Field of the Invention
The present invention relates to an apparatus for
monitoring the power sources of a storage battery in a power
supply system, which manages individual sources of power
stored in a storage battery.
Background of the Invention
A house is provided with a power supply system (see
Patent document 1) for converting AC voltage from a
commercial power source into DC voltage and supplying the DC
voltage to various types of household appliances. Among
recent power supply systems, a system has begun to be
popularized which is provided with a solar cell for
generating power from solar light power generation and which
can supply DC power to various types of appliances using not
only a commercial power source but also the solar cell.
Further, among power supply systems, there are also power
supply systems provided with a storage battery as a backup
power source for the systems, thus enabling power, which
could be generated by a commercial power source in the
nighttime when the power rate is low, or which could be

generated using solar light in surplus in the daytime, to be
reserved in the storage battery.
[Patent Document 1] Japanese Patent Application
Publication No. 2009-159690
In this case, in a storage battery, amounts of power
from multiple sources, such as power generated from a
commercial power source in the nighttime when the power rate
is low, or the surplus power of a solar cell remaining after
power generation in the daytime, are stored. However, at
the present time, the source from which the power stored in
the storage battery has been obtained cannot be known. In
the future, it is expected that there may be a need to know
from which of power sources the power stored in the storage
battery has been obtained and how much of the power is
stored in the storage battery, so that the development of
new technology for coping with such a need has been required.
Summary of the Invention
The present invention has been made keeping in mind
the above problems occurring in the prior art, and an object
of the present invention is to provide an apparatus for
monitoring the power sources of a storage battery in a power
supply system, which can determine from which of power
sources power stored in a storage battery is obtained and to
v.
what extent the power has been stored.

In accordance with an embodiment of the present
invention, there is provided a device for monitoring power
sources of a storage battery, including: a monitoring unit
for monitoring input and output of power to and from a
storage battery; and a power source management unit for
managing sources from which amounts of power stored in the
storage battery have been obtained and extents to which the
amounts of power have been stored in the storage battery.
With such configuration, when power is charged in the
storage battery, sources from which the power has been input
and the extent to which the power has been input from the
sources are monitored. When power is output from the
storage battery, sources from which the output power has
been obtained and the extent to which the power is to be
output are monitored. Therefore, the present configuration
enables the input and output of power of the storage battery
to be managed, so that it is possible to determine from
which of sources power stored in the storage battery has
been obtained and to what extent the power has been stored.
For this reason, whether power stored in the storage battery
has been purchased from an electric power company or has
been generated from natural energy can be determined, and as
a result, consciousness about energy savings can be
heightened.
The device for monitoring power sources of the storage
battery may be applied to a power supply system which

performs voltage conversion on a voltage obtained from a
grid or an independently power generating cell, and branches
and supplies the voltage to individual appliances, and which
is provided with the storage battery as a backup power
source of the grid or the independently power generating
cell.
With such configuration, since the surplus power
remaining in the system can be reversely supplied to the
grid when power generated by the independently power
generating battery is discharged to the load, a surplus
portion of power obtained from independent power generation
can be sold. Therefore, for example, since it is impossible
to collect power in the storage battery in the nighttime
when the power rate is low and sell the power in the daytime
where the power rate is high, it is possible to sell the
available power that may be sold to an electric power
company or the like according to a formal procedure.
The device may further include an independently
generated-power residual capacity calculation unit for
calculating surplus power, which remains in the power supply
system, of power generated by the independently power
generating cell; and a power reverse supply unit for
reversely supplying the surplus power to the grid.
With such configuration, of the power stored in the
storage battery, power supplied from the independently power
generating battery as a source can be sold, so that

independently generated power which is not a target to be
improperly sold can be sold over a preferable time span
desired by an electric power company.
According to the present invention, it can be
determined from which of sources power stored in the storage
battery has been obtained and to what extent the power has
been stored.
Brief Description of the Drawings
The objects and features of the present invention will
be apparent from the following description of embodiments
when taken in conjunction with the accompanying drawings, in
which:
Fig. 1 is a block diagram showing the configuration of
a power supply system according to an embodiment;
Fig. 2 is a diagram showing the configuration of a
system for managing the power sources of a storage battery;
Fig. 3 is a diagram showing the operating status of
the system in the daytime;
Fig. 4 is a diagram showing an operating status
notification screen;
Fig. 5 is a conceptual diagram showing the status of
an operation performed when a surplus portion of solar
light-generated power is sold;
Fig. 6 is a conceptual diagram showing the operating

