JP2024006239A - Electric power system - Google Patents

Abstract

To suppress a power supply to an AC wiring in a facility from a natural energy power generation device.SOLUTION: An electric power system is operated in accordance with rules (1) to (3) of that, in the case where a natural energy power generation device generates a power, a first operation for charging a first power storage battery by a first charging device is executed in a state where a power storage amount of the first power storage battery is less than a first reference value in (1), a second operation for charging a second power storage battery by a second charging device is executed in a state where the power storage amount of the first power storage battery is a first reference value or larger and the power storage amount of the second power storage battery is less than a second reference value in (2), and a third operation for supplying an AC power to an AC wiring by a DC and AC conversion device is executed in a state where the power storage amount of the first power storage battery is the first reference value or larger, and the power storage amount of the second power storage battery is the second reference value or more in (3).SELECTED DRAWING: Figure 1

Description

The technology disclosed herein relates to a power system.

Patent Document 1 discloses an electric power system that includes a natural energy power generation device and a storage battery. Natural energy power generation devices use natural energy (sunlight, wind power, etc.) to generate electricity. The storage battery can be charged with the power generated by the natural energy power generation device. The power system can also power AC wiring within the facility. The power system also includes a vehicle connection section. When a vehicle is connected to the vehicle coupling part, it becomes possible to charge the vehicle storage battery mounted on the vehicle by the electric power system.

JP2014-217236A

When power is supplied from a natural energy power generation device to AC wiring within a facility, it is necessary to convert the DC power supplied from the natural energy power generation device into AC power, resulting in energy loss. Additionally, when power is supplied from a natural energy power generation device to the AC wiring within a facility, the demand for electricity for the power company decreases, whereas in situations where the natural energy power generation device is unable to generate electricity, the demand for power for the power company increases. . For this reason, there is a concern that as such power systems become more widespread, fluctuations in power demand for electric power companies will increase, and the burden of adjusting the amount of power generation on the side of electric power companies will increase. Therefore, this specification proposes a power system that can suppress power supply from a natural energy power generation device to AC wiring within a facility.

The power system of item 1 disclosed in this specification is installed in a facility. This power system includes a DC wiring, a natural energy power generation device connected to the DC wiring and supplying DC power to the DC wiring, and a DC wiring connected to the DC wiring and supplied from the DC wiring. a first charging device that charges a first storage battery mounted on a vehicle with electric power; a second charging device that is connected to the DC wiring and that charges a second storage battery with DC power supplied from the DC wiring; A DC/AC converter is connected to the DC wiring and converts DC power supplied from the DC wiring into AC power and supplies the AC power to the AC wiring of the facility. When the natural energy power generation device is generating power, the first storage battery is connected to the first charging device, and the second storage battery is connected to the second charging device, the electric power system (1) in a state in which the amount of electricity stored in the first storage battery is less than a first reference value, the first charging device performs a first operation of charging the first storage battery; (2) the first storage battery (3) performing a second operation of charging the second storage battery by the second charging device in a state where the amount of electricity stored is equal to or more than a first reference value and the amount of electricity stored in the second storage battery is less than the second reference value; When the amount of electricity stored in the first storage battery is greater than or equal to the first reference value and the amount of electricity stored in the second storage battery is greater than or equal to the second reference value, the DC/AC converter may supply AC power to the AC wiring. It operates in accordance with the rules (1) to (3) of executing three operations.

Note that the facility means a facility that uses electricity. The facility may be a residential facility, a commercial facility, an industrial facility, a public facility, or any other facility. Further, the second storage battery may be a stationary storage battery or a storage battery mounted on a vehicle. Further, the first charging device and the second charging device may be any devices as long as they can control charging of the storage battery. For example, the first charging device and the second charging device may be a converter that converts DC voltage, or may be a switch (such as a breaker) that turns on/off the connection between the storage battery and the DC wiring. . Further, the natural energy power generation device may be a solar power generation device or a wind power generation device.

