Power System

Abstract

To perform flexible power supply management.SOLUTION: A power system S includes a stationary power supply 10, a power conversion device 30 for converting power of the stationary power supply 10, one or a plurality of chargers / dischargers 100 connected in parallel with the power conversion device 30, and a power control device 50 for controlling the power conversion device 30. The power conversion device 30 interconnects with a power system 1 via an interconnection line L0 and the chargers / dischargers 100 are for mobile bodies. The power control device 50 has two operation modes of a first operation mode and a second operation mode. The power control device 50 controls only an amount of electricity of the stationary power supply 10 in the first operation mode and controls an amount of electricity of a power supply 230 mounted on a mobile body 200 connected to a charger / discharger 100 in addition to the amount of electricity of the stationary power supply 10 in the second operation mode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power system that is interconnected with an electric power grid. [Background technology]

[0002] In recent years, effective utilization of the energy of batteries installed in electrically powered vehicles such as electric vehicles (EVs) and hybrid vehicles (HEVs) has been studied. Patent Document 1 discloses a technology (V2H) in which an electrically powered vehicle is connected to electrical equipment used in a home and supplies power to the electrical equipment in the home as an emergency power source in the event of a disaster or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-61432 Summary of the Invention [Problem to be solved by the invention]

[0004] It is expected that flexible power management will be possible in a power system that is interconnected with a power grid and includes a stationary power source, a power conversion device that converts the power of the stationary power source, and a charger / discharger connected in parallel with the power conversion device. [Means for solving the problem]

[0005] The power system includes a stationary power source, a power conversion device that converts the power of the stationary power source, one or more chargers / dischargers connected in parallel with the power conversion device, and a power control device that controls the power conversion device, wherein the power conversion device is connected to a power grid via an interconnection line, and the charger / discharger is for use in a mobile body.

[0006] The power control device has two operation modes: a first operation mode and a second operation mode. In the first operation mode, the power control device controls the amount of electricity only from the stationary power source, and in the second operation mode, it controls the amount of electricity from the stationary power source as well as the onboard power source of the mobile body connected to the charger / discharger. The "amount of electricity" includes remaining capacity [Ah], SOC [%], charge amount [Ah], discharge amount [Ah], discharge power [kW], charge power [kW], etc.

[0007] This technology can be applied to the operation methods and operation programs of power systems. [Effects of the Invention]

[0008] This configuration allows for flexible power management because the number of power sources controlled by the power control device and the amount of electricity that can be charged and discharged can be changed by switching the operation mode. [Brief explanation of the drawings]

[0009] [Figure 1] Power System Block Diagram [Figure 2] Perspective view of a charger and an electric vehicle [Figure 3] A diagram showing the changes in capacity of each power source [Figure 4] Flowchart of operation mode switching process [Figure 5] Operation mode switching process time flow [Figure 6] Diagram showing charging path [Figure 7] Diagram showing the discharge path [Figure 8] Priority diagram [Figure 9] Priority diagram [Figure 10] Flowchart of operation mode switching process [Figure 11] Operation mode switching process time flow [Figure 12] Flowchart of operation mode switching process [Figure 13]Operation mode switching process time flow [Figure 14] A diagram showing the changes in capacity of each power source [Figure 15] Power System Block Diagram [Figure 16] Diagram showing charging priorities DETAILED DESCRIPTION OF THE INVENTION

[0010] The power system includes a stationary power source, a power conversion device that converts the power of the stationary power source, one or more chargers / dischargers connected in parallel with the power conversion device, and a power control device that controls the power conversion device, wherein the power conversion device is connected to a power grid via an interconnection line, and the charger / discharger is for use in a mobile body.

[0011] The power control device has two operation modes: a first operation mode and a second operation mode. In the first operation mode, the power control device controls the amount of electricity only from the stationary power source, and in the second operation mode, the power control device controls the amount of electricity from the onboard power source of the mobile body connected to the charger / discharger in addition to the amount of electricity from the stationary power source.

[0012] In this configuration, the number of power sources to be controlled by the power control device and the amount of electricity that can be charged and discharged can be changed by switching the operation mode, enabling flexible power management.

[0013] For example, when the first operating mode is selected, the power control device controls only one type of power source, and only the stationary power source is controlled. During the first operating mode, the charger / discharger is independent of the power control device and operates as a charger for the mobile object. Therefore, if the mobile object is connected to the charger / discharger, the mobile object's onboard power source can be charged.

[0014] When the second operating mode is selected, the power control device controls two types of power sources: in addition to the amount of electricity from the stationary power source, it also controls the amount of electricity from the onboard power source of the mobile body connected to the charger / discharger. By adding the onboard power source of the mobile body to the list of controlled sources, the amount of electricity that can be controlled by the power control device increases compared to the first operating mode, which only controls stationary power sources. Therefore, it is expected to be used in applications that require charging and discharging large amounts of electricity.

[0015] In the second operation mode, the power control device may individually control the amount of electricity of the stationary power source and the amount of electricity of the onboard power source, or may control a total amount of electricity that is the sum of the two amounts of electricity. Individual control of the amount of electricity manages the amount of electricity for each power source, so there is a low risk that each power source will fall outside its usage range during the second operation mode. Control of the total amount of electricity controls the stationary power source and the onboard power source as a single power source that is the sum of the amounts of electricity of the two power sources during the second operation mode, and therefore has the advantage of reducing the calculation load on the power control device compared to individual control.

