Charging / discharging system for electric vehicle and charging / discharging method thereof

Abstract

To provide a charging / discharging system for an electric vehicle and a charging / discharging method thereof capable of realizing safe and reliable automatic return of a V2H stand when a power failure or the like occurs in a system power supply.SOLUTION: A V2H stand 8 for an electric vehicle is provided between an electric vehicle 5 and a residential load 4 that receives an electric power from a system power supply 2 or a distributed power supply 3, and charges and discharges a storage battery 6 of the electric vehicle 5. A power conditioner (PCS) 7 that converts a power from the system power supply 2 or the distributed power supply 3 stops its operation based on a PCS stop condition including a power failure of the system power supply 2, and restarts its operation based on a PCS restart condition. When the PCS 7 is stopped or restarted, an operation of the V2H stand 8 connected between the PCS 7 and the electric motor car 5 is stopped or restarted.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to charging and discharging of a storage battery mounted on an electric vehicle, and more particularly to a charging and discharging system for an electric vehicle and a charging and discharging method thereof that are capable of supplying power from the storage battery to a residential load. [Background technology]

[0002] In recent years, V2H (Vehicle to Home) has become popular, whereby users can utilize storage batteries installed in electric vehicles (EVs) and other electrically powered vehicles in times of disaster, and V2H stands are connected between the storage batteries of the electric vehicles and residential loads. In a charging / discharging system that includes this V2H stand, power from a grid power supply or a distributed power source such as a photovoltaic (PV) system is converted by a power conditioner and supplied to the storage batteries of the electric vehicles, and then from the storage batteries to the residential loads via the V2H stand.

[0003] As an example of this, there is known a charging / discharging device (V2H stand) that receives power from a grid power source or a distributed power source and supplies it to the battery of an electric vehicle, and that has a grid-connected (grid-connected operation) mode in which power is supplied to the load from the grid power source or the distributed power source, and a power outage operation (standalone operation) mode in which, in the event of a power outage in the grid power source, the anti-islanding function (a function that prevents startup unless a specified power supply source is connected) is disabled and power is supplied to the load from the distributed power source or the storage battery (for example, Patent Document 1).

[0004] Incidentally, for systems that connect with electric vehicles, such as V2H, the "Guidelines for Charging and Discharging Systems for Electric Vehicles (EV)" have been established, and in section 9.2.7 of these guidelines, recovery from a charge / discharge halt, it is stipulated that "If charge / discharge control is temporarily halted due to an abnormality or other reason, the EVPS (EV power station) should not automatically resume charge / discharge control. When resuming, the user (or maintenance personnel) must intervene through a process for re-operation and confirmation."

[0005] In the above-mentioned Patent Document 1, a grid connection button and a power outage operation button provided on the V2H stand are operated by the user, and the temporarily stopped charge / discharge control is manually restarted. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-80428 Summary of the Invention [Problem to be solved by the invention]

[0007] However, manual operation by users is cumbersome and time-consuming, and is prone to human error. In particular, with V2H rapid chargers that charge in a short time, high voltages and currents flow through the V2H stand, making safety and reliability an issue.

[0008] On the other hand, the proviso to the aforementioned guideline 9.2.7 states that "automatic recovery is permitted in the event of a power outage," and although automatic recovery on the EVPS side is permitted only in the event of a power outage, safe and reliable automatic recovery of V2H has not yet been achieved.

[0009] In view of the above, an object of the present invention is to provide a charging / discharging system for electric vehicles and a charging / discharging method therefor that enable safe and reliable automatic recovery of a V2H stand in the event of a system fluctuation factor, including a power outage in the grid power supply. [Means for solving the problem]

[0010] In order to achieve the above object, a charging / discharging system for an electric vehicle according to one embodiment of the present invention includes a V2H stand for an electric vehicle, which is provided between a residential load supplied with power from a grid power source or a distributed power source and the electric vehicle, and which charges and discharges a storage battery of the electric vehicle, A power conditioner that converts power from a grid power source or a distributed power source stops its operation based on a power conditioner stop condition, including a power outage of the grid power source, and restarts its operation based on a power conditioner restart condition; The V2H stand connected between the power conditioner and the electric vehicle is stopped or restarted when the power conditioner is stopped or restarted.