This electric power system charges the first storage battery according to rule (1) when the amount of electricity stored in both the first storage battery and the second storage battery is low. As a result, when the amount of electricity stored in the first storage battery reaches the first reference value, the power system charges the second storage battery according to rule (2). As a result, when the amount of electricity stored in the second storage battery reaches the second reference value, the power system supplies AC power to the AC wiring in the facility according to rule (3). In this way, the power system prioritizes the charging of the first storage battery and the second storage battery, and supplies AC power to the AC wiring within the facility when the amount of electricity stored in the first storage battery and the second storage battery are both high. supply Therefore, the frequency with which AC power is supplied from the power system to the AC wiring becomes lower than in the past. Thus, according to this power system, the frequency of conversion from DC power to AC power is reduced. Therefore, energy loss associated with conversion from DC power to AC power can be reduced, and fluctuations in power demand for electric power companies can be suppressed.

FIG. 1 is a configuration diagram of a power system 10. A graph showing the amounts of stored electricity B1 and B2. 5 is a flowchart showing the processing executed by the control device 68.

The configuration of the technology disclosed in this specification will be explained item by item following item 1 above.
(Item 2)
The power system according to item 1, wherein in the normal operation mode, conversion of AC power to DC power by the DC/AC converter is prohibited.
(Item 3)
The AC wiring is connected to a power system outside the facility,
The power system according to item 1 or 2, which operates so that reverse power flow in which power is supplied from the AC wiring to the power system does not occur.
(Item 4)
further comprising a device that outputs a predicted value of the amount of electricity that the vehicle will use within a predetermined number of days,
the second reference value such that the second operation shifts to the third operation when the total amount of electricity stored in the first storage battery and the second storage battery reaches the predicted value in the second operation; is set,
The power system according to any one of items 1 to 3.
(Item 5)
The power system according to item 4, wherein even if the total amount has reached the predicted value, the second operation is executed if the power demand in the AC wiring is lower than the reference demand amount.
(Item 6)
Any one of items 1 to 5, wherein when a power drop in the AC wiring is detected, regardless of the rules (1) to (3), the DC/AC converter supplies AC power to the AC wiring. Power system described in.

According to the configuration of item 2 above, it is possible to prevent power supplied from an external power system from being supplied to the vehicle.

According to the configuration of item 3 above, the burden on the electric power company due to reverse power flow can be reduced.

According to the configuration of item 4 above, it is possible to secure the required amount of electrical storage in the first storage battery and the second storage battery.

According to the configuration of item 5 above, the second storage battery can be further charged after securing the necessary amount of stored electricity.

According to the configuration of item 6 above, during a power outage or the like, power can be supplied from the natural energy power generation device to the AC wiring within the facility without giving priority to charging the first storage battery and the second storage battery.

The power system 10 shown in FIG. 1 is installed in a house 90. House 90 has AC wiring 92 inside. AC power is supplied to the AC wiring 92 from an external power system 80 . Inside the house 90, electrical equipment 94 and a power meter 96 are installed. The electrical appliances 94 are washing machines, refrigerators, air conditioners, lighting, etc., and are operated by AC power supplied from the AC wiring 92. Power meter 96 measures the amount of power consumed within house 90 .

The power system 10 includes a solar power generation device 20, a DC/DC converter 22, a stationary storage battery 30, a DC/DC converter 32, a vehicle charging device 40, an inverter 50, DC wiring 60, and a control device 68. .

The DC wiring 60 is a wiring to which a DC voltage is applied. A solar power generation device 20 is connected to the DC wiring 60 via a DC/DC converter 22 . A stationary storage battery 30 is connected to the DC wiring 60 via a DC/DC converter 32. A vehicle charging device 40 and an inverter 50 are connected to the DC wiring 60.

The solar power generation device 20 generates power using sunlight and outputs DC voltage. The DC/DC converter 22 converts the DC voltage output by the solar power generation device 20 into DC voltages of different magnitudes, and applies the converted DC voltage to the DC wiring 60.

