JP7254481B2 - power control system - Google Patents

Description

The present invention relates to a power control system that controls power supply to a building equipped with a photovoltaic power generation device.

By connecting a vehicle equipped with an on-board storage battery, such as an electric vehicle, to a building such as a house, it is possible not only to charge the electric vehicle from external system power such as the power grid, but also to use the electric power charged in the on-board storage battery at home. A power supply system is known that can be used (see Patent Literatures 1 and 2).

In addition, in Patent Document 1, a control device on the house side acquires the driving history etc. stored in the charge / discharge control unit of the electric vehicle, predicts the driving pattern and the driving distance, calculates the necessary charging amount, Based on this, it is described that an electric vehicle is charged from an external power system.

Furthermore, in Patent Document 2, in an area consisting of multiple houses, when the multiple houses mutually exchange power within the area, it is also possible to receive power supply from a vehicle electrically connected to each house. stated to be considered.

JP 2012-23955 A JP 2013-143892 A

Here, if the building is equipped with a photovoltaic power generation device, the generated power can be used as power for the house by charging an on-board storage battery of an electric vehicle. However, when using the on-board storage battery of an electric vehicle that is disconnected from the house when moving, if the electric vehicle cannot be charged with the power generated by the solar power generation device due to going out during the day, the house will be damaged. There is a risk that a situation may arise in which it is not possible to cover the total power consumption, and utility costs may increase due to the purchase of power from the external system during times when the power price is high.

Therefore, according to the present invention, by appropriately predicting the amount of power generated by the photovoltaic power generation device and the running schedule of the vehicle, it is possible to minimize the purchase of power from the external grid during times when the power price is high. The object is to provide a power control system.

In order to achieve the above object, a power control system of the present invention is a power control system for controlling the supply of power to a building equipped with a photovoltaic power generation device, wherein the power consumption of the building is predicted. a prediction unit, a power generation prediction unit that predicts the amount of power generated by the photovoltaic power generation device, a travel schedule prediction unit that predicts a travel schedule of a vehicle equipped with an in-vehicle storage battery connected to the building, and the in-vehicle storage battery and a charge/discharge control unit that controls charging and discharging of the charge/discharge control unit, the charge amount to be charged to the on-vehicle storage battery from the external system power is calculated by the power consumption prediction unit, the power generation prediction unit, and the traveling schedule prediction. determined based on part prediction.

Here, it is preferable that the charge amount is a charge amount in a time zone of late-night electric power. Further, in the charge/discharge control unit, based on the predictions of the power consumption prediction unit, the generated power prediction unit, and the travel schedule prediction unit, the generated surplus power amount and the consumption shortage during the time period when the vehicle is connected to the building The amount of charge is obtained by adding the predicted value of the surplus generated power amount to the remaining capacity value of the on-vehicle storage battery, and calculating the predicted value of the power consumption shortage and the amount of power consumed by the vehicle. It can be configured to be determined as a value obtained by subtracting the predicted value.

The power control system of the present invention configured as described above includes a power generation prediction unit that predicts the amount of power generated by the photovoltaic power generation device, and an on-board storage battery that is connected to the building, in addition to the power consumption prediction unit of the building. and a traveling schedule prediction unit for the vehicle. Then, the amount of charge to be charged from the external system power to the vehicle-mounted storage battery is determined based on the predictions of the power consumption predictor, the generated power predictor, and the travel schedule predictor.

In this way, by appropriately predicting the amount of power generated by the photovoltaic power generation device and the running schedule of the vehicle, the amount of charge that must be stored in the on-vehicle storage battery for the next day can be calculated, for example, during late-night power hours. Therefore, it is possible to cover it with power during the time when the power price is low, and it is possible to minimize the purchase of power from the external system during the time when the power price is high.