[0016] In the second operation mode, the power control device may charge the stationary power sources and the onboard power sources according to priority. Alternatively, it may discharge the power sources according to priority. By setting the priority, the charging order or discharging order of the power sources can be selected arbitrarily. This makes it possible to suppress the decrease in the amount of electricity stored in the stationary power sources, which are the main power sources of the power system, by, for example, prioritizing charging the stationary power sources and discharging the onboard power sources. By suppressing the decrease in the amount of electricity stored in the stationary power sources, it is possible to suppress the power system from going down due to a loss of the main power source.

[0017] In the second operating mode, the power control device may charge the onboard power sources of the multiple mobile bodies connected to the multiple chargers / dischargers according to priority. Alternatively, the power control device may discharge the onboard power sources according to priority. By setting the priority, the charging order or discharging order of the mobile bodies connected to the chargers / dischargers can be selected arbitrarily. For example, suppose that multiple chargers are connected to the mobile bodies, some of which are mobile bodies for specific purposes and some of which are mobile bodies for normal charging purposes. The specific purposes are emergency power supply purposes and power demand adjustment purposes. The normal charging purposes are for replenishing the energy of the mobile bodies.

[0018] In this case, after transitioning to the second operating mode, when charging each of the mobile bodies connected to multiple chargers, charging the mobile bodies for normal charging purposes first, and then charging the mobile bodies for specific purposes, can shorten the waiting time of users using the charger / discharger for normal charging purposes.

[0019] The power control device may select the second operation mode when there is a risk of a power outage in the power grid or in accordance with a request for power demand adjustment. If the second operation mode is selected in accordance with the risk of a power outage, power can be supplied to the load from two power sources, a stationary power source and an onboard power source, during a power outage. Power can be supplied to the load for a longer period of time compared to when power is supplied using only a stationary power source. If the second operation mode is selected in accordance with a request for power demand adjustment, power demand can be adjusted using two power sources, a stationary power source and an onboard power source. Compared to when demand adjustment is performed using only a stationary power source, a larger amount of electricity can be charged and discharged, making a significant contribution to balancing power supply and demand.

[0020] When the power control device transitions to the second operation mode due to the occurrence of a risk of a power outage in the power grid, the power control device may charge the stationary power source and the onboard power source during a preparation period until the power outage. In this configuration, after transitioning to the second operation mode, two power sources are charged during the preparation period until the power outage, so that sufficient power can be supplied to the load during the power outage in the power grid.

[0021] The charging target values ​​of the stationary power source and the onboard power source may be set smaller as the probability of a power outage in the power grid decreases. In this configuration, when the probability of a power outage is low, the amount of electricity stored in the power source is small, so there is little accumulation of wasted energy and energy utilization efficiency is high.

[0022] When the power control device transitions to the second operation mode in response to a request to increase power demand, the power control device may discharge the stationary power source and the onboard power source during a preparation period until demand adjustment. With this configuration, after transitioning to the second operation mode, the stationary power source and the onboard power source are discharged during the preparation period until demand adjustment, so that a chargeable amount of available electricity can be secured. Therefore, by charging the stationary power source and the onboard power source during the period in which demand adjustment is implemented, it is possible to contribute to the increase in power demand.

[0023] When the power control device transitions to the second operation mode in response to a request to reduce power demand, the power control device may charge the stationary power source and the onboard power source during a preparation period until demand adjustment. In this configuration, after transitioning to the second operation mode, the stationary power source and the onboard power source are charged during the preparation period until demand adjustment, so that a dischargeable amount of electricity can be secured. Therefore, discharging the stationary power source and the onboard power source during the implementation period of demand adjustment can contribute to reducing power demand.

[0024] <Embodiment 1> 1. Description of power system S1 1 is a block diagram of a power system S1. The power system S1 includes a stationary power source 10, a power conditioner 20, and a charger / discharger 100.

[0025] The stationary power source 10 is composed of a stationary generator 11 and a stationary battery 15. The stationary generator 11 may be a generator that uses renewable energy, such as a solar power generation panel PV. The stationary battery 15 may be a secondary battery that can be repeatedly charged and discharged, such as a lithium-ion secondary battery.

[0026] The power conditioner 20 includes a first converter circuit 21, a second converter circuit 25, an inverter circuit 30, a measurement unit 31, a grid-connection relay 33, a switching circuit 35, a measurement unit 38, and a power control device 50.

[0027] The stationary generator 11 is connected to the first converter circuit 21. The first converter circuit 21 is a DC / DC converter. The output of the stationary generator 11 can be controlled by the first converter circuit 21. The first converter circuit 21 may be a chopper.

[0028] The stationary battery 15 is connected to the second converter circuit 25. The second converter circuit 25 is a bidirectional DC / DC converter that charges and discharges the stationary battery 15. The second converter circuit 25 may be a bidirectional chopper. The second converter circuit 25 may include a measuring unit that measures the charging current and discharging current of the stationary battery 15. The measuring unit that measures the charging current and discharging current may be provided in the stationary battery 15.

[0029] The first converter circuit 21 and the second converter circuit 25 are each connected to the inverter circuit 30.

[0030] The inverter circuit 30 is a bidirectional conversion circuit that selectively performs inverse conversion (inverter) that converts DC to AC and forward conversion (converter) that converts AC to DC. The inverter circuit 30 may be a conversion circuit that only performs inverse conversion (inverter). The inverter circuit 30 is connected to the power system 1 via an interconnection line L0. The inverter circuit 30 is a power conversion device.

[0031] By causing the inverter circuit 30 to perform an inverse conversion operation, it is possible to convert DC power input from the stationary power source 10 into AC power and output it.