The stationary storage battery 30 is a chargeable/dischargeable battery (for example, a lithium ion battery, etc.). The stationary storage battery 30 outputs DC voltage. The DC/DC converter 32 can convert the DC voltage supplied from the stationary storage battery 30 into DC voltages of different magnitudes, and can apply the converted DC voltage to the DC wiring 60. Further, the DC/DC converter 32 converts the DC voltage supplied from the DC wiring 60 into a DC voltage of a different magnitude, and applies the converted DC voltage to the stationary storage battery 30 to charge the stationary storage battery 30. I can do it.

Vehicle charging device 40 has charging cable 42 . The charging cable 42 is connectable to the electric vehicle 70. The electric vehicle 70 has a vehicle storage battery 72. The electric vehicle 70 runs using electric power stored in the vehicle storage battery 72. When the charging cable 42 is connected to the electric vehicle 70, the vehicle charging device 40 is electrically connected to the vehicle storage battery 72. Vehicle charging device 40 includes a DC/DC converter. The vehicle charging device 40 converts the DC voltage supplied from the DC wiring 60 into DC voltages of different magnitudes, applies the converted DC voltage to the vehicle storage battery 72, and charges the vehicle storage battery 72.

Inverter 50 is connected to DC wiring 60 and AC wiring 92. The inverter 50 can convert DC power supplied from the DC wiring 60 into AC power, and perform DC-AC conversion to supply the converted AC power to the AC wiring 92. The inverter 50 can also perform AC-DC conversion by converting AC power supplied from the AC wiring 92 into DC power and supplying the converted DC power to the DC wiring 60. However, in the normal operation mode that is executed when no abnormality occurs in the power system 10, the control device 68 prohibits AC-DC conversion of the inverter 50. That is, in the normal operation mode, inverter 50 can perform DC-AC conversion.

The control device 68 is connected to the solar power generation device 20, the DC/DC converter 22, the stationary storage battery 30, the DC/DC converter 32, the vehicle charging device 40, the inverter 50, and the power meter 96 via a communication line (not shown). ing. The control device 68 receives a signal indicating the amount of power generation from the solar power generation device 20. The control device 68 receives a signal indicating the amount of stored electricity from the stationary storage battery 30. Control device 68 receives a signal indicating the amount of electricity stored in vehicle storage battery 72 from electric vehicle 70 via vehicle charging device 40 . Control device 68 controls solar power generation device 20, DC/DC converter 22, DC/DC converter 32, vehicle charging device 40, and inverter 50.

The control device 68 operates the DC/DC converter 22 during power generation by the solar power generation device 20 to supply DC power from the solar power generation device 20 to the DC wiring 60 . At the same time, control device 68 operates DC/DC converter 32, vehicle charging device 40, or inverter 50. When the DC/DC converter 32 operates while the solar power generation device 20 is generating power, the stationary storage battery 30 is charged with the power generated by the solar power generation device 20. When the vehicle charging device 40 operates while the solar power generation device 20 is generating power, the vehicle storage battery 72 is charged with the power generated by the solar power generation device 20. When the inverter 50 operates while the solar power generation device 20 is generating power, AC power converted from the DC power generated by the solar power generation device 20 is supplied to the AC wiring 92 . The control device 68 also operates the DC/DC converter 32 and the vehicle charging device 40 to supply power from the stationary storage battery 30 to the vehicle storage battery 72 when the solar power generation device 20 is not generating power. I can do it. In this case, the stationary storage battery 30 is discharged and the vehicle storage battery 72 is charged.