1 is a block diagram illustrating the configuration of a power control system according to an embodiment; FIG. FIG. 2 is a diagram for explaining the meanings of terms of generated surplus power and consumed power shortage; It is a figure explaining the flow of a process of the electric power control system of this Embodiment. FIG. 10 is an explanatory diagram illustrating charge/discharge control by the power control system when the electric vehicle does not go out on the next day (case 1); FIG. 10 is an explanatory diagram exemplifying charge/discharge control by the power control system when the electric vehicle does not go out the next day (case 2); FIG. 10 is an explanatory diagram illustrating charge/discharge control by the power control system when an electric vehicle is used to go out on the next day (Case 3); FIG. 10 is an explanatory diagram illustrating charge/discharge control by the power control system when an electric vehicle is used to go out on the next day (Case 4);

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the overall configuration of the power control system of the present embodiment will be described with reference to FIG. A house H, which is a building controlled by this power control system, is connected to the grid power network in order to receive external grid power from power plants of power companies, cogeneration facilities installed in each region, and the like.

Moreover, the house H is equipped with a solar cell panel 1 as a solar power generation device. Furthermore, this house H can be connected to a vehicle such as an electric vehicle 4 or a plug-in hybrid vehicle equipped with an on-vehicle storage battery 41 .

The power generated by the solar panel 1 can be temporarily stored in the onboard storage battery 41 . Furthermore, this house H is connected to an external communication network such as the Internet. Then, transmission/reception of data such as measured values and arithmetic processing results, transmission/reception of control signals, and the like are performed with an external management server 5 that is also connected to the communication network.

The power control system of the present embodiment has a configuration that is arranged in the house H as the house side and a configuration that is arranged in the management server 5 as the server side. Although the description is omitted in this embodiment, a plurality of houses H are connected to the management server 5 .

First, the configuration of the house H side to be processed will be described.
The house H includes a solar battery panel 1, a measuring device 2 for measuring the hourly power generated by the solar battery panel 1 and the hourly power consumption of the house H, a display monitor 3 as a display device, and an electric vehicle 4. It is mainly provided with a charge/discharge port for electrical connection.

The solar cell panel 1 is a device that uses solar cells to convert sunlight into electric power to generate power. This solar cell panel 1 is a device capable of supplying electric power only during hours when it can receive sunlight. Also, the DC power generated by the solar cell panel 1 is normally used after being converted into AC power by a power conditioner (not shown). The specifications such as the power generation capacity of the solar panel 1 installed in the house H are stored in the house information database 51 on the management server 5 side, which will be described later.

On the other hand, the charging/discharging port of the in-vehicle storage battery 41 is also connected to a power conditioner (not shown), similarly to the solar panel 1, to control charging/discharging. For example, the in-vehicle storage battery 41 is charged with low-price power such as late-night power supplied from the grid power network. Specifications such as the power storage capacity and rated output of the on-vehicle storage battery 41 are also stored in the management server 5 side in a later-described residence information database 51 .

Also, the house H is supplied with power from an external system through a distribution board, and various loads that consume power are installed. The various loads include, for example, an air conditioner such as an air conditioner, a hot water supply system, a lighting system such as a lighting stand and a ceiling light, and a household appliance such as a refrigerator and a television.

The measuring device 2 measures the amount of electric power actually generated by the solar panel 1 installed in the house H. FIG. The measuring device 2 also measures the amount of power consumed by the load installed in the house H. FIG. The measurement by the measuring device 2 can be performed every hour at arbitrary intervals such as seconds, minutes, and hours. The data of the measured value measured by the measuring device 2 is stored in the power consumption history database 52 on the management server 5 side, which will be described later.

In addition, in the power consumption history database 52, the power consumption of air conditioning loads such as air conditioners and hot water supply loads such as water heaters that are easily affected by weather conditions such as temperature, and other loads that are not easily affected by weather conditions such as temperature. The amount of power consumption of the load is categorized by load and stored.

The display monitor 3 displays the measured values measured by the measuring device 2, information indicating the control state of the management server 5, and the like. As the display monitor 3, a dedicated terminal monitor may be used, or a screen of a general-purpose device such as a personal computer may be used.

Next, the configuration of the management server 5 connected to the house H via a communication network will be described.
The management server 5 includes a communication unit 56 as communication means, a control unit 6 that performs various controls, a residence information database 51 as storage means, a power consumption history database 52, an electricity price database 53, a weather forecast database 54, and an outing and a pattern history database 55 .

The communication unit 56 sends specifications of various facilities, measured values, processing requests, etc. transmitted from the house H to the control unit 6 of the management server 5, and also to various databases (51, 52, 53, 54, 55). It has a function of sending stored data, results of arithmetic processing performed by the control unit 6, update programs, etc. to the house H. FIG.