[0011] According to this configuration, the power conditioner is stopped based on the conditions for stopping the power conditioner and then the V2H stand is stopped, and the power conditioner is restarted based on the conditions for restarting the power conditioner and then the V2H stand is restarted.By stopping and restarting the power conditioner under appropriate conditions and then stopping and restarting the V2H stand, safe and reliable automatic recovery of the V2H stand can be achieved.In addition, even if external communication is cut off, the power conditioner can determine a power outage and safely and reliably restart the V2H stand, which is particularly effective for automatic recovery in the event of a disaster.

[0012] Preferably, the charging / discharging system includes a PCS control unit that controls the operating state of the power conditioner, and a V2H control unit that controls the operating state of the V2H stand, The PCS control unit of the power conditioner is a power conditioner stop condition determination unit that detects fluctuation factors in the system, including a power outage of the grid power supply, an abnormal state inside the power conditioner, or restoration of power from the grid power supply during independent operation using a storage battery or a distributed power supply, and determines whether or not a condition for stopping the power conditioner is met; and a power conditioner stop control unit that performs control to stop operation of the power conditioner when the power conditioner stop condition is met; The power conditioner includes a power conditioner restart determination unit that detects that any of the power conditioner stop conditions is no longer satisfied or that operation has switched from grid-connected operation using the grid power source or the distributed power source to independent operation after a certain period of power outage of the grid power source, and determines whether or not the conditions for restarting the power conditioner are satisfied, and a power conditioner restart control unit that controls restarting the operation of the power conditioner when the power conditioner restart conditions are satisfied. The V2H control unit of the V2H stand includes a V2H stand stop control unit that performs control to stop operation of the V2H stand when the power conditioner is stopped, and a V2H stand restart control unit that performs control to restart operation of the V2H stand when operation of the power conditioner is restarted.

[0013] According to this configuration, the conditions for stopping the power conditioner are accurately determined, and when the stop conditions are met, the power conditioner is stopped and then the V2H stand is stopped, and the conditions for restarting the power conditioner are accurately determined, and when the restart conditions are met, the power conditioner is restarted and then the V2H stand is restarted.By stopping and restarting the power conditioner under accurate conditions and then stopping and restarting the V2H stand, safer and more reliable automatic recovery of the V2H stand can be achieved.In addition, even if external communication is cut off, the power outage can be determined within the power conditioner, allowing the V2H stand to be restarted safely and reliably, which is particularly effective for automatic recovery in the event of a disaster.

[0014] Preferably, the abnormal state inside the power conditioner includes an abnormal temperature of a circuit module, an internal bus overvoltage, a fan lock, and a communication abnormality. Therefore, the abnormal state inside the power conditioner can be more accurately detected to automatically restore the power conditioner, thereby achieving safer and more reliable automatic restoration of V2H.

[0015] Preferably, the V2H stand is a rapid charger that charges the battery of an electric vehicle in a short time. Therefore, even if the V2H stand is a rapid charger that uses high voltage and current, it is possible to achieve safer and more reliable automatic return of the V2H stand.

[0016] A charging / discharging method for an electric vehicle according to another embodiment of the present invention is performed by a charging / discharging system including a V2H stand for an electric vehicle that is provided between a residential load receiving power supply from a grid power source or a distributed power source and the electric vehicle and charges / discharges the storage battery of the electric vehicle. The PCS control unit of this charging / discharging system controls the operating state of the power conditioner, which converts power from a distributed power source or a grid power source, while the V2H control unit controls the operating state of the power conditioner and the V2H stand connected to the electric vehicle. The control of the PCS control unit of the power conditioner further includes a step of detecting fluctuation factors in the system, including a power outage of the grid power supply, an abnormal state inside the power conditioner, or restoration of power to the grid power supply during stand-alone operation using a storage battery or a distributed power supply, and determining whether or not a condition for stopping the power conditioner is met; a step of stopping the operation of the power conditioner when the power conditioner stop condition is met; a step of detecting that any of the power conditioner stop conditions is no longer met, or that operation has been switched from grid-connected operation using the grid power supply or the distributed power supply to stand-alone operation after a power outage of the grid power supply for a certain period of time, and determining whether or not a condition for restarting the power conditioner is met; and a step of restarting the operation of the power conditioner when the power conditioner restart condition is met; The charging and discharging method for an electric vehicle further includes, as control of a V2H control unit of the V2H stand, a step of stopping operation of the V2H stand when the power conditioner is stopped, and a step of restarting operation of the V2H stand when the operation of the power conditioner is restarted.