The control device 68 constantly monitors the storage amount B1 of the vehicle storage battery 72 and the storage amount B2 of the stationary storage battery 30. FIG. 2 illustrates the amounts of stored electricity B1 and B2. In FIG. 2, the maximum value B1max is the maximum value of the amount of electrical storage B1 that can be stored in the vehicle storage battery 72, and the maximum value B2max is the maximum value of the amount of electrical storage B2 that can be stored in the stationary storage battery 30. In FIG. 2, the amounts of stored electricity B1 and B2 are shown normalized so that the maximum value B1max and the maximum value B2max are equal. The lower limit value B1min is the minimum amount of electrical storage B1 necessary for the electric vehicle 70 to run stably. Therefore, the difference B1−B1min between the stored power amount B1 and the lower limit value B1min is the amount of power that can be substantially used by the electric vehicle 70. The first reference value B1ref is a reference value for determining whether or not to end charging in the charging process of the vehicle storage battery 72, which will be described later. In this embodiment, the first reference value B1ref is a fixed value. In FIG. 2, the first reference value B1ref is lower than the maximum value B1max, but the first reference value B1ref may be equal to the maximum value B1max. The second reference value B2ref is a reference value for determining whether or not to end charging in the charging process of the stationary storage battery 30, which will be described later. The second reference value B2ref is lower than the maximum value B2max. In this embodiment, the second reference value B2ref changes depending on the situation.

Next, the operation of the power system 10 when the solar power generation device 20 is generating power and the electric vehicle 70 is connected to the vehicle charging device 40 will be described in detail. FIG. 3 shows the operation of the power system 10 while the solar power generation device 20 is generating power. When the solar power generation device 20 starts generating power, the control device 68 starts the process shown in FIG. 2 .

In step S2, the control device 68 calculates the required power storage amount A based on the number of consecutive allowable days A1, the average vehicle mileage A2, and the amount of power consumption per unit distance A3. The number of consecutive allowable days A1 is the allowable number of consecutive days when the solar power generation device 20 is unable to generate electricity due to rainy weather or the like. The number of consecutive allowable days A1 is a value preset in the power system 10 and is stored in the control device 68. The average vehicle travel distance A2 is the average value of the distance that the electric vehicle 70 travels per day. The amount of power consumed per unit distance A3 is the amount of power required for the electric vehicle 70 to travel a unit distance (for example, 1 km). The average vehicle travel distance A2 and the power consumption per unit distance A3 are values calculated based on past travel results of the electric vehicle 70. Control device 68 reads average vehicle travel distance A2 and power consumption per unit distance A3 from electric vehicle 70. The control device 68 calculates the required amount of electrical storage A using the formula A=A1×A2×A3. That is, the required power storage amount A is the amount of power required to maintain the electric vehicle 70 in a drivable state when the solar power generation device 20 is unable to generate power for consecutive allowable days A1. In other words, if the amount of electricity stored in the vehicle storage battery 72 and the stationary storage battery 30 is less than the required amount of electricity storage A, if there are consecutive days in which the solar power generation device 20 is unable to generate electricity for the consecutive allowable number of days A1, then There is a high possibility that the electric vehicle 70 will be unable to run due to a lack of stored electricity.

Next, in step S4, the control device 68 calculates a second reference value B2ref based on the required electrical storage amount A and the first reference value B1ref. As described above, the difference B1−B1min is the amount of power that can be substantially used by the electric vehicle 70. Further, as described above, since the vehicle storage battery 72 can be charged by the stationary storage battery 30, the stored power amount B2 is the amount of power that can be used by the electric vehicle 70. Therefore, the amount of power that can be used by the electric vehicle 70 in the power system 10 is the sum of the difference B1-B1min and the amount of stored electricity B2. The control device 68 calculates the required storage amount A by calculating the sum of the difference B1-B1min and the storage amount B2 (that is, (B1ref1-B1min)+B2ref) when the vehicle storage battery 72 and the stationary storage battery 30 are each charged to the reference value. The second reference value B2ref is calculated so as to match the second reference value B2ref. That is, the control device 68 calculates the second reference value B2ref using the formula B2ref=A−(B1ref−B1min). In addition, in a situation where the amount of stored electricity B1 of the vehicle storage battery 72 is higher than the first reference value B1ref for some reason, the second reference value B2ref is determined by the formula B2ref=A-(B1-B1min) using the actual amount of stored electricity B1. may be calculated.