status of the system in the nighttime;
Fig. 7 is a conceptual diagram also showing the
operating status of the system in the nighttime;
Fig. 8 is a conceptual diagram showing the status when
the residual capacity of the storage battery is greatly
decreased; and
Fig. 9 is a conceptual diagram showing the status of
an operation performed when the storage battery is charged
from a grid.
Detailed Description of the Preferred Embodiments
Hereinafter, an embodiment of the present invention
will be described with reference to the accompanying
drawings which form a part hereof. The same reference
numerals will be assigned to the same or similar components
throughout the drawings, and redundant descriptions thereof
will be omitted.
Hereinafter, an embodiment in which an apparatus for
monitoring the power sources of a storage battery in a power
supply system according to the present invention is embodied
in a house will be described with reference to Figs. 1 to 9.
As shown in Fig. 1, a house is provided with a power
supply system 1 that supplies power to various types of
household appliances (a lighting device, an air conditioner,
household electronic appliances, audio and visual appliances,

etc.). The power supply system 1 not only operates various
types of appliances using a commercial AC power source (AC
power source) obtained from a grid 2, as a power source, but
also supplies power from a solar cell 3, generated using
solar light, to the various types of appliances, as power.
The solar cell 3 includes, for example, multiple cells 4.
The power supply system 1 supplies power not only to DC
appliances 5 configured to receive and be operated by the
power of a DC power source but also to an AC appliance 6
configured to receive and be operated by the power of the AC
power source. Further, the solar cell 3 corresponds to an
independently power generating battery, and the DC
appliances 5 and the AC appliance 6 constitute a load.
In the power supply system 1, a control unit 7 and a
DC distribution board (containing a DC breaker) 8 are
provided as the distribution board of the system 1.
Furthermore, in the power supply system 1, a control unit 9
and a relay unit 10 are provided as a device for controlling
the operation of the DC appliances 5 of the house.
An AC distribution board 11 for branching AC power is
connected to the control unit 7 via an AC power line 12.
The control unit 7 is connected to the grid 2 via the AC
distribution board 11, and is connected to the solar cell 3
via a DC power line 13. The control unit 7 receives AC
power from the AC distribution board 11, receives DC power
from the solar cell 3, and converts the power into

predetermined DC power, that is, appliance power.
Furthermore, the control unit 7 outputs the resulting DC
power to the DC distribution board 8 via a DC power line 14,
and outputs it to the storage battery unit 16 via a DC power
line 15. The control unit 7 receives AC power, converts the
DC power of the solar cell 3 or storage battery unit 16 into
AC power, and supplies the AC power to the AC distribution
board 11. The control unit 7 exchanges data with the DC
distribution board 8 via a signal line 17.
The DC distribution board 8 is a kind of breaker for
DC power. The DC distribution board 8 branches the DC power
input from the control unit 7, and outputs the resulting DC
power to the control unit 9 via a DC power line 18, or to
the DC relay unit 10 via a DC power line 19. Furthermore,
the DC distribution board 8 exchanges data with the control
unit 9 via a signal line 20, or with the relay unit 10 via a
signal line 21.
The multiple DC appliances 5 are connected to the
control unit 9. These DC appliances 5 are connected to the
control unit 9 via DC supply lines 22 that are each capable
of carrying both DC power and data over a single wire. The
DC supply lines 22 each carry both power and data to each of
the DC appliances 5 over a single wire using power line
communication that superimpose communication signals
transmitting data over a high-frequency carrier on DC
voltage, that is, power for the DC appliances. The control

