention.
Fig. 7 illustrates a block diagram showing an electric
device and a system configuration diagram of a power control
system including the electric device in accordance with a
fifth embodiment of the present invention.
Fig. 8 is a block diagram showing an electric device
in accordance with a sixth embodiment of the present
invention.
Detailed Description of the Preferred Embodiments
Embodiments of the present invention will be described
in detail below with reference to the accompanying drawings
which form a part hereof. Identical or similar parts
throughout the drawings will be designated by like reference
symbols and redundant description thereof will be omitted.
(First Embodiment)
A system configuration diagram of a power control
system in accordance with a first embodiment of the present
invention is shown in Fig. 1. The power control system

includes an appliance control device 1 and a surplus power
information transmission unit 2. The power control system
in accordance with the present embodiment is provided in a
house H into which a power line L1 and a power line L2 are
respectively led through a power meter Ml for power
purchasing and a power meter M2 for power selling. The
power line L1 is connected to an electric power system Wl of
a purchasing-side power provider and the power line L2 is
connected to an electric power system W2 of a power selling-
side power provider.
A power (AC power) supplied from the electric power
system Wl of the power-purchasing side power provider via
the power meter H1 for power purchasing is branched and
distributed to a distribution board 200 installed in the
house H and is fed to an electric device (hereinafter
referred to as an "appliance") 3. Further, the distribution
board 200 includes weekly breakers, quarter breakers or the
like for the electric power system Wl and the electric power
system W2.
In the house H, a self-generated electrical power
facility using a natural energy, such as a wind power or
solar light, is installed. In the present embodiment, e.g.,
a photovoltaic power system is installed. The photovoltaic
power system includes a photovoltaic power generation unit
100 including a .plurality of solar cells and a power
conditioner 101. The power conditioner 101, which is

implemented with a conventionally well-known component,
includes an inverter (not shown) for converting a DC power
outputted from the photovoltaic power generation unit 100
into an AC power, "or includes, in addition to the inverter,
a grid-connected protection device (not shown) disposed
between the inverter and the electric power systems Wl and
W2 .
In this case, the power conditioner 101 is configured
such that when the inverter converts a DC voltage outputted
from the photovoltaic power generation unit 100 into an AC
voltage, the output voltage (AC voltage) is adjusted to be
slightly higher than the system voltage of the electric
power system W2 of the power selling-side power provider,
thus selling (reversely supplying) the AC power to the
relevant electric power system W2.
However, in the electric power system W2 of the power
selling-side power provider, when the system voltage
increases and exceeds a predetermined upper limit due to a
reduced demand for power (e.g., the stoppage of the use by a
large consumer, such as a plant), the power conditioner 101
suppresses the rise in the output voltage of the inverter so
that the output voltage does not exceed the upper limit,
thus stopping the power from being sold (reversely supplied)
to the electric power system W2. Further, such a function
of the power conditioner 101 is generally called a "voltage
rise suppression function."

In the distribution board 200, there is installed the
surplus power information transmission unit 2 which detects
a surplus portion of a power generated by the self-generated
electrical power facility (photovoltaic power system) and
transmits surplus power information (information indicating
that the surplus portion of the power has been generated,
hereinafter, the same as the above) via a transmission line
Ls1. The surplus power information transmission unit 2
monitors the voltage of the primary side of the power meter
M2 for power selling (i.e., the side of the distribution
board 200) and the output voltage of the power conditioner
101. When the voltage of the primary side is higher than
the upper limit and the output voltage of the power
conditioner 101 is lower than the voltage of the primary
side, the surplus power information transmission unit 2
determines that the voltage rise suppression function of the
power conditioner 101 has been fulfilled to stop the selling
of power (reverse power supply) to the electric power system
W2 of the power selling-side power provider.
In other words, it is determined that surplus power
has been generated, and therefore, the surplus power
information transmission unit 2 transmits surplus power
information. That is, in the present embodiment, the
surplus power information transmission unit 2 functions as a
surplus power detection means.
The surplus power information transmitted from the

surplus power information transmission unit 2 via the
transmission line Ls1 is received by the surplus power
information reception unit 11 in the appliance control
device 1 that controls the operations of one or more
electric devices 3. The appliance control device 1 includes
an appliance control unit 10 having a microcomputer as its
principal component, and an operation information storage
unit 12 implemented as rewritable non-volatile semiconductor
memory, such as a flash memory, in addition to the surplus
power information reception unit 11.
The appliance control unit 10 receives the surplus
power information from the surplus power information
reception unit 11, and controls the operation of the
appliance 3 by outputting a control signal to the appliance
3 on the basis of the surplus power information and the
operation information retained (stored) in the operation
information storage unit 12. In this case, the operation
information retained in the operation information storage
unit 12 refers to information required to control appliance
3 to be controlled. In detail, the operation information
denotes information, such as commands for allowing the
appliance 3 to start or stop a predetermined operation, and
the amount of power consumed when the relevant operation is
executed.
Further, the term "predetermined operation" may be,
e.g., a defrosting operation or an ice-making operation when

the appliance 3 is a refrigerator, or may be a cooling or
heating operation performed so that room temperature is kept
at a set temperature or an operation of cleaning an internal
filter or an internal fan when the appliance 3 is air-
conditioning equipment (air conditioner). The "predetermined
operation" further may be an operation of purifying air
within the room or an operation of cleaning an internal
filter or the like when the appliance 3 is an air cleaner,
or may be an error checking operation or a defragmentation
operation performed on a storage device, such as a hard disk
device, when the appliance 3 is a personal computer.
Moreover, the appliance control unit 10 transmits the
control signal including a command required to start or stop
the predetermined operation to the appliance 3 via the
transmission line Ls2 .
The appliance 3 includes a control signal reception
unit 31 for receiving the control signal transmitted from
the appliance control unit 10 via the transmission line Ls2,
an execution unit 32 for executing the predetermined
operation described above, and a control unit 30 for
controlling the execution of the predetermined operation by
the execution unit 32 in compliance with the command
included in the control signal received by the control
signal reception unit 31. Further, the execution unit 32
executes the predetermined operation by using (consuming) a
power (AC power) supplied through a power line Lp1 branched