[0032] By operating the inverter circuit 30 in a forward conversion mode, AC power input from the power grid 1 can be converted into DC power and output. The output DC power can be used to charge the stationary battery 15. The stationary battery 15 can also be charged with surplus power from the stationary generator 11.

[0033] The measurement unit 31 measures the output voltage Vinv and the output current Iinv during inverse conversion operation of the inverter circuit 30. The measurement unit 31 measures the input voltage Vinv and the input current Iinv during forward conversion operation. The measurement results of the measurement unit 31 are input to the power control device 50.

[0034] The interconnection relay 33 is installed on the interconnection line L0. When there is no abnormality in the power conditioner 20 or the power system 1, the interconnection relay 33 is controlled to be closed.

[0035] The power system 1 is a system operated by an electric utility company and includes a system power source 3. A measuring instrument 5 is installed at a power receiving point A of the power system S1.

[0036] The measuring instrument 5 measures the received power Pgrid of the power system S1. The received power Pgrid is the power that the power system S1 receives from the power grid 1 (power at the power receiving point A). The measurement result Pgrid of the measuring instrument 5 is transmitted to the power control device 50 via a communication line. The dashed line F shown in FIG. 1 indicates the boundary between the power grid 1 and the power system S1.

[0037] A first load 70A is connected to point B on the interconnection line L0 via a first branch line L1.

[0038] The switching circuit 35 is a circuit that switches the connection point of the second branch line L2 with respect to the interconnection line L0. The switching circuit 35 includes a first switch 36 and a second switch 37. The first switch 36 and the second switch 37 are connected in series.

[0039] The first switch 36 is connected to the end point C on the power grid 1 side of the interconnection relay 33, out of the end points C and D of the interconnection relay 33. The second switch 37 is connected to the end point D on the inverter circuit 30 side of the interconnection relay 33, out of the end points C and D of the interconnection relay 33.

[0040] A second load 70B is connected to a connection point E of the two switches 36 and 37 via a second branch line L2.

[0041] By closing the first switch 36 and opening the second switch 37, the second load 70B can be connected to point C of the interconnection relay 33. By opening the first switch 36 and closing the second switch 37, the second load 70B can be connected to point D of the interconnection relay 33.

[0042] When there is no abnormality in the power conditioner 20 or the power grid 1, the first switch 36 is controlled to be closed, and the second switch 37 is controlled to be open.

[0043] The second switch 37 is for independent operation, and the second load 70B is a specific load to which power is supplied by the independent operation of the power conditioner 20. The second load 70B is a load to which it is desirable to supply power and keep it running even during a power outage, such as an elevator, refrigerator, or air conditioner. The second load 70B is connected to a terminal block or breaker provided on the distribution board of the power conditioner 20.

[0044] The isolated operation refers to a state in which a distributed power source connected to a grid power source is disconnected from the grid and power is supplied from the distributed power source to a load on the customer premises. In this example, the power conditioner 20 is disconnected from the power grid 1 and power is supplied from the power conditioner 20 to a second load 70B corresponding to the load on the customer premises.

[0045] The measurement unit 38 is installed at point C on the interconnection line L0. The measurement unit 38 measures the system voltage Vgrid of the power system 1. The measurement result of the measurement unit 38 is input to the control device 50.

[0046] The second branch line L2 is connected to a charger / discharger 100. The charger / discharger 100 is in parallel with the inverter circuit 30 when viewed from the second load 70B, and is also in parallel with the second load 70B when viewed from the inverter circuit 30.

[0047] The power control device 50 has a CPU 51, a memory 53, a first communication unit 55, and a second communication unit 57. The memory 53 stores a control program for the inverter circuit 30 and a program for switching between operation modes. In addition, the memory 53 stores data necessary for controlling the inverter circuit 30 and switching between operation modes.

[0048] The power control device 50 can control switching between forward conversion operation and inverse conversion operation by issuing commands to the inverter circuit 30. Based on the measurement values ​​(Vinv, Iinv) of the measurement unit 31, the power control device 50 monitors the output power Pinv of the inverter circuit 30 during inverse conversion operation and the input power Pinv during forward conversion operation.

[0049] The power control device 50 can control the output power Pinv during the reverse conversion operation of the inverter circuit 30 by controlling the output of the stationary generator 11 and the output of the stationary battery 15 through the first converter circuit 21 and the second converter circuit 25. The power control device 50 can control the charge / discharge amount of the stationary battery 15 through the second converter circuit 25.

[0050] The first communication unit 55 is for communication connection with the network NW. A first server device 150 and a second server device 160 are connected to the network NW.

[0051] The first server device 150 provides a service of distributing weather forecast information. The second server device 160 is a server operated by an aggregator business operator, and distributes information on power demand adjustment to the operator of the power system S1. The aggregator business operator is a business operator that provides energy management services by aggregating the power demand of distributed power sources and consumers. The information on power demand adjustment may be information on a notice of the initiation of demand response, or may be other information. In the first embodiment, information on a notice of the initiation of demand response is distributed.

[0052] The charger / discharger 100 includes a bidirectional converter 110 , a control unit 121 , a storage unit 123 , and a communication unit 127 .

[0053] The bidirectional converter 110 is a bidirectional conversion circuit that selectively performs forward conversion (converter function) to convert alternating current power AC into direct current power DC, and inverse conversion (inverter function) to convert direct current power DC into alternating current power AC.

[0054] 2 is a perspective view of the charger / discharger and the electric vehicle. The charger / discharger 100 can be connected to the electric vehicle 200 via an electric cable 130, and can charge or discharge the on-board battery 230 of the electric vehicle 200.