The mansion information database 51 contains mansion codes (identification numbers) of a plurality of houses H, addresses associated with the mansion codes, construction years, insulation performance, floor plans, electrical wiring, materials used, specifications of the solar panel 1 (power generation capacity), specifications (storage capacity, rated output) of the vehicle-mounted storage battery 41 of the connected electric vehicle 4, and other information is stored.

In the power consumption history database 52, data of measured values measured at each house H and received by the management server 5 via the communication unit 56 are stored. By storing the measured value in association with the house code, it is possible to identify which house H the measured value was obtained from.

Furthermore, the history of power consumption stored in the power consumption history database 52, as described above, is the power consumption of air conditioning loads such as air conditioners and hot water supply loads such as water heaters that are susceptible to weather conditions such as temperature. and the power consumption of other loads, which are not easily affected by weather conditions such as temperature, are categorized by load.

The power price database 53 also stores information on power prices (purchased power prices seen from the resident side) that change depending on the time of day set by the power company or the like that supplies power from the external system.

For example, the purchase price of late-night electricity from 23:00 to 6:00 the next day is set lower than the purchase price of other daytime electricity. The power price database 53 stores the time when the power price changes and the power price (unit price) in each time period. The power price database 53 also stores the purchase price at which the power company or the like purchases the power generated by the solar panel 1 (power selling price from the perspective of the resident).

The weather forecast database 54 stores the weather forecast data for the next day, such as the temperature and the amount of solar radiation, received from a server (not shown) of the Meteorological Agency, a weather forecast company, etc. via a communication network. .

The going-out pattern history database 55 stores information on connection or disconnection of the electric vehicle 4 to the house H, information on the charging/discharging history of the in-vehicle storage battery 41, and the like. The data in the outing pattern history database 55 is used by the travel schedule prediction unit 64, which will be described later.

The control unit 6 is provided with a charge/discharge control unit 61 , a power consumption prediction unit 62 , a power generation prediction unit 63 , and a travel schedule prediction unit 64 .

The power consumption prediction unit 62 is means for predicting power consumption for each unit time (in this embodiment, the unit time is 1 hour). For example, the hourly power consumption of the house H on the previous day and the next day can be predicted. The power consumption prediction unit 62 predicts the hourly power consumption of the air-conditioning load and hot water supply load, which are susceptible to weather conditions such as temperature, based on weather forecast data. Hourly power consumption of other loads is predicted based on past history data, and the power consumption of the house H is predicted for each hour by adding up these data.

Specifically, in predicting the hourly power consumption of the air conditioning load and the hot water supply load, the weather forecast data for the next day, such as the temperature, stored in the weather forecast database 54 is referred to, and the power consumption forecasting unit 62 predicts the hourly Predict power consumption per unit. When estimating the power consumption of other loads for each hour, the past history data categorized and stored in the power consumption history database 52 is referred to, and the power consumption prediction unit 62 predicts the power consumption for each hour. do. Then, by summing up these, the hourly power consumption of the house H is predicted.

The generated power prediction unit 63 predicts the generated power of the solar cell panel 1 for each hour. For example, it is possible to predict the hourly power generation of the house H on the previous day and the next day. Specifically, in predicting the hourly power generation of the solar cell panel 1, the next day's weather forecast data such as the amount of solar radiation stored in the weather forecast database 54 is referred to, and the power generation prediction unit 63 predicts the Predict the generated power for each H hour.

The travel schedule prediction unit 64 predicts the amount of time the electric vehicle 4 will be used when going out or staying at home, and the amount of electric power required to run the electric vehicle 4 . The pattern of connection or non-connection of the electric vehicle 4 to the house H, the pattern of the remaining capacity of the on-vehicle storage battery 41 after running, etc. are stored in the outing pattern history database 55, and machine learning etc. are performed based on the data. Then, the driving schedule of the electric vehicle 4 by the residents can be predicted. For example, if the next day is Tuesday, there is a high possibility that the person will go out during the daytime, and the travel distance on Sunday will be longer than usual (the remaining capacity of the vehicle-mounted storage battery 41 will be less). In addition, the travel schedule prediction unit 64 can acquire the remaining capacity value of the vehicle-mounted storage battery 41 at an arbitrary time.