at the distribution board 200. However, it is apparent that
the power consumed by the appliance 3 also includes powers
used (consumed) by the control signal reception unit 31 and
the control unit 30, as well as the power used by the
execution unit 32. Here, a media forming the transmission
lines Ls1 and Ls2 may be dedicated signal lines or electric
waves. Alternatively, the media may be implemented by using
Power Line Carrier (PLC) communications that allow control
signals to be overlapped therewith to be transmitted through
the power line Lp1.
The power control system in accordance with the
present embodiment basically feeds a power generated by the
photovoltaic power generation unit 100 to the appliance 3
(but these also include appliances other than a target of
the control of the appliance control device 1) via the
distribution board 200 while selling (reversely supply) a
surplus portion of the generated power, which exceeds the
power consumed by the appliance 3, to the electric power
system W2 of the power selling-side power provider.
Further, when the power consumed by the appliance 3 exceeds
the amount of power generated by the photovoltaic power
generation unit 100, the power control system feeds the
power supplied (purchased) from the electric power system W1
of the power purchasing-side power provider to the appliance
3 via the distribution board 200 (i.e., a so-called grid-
connected operation is executed). Further, although only

one target appliance 3 to be controlled is shown in Fig. 1,
it is possible that a plurality of target appliances 3 to be
controlled may be provided, and the illustration of
appliances other than the targets to be controlled is
omitted.
Next, the operation of the power control system in
accordance with the present embodiment will be described
with reference to the sequence diagram of Fig. 2.
First, when detecting the generation of a surplus
power in step S1, the surplus power information transmission
unit 2 transmits surplus power information to the appliance
control device 1 via the transmission line Ls1 in step S2.
Herein, the surplus power information also includes
information indicative of the amount of the surplus power.
The appliance control device 1 receives the surplus
power information transmitted via the transmission line Lsl
by the surplus power information reception unit 11 and
transfers the surplus power information to the appliance
control unit 10. The appliance control unit 10 determines
whether to start a predetermined operation of the appliance
3 on the basis of information on the amount of the surplus
power, included in the surplus power information, and
information on the power consumption of the appliance 3,
included in the operation information retained in the
operation information storage unit 12, in step S3.
In detail, the appliance control unit 10 determines

that the start of the predetermined operation is possible if
the amount of surplus power is greater than the power
consumption of the appliance 3, or determines that the start
of the predetermined operation is impossible if the amount
of the surplus power is less than the power consumption
thereof. If it is determined that the start is possible,
the appliance control unit 10 reads a command for an
operation start request stored in the operation information
storage unit 12 and transmits a control signal including the
command to the appliance 3 via the transmission line Ls2 in
step S4. In contrast, if it is determined that the start is
impossible, the appliance control unit 10 stops subsequent
processes.
Then, the appliance 3 receives the control signal
transmitted via the transmission line Ls2 by the control
signal reception unit 31, and transfers the command included
in the control signal to the control unit 30. The control
unit 30 controls the execution unit 32 in compliance with
the command and allows the execution unit 32 to execute the
predetermined operation in step S5. In this way, the
surplus portion of the power (surplus power) generated by
the photovoltaic power generation unit 100 is consumed by
the appliance 3 which executes the predetermined operation.
In this case, the surplus power varies depending on
the amount of power generated by the photovoltaic power
generation unit 100 and the power demand of the electric

power system W2. Accordingly, when detecting that a
variation amount of the surplus power has reached a
predetermined amount, on the basis of a comparison between
the voltage of the primary side and the output voltage of
the power conditioner 101 in step S6, the surplus power
information transmission unit 2 transmits the surplus power
information indicative of the variation in surplus power to
the appliance control device 1 via the transmission line Ls1
in step S7 . In this case, the surplus power information
includes information on the amount of surplus power that
remains after having been varied.
The appliance control device 1 receives the surplus
power information transmitted via the transmission line Lsl
by the surplus power information reception unit 11, and
transfers the surplus power information to the appliance
control unit 10. The appliance control unit 10 determines
whether to stop the predetermined operation of the appliance
3 on the basis of both information on the amount of the
surplus power, which remains after the variation of the
surplus power, included in the surplus power information,
and information on the power consumption of the appliance 3
included in the operation information retained in the
operation information storage unit 12 in step S8.
In detail, the appliance control unit 10 determines
not to stop the predetermined operation if the amount of the
surplus power that remains after the variation of the

surplus power is greater than the power consumption of the
appliance 3, or determines to stop the predetermined
operation if the amount of the surplus power that remains
after the variation of the surplus power is less than the
power consumption thereof. If it is determined to stop the
operation, the appliance control unit 10 reads a command for
an operation stop request retained in the operation
information storage unit 12 and transmits a control signal
including the relevant command to the appliance 3 via the
transmission line Ls2 in step S9. In contrast, if it is
determined not to stop the operation, the appliance control
unit 10 stops subsequent processes.
Then, the appliance 3 receives the control signal
transmitted via the transmission line Ls2 by the control
signal reception unit 31 and transfers a command included in
the control signal to the control unit 30. The control unit
30 controls the execution unit 32 in compliance with the
command to stop the predetermined operation of the execution
unit 32 in step S10. That is, in the case where the amount
of the surplus power generated by the photovoltaic power
generation unit 100 is less than the power consumption of
the appliance 3 that executes a predetermined operation, if
the appliance 3 continues the execution of the predetermined
operation, power needs to be purchased (fed) from the
electric power system W1 of the power purchasing-side power
provider. In such a case, since a power is not saved, the