[0017] According to this configuration, the conditions for stopping the power conditioner are accurately determined, and when the stop conditions are met, the power conditioner is stopped and then the V2H stand is stopped, and the conditions for restarting the power conditioner are accurately determined, and when the restart conditions are met, the power conditioner is restarted and then the V2H stand is restarted.By stopping and restarting the power conditioner under accurate conditions and then stopping and restarting the V2H stand, safe and reliable automatic V2H recovery can be achieved.In addition, even if external communication is cut off, the power outage can be determined within the power conditioner and the V2H stand can be restarted safely and reliably, which is particularly effective for automatic recovery in the event of a disaster. [Effects of the Invention]

[0018] In the present invention, the power conditioner is stopped based on the conditions for stopping the power conditioner and then the V2H stand is stopped, and the power conditioner is restarted based on the conditions for restarting the power conditioner and then the V2H stand is restarted. Therefore, by stopping and restarting the power conditioner under appropriate conditions and then stopping and restarting the V2H stand, safe and reliable automatic recovery of the V2H stand can be achieved. Furthermore, even if external communication is interrupted, the power conditioner can determine a power outage and safely and reliably restart the V2H stand, which is particularly effective for automatic recovery in the event of a disaster. This enables sufficiently safe and reliable automatic recovery of the V2H stand when a system fluctuation factor, including a power outage in the grid power supply, occurs. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a block diagram showing a charging / discharging system for an electric vehicle according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing a PCS control unit of a power conditioner in the charging / discharging system. [Figure 3]FIG. 2 is a block diagram showing a V2H control unit of a V2H stand in the charging and discharging system. [Figure 4] FIG. 3 is a characteristic diagram showing the operation of the charging / discharging system. [Figure 5] FIG. 3 is a characteristic diagram showing the operation of the charging / discharging system. [Figure 6] 3 is a flowchart showing the operation of the present charging / discharging system. DETAILED DESCRIPTION OF THE INVENTION

[0020] Figure 1 is a block diagram showing a charging / discharging system for an electric vehicle according to one embodiment of the present invention. This charging / discharging system 1 for an electric vehicle is provided between a residential load 4 that receives power supply from a grid (commercial) power source 2 or a distributed power source 3 such as a solar cell (PV) and an electric vehicle 5 such as an electric vehicle (EV), and includes a V2H stand 8 for the electric vehicle that charges and discharges a storage battery 6 of the electric vehicle 5. This V2H stand 8 is, for example, a rapid charger that charges the storage battery 6 of the electric vehicle 5 in a short period of time.

[0021] A power conditioner (PCS) 7 is provided between the grid power supply 2 and the solar cell (PV) 3, and converts power from the grid power supply 2 or the solar cell (PV) 3. The PCS 7 includes a PCS control unit 10 that controls its operating state, a DC / DC converter 12, a bidirectional DC / AC inverter 13, and a communication unit 14 that communicates with external systems such as power outage monitoring systems. For example, by switching control by the PCS control unit 10, the DC / DC converter 12 converts the DC power from the solar cell (PV) 3 into predetermined DC power, and the bidirectional DC / AC inverter 13 converts the DC power from the solar cell (PV) 3 into predetermined AC power, and also converts the AC power from the grid power supply 2 into predetermined DC power.

[0022] Furthermore, the switch SW1 turns on and off the connection between the system power supply 2 and the bidirectional DC / AC inverter 13. The switch SW2 turns on and off the connection between the bidirectional DC / AC inverter 13 and the load 4 connected to a switching box SW3 (described later).

[0023] The detection unit 9 detects a power outage (abnormality) in the grid power supply 2 based on the output voltage, output current, grid frequency, etc. of the grid power supply 2. The output voltage and output current are detected by a voltmeter and an ammeter, respectively. Regarding the grid frequency, for example, the frequency of the output voltage of the bidirectional DC / AC inverter 13 is controlled to detect a grid overfrequency. The switching box SW3 switches between the connection between the grid power supply 2 and the residential load 4 on the C1 side, and the connection between the bidirectional DC / AC inverter 13 and the load 4 via SW2 on the C2 side.