Next, the control device 68 determines and executes the operation contents in steps S6 to S16. In step S6, the control device 68 determines whether the amount of electrical storage B1 of the vehicle storage battery 72 is less than the first reference value B1ref. If YES in step S6, the control device 68 operates the vehicle charging device 40 to charge the vehicle storage battery 72 in step S12. If NO in step S6, in step S8, the control device 68 determines whether the amount of stored electricity B2 of the stationary storage battery 30 is less than the second reference value B2ref. If YES in step S8, the control device 68 operates the DC/DC converter 32 to charge the stationary storage battery 30 in step S14. If NO in step S8, control device 68 calculates the AC power demand within house 90 based on the detected value of power meter 96 in step S10. The control device 68 determines whether there is a demand for AC power in the house 90 (i.e., whether the electrical equipment 94 is being used or not) by determining whether the calculated AC power demand is equal to the standard demand. ) is determined. If NO in step S10, the control device 68 operates the DC/DC converter 32 to charge the stationary storage battery 30 in step S14. If YES in step S10, control device 68 operates inverter 50 to supply AC power to AC wiring 92 in step S16.

After performing steps S12 to S16 for a predetermined period of time, the control device 68 determines whether or not there is a power supply destination in step S18. When the storage amount B1 of the vehicle storage battery 72 is equal to or higher than the first reference value B1ref, the storage amount B2 of the stationary storage battery 30 is the maximum value B2max, and there is no demand for AC power within the house 90, the control device 68 determines that there is no power supply destination. In other cases, the control device 68 determines that there is a power supply destination. If there is a power supply destination, the control device 68 determines YES in step S18, and re-executes the process from step S6. If there is no power supply destination, the control device 68 determines NO in step S18, and executes step S20.

In step S20, the control device 68 determines whether the amount of stored electricity B1 is less than the maximum value B1max. If the stored power amount B1 is less than the maximum value B1max, the control device 68 executes step S12 to charge the vehicle storage battery 72. Steps S20 and S12 are repeated until the amount of stored electricity B1 reaches the maximum value B1max. When the amount of stored electricity B1 reaches the maximum value B1max, the control device 68 determines NO in step S20, and stops the power generation of the solar power generation device 20 in step S22.

Steps S6 to S22 will be explained in more detail. If the storage amount B1 of the vehicle storage battery 72 is less than the first reference value B1ref, the control device 68 determines YES in step S6, and charges the vehicle storage battery 72 in step S12. The control device 68 charges the vehicle storage battery 72 by repeating steps S6, S12, and S18 until the storage amount B1 of the vehicle storage battery 72 reaches the first reference value B1ref. In this way, when the storage amount B1 of the vehicle storage battery 72 is less than the first reference value B1ref, the control device 68 controls The vehicle storage battery 72 is charged. That is, the control device 68 performs charging of the vehicle storage battery 72 with the highest priority.

If the amount of stored electricity B1 of the vehicle storage battery 72 has reached the first reference value B1ref and the amount of stored electricity B2 of the stationary storage battery 30 is less than the second reference value B2ref, the control device 68 performs the following in step S6. The determination is NO, and the determination is YES in step S8. Therefore, the control device 68 charges the stationary storage battery 30 in step S14. The control device 68 charges the stationary storage battery 30 by repeating steps S6, S8, S14, and S18 until the storage amount B2 of the stationary storage battery 30 reaches the second reference value B2ref. In this manner, the control device 68 controls the control device 68 when the storage amount B1 of the vehicle storage battery 72 has reached the first reference value B1ref and when the storage amount B2 of the stationary storage battery 30 is less than the second reference value B2ref. , the stationary storage battery 30 is charged regardless of the AC power demand within the house 90. That is, the control device 68 performs charging of the stationary storage battery 30 with second priority.