unit 9 obtains the DC power of the DC appliances 5 via the
DC power line 18, and determines which of the DC appliance 5
is to be controlled and how to control the DC appliance 5,
based on operating instructions obtained from the DC
distribution board 8 via the signal line 20. Furthermore,
the control unit 9 outputs DC voltage and operating
instructions to the determined DC appliance 5 over the DC
supply line 22, and controls the operation of the DC
appliance 5.
Switches 23 that are manipulated when the operations
of the household DC appliances 5 are switched are connected
to the control unit 9 via the DC supply line 22 .
Furthermore, a sensor 24 for detecting, for example, radio
waves transmitted by an infrared remote control is connected
to the control unit 9 via the DC supply line 22.
Accordingly, the DC appliances 5 are controlled by
transmitting communication signals over the DC supply line
22 in response not only to an operating instruction from the
DC distribution board 8 but also to the manipulation of the
switches 23 or the detection of the sensor 24.
Multiple DC appliances 5 are connected to the relay
unit 10 via respective DC power lines 25. The relay unit 10
obtains the DC power of the DC appliances 5 via the DC power
line 19, and determines which of the DC appliances 5 is to
be operated based on an operating instruction obtained from
the DC distribution board 8 via the signal line 21.

Furthermore, the relay unit 10 controls the operation of the
determined DC appliance 5 in such a way that a contained
relay selectively turns on and off the supply of power via
the DC power line 25. Furthermore, multiple switches 26 for
manually manipulating the DC appliances 5 are connected to
the relay unit 10, and the DC appliances 5 are controlled by
selectively turning on and off the supply of power over the
DC power line 25 using the relay in response to the
manipulation of the switches 26.
A DC outlet 27 that is suitably attached to the house,
for example, in the form of a wall outlet or a bottom outlet,
is connected to the DC distribution board 8 via the DC power
line 28. When the plug (not shown) of the DC appliance is
inserted into the DC outlet 27, DC power can be directly
supplied to the appliance.
Furthermore, a power meter 2 9 capable of remotely
measuring the amount of power of the grid 2 used is
connected between the grid 2 and the AC distribution board
11. The power meter 29 is equipped not only with the
function of remotely measuring the amount of commercial
power used but also with, for example, the function of power
line communication or wireless communication. The power
meter 29 transmits the results of the measurement to an
electric power company or the like via power line
communication or wireless communication.
The power supply system 1 is provided with a network

system 3 0 that enables various types of household appliances
to be controlled via network communication. The network
system 3 0 is provided with a home server 31 that functions
as the control unit of the network system 30. The home
server 31 is connected to an external management server 32
via a communication network N, such as the Internet, and
also to premise equipment 34 via a signal line 33.
Furthermore, the home server 31 operates using DC power,
obtained from the DC distribution board 8 via the DC power
line 35, as power.
A control box 3 6 for managing the operational control
of various types of home appliances using network
communication is connected to the home server 31 via a
signal line 37. The control box 36 is connected to the
control unit 7 and the DC distribution board 8 via the
signal line 17, and may also directly control the DC
appliances 5 via a DC supply line 38. A gas/water meter 39
capable of remotely measuring, for example, the amounts of
gas or water used is connected to the control box 36 which
is in turn connected to the control panel 4 0 of the network
system 30. A monitoring appliance 41 including, for example,
a door phone receiver, a sensor or a camera is connected to
the control panel 40.
When instructions to operate the various types of home
appliances are input via the communication network N, the
home server 31 notifies the control box 36 of the

instructions, and operates the control box 36 so that the
various types of appliances perform operations based on the
operating instructions. Furthermore, the home server 31 may
provide various types of information, obtained from the
gas/water meter 39, to the management server 32 via the
communication network N, and, upon receiving notification
that the monitoring appliance 41 has detected an abnormality
from the control panel 40, may also provide the notification
to the management server 32 via the external communication
network N.
As shown in Fig. 2, the control unit 7 is provided
with a DC/DC converter 42 connected to the solar cell 3.
The DC/DC converter 42 converts a DC voltage output from the
solar cell 3 into a voltage of a predetermined value and
outputs the resulting DC voltage to the DC distribution
board 8 or the storage battery unit 16. The DC power output
to the DC distribution board 8 is supplied to the DC
appliances 5 as appliance power. Further, the DC power
output to the storage battery unit 16 is stored in the
storage battery 43 of the storage battery unit 16.
The control unit 7 is provided with a bidirectional
AC/DC converter 44 connected to the AC distribution board 11.
The bidirectional AC/DC converter 44 outputs AC power
obtained from the grid 2 into DC power and outputs the DC
power to the DC distribution board 8 or the storage battery
unit 16 or, on the contrary, converts DC power obtained from,