[0055] Specifically, the on-board battery 230 can be charged by the forward conversion operation of the bidirectional converter 110, and can be discharged by the reverse conversion operation of the bidirectional converter 110. The charger / discharger 100 may include a measurement unit that measures the charging current and the discharging current.

[0056] The charger / discharger 100 can be used for normal charging purposes and special purposes. The normal charging purpose is to supply energy to the electric vehicle 200 (for driving). The special purpose is to use the on-board battery 230 of the electric vehicle 200 as an emergency power source or to adjust power demand. The electric vehicle 200 is an example of a "mobile body," and the on-board battery 230 is an example of an "on-board power source."

[0057] The electric cable 130 includes a power line 130A for charging and discharging, as well as a signal line 130B. The control unit 121 is connected to the electric vehicle 200 via the signal line 130B so as to be able to communicate with the electric vehicle 200.

[0058] The control unit 121 receives information on the remaining capacity [Ah] of the mounted battery 230 from the vehicle ECU 210 of the electric vehicle 200. The control unit 121 calculates the charge amount [Ah] and discharge amount [Ah] of the mounted battery 230 based on the charge current and discharge current of the mounted battery 230, and can manage the remaining capacity [Ah] during and after charging and the remaining capacity [Ah] during and after discharging of the mounted battery 230.

[0059] The storage unit 123 stores data on the charge / discharge history of the electric vehicle 200 and the remaining capacity of the mounted battery 230. The charger / discharger 100 is communicably connected to the power control device 50 of the power conditioner 20 via a communication unit 127.

[0060] 2. Switching the operating mode The power control device 50 has two operation modes: a first operation mode and a second operation mode. The first operation mode and the second operation mode differ in the number of batteries controlled by the power control device 50 and the chargeable / dischargeable capacity [Ah].

[0061] Figure 3 shows the changes in capacity of the stationary battery 15 and the on-board battery 230. Q1 is the remaining capacity [Ah] of the stationary battery 15, and Q2 is the remaining capacity [Ah] of the on-board battery 230. The remaining capacity Q is the capacity stored in the battery and changes with charging and discharging. The dotted frame K in Figure 3 indicates the power source to be controlled by the power control device 50.

[0062] In the first operating mode, the number of power sources controlled by the power control device 50 is "1", and the power control device 50 controls the remaining capacity Q1 of only the stationary battery 15. The remaining capacity can be controlled by adjusting the charge / discharge amount of the battery. The remaining capacity can be determined from the amount of change in capacity due to charging / discharging. The amount of change in capacity due to charging / discharging can be calculated using time integration of current, etc. During the first operating mode, the charger / discharger 100 is independent of the power control device 50 and operates as a charger for normal charging purposes.

[0063] In the second operating mode, the number of power sources controlled by the power control device 50 is "2", and in addition to controlling the remaining capacity Q1 of the stationary battery 15, the power control device 50 controls the remaining capacity Q2 of the onboard battery 230 of the electric vehicle 200 via the charger / discharger 100.

[0064] The power control device 50 may individually control the remaining capacity Q1 of the stationary battery 15 and the remaining capacity Q2 of the mounted battery 230, or may control the total remaining capacity QT of the remaining capacity Q1 of the stationary battery 15 and the remaining capacity Q2 of the mounted battery 230. In the first embodiment, the total remaining capacity QT is controlled. Q1 and Q2 are examples of "electrical quantity", and QT is an example of "total electrical quantity".

[0065] QT=Q1+Q2

[0066] The initial setting of the operation mode is the first operation mode. The power control device 50 switches from the first operation mode to the second operation mode when there is a risk of a power outage in the power system 1 or when there is a request to adjust the demand for power.

[0067] Fig. 4 is a flowchart of the process of switching the operation mode of the power control device 50, and Fig. 5 shows the time flow thereof. In this example, the operation mode is switched when a risk of a power outage occurs in the power system 1.

[0068] The operation mode switching process is made up of seven steps S10 to S70. After starting up, the power conditioner 20 proceeds to S10 and selects the first operation mode.

[0069] During the first operating mode, the power control device 50 controls only the remaining capacity Q1 of the stationary battery 15. During the first operating mode, the power control device 50 controls the remaining capacity Q1 of the stationary battery 15 to be equal to or greater than a lower limit value by controlling the charge / discharge amount using the second converter circuit 25.

[0070] The power control device 50 charges or discharges the stationary battery 15 within a range not below a lower limit based on the balance between the amount of power generated by the stationary generator 11 and the size of the first load 70A and the second load 70B.

[0071] Power consumption can be reduced by controlling the charging and discharging of the stationary battery 15. The magnitude of the loads 70A and 70B can be estimated from the amount of power generated by the stationary generator 11 and the received power Pgrid.

[0072] During the first operation mode, the charger / discharger 100 is independent of the power control device 50, and when an electric vehicle 200 for normal charging is connected, the charger / discharger 100 charges the onboard battery 230 of the electric vehicle 200. During the first operation mode, the charger / discharger 100 and the electric vehicle 200 connected thereto are loads of the power conditioner 20.

[0073] During the first operation mode, the power control device 50 accesses the first server device 150 to acquire weather forecast information and determines whether there is a risk of a power outage in the power system 1 (S20). For example, when information about the approach of a large typhoon is acquired from the first server device 150, it determines that there is a risk of a power outage.

[0074] When there is a risk of a power outage in the power system 1, the power control device 50 switches the operation mode from the first operation mode to the second operation mode (S30). When switching to the second operation mode, the power control device 50 transmits a change notification to the charger / discharger 100 to notify it of the change in operation mode.