Then, the charge/discharge control unit 61 controls charging/discharging of the vehicle-mounted storage battery 41 based on the predicted power consumption and power generation amount of the house H, the driving schedule of the electric vehicle 4, and the remaining capacity of the vehicle-mounted storage battery 41. conduct. Before describing the details of control by the charge/discharge control unit 61, the relationship between generated power (power generation) and power consumption will be described with reference to FIG.

In FIG. 2, "power generation" refers to power generated by the solar cell panel 1 in units of hours, and "power consumption" refers to power consumption of the house H in units of hours. "Surplus generated power" is the positive power of the value obtained by subtracting the power consumption from the power generated in units of time. amount”.

On the other hand, "underpower consumption" is the power that is the positive value obtained by subtracting power generation from power consumption in units of time. Become. In other words, when the power generation exceeds the power consumption, it is accumulated as "surplus power generation", and when the power consumption exceeds the power generation, it is accumulated as "under-consumption power".

Next, “midnight charging” in which the vehicle-mounted storage battery 41 of the electric vehicle 4 is charged with late-night power and “surplus charging” in which the power generated by the solar panel 1 is charged will be described. In the "late-night charge", late-night power with a low unit price is purchased from the system power network and charged to the vehicle-mounted storage battery 41 .

On the other hand, the power generated by the solar cell panel 1 during the daytime can be consumed as indoor power that can be used in the house H. In addition, the generated surplus power can be sold to the power grid. Furthermore, the vehicle-mounted storage battery 41 can be charged without selling the generated surplus power. This is the "excess charge".

Then, when the power generated by the solar panel 1 falls below the power consumption, the power charged in the vehicle-mounted storage battery 41 is discharged to the house H to compensate. In addition, the power consumption of the house H can be covered by the discharge of the vehicle-mounted storage battery 41 even in the late-night hours.

Next, charge/discharge control by the control unit 6 will be described with reference to the flow of processing of the power control system of the present embodiment shown in FIG.
In the power control system of the present embodiment, for example, at a predetermined time every day, arithmetic processing for determining the amount of charge due to late-night charging is performed. For example, it is determined whether or not the current time is one hour before the start time (for example, 23:00) of the late-night electricity price (late-night rate), and the arithmetic processing is started when the current time reaches 22:00. In the following processing, "next day" refers to 24 hours (for example, from 23:00 to the next 23:00) starting from the start time of the late-night charge.

In the determination of the charging amount by late-night charging, the generated power is predicted (S21). The amount of power generated by the solar cell panel 1 of the house H on the next day is the amount of solar radiation (S11) for the next day obtained from the weather forecast database 54, and the past power generation amount (S12) obtained from the power consumption history database 52. is predicted by the generated power prediction unit 63 based on such data. Therefore, the predicted power generation amount varies greatly depending on whether the weather forecast for the next day is "cloudy" or "rainy" or "sunny". A predicted value A is assumed to be the predicted generated power.

On the other hand, the power consumption of the house H on the next day is predicted by the power consumption prediction unit 62 based on data such as past power consumption (S13) obtained from the power consumption history database 52. FIG. This predicted power consumption is set as a predicted value B (S22).

In addition, the driving schedule prediction unit 64 predicts the time period when the electric vehicle 4 will be connected to the house H on the next day (EV home time) and the amount of driving power required for driving the electric vehicle 4 (the amount of driving power when the EV goes out). It is estimated based on the data stored in the outing pattern history database 55 .

Then, from the predicted driving schedule of the electric vehicle 4 for the next day (EV outing schedule (S14)), the EV home time at which the electric vehicle 4 will be in the connected state without going out is obtained as a predicted value C (S23).

Also, the amount of electric power for running the electric vehicle 4 when going out as an EV is acquired as a predicted value D (S24). Furthermore, the current remaining capacity value E of the vehicle-mounted storage battery 41 (EV storage battery) is acquired by the travel schedule prediction unit 64 (S15).

Using the predicted value A−predicted value D and the remaining capacity value E obtained in this manner, the charge/discharge control unit 61 determines the amount of charge (EV charge amount V) is calculated. First, prediction of surplus power generation and power consumption deficit at predicted value C of EV home time are performed (S25).