predetermined operation of the appliance 3 is immediately
stopped.
As described above, in accordance with the power
control system in the present embodiment, the surplus power
is consumed by allowing one or more appliances 3 to execute
predetermined operations. This results in the advantage
that a surplus portion of a power generated by the self-
generated electrical power facility, such as a photovoltaic
power system or the like, can be efficiently consumed, thus
promoting power savings.
In this case, the surplus power information
transmission unit 2 in the present embodiment detects the
generation of the surplus power based on whether or not the
power conditioner 101 executes the suppressing of voltage
rise, but the method of detecting a surplus power is not
limited thereto. For example, when a notification (message)
indicating the stoppage of power selling is sent from the
power selling-side power provider to the appliance control
device 1 over a data communications network, such as the
Internet, the generation of the surplus power can be
detected based on the corresponding notification, the amount
of the power generated by the photovoltaic power generation
unit 100, and the power consumption of the appliance 3.
(Second Embodiment)
A power control system in accordance with a second
embodiment of the present invention is characterized in that

a device consuming the surplus power is a chargeable
appliance 3' having a secondary cell (e.g., a nickel metal
hydride battery, a lithium-ion battery or the like) as a
power source, and in that an appliance control device 1
controls charging of the secondary cell provided in the
chargeable appliance 3'. However, since the basic
configuration of the power control system of the present
embodiment is common to that of the first embodiment, the
common components will be designated by like reference
symbols with no illustration or description made thereon.
As shown in Fig. 3, the appliance control device 1 in
the present embodiment includes a surplus power information
reception unit 11 for receiving surplus power information
transmitted from a surplus power information transmission
unit 2 via a transmission line Ls1, a charging operation
information storage unit 12' for retaining (storing)
charging operation information on the chargeable appliance
3' , an AC/DC conversion unit 13 for converting an AC power
fed via a power line Lp1 into a DC power and supplying the
DC power to the chargeable appliance 3' , and an appliance
charging control unit 10' for controlling the AC/DC
conversion unit 13.
In this case, the charging operation information
retained in the charging operation information storage unit
12' is information required to control the charging
operation of the chargeable appliance 3' that is a target to

be controlled, and specifically includes information, such
as an internal command for starting or stopping the
operation of the AC/DC conversion unit 13 or an internal
command for adjusting an output voltage and an output
current, and a voltage value -and current value of a DC power
required to charge the secondary cell of the chargeable
appliance 3'.
Therefore, when the surplus power information
reception unit 11 receives the surplus power information
from the surplus power information transmission unit 2 and
transfers the surplus power information to the appliance
charging control unit 10', the appliance charging control
unit 10' compares the amount of the surplus power included
in the surplus power information with the amount of a power
required to charge the secondary cell of the chargeable
appliance 3' (amount of charging power) which is included in
charging operation information retained in the charging
operation information storage unit 12'.
If the amount of the surplus power is greater than the
amount of the charging power, the appliance charging control
unit 10' assigns the internal command read from the charging
operation information storage unit 12' to the AC/DC
conversion unit 13 so that the AC/DC conversion unit 13
executes an AC/DC conversion operation. In contrast, if the
amount of the surplus power is less than the amount of the
charging power, the appliance charging control unit 10'

stops subsequent processes.
Further, when the AC/DC conversion unit 13 starts to
perform the AC/DC conversion operation in compliance with
the internal command, the surplus power (AC power) fed via
the power line Lp1 is converted into a DC power and is used
(consumed) in the charging operation of the chargeable
appliance 3' . However, similarly to the first embodiment,
when the amount of the surplus power is changed and becomes
less than the amount of the charging power, the appliance
charging control unit 10' assigns the internal command to
the AC/DC conversion unit 13 to stop the AC/DC conversion
operation.
As described above, in accordance with the power
control system in the present embodiment, the secondary cell
of the chargeable electric device 3' is charged by using the
surplus power, thus enabling the surplus power to be
efficiently consumed. Further, control performed by the
appliance control device 1 in the first embodiment is
executed by the appliance control device 1 in the present
embodiment.
In detail, when the operation information that was
retained in the operation information storage unit 12 of the
appliance control device 1 in first embodiment is retained
in the charging operation information storage unit 12' of
the appliance control device 1 in the present embodiment,
and the appliance charging control unit 10' further performs

processes that were executed by the appliance control unit
10 of the appliance control device 1 in first embodiment, it
is possible for the surplus power to be consumed by allowing
the appliance 3 to execute the predetermined operation while
the surplus power is also consumed by allowing the
chargeable appliance 3' to execute the charging operation.
(Third Embodiment)
As shown in Fig. 5, a power control system in
accordance with a third embodiment of the present invention
is different from the power control system in the first
embodiment in that it includes a electric storage device 103
for storing a DC power (i.e., accumulating electricity)
generated by a photovoltaic power generation unit 100, a DC
distribution board 102 for individually distributing the DC
power generated by the photovoltaic power generation unit
100 to the electric storage device 103, a DC distribution
line Lp2 in a house H, and a power conditioner 101, and DC
appliances 4 (41 to 43) for using (consuming) the DC power
supplied (fed) via the DC distribution line Lp2. However,
the same reference numerals are assigned to components
common to those of the power control system in the first
embodiment, and a description thereof is omitted.
Herein, the power conditioner 101 in the present
embodiment includes an AC/DC converter (not shown) for
converting AC power supplied from the electric power system
W1 of a power purchasing-side power provider via a