for example, the solar cell 3, into AC power and supplies
the AC power to the AC distribution board 11.
A DC/DC converter 4 5 connected to the DC/DC converter
42 and to the bidirectional AC/DC converter 44 is connected
to the DC distribution board 8. The DC/DC converter 45
converts the DC voltage obtained from the control unit 7
into a voltage of a predetermined value and outputs the
resulting voltage to the various types of DC appliances 5
through breakers 46.
The storage battery unit 16 is provided with a DC/DC
converter 47 for converting a DC voltage input and output to
and from the unit 16 into a voltage of a predetermined value.
The DC/DC converter 47 converts a DC voltage input from the
control unit 7 into a voltage of a predetermined value when
the storage battery 43 is charged with the DC voltage, or
converts the DC voltage of the storage battery 43 into a
voltage of a predetermined value when the DC voltage is
output to the control unit 7. Further, the DC/DC converter
4 7 is configured to suitably convert discharge current
flowing through the DC/DC converter 47 on the basis of the
input voltage.
The power supply system 1 is provided with a storage
battery power source management system 4 8 for managing
sources from which amounts of power stored in the storage
battery 4 3 have been obtained. In the present embodiment,
the system power sources of the power supply system 1

include the grid 2 and the solar cell 3, so that amounts of
power that are supplied from the grid 2 and the solar cell 3,
which are sources, are stored in the storage battery 43.
Accordingly, the storage battery power source management
system 4 8 manages the extents to which grid power Wall and
solar 1ight-generated, power Wv are respectively stored in
the storage battery 43. Further, the solar light-generated
power Wv corresponds to the generated power.
In this case, the AC distribution board 11 is provided
with a grid power detection unit 49 for detecting the grid
power Wall. Further, the control unit 7 is provided with a
solar light-generated power detection unit 50 for detecting
power output from the DC/DC converter 42 (hereinafter
referred to as "solar light-generated power Wv"), a
bidirectional AC/DC power detection unit 51 for detecting
power input and output to and from the bidirectional AC/DC
converter 44 (hereinafter referred to as "bidirectional
AC/DC power Ws"), and a DC usage power detection unit 52 for
detecting power used by the DC appliances 5 (hereinafter
referred to as "DC usage power Wc"). Furthermore, the power
detection units 49 to 52 constitute a monitoring means.
The control unit 7 is provided with a control circuit
5 3 as the control unit of the storage battery power source
management system 48. The control circuit 53 is connected
to the individual power detection units 49 to 52, and is
configured to calculate input power that is obtained from

the grid 2 or the solar cell 3, output power that is
supplied to the DC appliances 5 or the AC appliance 6, or
storage battery power Wb that is stored in the storage
battery 43, on the basis of the detected values obtained
from the power detection units 49 to 52.
The control circuit 53 is provided with a measured
data collection unit 54 for collecting detected signals
output from the respective power detection units 49 to 52.
The measured data collection unit 54 collects amounts of
power from the individual power detection units 49 to 52 at
a polarity in which the direction of arrows in Fig. 2 is a
forward direction.
The control circuit 53 is provided with a calculation
control unit 55 for calculating various types of power Wall,
Wv, Ws, and Wc on the basis of the detected signals output
from the measured data collection unit 54. The calculation
control unit 55 detects grid power Wall based on the
detected signal output from the grid power detection unit 49,
solar light-generated power Wv based on the detected signal
output from the solar light-generated power detection unit
50, bidirectional AC/DC power Ws based on the detected
signal output from the bidirectional AC/DC power detection
unit 51, and DC usage power Wc based on the detected signal
output from the DC usage power detection unit 52. Further,
the power used by the AC appliance 6 (AC usage power Wac) is
calculated by subtracting the bidirectional AC/DC power Ws

from the grid power Wall. Furthermore, the measured data
collection unit 54 and the calculation control unit 55
constitute a power source management means.
The calculation control unit 55 calculates storage
battery power Wb to be supplied to the storage battery 43
based on the various types of power Wall, Wv, Ws, Wc and Wac.
Further, the storage battery power Wbl supplied from the
solar cell 3 is calculated by the following Equation (A) and
storage battery power Wb2 supplied from the grid 2 is
calculated by the following Equation (B).
In this case, Equation (A) is given on condition that
the measured polarity of the bidirectional AC/DC power Ws is
a minus polarity when the storage battery 43 is charged
using solar light power generation. Further, Equation(B) is
given on condition that the solar light-generated power Wv
is r0j .