[0075] After receiving the change notification, if the electric vehicle 200 for a specific purpose is connected to the charger / discharger 100, the charger / discharger 100 controls the remaining capacity Q2 of the mounted battery 230 of the electric vehicle 200 in accordance with an instruction from the power control device 50.

[0076] After switching to the second operation mode, the power control device 50 charges the stationary battery 15 and the onboard battery 230 using the inverter circuit 30 and the charger / discharger 100 during the preparation period W1 until the power outage (S40). Specifically, the two batteries 15, 230 are charged to a charge target value QW. Figure 6 shows an example of charging paths R1, R2 for the two batteries 15, 230.

[0077] The charging target value QW is a target value of the total remaining capacity QT of the remaining capacity Q1 of the stationary battery 15 and the remaining capacity Q2 of the onboard battery 230. The charging target value QW is equal to or greater than the amount of electricity supply I×T during a power outage.

[0078] QW>I×T I [A] is the current consumption of the second load 70B, and T [h] is the expected power outage time.

[0079] If a power outage occurs in the power grid 1 due to the approach of a large typhoon, the power control device 50 switches the interconnection relay 33 and the first switch 36 from closed to open, and further switches the second switch 37 from open to closed. A power outage in the power grid 1 can be determined from the system voltage Vgrid and the output voltage Vinv of the inverter circuit 30.

[0080] Thereafter, the power control device 50 uses the inverter circuit 30 and the charger / discharger 100 to discharge the stationary battery 15 and the onboard battery 230 and supply power to the second load 70B (S50). The power control device 50 controls the total remaining capacity QT of the two batteries 15, 230 even during discharge. The total remaining capacity QT can be calculated from the total remaining capacity at the start of discharge and the total discharge amount of the two batteries 15, 230. The total discharge amount may be calculated by calculating the discharge amounts of the two batteries 15, 230 and adding them up. It may also be calculated from the sum of the discharge currents of the two batteries 15, 230 and the discharge time. Figure 7 shows an example of discharge paths R3, R4 for the two batteries 15, 230.

[0081] Since the charge target value QW of the two batteries 15, 230 is equal to or greater than the amount of electricity supply I×T during a power outage, power supply to the second load 70B can be continued for at least the predicted power outage period T after the power outage occurs.

[0082] When the power system 1 recovers from the power outage, the power control device 50 stops discharging the stationary battery 15 and the onboard battery 230 (S60).

[0083] Thereafter, the interconnection relay 33 is switched from open to closed while being synchronized with the power system 1. As a result, the power system S1 is interconnected with the power system 1.

[0084] After being connected to the power system 1, the power control device 50 switches the operation mode from the second operation mode to the first operation mode (S70).

[0085] After changing the operation mode, the power control device 50 transmits a change notification to the charger / discharger 100. After transmitting the change notification, the charger / discharger 100 returns to a control state independent of the power control device 50 and operates as a charger for normal charging.

[0086] 3.Priority In the second operation mode, the power control device 50 may set priorities when charging the two batteries 15, 230. For example, as shown in Fig. 8, the stationary battery 15 may be given a higher priority than the on-board battery 230, and the stationary battery 15 may be charged first, and then the on-board battery 230 may be charged after the stationary battery 15 has been charged.

[0087] In the second operation mode, the power control device 50 may set priorities when discharging the two batteries 15, 230. For example, as shown in Fig. 8, the priority of the onboard battery 230 may be set higher than the priority of the stationary battery 15, so that the onboard battery 230 is discharged first, and then the stationary battery 15 is discharged after the onboard battery is discharged.

[0088] By giving a higher priority to the stationary battery 15 for charging and the on-board battery 230 for discharging, it is possible to maintain, for example, a remaining capacity Q1 of the stationary battery 15, which is the main power source of the power system S1, during the second operating mode. By maintaining a remaining capacity Q1 of the stationary battery 15, which is the main power source, it is possible to prevent the power system S1 from going down due to a loss of the main power source.

[0089] The priority may be determined by the remaining capacity. As shown in Fig. 9, during charging, the battery with the lesser remaining capacity of the two batteries 15, 230 may be given a higher priority than the battery with the more remaining capacity, so that the battery with the lesser remaining capacity is charged first, followed by the battery with the more remaining capacity.

[0090] When discharging, the battery with the larger remaining capacity of the two batteries 15, 230 may be given higher priority than the battery with the smaller remaining capacity, and the battery with the larger remaining capacity may be discharged first, followed by the battery with the smaller remaining capacity.

[0091] By giving a higher priority to charging the battery with a lower remaining capacity and a higher priority to discharging the battery with a higher remaining capacity, it is possible to balance the capacities of the two batteries 15, 230 during the second operation mode. In Fig. 9, the battery with a lower remaining capacity is described as "low capacity" and the battery with a higher remaining capacity is described as "high capacity." The priority of charging and discharging the two batteries 15, 230 is not limited to the example described in this embodiment (battery type and remaining capacity), and may be set based on other conditions.

[0092] 4.Effectiveness In this configuration, the number of batteries to be controlled by the power control device 50 and the chargeable / dischargeable capacity [Ah] can be changed by switching the operation mode, allowing for flexible power supply management.

[0093] During the second operating mode, the power control device 50 centrally controls the two batteries, the stationary battery 15 and the onboard battery 230, enabling more precise power supply control according to the characteristics and capacity of each battery than would be possible if the two batteries were controlled independently.