When each of the stored electricity amounts B1 and B2 has reached the reference value and there is a demand for AC power within the house 90, the control device 68 determines NO in step S6, and determines NO in step S8. Then, it is determined as YES in step S10. Therefore, the control device 68 supplies AC power from the inverter 50 to the AC wiring 92 in step S16. The control device 68 repeats steps S6, S8, S10, S16, and S18 to supply AC power from the inverter 50 to the AC wiring 92 until the demand for AC power disappears. In this way, the control device 68 controls the AC power from the inverter 50 to the AC wiring 92 when each of the stored electricity amounts B1 and B2 has reached the reference value and there is a demand for AC power within the house 90. supply

When each of the stored electricity amounts B1 and B2 has reached the reference value and there is no demand for AC power within the house 90, the control device 68 determines NO in step S6, and determines NO in step S8. However, the determination in step S10 is NO. Therefore, the control device 68 charges the stationary storage battery 30 in step S14. The control device 68 charges the stationary storage battery 30 by repeating steps S6, S8, S10, S14, and S18 until the storage amount B2 of the stationary storage battery 30 reaches the maximum value B2max.

When the amount of stored electricity B1 reaches the first reference value B1ref, the amount of stored electricity B2 reaches the maximum value B2max, and there is no demand for AC power within the house 90 by performing steps S12, S14, or S16, the control The device 68 determines NO in step S18. In this case, the control device 68 charges the vehicle storage battery 72 to the maximum value B1max in step S20, and then stops power generation by the solar power generation device 20 in step S22.

As described above, in the power system 10 of the first embodiment, when each of the stored power amounts B1 and B2 is less than the reference value and there is a demand for AC power, the control device 68 first controls the storage battery 72 for the vehicle. is charged to the first reference value B1ref. Next, the control device 68 charges the stationary storage battery 30 to the second reference value B2ref. Next, the control device 68 supplies AC power, and then charges the stationary storage battery 30 to the maximum value B2max when the demand for AC power disappears. In this way, charging of the vehicle storage battery 72 and the stationary storage battery 30 to the reference value is given priority over the supply of AC power. Therefore, the frequency of operation of the inverter 50 is reduced, and energy loss in the inverter 50 is suppressed. Furthermore, since the frequency of AC power supply to the house 90 becomes lower, fluctuations in the power demand for the power system 80 become smaller. This reduces the burden on electric power companies.

Furthermore, as described above, the power system 10 supplies AC power to the AC wiring 92 after securing the required amount of stored electricity A as the total amount of stored electricity B1 and B2. The required storage amount A is calculated by the formula A=A1×A2×A3, and the second reference value B2ref is calculated by the formula B2ref=A-(B1ref-B1min), so the storage amounts B1 and B2 are each the reference value. By reaching , the necessary amount of power (that is, the predicted value of the required amount of power) for the number of consecutive allowable days A1 is secured. Therefore, even if it is not possible to continuously generate power for the same number of consecutive days A1 due to rain or the like after the stored electricity amounts B1 and B2 reach their respective reference values, the electric vehicle 70 can be used within the period of that number of days. can be maintained as possible.

Further, as described above, when the amount of stored electricity B1 is equal to or greater than the first reference value B1ref, the amount of stored electricity B2 is the maximum value B2max, and there is no demand for AC power, the control device 68 returns NO in step S18. Then, in step S20, the vehicle storage battery 72 is charged to the maximum value B1max, and then, in step S22, power generation by the solar power generation device 20 is stopped. Therefore, AC power is prevented from being supplied from the power system 10 to the AC wiring 92 in a state where there is no demand for AC power. Therefore, reverse power flow in which power is supplied from the AC wiring 92 to the power system 80 is prevented. When a reverse power flow occurs, there is a possibility that the power quality on the power system 80 side will deteriorate. In order to cope with reverse power flow, it is necessary to prepare equipment on the power system 80 side, which increases the burden on the power company. In this embodiment, since reverse power flow can be prevented, the burden on the electric power company can be reduced.

Furthermore, as described above, in the normal operation mode, AC-DC conversion of the inverter 50 is prohibited. Therefore, in the normal operation mode, the vehicle storage battery 72 is charged only with the electric power generated by the solar power generation device 20. Therefore, the electric vehicle 70 can run using only clean energy.