distribution board 200 into a DC power, as well as an
inverter for converting the DC power generated by the
photovoltaic power generation unit 100 into an AC power.
Further, the DC power converted by the AC/DC converter of
the power conditioner 101 is supplied from the DC
distribution board 102 to the DC appliances 4 via the DC
distribution line Lp2.
The electric storage device 103 includes, e.g., a
lead-acid battery and a protection device for protecting the
lead-acid battery from overcharging or over-discharging.
The DC distribution board 102 includes a DC breaker (not
shown) for separating the photovoltaic power generation unit
100 from the power conditioner 101 and separating the
electric storage device 103 from the DC distribution line
Lp2 .
Each of the DC appliances 4 has components (a control
unit, a control signal reception unit, and an execution
unit) that are common to the appliance 3 for AC power shown
in Fig. 1, except that the using power thereof is a DC
power, and thus the illustration and description of detailed
configuration of each of the DC appliances 4 are omitted.
The power control system in accordance with the
present embodiment basically supplies a power generated by
the photovoltaic power generation unit 100 from the DC
distribution board 102 to the DC appliances 4 via the DC
distribution line Lp2 while supplying the power to

appliances 3 (3a to 3c) for AC power via the distribution
board 200. The power control system charges the electric
storage device 103 when the generated power is greater than
the power consumed by the appliances 3 and the DC appliances
4. Further, a surplus portion of the generated power, which
exceeds the storage capacity of the electric storage device
103, is sold (reversely supplied) to the electric power
system W2 of the power selling-side power provider.
When the amount of power consumed by the appliances 3
and the DC appliances 4 is greater than the amount of power
generated by the photovoltaic power generation unit 100 and
the amount of the power stored in the electric storage
device 103, the power control system feeds the power,
supplied (purchased) from the electric power system W1 of
the power purchasing-side power provider, to the appliances
3 via the distribution board 200 as well as feeding the
power to the DC appliances 4 via the power conditioner 101
and the DC distribution board 102.
Herein, the power generated by the photovoltaic power
generation unit 100, the power stored in the electric
storage device 103, and the power consumed by the DC
appliances 4 can be detected by the DC distribution board
102, and the power consumed by the appliances 3 can be
detected by the distribution board 200. The DC distribution
board 102 transfers the detected information to the
distribution board 200, so that the distribution board 200

can calculate the surplus power in the house H. Further,
although the number of the appliances 3 for AC power and the
number of the DC appliances 4 are shown as being only three
respectively in Fig. 5, the numbers are not limited to
those.
Further, as shown in Fig. 4, the appliance control
device 1 of the present embodiment is identical to the
appliance control device 1 of the first embodiment in that
the appliance control unit 10 and the surplus power
information reception unit 11 are provided. However, the
appliance device 1 is different from that of the first
embodiment in that, instead of the operation information
storage unit 12, a surplus power usage candidate list
storage unit 14 for retaining a list of surplus power usage
candidates is provided. Further, in Fig. 4, the
illustration of the DC appliances 4 is omitted.
The surplus power usage candidate list storage unit 14
is implemented with a rewritable non-volatile semiconductor
memory (e.g., a flash memory or the like) similarly to the
operation information storage unit 12. The surplus power
usage candidate list retained in the surplus power usage
candidate list storage unit 14 is a list including
information required to control the appliances 3 (3a to 3c)
and DC appliances 4 (41 to 43) that are targets to be
controlled. Specifically, the surplus power usage candidate
list is a list in which IDs of respective appliances 3a to

3c and those of the DC appliances 41 to 43 are correlated
with commands for starting or stopping the predetermined
operations of the appliances 3a to 3c and the DC appliances
41 to 43 and the amounts of power consumption of the
appliances 3a to 3c and DC appliances 41 to 43 when the
corresponding operations are performed.
Next, the operation of the power control system in
accordance with the present embodiment will be described.
When the surplus power information reception unit 11
receives the surplus power information from the surplus
power information transmission unit 2 and transfers it to
the appliance control unit 10, the appliance control unit 10
selects a combination of the appliances 3 and the DC
appliances 4 that can most efficiently use the surplus
power, on the basis of information on the amount of surplus
power included in the surplus power information and on
amounts of the power consumptions of the appliances 3a to 3c
and the DC appliances 41 to 43 that are included in the
surplus power usage candidate list retained in the surplus
power usage candidate list storage unit 14.
More specifically, the appliance control unit 10
primarily determines whether the amount of surplus power
exceeds a minimum amount of the power consumption in the
surplus power usage candidate list, and stops subsequent
processes if the amount of surplus power does not exceed the
minimum amount of power consumption. Further, if the amount

of surplus power exceeds the minimum amount of power
consumption in the surplus power usage candidate list, the
appliance control unit 10 selects a combination of the
appliances 3 and the DC appliances 4 of which the sum of
power consumptions is equal to or less than the amount of
surplus power and differs least from the amount of surplus
power, among the individual appliances 3 and the DC
appliances 4 included in the surplus power usage candidate
list. Further, the appliance control unit 10 transmits a
control signal, which includes a command for an operation
start request read from the surplus power usage candidate
list storage unit 14 and in which the identification codes
(ID codes) of the respective appliances 3 and DC appliances
4 are set in a destination address, to the transmission line
Ls2 in order to allow the selected appliances 3 and DC
appliances 4 to individually start predetermined operations.
Each of the appliances 3 and DC appliances 4 executes
a predetermined operation in compliance with the command
included in the control signal only when the ID code set in
the destination address of the control signal is identical
to its own ID code. In this case, each of the DC appliances
4 is supplied with the surplus power of the photovoltaic
power generation unit 100 via the DC distribution line Lp2.
Meanwhile, each of the appliances 3 is supplied with AC
power via the power line Lpl after the surplus power of the
photovoltaic power generation unit 100 has been converted