[0024] The V2H stand 8 is connected to a connection point P between the DC / DC converter 12 and the bidirectional DC / AC inverter 13 of the PCS 7 via a switch SW4, and is equipped with a V2H control unit 15 that controls the operating state of the V2H stand 8, a bidirectional DC / DC converter 16, a communication unit 17 connected to the communication unit 14 of the PCS 7, and a switch SW5.

[0025] A storage battery 6 mounted on an electric vehicle 5 is connected to a V2H stand 8 via its switch SW5. The storage battery 6 receives power from a grid power supply 2 and a solar cell (PV) 3 through switching control of a bidirectional DC / DC converter 16 by a V2H control unit 15 of the V2H stand 8, and supplies power to a residential load 4.

[0026] This charging / discharging system 1 normally operates in grid-connected mode, supplying power from a power grid 2 or a solar cell (PV) 3 to a residential load 4, and during a power outage, operates in independent mode, supplying power from the solar cell (PV) 3 or a storage battery 6 to the residential load 4.

[0027] That is, in grid-connected operation, switches SW4 and SW5 are off, the PCS 7 is not connected to the V2H stand 8, and the storage battery 6 of the electric vehicle 5, and the V2H 8 and the storage battery 6 are disconnected. Then, the switching box SW3 is switched to the C1 side, and power is supplied to the residential load 4 from the grid power supply 2, or from the photovoltaic (PV) 3 when switch SW1 is on.

[0028] In stand-alone operation, switches SW4 and SW5 are on, and the PCS 7, V2H stand 8, and storage battery 6 of the electric vehicle 5 are all connected. Switching box SW3 is switched to the C2 side, the grid power supply 2 is disconnected, and with switch SW2 on, power is supplied to the residential load 4 from the photovoltaic (PV) 3 or the storage battery 6 of the electric vehicle 5.

[0029] As shown in Figure 2, the PCS control unit 10 controls the entire PCS7 and includes a PCS stop condition determination unit 21 that determines whether the conditions for stopping the PCS7 are met, a PCS stop control unit 22 that controls the operation of the PCS7 to stop when the PCS stop conditions are met, a PCS restart determination unit 23 that determines whether the conditions for restarting the PCS7 are met, and a PCS restart control unit 24 that controls the restart of the PCS7 when the PCS restart conditions are met.

[0030] The PCS stop condition A is a system fluctuation factor including a power outage (a1) of the system power supply 2, an abnormal state (a2) inside the PCS 7, or a restoration of power (a3) ​​of the system power supply 2 during independent operation. The PCS stop condition determination unit 21 detects this PCS stop condition A and determines whether it is satisfied. If this PCS stop condition A is satisfied, the PCS stop control unit 22, which controls the operation of the PCS 7 to be stopped, outputs a PCS stop signal to the communication unit 14.

[0031] The PCS restart condition B includes (b1) that none of the PCS stop conditions are satisfied, or (b2) that after a certain period of power outage of the system power source 2, the system switches from grid-connected operation using the system power source 2 or the distributed power source 3 to independent operation using the distributed power source 3 or the storage battery 6. The PCS restart determination unit 23 detects this PCS restart condition B and determines whether it is satisfied. If this PCS restart condition B is satisfied, the PCS restart control unit 24, which controls the restart of the PCS 7, outputs a PCS restart signal to the communication unit 14.

[0032] The power outage of the system power supply 2 includes detection of overvoltage, undervoltage, overfrequency, underfrequency, and DC component of the system power supply 2, and is detected by the detection unit 9.

[0033] Abnormal conditions inside the PCS 7 include temperature abnormalities in circuit modules (not shown), internal bus overvoltage, fan lock, and communication failures in the communication unit 14, and are detected by internal temperature sensors and voltage sensors (also not shown).

[0034] As shown in Figure 3, the V2H control unit 15 controls the entire V2H stand 8 and is equipped with a V2H stand stop control unit 31 that controls the stopping of operation of the V2H stand 8 when the PCS 7 is stopped and a PCS stop signal is output from the communication unit 17, and a V2H stand restart control unit 32 that controls the restarting of operation of the V2H stand 8 when the PCS 7 is restarted and a PCS restart signal is output from the communication unit 17.