Further, the control device 68 can detect the voltage of the AC wiring 92 using a sensor (not shown). When the control device 68 detects a power outage in the house 90 due to a voltage drop in the AC wiring 92, it switches the operation to a power outage mode. In power outage mode, controller 68 does not execute the flowchart of FIG. In the power outage mode, controller 68 operates inverter 50 to supply AC power from power system 10 to AC wiring 92 . This allows the electrical equipment 94 to be used during a power outage.

Note that in the above-described embodiment, the number of consecutive allowable days A1 is a fixed value, but the number of consecutive allowable days A1 may be changed depending on the situation. Further, in the embodiment described above, the average vehicle travel distance A2 and the power consumption per unit distance A3 were calculated each time based on the past travel record of the electric vehicle 70. However, the average vehicle travel distance A2 and the power consumption per unit distance A3 may be fixed values. That is, the required amount of electrical storage A may be stored in the control device 68 as a fixed value.

In the above embodiment, the vehicle storage battery 72 is an example of a first storage battery, and the stationary storage battery 30 is an example of a second storage battery. In the above embodiment, the second storage battery is a stationary storage battery, but it is also possible that the second storage battery is a vehicle storage battery installed in an electric vehicle (that is, another electric vehicle different from the electric vehicle 70). Good too.

Further, in the above embodiment, if the reference value B1ref is equal to the maximum value B1max, step S20 is unnecessary.

Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness singly or in various combinations, and are not limited to the combinations described in the claims as filed. Furthermore, the techniques illustrated in this specification or the drawings simultaneously achieve multiple objectives, and achieving one of the objectives has technical utility in itself.

10: Power system 20: Solar power generation device 22: DC/DC converter 30: Stationary storage battery 32: DC/DC converter 40: Vehicle charging device 42: Charging cable 50: Inverter 60: DC wiring 68: Control device 70: Electric Car 72 : Vehicle storage battery 80 : Power system 90 : House 92 : AC wiring 94 : Electrical equipment

Claims (6)

An electric power system installed in a facility,
DC wiring and
a natural energy power generation device connected to the DC wiring and supplying DC power to the DC wiring;
a first charging device that is connected to the DC wiring and charges a first storage battery mounted on the vehicle with DC power supplied from the DC wiring;
a second charging device that is connected to the DC wiring and charges a second storage battery with DC power supplied from the DC wiring;
a DC-AC converter connected to the DC wiring, converting DC power supplied from the DC wiring into AC power and supplying the AC power to the AC wiring of the facility;
has
When the natural energy power generation device is generating power, the first storage battery is connected to the first charging device, and the second storage battery is connected to the second charging device,
(1) When the amount of electricity stored in the first storage battery is less than a first reference value, the first charging device performs a first operation of charging the first storage battery;
(2) When the amount of electricity stored in the first storage battery is greater than or equal to the first reference value and the amount of electricity stored in the second storage battery is less than the second reference value, the second charging device charges the second storage battery. perform an action,
(3) When the amount of electricity stored in the first storage battery is greater than or equal to the first reference value and the amount of electricity stored in the second storage battery is greater than or equal to the second reference value, the DC/AC converter applies AC power to the AC wiring. performing a third operation of supplying;
An electric power system that operates according to rules (1) to (3). The power system according to claim 1, wherein in the normal operation mode, conversion of AC power to DC power by the DC/AC converter is prohibited. The AC wiring is connected to a power system outside the facility,
The power system according to claim 1 or 2, which operates so as to prevent a reverse power flow in which power is supplied from the AC wiring to the power system. further comprising a device that outputs a predicted value of the amount of electricity that the vehicle will use within a predetermined number of days,
the second reference value such that the second operation shifts to the third operation when the total amount of electricity stored in the first storage battery and the amount of electricity stored in the second storage battery reaches the predicted value in the second operation; is set,
The power system according to claim 1 or 2. The power system according to claim 4, wherein even if the total amount has reached the predicted value, the second operation is executed if the power demand in the AC wiring is lower than the reference demand amount. The electric power according to claim 1 or 2, wherein when a power drop in the AC wiring is detected, regardless of the rules (1) to (3), the DC/AC converter supplies AC power to the AC wiring. system.

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