into the AC power by the power conditioner 101.
As described above, in the power control system in the
present embodiment, even if the amount of surplus power is
greater than the total amount of powers consumed by
individual appliances 3 and DC appliances 4, the appliance
control unit 10 selects a combination of the appliances 3
and DC appliances 4, of which the sum of the power
consumptions does not exceed the amount of surplus power, as
power usage candidates, and allows the plurality of
selected appliances 3 and DC appliances 4 to execute
predetermined operations, thus more efficiently using the
surplus power without any waste of power.
(Fourth Embodiment)
Since a basic system configuration of a power control
system in accordance with a fourth embodiment of the present
invention is common to that of the third embodiment 3 (refer
to Fig. 5), the same reference numerals are assigned to
common components, and the illustration and description
thereof will be omitted.
In the present embodiment, as shown in Fig. 6, a
surplus power prediction information transmission unit 2' is
provided in a distribution board 200 and is configured to
transmit both surplus power prediction information and
surplus power information indicative of an actually
generated surplus power to an appliance control device 1 via
a signal line (transmission line) Ls1. The surplus power

prediction information is obtained by predicting the time at
which the surplus power is generated and the amount of the
surplus power, on the basis of the amount of the power
generated by a photovoltaic power generation unit 100 and a
demand for the power.
The surplus power prediction information transmission
unit 2' predicts the time at which the surplus power is
estimated to be generated in the individual time slots of a
day (e.g., time slots corresponding to every one or several
hours), and the amount of surplus power generated at that
time, on the basis of patterns (time slots) of voltage rise
suppression performed by the power conditioner 101 in a day,
patterns of power generation (the amount of power generated
in individual time slots) by the photovoltaic power
generation unit 100, patterns of usual power consumption
(the amount of powers consumed in the individual time slots)
by the respective appliances 3 (also including DC appliances
4, hereafter the same as the above), and allowable residual
power stored in the electric storage device 103.
However, the method of predicting the time of
generation of the surplus power and the amount of the
surplus power are not limited to the above method. For
example, when a notification indicating the stoppage of
power selling (e.g., a message indicating that power selling
will be stopped from A time on 0 month X date) is sent from
the power selling-side power provider to the appliance

control device 1 over a data communications network, such as
the Internet, the time at which the surplus power is
generated and the amount of the surplus power can be
predicted based on the relevant notification and the above-
described individual patterns.
The appliance control device 1 in accordance with the
present embodiment includes a surplus power prediction
information reception unit 11' for receiving the surplus
power prediction information and the surplus power
information, which have been transmitted from the surplus
power prediction information transmission unit 2' via the
signal line Ls1, and for transferring the relevant
information to the appliance control unit 10. Further, in
the present embodiment, a surplus power usage candidate list
retained in the surplus power usage candidate list storage
unit 14 includes the time (activation time) taken to
activate a relevant appliance 3 that is the power using
candidate in a power off state (a waiting state), or a
command required to activate a relevant appliance 3.
Next, the operation of the power control system in
accordance with the present embodiment will be described.
The surplus power prediction information reception unit 11'
receives the surplus power prediction information, which has
been predicted by and transmitted from the surplus power
prediction information transmission unit 2', and transfers
it to the appliance control unit 10. Then, the appliance

control unit 10 selects a combination of the appliances 3
that can most efficiently use a surplus power (predicted
value), on the basis of a predicted value for the amount of
surplus power included in the surplus power prediction
information and the amount of the power consumption of the
appliances 3 included in the surplus power usage candidate
list retained in . the surplus power usage candidate list
storage unit 14.
In detail, the appliance control unit 10 primarily
determines whether the amount of surplus power (predicted
value) exceeds the minimum amount of power consumption in
the surplus power usage candidate list, and stops subsequent
processes if the amount of surplus power does not exceed the
minimum amount of power consumption. In contrast, if the
amount of surplus power (predicted value) exceeds the
minimum amount of power consumption in the surplus power
usage candidate list, the appliance control unit 10 selects
a combination of the appliances 3, of which sum of power
consumptions is equal to or less than the amount of the
surplus power (predicted value) and differs least from the
amount of the surplus power (predicted value), among the
individual appliances 3 included in the surplus power usage
candidate list. Further, the appliance control unit 10
sends a control message, that includes an activation
command, to each of the selected appliances 3 in timing
prior to the surplus power generation time (the predicted

time) by the activation time thereof to thereby activate the
selected appliance 3 before the corresponding predicted
time .
Further, when the surplus power prediction information
transmission unit 2' actually detects the generation of the
surplus power and sends the surplus power information, the
appliance control unit 10 that receives the surplus power
information via the surplus power prediction information
reception unit 11' transmits a command for an operation
start request, which is read from the surplus power usage
candidate list storage unit 14, to the individual one of the
appliances 3 that have been selected. Then, the appliances
3 having received the command execute the predetermined
operations by using (consuming) the surplus power.
Therefore, the power control system in accordance with
the present embodiment is advantageous in that the surplus
power generation time and the amount of the surplus power
are predicted and the appliances 3 are previously activated
correspondingly to the time at which the surplus power is
generated, thus more efficiently using the surplus power.
(Fifth Embodiment)
A fifth embodiment of an electric device in accordance
with the present invention will be described. Fig. 7
illustrates a configuration of a power control system
including an electric device 5 in accordance with the
present embodiment. In the power control system of present