That is, the predicted value F of the generated surplus power amount is positive (plus) obtained by subtracting the power consumption (predicted value B) from the generated power (predicted value A) for each unit time during the EV home time period (predicted value C). It is calculated as an integrated value of values. In addition, the predicted value G of the consumption shortage power amount is positive (plus) by subtracting the generated power (predicted value A) from the power consumption (predicted value B) for each unit time during the EV home time period (predicted value C). It is calculated as an integrated value of values.

Then, using the predicted value F of the generated surplus power amount and the predicted value G of the insufficient consumed power amount calculated in this way, the amount of charge (EV charge amount V) to charge the vehicle-mounted storage battery 41 during the late-night rate period. is determined by the following formula (S26).
EV charging amount V = Remaining capacity value E + Surplus generated power F - Consumed power shortage G - Driving power D

Next, an example of operation control by the power control system of the present embodiment and its action will be described.
4 to 7 are explanatory diagrams showing examples (Case 1 to Case 4) of charge/discharge control by the power control system of the present embodiment. These figures illustrate the control for the next day after determining the charging amount for late-night charging.

The determination of the charge amount (EV charge amount V) of the vehicle-mounted storage battery 41 by late-night power starts at a time (22:00), for example, one hour before the late-night charge time zone. At this time, the remaining capacity value E of the EV storage battery (in-vehicle storage battery 41) is confirmed (S15 in FIG. 3).

Next, the amount of power generated by the solar panel 1, the power consumption of the house H, and the EV outing schedule (S14 in FIG. 3) are predicted for the next 24 hours (from 23:00 to 23:00), which is the next day. conduct.
Then, the amount of charge (EV charge quantity V) is determined (S21-S26 in FIG. 3).

Case 1 shown in FIG. 4 is an example of a case where it is predicted that the electric vehicle 4 will not go out the next day, that is, a case where the house H and the electric vehicle 4 are in a connected state all day long. In this case 1, based on the weather forecast data that the next day will be sunny with sufficient solar radiation, it is predicted that the on-vehicle storage battery 41 can be surplusly charged (EV charging) with surplus power generated during the day. As a result, the charging amount (EV charging amount V) of the vehicle-mounted storage battery 41 by late-night power is determined to be 0, and midnight charging is not performed.

Since the electric vehicle 4 is connected throughout the day, until around 6:00 when the power consumption exceeds the generated power (power generation) of the solar battery panel 1, the discharge (EV discharge) from the onboard storage battery 41 causes the house H to operate. discharge control to cover the power consumption of

Subsequently, during the daytime when the power generation exceeds the power consumption, charging control is performed to charge the in-vehicle storage battery 41 with the surplus power generation exceeding the home power consumption. Then, after the evening when the power generation declines and the power consumption exceeds the power generation again, discharge control is performed to cover the power consumption by EV discharge.

On the other hand, case 2 shown in FIG. 5 is also a case where it is predicted that the electric vehicle 4 will not go out on the next day. This is an example of a case where power consumption is predicted to be high during the night until midnight.

In this case 2, the charging amount of the on-vehicle storage battery 41 by late-night power is determined by the formula for calculating the EV charging amount V (S26 in FIG. 3), and the on-vehicle storage battery 41 is charged by the external system power purchased from the grid power network at midnight. (EV power purchase charging) is performed.

Then, as in case 1, until around 8:00 and after 15:00 when the power consumption exceeds the power generation, the discharge control is performed so that the power consumption is covered by the EV discharge. Also, during the daytime when the power generation exceeds the power consumption, charging control is performed to charge the in-vehicle storage battery 41 with the surplus power generation exceeding the home power consumption.

On the other hand, case 3 shown in FIG. 6 is a case where it is predicted that the electric vehicle 4 will go out during the daytime on the next day (EV going out). It is predicted that surplus power will be generated during the EV going out time period from 11:00 to 16:00 when the electric vehicle 4 is disconnected from the house H.

In Case 3, the electric vehicle 4 is temporarily disconnected during the day, but since the power generation exceeds the power consumption in the morning, the electric vehicle 4 is connected to the house H in the morning. Sometimes, charging control is performed to excessively charge the vehicle-mounted storage battery 41 with the surplus power generated.

Then, the EV charging in the morning can cover the running power amount of the electric vehicle 4 when the EV goes out and the power consumption after the evening when the power consumption exceeds the power generation. In addition, the surplus power generated when the EV goes out will be sold to the power grid.