[0035] In this way, in this charging / discharging system 1, the PCS stop conditions, including a power outage of the grid power supply 2, are accurately determined within the PCS 7, and when the PCS stop conditions are met, the PCS 7 is stopped and then the V2H stand 8 is stopped, and when the PCS restart conditions are met, the PCS 7 is restarted and then the V2H stand 8 is restarted.By stopping and restarting the PCS 7 under accurate conditions and then stopping and restarting the V2H stand 8, sufficient safety and reliability are ensured by regulating the operation of the V2H stand 8 via the PCS 7. Furthermore, even if external communications are cut off during a disaster or other such event, the power outage is determined within the PCS 7, so that the V2H stand 8 can be restarted safely and reliably.

[0036] Figure 4 is a characteristic diagram showing a pattern in which the grid power supply 2 is restored during stand-alone operation and the system switches to grid-connected operation. (a) When the restoration of power from the grid (commercial) power supply 2 is detected at point P1, (c) the stand-alone output voltage becomes 0, (e) the PCS 7 ends stand-alone operation and prepares for grid connection, and (f) the storage battery 6 is disconnected in V2H8. After that, (e) the PCS 7 starts grid-connected operation.

[0037] Figure 5 is a characteristic diagram showing a pattern in which a power outage occurs in the grid power supply 2 during grid-connected operation and the system switches to isolated operation. (a) When a power outage in the grid (commercial) power supply 2 is detected at point P2, (b) the grid output current becomes 0, (e) the PCS 7 switches from grid-connected operation and prepares for isolated operation, and (f) the V2H 8 disconnects the storage battery 6. After that, (c) the isolated output voltage rises, and (e) the PCS 7 starts isolated operation.

[0038] 6 is a flowchart showing the operation of a charging / discharging device for an electric vehicle. When the V2H automatic return process is started (step S1), first, while the power conditioner (PCS) 7 is operating (step S2), information on the return destination of the V2H stand 8 is updated (step S3). This information on the return destination is information on the connection status between the V2H stand 8 and the storage battery 6.

[0039] Next, it is determined whether the PCS stop condition is met (step S4). If it is determined that the stop condition is not met, the process returns to step S1. If it is determined that the stop condition is met, the PCS 7 is stopped (step S5). Thereafter, the switching control of the V2H stand 8 is stopped (step S6).

[0040] Next, it is confirmed whether or not the restart condition of the PCS 7 is satisfied (normal state) (step S7). If it is determined that the restart condition is not satisfied (abnormal state), the process returns to step S7.

[0041] If it is determined that the restart conditions are met (the PCS 7 is in a normal state), the PCS 7 is automatically restored (step S8). Next, while the PCS 7 is operating (step S9), the destination of the V2H stand 8 to be restored is confirmed (step S10).

[0042] If the V2H stand 7 is connected to the storage battery 6 in step S10, switching control of the V2H stand 8 is started and automatic return is performed (step S10), and the V2H automatic return process ends (step S11). If the V2H stand 7 is not connected to the storage battery 6 in step S10, the process also ends (step S11).

[0043] As described above, in the present invention, the PCS stop condition determination unit 21 accurately determines the conditions for stopping the PCS 7, and when the stop condition is met, the PCS 7 is stopped and then the V2H stand 8 is stopped. The PCS restart determination unit 23 accurately determines the conditions for restarting the PCS 7, and when the restart condition is met, the PCS 7 is restarted and then the V2H stand 8 is restarted. Therefore, by stopping and restarting the PCS 7 under the appropriate conditions and then stopping and restarting the V2H stand 8, sufficiently safe and reliable automatic V2H recovery can be achieved. Furthermore, even if external communication is interrupted, the PCS 7 can determine a power outage and safely and reliably restart the V2H stand 8, which is particularly effective for automatic recovery in the event of a disaster. This enables safe and reliable automatic recovery of the V2H stand 8 when a system fluctuation factor, such as a power outage of the grid power supply 2, occurs.

[0044] In the above embodiment, an electric vehicle (EV) is used as an example of an electrically powered vehicle, but the present invention is not limited to this and may be, for example, a hybrid vehicle (HV) or a fuel cell vehicle (FCV).

[0045] In the above embodiment, a photovoltaic (PV) power source is used as an example of a distributed power source, but the present invention is not limited to this and may be, for example, a fuel cell (FC) power source or a wind power source (WP) power source.