invention, the same reference numerals are assigned to
components common to those of the power control system of
the first embodiment, and the illustration and description
thereof will be omitted.
The electric device 5 includes a control unit 50
having a microcomputer as its principal component, a surplus
power information reception unit 51, an execution unit 52
for executing a predetermined operation, an operation
information storage unit 53 implemented as rewritable non-
volatile semiconductor memory, such as a flash memory, and a
switch manipulation unit 54. The surplus power information
reception unit 51 receives surplus power information
transmitted from a surplus power information transmission
unit 2 installed in a distribution board 200 via a signal
line Ls1.
The control unit 50 receives the surplus power
information from the surplus power information reception
unit 51 and performs the control of assigning an internal
command to the execution unit 52 to start or stop a
predetermined operation (hereinafter, referred to as
"automatic control upon the generation of surplus power") on
the basis of the surplus power information and operation
information retained (stored) in the operation information
storage unit 53. In this case, the term operation
information retained in the operation information storage
unit 53 refers to information, such as an internal command

for allowing the execution unit 52 to start or stop a
predetermined operation and the amount of the power consumed
when a relevant operation is executed.
However, when the operation executed by the execution
unit 52 by using the automatic control upon the generation
of surplus power is an operation programmed such that the
control unit 50 prompts the operation to be executed by the
execution unit 52 at every scheduled time set with a
predetermined interval, information, such as the scheduled
time at which the relevant operation is to be executed, the
time taken to execute the relevant operation or the like is
also included in the operation information.
Further, the "predetermined operation" may include,
e.g., a defrosting operation or a ice-making operation when
the electric device 5 is a refrigerator or may include a
cooling or heating operation performed so that room
temperature is maintained at a set temperature or an
operation of cleaning an internal filter or an internal fan
when the electric device 5 is air-conditioning equipment
(air conditioner). The "predetermined operation" may
further include an operation of purifying air within the
room or an operation of cleaning an internal filter or the
like when the electric device 5 is an air cleaner or may
include an error checking operation or a defragmentation
operation performed on a storage device, such as a hard disk
device, when the appliance 3 is a personal computer.

The switch manipulation unit 54 has a human-
manipulatable switch, such as a dip switch or a push-button
switch. The switch manipulation unit 54 receives a
manipulation input required to switch the
validity/invalidity of automatic control upon the generation
of surplus power by means of the manipulation of the switch
and outputs the manipulation input to the control unit 50.
That is, when the switch manipulation unit 54 receives a
manipulation input that causes the automatic control upon
the generation of surplus power to be valid, the operation
mode of the control unit 50 is set to be ON, whereas when
the switch manipulation unit 54 receives a manipulation
input that causes the automatic control upon the generation
of surplus power to be invalid, the operation mode of the
control unit 50 is set to be OFF.
When the operation mode is set to be OFF, the control
unit 50 performs no automatic control upon the generation of
surplus power even when surplus power information is
received from the- surplus power information reception unit
51. However, although the operation mode is set to be OFF,
when the operation executed by the execution unit 52 by
using the automatic control upon the generation of surplus
power is the programmed one to be executed by the execution
unit 52 at the scheduled time, as described above (e.g., the
defrosting operation of.a refrigerator or the cleaning of an
air conditioner and the like) , the control unit 50 allows

the execution unit 52 to execute the predetermined operation
by assigning an internal command to the execution unit 52 at
the scheduled time.
Meanwhile,' when the operation mode is set to be ON,
the control unit 50 performs the automatic control upon the
generation of surplus power when the surplus power
information is received from the surplus power information
reception unit 51. In detail, when the amount of the
surplus power included in the surplus power information is
greater than an amount of power consumption included in the
operation information retained in the operation information
storage unit 53, the control unit 50 starts a predetermined
operation by assigning an internal command to the execution
unit 52. In contrast, when the amount of surplus power is
less than the amount of the power consumption, the control
unit 50 stops the process of relevant automatic control
without assigning the internal command. When the internal
command for starting the predetermined operation is received
from the control unit 50, the execution unit 52 executes the
predetermined operation by using (consuming) the surplus
power fed via the power line Lp1.
In this regard, in the case where the operation to be
executed by the execution unit 52 by using the automatic
control upon the generation of surplus power is the
programmed one to be executed by the execution unit 52 at a
scheduled time, as described above (e.g., the defrosting of

a refrigerator, the filter cleaning of an air conditioner or
the like), if the above operation is executed by the
execution unit 52 at a time other than the scheduled time
due to the generation of surplus power, the control unit 50
preferably determines new scheduled time with regular
interval by setting the time at which the automatic control
is performed as a starting point. Then, the initially
scheduled times are changed with the newly determined
scheduled times. That is, since it is sufficient to execute
the defrosting of the refrigerator or the filter cleaning of
the air conditioner at prescribed intervals, unnecessary
power is consumed if such an operation is executed at
intervals shorter than the prescribed intervals.
As described above, in the electric device 5 in
accordance with the present embodiment, when a surplus power
is generated, it is consumed by having the execution unit 52
to execute a predetermined operation, thus enabling the
surplus power generated by the self-generated electrical
power facility, such as the photovoltaic power system or the
like, to be efficiently consumed and promoting power
savings.
(Sixth Embodiment)
A sixth embodiment of an electric device in accordance
with the present invention will be described. Since the
configuration of • a power control system including an
electric device 5 in accordance with the present embodiment

is common to that of the fifth embodiment, the same
reference numerals are assigned to common components and the
illustration and description thereof will be omitted.
The electric device 5 in accordance with the present
embodiment is a device operated by using a secondary cell as
a power source, such as a DMP (Digital Music Player), an
electric razor, an electric toothbrush or the like. As
shown in Fig. 8, the electric device 5 includes a battery
unit 57 including a secondary cell and a charging circuit
for the secondary cell, a charging control unit 55 for
controlling the charging circuit of the battery unit 57 to
start or to stop charging, a charging operation information
storage unit 56 for storing information required to control
the charging of the battery unit 57 (charging operation
information), and an execution unit (not shown), in addition
to a surplus power information reception unit 51 and a
switch manipulation unit 54. Further, the execution unit is
configured to execute the principal function of the electric
device 5, e.g., the function of reading music data stored in
a storage medium and converting the music data into
electrical signals in the case of the DMP, the function of
driving a razor blade in the case of the electric razor, and
the function of vibrating a brush in the case of the
electric toothbrush.
With this regard, the charging operation information
retained in the charging operation information storage unit