The calculation control unit 55 determines from which
of sources the storage battery power Wb has been obtained
when power is charged in the storage battery 43, and
calculates the sources from which the power contained in the
storage battery 43 has been obtained and the extent of the
power contained in the storage battery. For example, when
the available capacity of the storage battery 43 is a

maximum of 100% that is a chargeable capacity, percentages
at which the grid power Wall and the solar light-generated
power Wv are respectively stored, relative to the maximum
percentage, are detected. Even when power is discharged
from the storage battery 43, the calculation control unit 55
determines from which of sources the discharged power has
been obtained and to what extent the amounts of power from
the sources have been discharged. Further, the calculation
control unit 55 writes records of the residual capacity of
the storage battery 43 in memory 56, stores them in the
memory 56, and updates stored values whenever the power
sources of the storage battery 43 are checked. Further, the
memory 56 constitutes a power source management means.
The control circuit 53 is provided with an
independently generated power residual capacity calculation
unit 57 for calculating the amount of surplus power, which
is not used by the power supply system 1, of the solar
light-generated power Wv. The independently generated power
residual capacity calculation unit 57 calculates the amount
of power, that is, the surplus power Wov (see Fig. 5), which
is obtained by subtracting the amount of power consumed in
charging the storage battery 43 (hereinafter referred to as
"charging power Wj" (see Fig. 3)) and the amount of power
supplied to the DC appliances 5 or the AC appliance 6 as
operating power (hereinafter referred to as "total load
power Wad" (see Figs. 3 and 5)) from the solar light-

generated power Wv. Further, the independently generated
power residual capacity calculation unit 57 corresponds to
an independently generated power residual capacity
calculation means.
As shown in Fig. 2, the control circuit 53 is provided
with a power selling execution unit 58 for reversely
supplying and selling the solar light-generated power Wv or
the storage battery power Wb to the grid 2. The power
selling execution unit 58 transmits the surplus power Wov,
which is not consumed by the power supply system 1, of the
solar light-generated power Wv, or the solar light-generated
power Wv contained in the power of the storage battery 43,
to the grid 2, and then allows the power to be sold to the
grid 2. The power selling execution unit 58 checks the
extent of the solar light-generated power Wv stored in the
storage battery 43 by referring to the memory 56 when
selling the power of the storage battery 43. The power
selling execution unit 58 constitutes a power reverse supply
means and a reverse supply permission means.
The control circuit 53 is provided with a display
control unit 60 for displaying the status of the operation
of the power supply system 1 on a display unit 59. The
display control unit 60 visually displays sources from which
the amounts of power contained in the storage battery 43
have been obtained, the extents to which respective amounts
of power are contained in the storage battery 43, the extent

to which the power from the grid 2 or the solar cell 3 flows
through the various types of appliances 5 and 6, the extent
to which the power of the power supply system 1 has been
sold, etc. on the display unit 59. These values are
displayed, for example, in pictures or the like so that they
can be easily and visually imaged. Further, the display
unit 59 is implemented as a color liquid crystal display and
is installed, for example, in a home.
Next, the operation of the power supply system 1 of
the present embodiment will be described with reference to
Figs. 3 to 9.
As shown in Fig. 3, a situation is assumed in which
the DC appliances 5 and the AC appliance 6 are operated
using solar light-generated power Wv when solar light power
generation is possible in the daytime and the storage
battery 43 has been consumed to some degree. In this case,
when the solar light-generated power Wv is less than the sum
(hereinafter referred to as "total power Wk") of the
charging power Wj required to fill an empty area of the
storage battery 43, and the total load power Wad required to
operate the appliances 5 and 6, the solar light-generated
power Wv is consumed by the storage battery 43 and the
appliances 5 and 6. Further, when the solar light-generated
power Wv is insufficient, the insufficient power is
supplemented with the grid power Wall.
In this case, the calculation control unit 55