[0046] The present invention is not limited to the above-described embodiments, and various additions, modifications, and omissions are possible without departing from the spirit of the present invention. Therefore, such additions, modifications, and omissions are also included in the scope of the present invention. [Explanation of symbols]

[0047] 1: Charging and discharging system for electric vehicles 2: Grid (commercial) power supply 3: Distributed power source (solar PV) 4: Residential load 5: Electric vehicles (EV) 6: Storage battery 7: Power conditioner (PCS) 8: V2H Stand 9: Detection unit 10: PCS control unit 12: DC / DC converter 13: Bidirectional DC / AC inverter 15: V2H control unit 16: Bidirectional DC / DC converter 21:PCS stop condition judgment section 22: PCS stop control unit 23:PCS restart determination section 24: PCS restart control unit 31: V2H stop control unit 32: V2H restart control unit

Claims

1. A charging / discharging system including a V2H stand for an electric vehicle, the V2H stand being provided between a residential load receiving power supply from a grid power source or a distributed power source and an electric vehicle, and charging / discharging a storage battery of the electric vehicle, A power conditioner that converts power from a grid power source or a distributed power source stops its operation based on a power conditioner stop condition, including a power outage of the grid power source, and restarts its operation based on a power conditioner restart condition; A V2H stand connected between a power conditioner and an electric vehicle is a charging / discharging system for electric vehicles, whose operation is stopped or restarted when the power conditioner is stopped or restarted.

2. In claim 1, further: A PCS control unit that controls the operating state of the power conditioner and a V2H control unit that controls the operating state of the V2H stand, The PCS control unit of the power conditioner is a power conditioner stop condition determination unit that detects fluctuation factors in the system, including a power outage of the grid power supply, an abnormal state inside the power conditioner, or restoration of power from the grid power supply during independent operation using a storage battery or a distributed power supply, and determines whether or not a condition for stopping the power conditioner is met; and a power conditioner stop control unit that performs control to stop operation of the power conditioner when the power conditioner stop condition is met; The power conditioner restart determination unit detects that any of the power conditioner stop conditions is no longer satisfied or that operation has been switched from grid-connected operation by the grid power source or the distributed power source to the independent operation after a certain period of power outage of the grid power source, and determines whether or not the conditions for restarting the power conditioner are satisfied; and the power conditioner restart control unit controls to restart the operation of the power conditioner when the power conditioner restart conditions are satisfied. A charging and discharging system for electric vehicles, in which the V2H control unit of the V2H stand is equipped with a V2H stand stop control unit that controls the stopping of operation of the V2H stand when the power conditioner is stopped, and a V2H stand restart control unit that controls the restarting of operation of the V2H stand when the operation of the power conditioner is restarted.

3. In claim 2, The power conditioner stop condition determination unit determines abnormal conditions within the power conditioner, including temperature abnormalities in the circuit module, internal bus overvoltage, fan lock, and communication abnormalities.

4. A charging / discharging system for an electric vehicle, wherein the V2H stand according to claim 1 or 2 is a rapid charger that charges a storage battery of the electric vehicle in a short time.

5. A charging / discharging method executed by a charging / discharging system including a V2H stand for an electric vehicle, the V2H stand being provided between a residential load receiving power supply from a grid power source or a distributed power source and an electric vehicle, and charging / discharging a storage battery of the electric vehicle, The PCS control unit controls the operating state of a power conditioner that converts power from a distributed power source or a grid power source, and the V2H control unit controls the operating state of a V2H stand connected between the power conditioner and the electric vehicle, The control of the PCS control unit of the power conditioner further includes a step of detecting fluctuation factors in the system, including a power outage of the grid power supply, an abnormal state inside the power conditioner, or restoration of the grid power supply during independent operation using a storage battery or a distributed power supply, and determining whether or not a condition for stopping the power conditioner is met; and a step of stopping the operation of the power conditioner when the power conditioner stopping condition is met. The method includes a step of detecting that any of the power conditioner stop conditions is no longer satisfied or that the system has switched from grid-connected operation by the grid power source or the distributed power source to the stand-alone operation after a certain period of power outage of the grid power source, and determining whether or not a condition for restarting the power conditioner is satisfied; and a step of restarting the operation of the power conditioner when the power conditioner restart condition is satisfied, The charging and discharging method for an electric vehicle further includes, as control of a V2H control unit of the V2H stand, a step of stopping operation of the V2H stand when the power conditioner is stopped, and a step of restarting operation of the V2H stand when the operation of the power conditioner is restarted.

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