[0094] <Embodiment 2> In the first embodiment, when there is a risk of a power outage in the power grid 1, the operation mode of the power control device 50 is switched from the first operation mode to the second operation mode. After the transition to the second operation mode, the stationary battery 15 and the onboard battery 230 are charged during the preparation period W1 until the power outage.

[0095] The charge target value QW of the two batteries 15, 230 may be smaller as the power outage occurrence probability X is lower. The charge target value QW may be, for example, the product of the power outage occurrence probability X [%] and the charge target reference value QWo [Ah]. QW=X(QWo)

[0096] The probability of a power outage, X, can be estimated from the path and size of the typhoon. It may also be estimated by taking past statistics into consideration. The charge target reference value, QWo, is the charge target value, QW, when X=100%.

[0097] In this configuration, when the probability X of power outage occurrence is low, the amount of energy stored in the batteries 13, 230 is small, so there is little wasted energy stored and the energy utilization efficiency is high.

[0098] <Embodiment 3> In the first and second embodiments, when a power outage in the power system 1 is predicted, the operation mode of the power control device 50 is switched from the first operation mode to the second operation mode.

[0099] In the third embodiment, the operation mode of the power control device 50 is switched from the first operation mode to the second operation mode in accordance with a request for power demand adjustment. As an example of a request for power demand adjustment, an example will be described in which the operation mode of the power control device 50 is switched from the first operation mode to the second operation mode in accordance with a "DR activation notice" from an aggregator company. The operation mode may be switched to the second operation mode in accordance with a request for demand adjustment in a form other than a DR activation notice.

[0100] DR (Demand Response) is a method in which the owner of a consumer-side energy resource or a third party controls that energy resource to change the electricity demand pattern.

[0101] There are two types of DR (Demand Response): "Downward DR" and "Upward DR." "Downward DR" reduces the demand for electricity, while "upward DR" increases the demand for electricity.

[0102] The power control device 50 can receive DR information from the second server device 160 operated by the aggregator company via the network NW.

[0103] Figure 10 is a flowchart showing the process of switching the operation mode in response to a "pre-announcement of the initiation of downward DR," and Figure 11 shows the time flow. The operation mode switching process consists of eight steps. After startup, the power control device 50 proceeds to S10 and selects the first operation mode.

[0104] During the first operating mode, the power control device 50 controls the remaining capacity Q1 of only the stationary battery 15. During the first operating mode, the power control device 50 controls the remaining capacity Q1 of the stationary battery 15 to be equal to or greater than a lower limit value by controlling the charge / discharge amount of the stationary battery 15 using the second converter circuit 25.

[0105] During the first operation mode, the power control device 50 checks whether a "DR implementation notice" has been received from the second server device 150 (S21). If a "DR implementation notice" has not been received, the power control device 50 continues the first operation mode.

[0106] When the power control device 50 receives the "DR activation notice," it accesses the second server device 160 to acquire "DR information" (S25). The "DR information" includes, for example, the type of DR, the date and time of DR implementation, and the amount of power demand adjustment [Ah].

[0107] Thereafter, the power control device 50 switches the operation mode from the first operation mode to the second operation mode (S30).

[0108] When the operation mode is switched to the second operation mode, the power control device 50 transmits a change notification to the charger / discharger 100 to notify the charger / discharger 100 of the change in operation mode.

[0109] After receiving the change notification, the charger / discharger 100 controls the remaining capacity Q2 of the mounted battery 230 of the electric vehicle 200 in accordance with an instruction from the power control device 50.

[0110] After transitioning to the second operating mode, if the DR to be activated is "downward DR," the power control device 50 charges the stationary battery 15 of the stationary power source 10 and the onboard battery 230 of the electric vehicle 200 during the preparation period W1 until the DR is executed (S41).

[0111] Specifically, the two batteries 15, 230 are charged to a charging target value QW using the inverter circuit 30 and the charger / discharger 100. The charging target value QW is a target value for the total remaining capacity QT of the two batteries 15, 230, and is equal to or greater than the demand adjustment amount [Ah] of the DR information.

[0112] When the date and time for implementing the "downward DR" arrives, the power control device 50 starts discharging the stationary battery 15 and the onboard battery 230 using the inverter circuit 30 and the charger / discharger 100 (S51). The discharge reduces demand, enabling the supply and demand of electricity to be balanced.

[0113] When the implementation period W2 of the "lowering DR" ends, the power control device 50 stops discharging the stationary battery 15 and the onboard battery 230 (S61).

[0114] After the discharge is stopped, the power control device 50 switches the operation mode from the second operation mode to the first operation mode (S70). After switching the operation mode, the power control device 50 transmits a change notification to the charger / discharger 100.

[0115] The charger / discharger 100 that has transmitted the change notification returns to a control state independent of the power control device 50 and operates as a charger for normal charging.

[0116] Fig. 12 is a flowchart of the operation mode switching process accompanying "announcement of the activation of an upward DR," Fig. 13 is a time flow thereof, and Fig. 14 is a diagram showing the transition of the capacity of each battery. When the activated DR is "upward DR," charging and discharging are reversed, and after transitioning to the second operation mode, the power control device 50 discharges the stationary battery 15 and the onboard battery 230 during the preparation period W1 until the DR is executed (Fig. 12: S43).

[0117] Specifically, the two batteries 15, 230 are discharged to a discharge target value QW using the inverter circuit 30 and the charger / discharger 100. The discharge target value QW is a target value for the total remaining capacity QT of the two batteries 15, 230, and is a capacity value at which the total available capacity XT of the two batteries 15, 230 is equal to or greater than the demand adjustment amount [Ah] in the DR information (see FIGS. 13 and 14).