On the other hand, case 4 shown in FIG. 7 is also a case where it is predicted that the electric vehicle 4 will go out on the next day. This is an example of a case where power consumption is predicted to be high during the night until midnight.

In this case 4, the charging amount of the on-vehicle storage battery 41 by late-night power is determined by the formula for calculating the EV charge amount V (S26 in FIG. 3), and the on-vehicle storage battery 41 is charged by the external system power purchased from the grid power network at midnight. (EV power purchase charging) is performed.

Until around 8:00 when the power consumption exceeds the power generation, discharge control is performed to cover the power consumption by EV discharge. Further, when the electric vehicle 4 is connected to the house H in the morning, charging control is performed to excessively charge the in-vehicle storage battery 41 with the surplus power generated.

In addition, the surplus power generated when the EV goes out is sold to the power grid. In this case 4, the electric vehicle 4 is predicted to be disconnected from the house H from 11:00 to 16:00. Can not. Therefore, the amount of power consumption in this time period that exceeds the power generation is covered by external system power (purchased power) purchased from the system power network.

The power control system of the present embodiment configured as described above includes a power consumption prediction unit 62 that predicts the power consumption of the house H, and a power generation prediction unit 63 that predicts the power generation amount of the solar cell panel 1. and a travel schedule prediction unit 64 for the electric vehicle 4 on which the on-vehicle storage battery 41 connected to the house H is mounted.

Then, the power consumption prediction unit 62, the generated power prediction unit 63, and the travel schedule prediction unit 64 predict the EV charging amount V to be charged from the grid power network to the on-vehicle storage battery 41 (predicted value A−predicted value D) and the remaining capacity value E and based on

In this way, by appropriately predicting the amount of power generated by the solar panel 1 and the running schedule of the electric vehicle 4, the EV charging amount V that must be stored in the vehicle-mounted storage battery 41 to be required for the next day can be calculated late at night. It is possible to cover with the power from the external system during the time period when the power price is low, which is called the rate period, and it is possible to suppress the purchase of power from the external system during the time period when the power price is high as much as possible.

Further, if the prediction by the travel schedule prediction unit 64 is performed based on the data stored in the going-out pattern history database 55, such as the charging/discharging history data of the in-vehicle storage battery 41, the travel pattern of the resident can be predicted by accumulating the data. Accuracy is improved, and a more appropriate charge amount determination for late-night charging can be made.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment. Included in the invention.
For example, in the above embodiment, since the power purchase price during the late-night rate period is low, the term "midnight charging" has been described. The time period can be defined as "a time period during which the external system power is charged to the vehicle-mounted storage battery".

1: Solar panel (solar power generation device)
4: Electric vehicle (vehicle)
41: Vehicle-mounted storage battery 61: Charge/discharge control unit 62: Power consumption prediction unit 63: Generated power prediction unit 64: Driving schedule prediction unit H: House (building)
V: EV charging amount (charging amount)

Claims (1)

A power control system for controlling the supply of power to a building equipped with a photovoltaic power generation device,
a power consumption prediction unit that predicts the power consumption of the building;
a power generation prediction unit that predicts the power generation amount of the photovoltaic power generation device;
a travel schedule prediction unit that predicts a travel schedule of a vehicle equipped with an in-vehicle storage battery connected to the building;
A charge/discharge control unit that controls charging and discharging of the in-vehicle storage battery,
The travel schedule prediction unit uses the history of the remaining capacity value of the in-vehicle storage battery to predict the travel power amount of the vehicle,
The charging/discharging control unit determines an amount of charge in the late-night power time period for charging the on-vehicle storage battery from external system power, based on the predictions of the power consumption predicting unit, generated power predicting unit, and travel schedule predicting unit. and
In the charge/discharge control unit, based on the predictions of the power consumption prediction unit, the power generation prediction unit, and the travel schedule prediction unit, the amount of surplus power generated and the amount of power shortage consumed during the time zone when the vehicle is connected to the building and
The amount of charge is determined as a value obtained by subtracting the predicted value of the consumed power amount and the predicted value of the running power amount from the value obtained by adding the predicted value of the generated surplus power amount to the remaining capacity value of the on-vehicle storage battery. A power control system characterized by :

Images