56 refers to information used to control the charging
operation of the battery unit 57, and specifically means
information on an internal command for allowing the charging
circuit of the battery unit 57 to start or to stop the
charging operation, or the amount of power required for
charging. Further, in the present embodiment, the charging
control unit 55 has an automatic charging function of
causing the charging circuit of the battery unit 57 to start
charging when the residual capacity of the secondary cell is
less than a predetermined threshold value. The relevant
threshold value is retained in the charging operation
information storage unit 56 as two types of threshold values
including a first threshold value near to a value of full
charging and a second threshold value almost corresponding
to the amount of power consumption of one-time use of the
electric device 5.
When the operation mode is set to be OFF by the switch
manipulation unit -'54, the charging control unit 55 does not
allow the battery unit 57 to automatically execute a
charging operation in response to simply receiving the
surplus power information from the surplus power information
reception unit 51. The charging control unit 55 allows the
battery unit 57 to execute a charging operation only when
the residual capacity of the secondary cell is less than the
first threshold value.
In contrast, when the operation mode is set to be ON,

the charging control unit 55 does not cause the battery unit
57 to execute a charging operation only by using the fact
that the residual capacity of the secondary cell is less
than the first threshold value. In this case, when the
surplus power information is received from the surplus power
information reception unit 51, the charging control unit 55
assigns the internal command to the battery unit 57 to start
a charging operation if the amount of surplus power included
in the surplus power information is greater than the amount
of the power consumption included in the charging operation
information retained in the charging operation information
storage unit 56. In contrast, if the amount of surplus
power is less than the power consumption, the charging
control unit 55 stops subsequent processes without assigning
an internal command.
In the battery unit 57, when the internal command for
starting the charging operation is received from the
charging control unit 55, the charging circuit charges the
secondary cell by using (consuming) the surplus power fed
via the power line Lp1. Further, even in this case, it is
apparent that when the residual capacity of the secondary
cell is less than the second threshold value, the charging
control unit 55 causes the battery unit 57 to execute the
charging operation.
As described above, in the electric device 5 in the
present embodiment, the secondary cell of the battery unit

57 is charged with the surplus power, thus enabling the
surplus power to be efficiently consumed. Further, when the
control unit 50, the execution unit 52, and the operation
information storage unit 53 described in the fifth
embodiment are provided in the electric device 5 in the
present embodiment, the surplus power can be used not only
to charge the secondary cell but also to execute
predetermined operations using the execution unit 52, thus
enabling the efficient use of the surplus power.
In the first to sixth embodiments described above,
although it has -been described that the electric power
system W1 of the power purchasing-side power provider and
the electric power system W2 of the power selling-side power
provider feed a power to the house H via their own dedicated
power lines L1 and L2, parts or all of the power lines L1
and L2 may be shared in common between the two electric
power systems Wl and W2. Further, in the first to sixth
embodiments, although the power purchasing-side power
provider and the power selling-side power provider have been
described as being separate power providers, they may be the
same power provider. In that case, the power meter Ml for
power purchasing and the power meter M2 for power selling
are connected in series with a power line used in common to
purchase and sell the power.
Further, in the above embodiments, although a house
has been used to exemplify the place to which the power

control system is applied, the place is not limited to this
example, and the power control system can be installed in
and applied to apartments, such as mansions, offices or the
like in office buildings.
(Other modifications)
Although the present invention has been described as
in the above embodiments, it is apparent that the present
invention is not limited thereto. The following cases are
also included in the present invention.
(1) The appliance control device includes, in detail,
a computer system including a microprocessor, Read Only
Memory (ROM), Random Access Memory (RAM), a hard disk unit,
a display unit, a keyboard, a mouse or the like. The RAM or
hard disk unit-' stores a computer program. The
microprocessor is operated by the computer program, and the
appliance control device carries out the functions of the
program. The computer program is implemented by combining a
plurality of instruction codes indicative of instructions
related to the computer so as to carry out predetermined
functions. Further, each device is not limited to the
computer system including all of a microprocessor, ROM, RAM,
a hard disk unit, a display unit, a keyboard, a mouse or the
like and may be a computer system including some of them.
(2) Some or all of the components forming the
appliance control device may be implemented as a single
system LSI (Large Scale Integration). A system LSI is an

ultra-multifunctional LSI manufactured by integrating a
plurality of components on a single chip, and is, in
particular, a computer system including a microprocessor,
ROM, RAM and the like. The RAM stores a computer program.
The microprocessor is operated by the computer program, so
that the system LSI achieves the functions thereof.
Further, each part of components included in the
appliance control device may be implemented as a single chip
or may be implemented as a single chip to include some or
all of the components.
Furthermore, although referred to as a system LSI
here, the circuit may also be referred to as an Integrated
Circuit (IC) , LSI, super LSI or ultra LSI depending on the
difference in the degree of integration. Further, the
technique of integrated circuit implementation is not
limited to LSI and may be implemented as a dedicated circuit
or a general-purpose processor. A Field Programmable Gate
Array (FPGA) enabling programming after the manufacture of
an LSI, or a reconfigurable processor enabling the
connection or setting of circuit cells in the LSI to be
reconfigured, may be used.
Furthermore, if integrated circuit implementation
technique replacing an LSI appears thanks to other
technologies that develop or are derived from semiconductor
technology, it is apparent that the integration of
functional blocks may be achieved using such technique.