[0118] XT=X1+X2 X1 is the free capacity of the stationary battery 15, and X2 is the free capacity of the on-board battery 230.

[0119] If there is a possibility that the remaining capacity Q1, Q2 of either of the two batteries 15, 230 will fall below the lower limit due to discharging, the discharging may be limited so that the remaining capacity Q1, Q2 does not fall below the lower limit.

[0120] When the implementation date and time of "upward DR" arrives, the power control device 50 starts charging the stationary battery 15 and the onboard battery 230 using the inverter circuit 30 and the charger / discharger 100 (FIG. 12: S53). Charging increases demand, making it possible to balance the supply and demand of electricity.

[0121] When the implementation period W2 of the "upward DR" ends, the power control device 50 stops charging the stationary battery 15 and the onboard battery 230 (FIG. 12: S63).

[0122] In this configuration, the second operation mode increases the number of batteries controlled by the power control device 50 and the chargeable / dischargeable capacity [Ah] compared to the first operation mode, and therefore increases the amount of interchangeable power when DR is performed. This makes it possible to balance the supply and demand of power, contributing to energy conservation policies.

[0123] <Embodiment 4> The first to third embodiments disclose a power system S1 having one charger / discharger 100. The fourth embodiment discloses a power system S2 having a plurality of chargers / dischargers 100.

[0124] 15, the power system S2 includes two chargers / dischargers 100A and 100B. The two chargers / dischargers 100A and 100B are connected in parallel, and two electric vehicles 200A and 200B can be connected simultaneously.

[0125] When the first operation mode is switched to the second operation mode, if electric vehicles 200A and 200B are connected to two chargers / dischargers 100A and 100B, respectively, the power control device 50 may control the remaining capacity Q2A of the on-board battery 230A of the electric vehicle 200A and the remaining capacity Q2B of the on-board battery 230B of the electric vehicle 200B in addition to the remaining capacity Q1 of the stationary battery 15.

[0126] The two chargers / dischargers 100A and 100B may have the same settings or different settings. For example, the charger / discharger 100A may be set to perform both charging and discharging (first setting), and the charger / discharger 100B may be set to only charge and not discharge (second setting).

[0127] The charger / discharger 100A in the first setting can be used for specific purposes (emergency power supply or demand adjustment), and the charger / discharger 100B in the second setting can be used for normal charging.

[0128] When a risk of power outage is predicted or when there is a request to adjust power demand, if two electric vehicles 200A and 200B are connected to two chargers / dischargers 100A and 100B, priorities may be set for charging the two onboard batteries 230A and 230B during the preparation period W1.

[0129] Alternatively, the onboard battery 230A of the electric vehicle 200A connected to the charger / discharger 100A with the first setting (special use) may be charged first, and the onboard battery 230B of the electric vehicle 200B connected to the charger / discharger 100B with the second setting (normal charging use) may be charged later (FIG. 16: priority 1). Giving priority to charging the first setting (special use), this is effective in securing capacity for emergency and demand adjustment when the preparation period W1 is short.

[0130] The on-board battery 230B of the electric vehicle 200B connected to the charger / discharger 100B with the second setting (for normal charging) may be charged first, and the on-board battery 230A of the electric vehicle 200A connected to the charger / discharger 100A with the first setting (for specific charging) may be charged later (FIG. 16: priority 2). When charging with the second setting (for normal charging) is given priority, the waiting time of a user using the charger / discharger 100B for normal charging can be shortened.

[0131] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0132] (1) In the embodiment, the charger / discharger 100 is used to charge / discharge the onboard battery 230 of the electric vehicle 200. This is not limited to the electric vehicle 200, but the onboard battery of a hybrid vehicle or an electric motorcycle may also be charged / discharged. The charger / discharger 100 can be widely applied to any mobile body equipped with a chargeable / dischargeable power source, such as a vehicle towing a container equipped with a battery (storage battery).

[0133] (2) In the above embodiment, the stationary power source 10 is composed of the stationary generator 11 and the stationary battery 15. The stationary generator 11 may be omitted, and the stationary power source 10 may be composed of only the stationary battery 15. The stationary battery 15 is not limited to a secondary battery, and may be a capacitor. There may be multiple stationary batteries 15. The stationary battery 15 may be a group of multiple batteries connected in parallel and controlled collectively.

[0134] (3) In the above embodiment, the second operating mode is selected when there is a risk of a power outage in the power grid 1 or when there is a request for power demand adjustment. The second operating mode may be selected not only when there is a risk of a power outage in the power grid 1 or when there is a request for power demand adjustment, but also when there is a need to control the charging and discharging of the stationary battery 15 and the onboard battery 230, such as when large charging or discharging is required in the power systems S1 and S2.

[0135] (4) In the above embodiment, the power control device 50 controls the remaining capacity Q1 of the stationary battery 15 in the first operating mode, and controls the remaining capacity Q2 of the onboard battery 230 in addition to the remaining capacity Q1 of the stationary battery 15 in the second operating mode. Instead of Q1 and Q2 (remaining capacity), the SOC [%] of the stationary battery 15 and the onboard battery 230 may be controlled. The charge amount [Ah], discharge amount [Ah], discharge power [kW], and charge power [kW] of the stationary battery 15 and the onboard battery 230 may also be controlled. The SOC [%] indicates the state of charge and is the ratio of the remaining capacity to the full charge capacity. The charge amount [Ah] and discharge amount [Ah] are the amounts of charge that flow into and out of the battery due to charging and discharging, and can be calculated by current integration, etc. The remaining capacity [Ah], SOC [%], charge amount [Ah], discharge amount [Ah], discharge power [kW], and charge power [kW] are forms of the "electrical quantity" of the power source.