determines the amount of the solar light-generated power Wv
stored in the storage battery 43, and stores the determined
amount in the memory 56. Therefore, it is determined from
which of sources the power stored in the storage battery 43
has been obtained, and to what extent the power has been
stored in the storage battery 43, that is, percentages (%)
at which the solar light-generated power Wv and the grid
power Wall have been respectively stored in the capacity of
the storage battery 43.
Further, the display control unit 6 0 displays the
operating status of the power supply system 1 on the display
unit 59 via an operating status notification screen 61 shown
in Fig. 4. In the operating status notification screen 61,
a residual capacity indication 62 for the storage battery 43
is displayed to provide notification of sources from which
the power contained in the storage battery 43 has been
obtained and the extents to which the amounts of power from
the sources are contained in the storage battery 43, or an
energy flow indication 63 is displayed to show how much of
the power from the solar cell 3 (grid 2) is sent to the
appliances 5 and 6 and is to be sold to the grid 2. In the
energy flow indication 63, the intensity of power is
indicated according to, for example, the thickness of arrows.
In this case, as shown in Fig. 5, it is assumed that,
for example, the storage battery 43 is fully charged or the
number of appliances 5 and 6 that are used is reduced, and

then the solar light-generated power Wv becomes greater than
the total power Wk. When determining that the solar light-
generated power Wv becomes greater than the total power Wk,
the independently generated power residual capacity
calculation unit 57 outputs both a difference between the
two power values (surplus power Wov) and notification of
power selling permission to the power selling execution unit
58. The power selling execution unit 58 reversely supplies
and sells the surplus power Wov to the grid 2 in response to
the notification from the independently generated power
residual capacity calculation unit 57. That is, when a
relationship of r Wv > Ws+Wb+Wc j is established, power of
r Wv-Ws-Wb-Wc j is reversely supplied as the surplus power
Wov.
Next, for example, as shown in Fig. 6, when the
storage battery 43 has sufficient ability to supply power to
the various types of appliances 5 and 6 in the state in
which there remains sufficient storage battery 43 capacity
in the night time, only the solar light-generated power Wv
of the storage battery 43 is reversely supplied and sold to
the grid 2. The power selling execution unit 58 calculates
possible power to be reversely supplied on the basis of
power storage records stored in the memory 56 when power is
charged in the storage battery 43, and sells the possible
power to, for example, an electric power company or the like.
In this case, when the supply of power to the DC

appliances 5 or the AC appliance 6 is required, the solar
light-generated power Wv of the storage battery 43 is
supplied to the appliances, as shown in Fig. 6, and natural
energy is primarily used. Meanwhile, when the solar light-
generated power Wv remaining in the storage battery 43 is
insufficient, the grid power Wall of the storage battery 43
is used as power, as shown in Fig. 7. Further, the
calculation control unit 55 gradually detects usage power
consumed from the storage battery 4 3 and places where the
power has been used, and updates the power storage records
stored in the memory 56 whenever such detection occurs.
When a large amount of power of the storage battery 43
is consumed, the residual capacity of the storage battery 43
approaches a low limit, as shown in Fig. 8. However, one of
the functions of the storage battery 43 is it being used as
a backup power source in case of a grid power failure, so
that there is a need to recover the residual capacity of the
storage battery to a required minimum level. Therefore,
when the residual capacity of the storage battery 43 is low,
the control circuit 53 charges the storage battery 43. In
this case, the solar light-generated power Wv is primarily
used, and the storage battery 43 is charged with the grid
power Wall, for example, in the nighttime or in bad weather,
as shown in Fig. 9.
Meanwhile, in the present embodiment, when power is
charged in the storage battery 43, a source from which the

charging power Wj has been obtained and the extent to which
the power Wj has been sent from the source are determined,
and when the storage battery 43 is discharged, a source from
which the power used for discharging has been obtained and
the extent to which the power has been used are also
determined. Therefore, it is possible to determine from
which of sources the power stored in the storage battery 43
has been obtained and to what extent the power has been
stored. For this reason, it is possible to more effectively
use natural energy such as solar light in the present
embodiment in such a way as to primarily use the solar
light-generated power Wv contained in the storage battery 43.
In accordance with the configuration of the embodiment,
the following advantages can be obtained.
(1) Since the charging/discharging of the storage
battery 43 is managed having incorporated the sources of
power, it is possible to determine sources from which
amounts of power stored in the storage battery 4 3 have been
obtained and the extents to which the amounts of power have
been stored. Therefore, if the solar light-generated power
Wv is primarily used when the storage battery 43 is
discharged, power requiring no power rate is primarily
consumed, thus realizing very high energy saving effects.
(2) When the power supply system 1 operates using the
solar light-generated power Wv as power, surplus power Wov
of the power Wv, which is not consumed by the power supply