There may be a possibility for bio-technology to be applied.
(3) Some or all of the components included in the
appliance control device may be implemented as an IC card or
a single module that is attachable to and detachable from
each device. The IC card or the module is a computer system
including a microprocessor, ROM, RAM or the like. The IC
card or the module may include the above ultra-
multifunctional LSI. The microprocessor is operated by the
computer program, so that the IC card or the module carries
out the function thereof. The IC card or the module may
have anti-tamper characteristics.
(4) The present invention also includes a power
control method that can efficiently consume a surplus power
generated by a self-generated electrical power facility.
The present invention includes a computer program in which
the above method is implemented by a computer, and also
includes a digital signal implemented as the computer
program.
Further, the present invention includes a storage
medium from which the computer program or the digital signal
can be read by the computer, e.g., a flexible disk, a hard
disk, Compact Disk-ROM (CD-ROM), a Magneto-Optical (MO)
drive, a Digital Versatile Disk (DVD), DVD-ROM, DVD-RAM, a
Blur-ray Disk (BD), semiconductor memory or the like.
Further, the present invention also includes the digital
signal stored in the storage medium.

Further, the present invention may transmit the
computer program or the digital signal over a network
representing a telecommunications line, a wireless or wired
communications line or the Internet, or via data
broadcasting.
Further, the present invention is a computer system
provided with a microprocessor and memory, wherein the
memory may store the computer program and the microprocessor
may be operated in accordance with the computer program.
Further, the program or the digital signal may be
executed by different independent computer systems by
storing in the storage medium and transferring it, or
transferring it via the network or the like.
(5) It may be possible to individually combine the
above embodiments and the modifications.
In accordance with the present invention, a power
control system and electric device capable of efficiently
consuming a surplus portion of power generated by a self-
generated electrical power facility, such as a photovoltaic
power system.
While the invention has been shown and described with
respect to the embodiments, the present invention is not
limited thereto. It will be understood by those skilled in
the art that various changes and modifications may be made
without departing from the scope of the invention as defined
in the following claims.

WE CLAIM:
1. A power control system configured to control electric
devices to consume a power generated by a self-generated
electrical power facility using a natural energy,
comprising:
a surplus power detection unit for detecting a surplus
power generated by the self-generated electrical power
facility; and
an appliance control unit for controlling operations
of the electric devices,
wherein the appliance control unit performs a control
such that when the surplus power detection unit detects the
surplus power, one or more of the electric devices
respectively execute predetermined operations and consume
the surplus power.
2. The power control system of claim 1, wherein the
electric devices include one or more chargeable electric
devices, each having a secondary cell as a power source,
and, when the surplus power detection unit detects the
surplus power, the appliance control unit performs a control
such that the surplus power is supplied to the chargeable
electric devices and each of the chargeable electric devices
executes a charging operation.

3. The power control system of claim 1 or 2, further
comprising an appliance information storage unit for storing
information on predetermined operations that are executed by-
electric devices in power usage candidates for the surplus
power,
wherein, when the surplus power detection unit detects
the surplus power, the appliance control unit performs a
control such that a combination of electric devices which
efficiently consumes the surplus power is selected among the
power usage candidates on the basis of the information on
the predetermined operations stored in the appliance
information storage unit, and the selected electric devices
consume the surplus power by executing the respective
predetermined operations.
4. The power control system of claim 3, further comprising
a surplus power prediction unit for predicting a time at
which the surplus power is generated and an amount of the
surplus power, based on an amount of a power generated by
the self-generated electrical power facility and a demand
for the power,
wherein the appliance information storage unit stores
information on times taken to activate the electric devices
in the power usage candidates for the surplus power,
together with the information on the predetermined
operations, and

wherein the appliance control unit selects a
combination of electric devices which efficiently consume
the surplus power among the power usage candidates, based on
the amount of the surplus power predicted by the surplus
power prediction unit, the information on the predetermined
operations stored in the appliance information storage unit,
and the information on the times taken to activate the
electric devices, thus activating the selected electric
devices before the surplus power generation time predicted
by the surplus power prediction unit, and enables the
surplus power to be supplied to the selected electric
devices when the surplus power detection unit detects the
surplus power to allow the electric devices to execute the
predetermined operations.
5. An electric device configured to consume a power
generated by a self-generated electrical power facility
using a natural energy, comprising:
an execution unit for executing a predetermined
operation upon power supply;
a control unit for controlling the execution unit; and
a surplus power detection unit for detecting a surplus
power from the self-generated electrical power facility,
wherein, when the surplus power detection unit detects
the surplus power, the control unit controls the execution
unit to consume the surplus power by executing the

predetermined operation.
6. The electric device of claim 5, wherein the execution
unit is a secondary cell, and, when the surplus power
detection unit detects the surplus power, the control unit
controls the surplus power to be supplied to charge the
secondary cell.

ABSTRACT
A power control system controls electric devices so as
to consume a power generated by a self-generated power
facility using a natural energy, which is provided with a
surplus power detection unit that detects the surplus
portion of power generated by the self-generated power
facility, and a device control unit that controls the
operation of a plurality of electric devices. When the
surplus power detection unit detects the surplus power, the
device control unit controls one or more of a plurality of
electric devices to perform predetermined operations so as
to consume the surplus power.