[0136] (5) In the above embodiment, the power control device 50 controls the total remaining capacity QT of the remaining capacity Q1 of the stationary battery 15 and the remaining capacity Q2 of the onboard battery 230 in the second operating mode. The capacity control of the two batteries 15, 230 by the power control device 50 is not limited to total value control. The remaining capacities Q1 and Q2 of each battery 15, 230 may be controlled individually. For example, to prepare for the risk of a power outage, the power control device 50 may set target values ​​for the remaining capacities Q1 and Q2 of each battery 15, 230 and individually charge the remaining capacities Q1 and Q2 of each battery 15, 230 to the target values ​​during the preparation period W1. The power control device 50 also controls the remaining capacities Q1 and Q2 individually during the power outage period T by controlling the discharge current of each battery 15, 230. The remaining capacities Q1 and Q2 can be calculated from the discharge amounts of each battery 15, 230.

[0137] (6) In the above-described fourth embodiment, an example was shown in which priorities were assigned to the charging of the onboard batteries 230A, 230B depending on the intended use of the charger / discharger during the preparation period W1. The priorities may be set based on other purposes or other conditions, not limited to the intended use of the charger / discharger. The priorities are applicable not only to charging but also to discharging. For example, when using two chargers / dischargers 100A, 100A in the first setting to discharge the onboard batteries of two electric vehicles during the power outage period T, one onboard battery may be given priority and discharged first, and then the remaining onboard battery may be discharged.

[0138] (7) The priority of charging or discharging among onboard batteries may be as follows: A vehicle that is likely to be used as an emergency power source or for demand adjustment may have a higher charging priority or discharging priority, and a visitor vehicle may have a lower discharging priority. [Explanation of symbols]

[0139] 1 Power system 3 grid power supply 10 Stationary power sources 11 Stationary generator 15 Stationary Battery 20 Power Conditioner 30 Inverter circuit (an example of the "power conversion device" of the present invention) 50 Power control device 100 charger / discharger 200 Electric vehicle (an example of the "mobile body" of the present invention) 230 On-board battery (an example of the "on-board power source" of the present invention)

Claims

1. 1. An electric power system comprising: A fixed power source, a power conversion device that converts the power of the stationary power source; One or more chargers / dischargers connected in parallel with the power conversion device; a power control device that controls the power conversion device, The power conversion device is connected to an electric power grid via an interconnection line, the charger / discharger is for use in a mobile body, The operation modes of the power control device include: There are two operation modes: the first operation mode and the second operation mode. The power control device includes: In the first operation mode, only the stationary power source controls the amount of electricity; In the second operation mode, the amount of electricity of an on-board power source of the moving body connected to the charger / discharger is controlled in addition to the amount of electricity of the stationary power source; The power control device selects the second operation mode when there is a risk of a power outage in the power grid or in accordance with a request for power demand adjustment, When the power control device transitions to the second operation mode due to the occurrence of a risk of a power outage in the power grid, the power system charges the stationary power source and the onboard power source during a preparation period until the power outage.

2. The power system according to claim 1, The charging target values ​​of the stationary power source and the onboard power source are smaller as the probability of a power outage occurring in the power grid is lower.

3. A power system, A fixed power source, a power conversion device that converts the power of the stationary power source; One or more chargers / dischargers connected in parallel with the power conversion device; a power control device that controls the power conversion device, The power conversion device is connected to an electric power grid via an interconnection line, the charger / discharger is for use in a mobile body, The operation modes of the power control device include: There are two operation modes: the first operation mode and the second operation mode. The power control device includes: In the first operation mode, only the stationary power source controls the amount of electricity; In the second operation mode, the amount of electricity of an on-board power source of the moving body connected to the charger / discharger is controlled in addition to the amount of electricity of the stationary power source; The power control device selects the second operation mode when there is a risk of a power outage in the power grid or in accordance with a request for power demand adjustment, When the power control device transitions to the second operation mode in response to a request to increase power demand, the power system discharges the stationary power source and the onboard power source during a preparation period until demand adjustment.

4. A power system, A fixed power source, a power conversion device that converts the power of the stationary power source; One or more chargers / dischargers connected in parallel with the power conversion device; a power control device that controls the power conversion device, The power conversion device is connected to an electric power grid via an interconnection line, the charger / discharger is for use in a mobile body, The operation modes of the power control device include: There are two operation modes: the first operation mode and the second operation mode. The power control device includes: In the first operation mode, only the stationary power source controls the amount of electricity; In the second operation mode, the amount of electricity of an on-board power source of the moving body connected to the charger / discharger is controlled in addition to the amount of electricity of the stationary power source; The power control device selects the second operation mode when there is a risk of a power outage in the power grid or in accordance with a request for power demand adjustment, When the power control device transitions to the second operation mode in response to a request to reduce power demand, the power system charges the stationary power source and the onboard power source during a preparation period until demand adjustment.

5. A power system according to any one of claims 1 to 4, the power control device, in the second operation mode, controls the amount of electricity of the stationary power source and the amount of electricity of the onboard power source individually, or controls a total amount of electricity obtained by adding together the two amounts of electricity.

6. A power system according to any one of claims 1 to 4, In the second operation mode, the power control device charges or discharges the stationary power source and the onboard power source according to priority.

7. A power system according to any one of claims 1 to 4, In the second operation mode, the power control device charges or discharges, in accordance with priority, on-board power sources of a plurality of moving bodies connected to a plurality of the chargers / dischargers.

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