system 1, can be sold. Therefore, since it is impossible to,
for example, charge the storage battery 43 with the grid 2
in the nighttime when the power rate is low, and sell this
power in the daytime when the power rate is high, desirable
power that can be sold may be sold to an electric power
company or the like according to a formal procedure.
(3) The solar light-generated power Wv of the power
in the storage battery 43 can be sold. Therefore, power
that is independently generated by the power supply system 1
and that is not a target to be improperly sold can be sold
to the electric power company in a desirable time span in
which the electric power company requires power. That is,
the power stored in the storage battery 43 can be sold
without creating an impropriety.
(4) If the solar light-generated power Wv is
primarily used when the power of the storage battery 43 is
used, there is no need to use as much grid power Wall
relative to the power rate as possible, thus enabling
natural energy to be effectively used.
(5) Since the operating status notification screen 61
can be displayed on the display unit 59, visual notification
can be provided to a user in relation to a source from which
power stored in the storage battery 43 has been obtained,
the extent to which the power has been stored in the storage
battery 43, the extent to which power from the grid 2 or the
solar cell 3 flows through various types of appliances 5 and

6, and the degree to which the power of the system 1 is sold.
Further, the embodiment is not limited to the above-
described configuration and may be modified into the
following forms:
/*'' The monitoring means is not limited to the power
detection units 49 to 52 for indicating values depending on
power, and any type of means may be used as long as it can
indicate the charging source of the storage battery 4 3 and
the amount of power thereof.
The grid power Wall of the power stored in the storage
battery 43 may be prohibited from being sold.
The selling of power may be prohibited, for example,
in the nighttime, without being able to be freely executed
regardless of it being nighttime or daytime.
The independently power generating battery is not
limited to the solar cell 3, and may be, for example, a fuel
cell.
The storage battery 43 is not limited to a battery
implemented as a secondary battery, a condenser, or the like
and any type of storage battery may be employed as long as
it can collect charges.
The power supply system 1 is not limited to a house,
and may be applied to, for example, other buildings such as
a factory.
The grid 2 is not limited to the commercial AC power
source, and any type of source that supplies a DC voltage

can also be used.
Next, the technical spirit that can be understood from
the above embodiment and other embodiments will be
additionally described together with the advantages thereof.
There is provided a power line communication control
unit for supplying power and data to a load via power line
communication and controlling the load. According to this
configuration, since the load can be controlled using power
line communication, power and data can be supplied to the
load using a small amount of wiring.
While the invention has been shown and described with
respect to the embodiments, it will be understood by those
skilled in the art that various changes and modification may
be made without departing from the scope of the invention as
defined in the following claims.

What is claimed is:
1. A device for monitoring power sources of a storage
battery, comprising:
a monitoring unit for monitoring input and output of
power to and from a storage battery; and
a power source management unit for managing sources
from which amounts of power stored in the storage battery
have been obtained and extents to which the amounts of power
have been stored in the storage battery.
2. The device of claim 1, wherein the device for
monitoring power sources of the storage battery is applied
to a power supply system which performs voltage conversion
on a voltage obtained from a grid or an independently power
generating cell, and branches and supplies the voltage to
individual appliances, and which is provided with the
storage battery as a backup power source of the grid or the
independently power generating cell.
3. The device of claim 2, further comprising:
an independently generated-power residual capacity
calculation unit for calculating surplus power, which
remains in the power supply system, of power generated by
the independently power generating cell; and
a power reverse supply unit for reversely supplying

the surplus power to the grid.
4. The device of claim 2 or 3, further comprising a
reverse supply permission unit for permitting power, which
is supplied from the independently power generating cell as
a source, of the power stored in the storage battery, to be
reversely supplied to the grid.

ABSTRACT

A device for monitoring power sources of a storage
battery includes a monitoring unit for monitoring input and
output of power to and from a storage battery; and a power
source management unit for managing sources from which
amounts of power stored in the storage battery have been
obtained and extents to which the amounts of power have been
stored in the storage battery.