Power management system

Abstract

To suppress considerable reduction of a power adjustment amount regardless of participation in the power adjustment of the electric vehicle which executes specific control setting a charge / discharge current of a power storage device to zero.SOLUTION: A server 200 divides electric vehicles that participate in a power adjustment into a vehicle group A and a vehicle group B (S11). The vehicle group A executes offset learning of a current sensor, setting a charge / discharge current of a power storage device to zero in a fixed frequency after start of charge / discharge. The vehicle group B executes offset learning in a higher frequency than the fixed frequency during a predetermined period after start of charge / discharge and then executes offset learning in the fixed frequency. The server 200 instructs charge / discharge start timing in such a manner that the number of electric vehicles 10 to execute the offset learning at the same timing becomes equal to or less than a predetermined number and in such a manner that the electric vehicles 10 of the vehicle group B execute the offset learning at least once within a reaction time of the power adjustment (S12 and S13).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a power management system. [Background technology]

[0002] For example, Japanese Patent Application Publication No. 2009-171666 (Patent Document 1) describes a method of setting the current flowing through a battery (power storage device) to zero at regular time intervals during external charging of a plug-in hybrid vehicle (PHEV), and calculating an offset value for a current sensor that detects the battery current. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-171666 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, efforts have been made to equalize the supply and demand of electricity by using virtual power plants (VPPs) that use electric vehicles as energy resources. For example, in periods when the supply of electricity is greater than the demand for electricity, electricity is stored in the power storage device of the electric vehicle, and in periods when the demand for electricity is greater than the supply of electricity, the electricity stored in the power storage device of the electric vehicle is discharged, thereby equalizing the supply and demand of electricity.

[0005] When an electric vehicle is used as a power adjustment resource, as described in Patent Document 1, if the current flowing through the power storage device is set to zero at every predetermined time and the offset value of the current sensor is calculated, the power adjustment may not be performed well. For example, if the control specifications of the electric vehicles are the same, the cycle for calculating the offset value of the current sensor will be almost the same, so the timing for setting the current flowing through the power storage device to zero may be almost the same for the electric vehicles participating in the power adjustment. For this reason, there is a concern that the number of electric vehicles participating in the power adjustment in which the current flowing through the power storage device becomes zero at the same time will increase, and the charging amount or discharging amount due to the power adjustment will be significantly reduced.

[0006] In addition, there may be an electric vehicle that is set to a period during which the offset value of the current sensor is calculated more frequently (the predetermined time is shorter) after the start of charging / discharging of the power storage device. In this case, there is a concern that the charging amount or discharging amount may be significantly reduced more frequently due to power adjustment.

[0007] An object of the present disclosure is to prevent a large decrease in the amount of power adjustment even when an electrically powered vehicle that executes specific control by setting the charge / discharge current of a power storage device to zero participates in power adjustment. [Means for solving the problem]

[0008] The power management system disclosed herein uses a plurality of electric vehicles, each of which is equipped with a power storage device, as a power adjustment resource. Each electric vehicle has a control device, and the control device is configured to execute specific control by setting the charge / discharge current of the power storage device to zero at a predetermined frequency. The plurality of electric vehicles include a first vehicle that executes the specific control at a constant frequency, and a second vehicle that executes the specific control at a frequency higher than the constant frequency for a predetermined period from the start of charging / discharging of the power storage device. The power management system includes a charge / discharge instruction means for instructing charging / discharging of the plurality of electric vehicles. The charge / discharge instruction means instructs the timing of starting charging / discharging of each electric vehicle so that the number of electric vehicles that execute the specific control at the same timing during power adjustment is equal to or less than a predetermined number, and instructs the timing of starting charging / discharging so that the second vehicle executes the specific control at least once within the response time of the power adjustment.

[0009] In the present disclosure, "charging / discharging" includes at least one of "charging" and "discharging." Therefore, "charge / discharge start timing" is at least one of "charge start timing" and "discharge start timing." The response time is the allowable period from receiving a command for power adjustment until the commanded amount of adjustment is achieved.

[0010] The charge / discharge instruction means instructs the timing to start charging / discharging for each electric vehicle so that the number of electric vehicles executing specific control at the same timing during power adjustment is equal to or less than a predetermined number, thereby making it possible to suppress the number of vehicles whose current flowing through the power storage device simultaneously becomes zero during power adjustment. Also, since the charge / discharge start timing is instructed so that the second vehicle executes specific control at least once within the response time of power adjustment, it is possible to reduce the frequency with which the current flowing through the power storage devices of a plurality of electric vehicles simultaneously becomes zero during power adjustment (after the response time has elapsed). Effect of the Invention

[0011] According to the present disclosure, even if an electrically powered vehicle that executes specific control by setting the charge / discharge current of a power storage device to zero participates in power adjustment, a large decrease in the amount of power adjustment can be suppressed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a schematic overall configuration of a power management system according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a schematic configuration diagram of an electric vehicle. [Diagram 3] 1A to 1C are diagrams illustrating a sequence of a charge / discharge start timing instruction according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will now be described in detail with reference to the accompanying drawings, in which the same or corresponding parts are designated by the same reference numerals and will not be described repeatedly.

[0014] Fig. 1 is a diagram showing a schematic overall configuration of a power management system according to the present embodiment. Referring to Fig. 1, the power management system 1 includes a power system PG, a plurality of electric vehicles 10A, 10B, a server 100, and a server 200. Note that the basic configuration of electric vehicles 10A, 10B is the same, and when no particular distinction is made, they will be referred to as electric vehicle 10.

[0015] The power system PG is a power network constructed by power plants and power transmission and distribution facilities (not shown), and is maintained and managed by a power company. The power company corresponds to the manager of the power system PG. The server 100 is a server managed by an aggregation coordinator, and distributes the amount of power adjustment to resource aggregators in response to a request from the power company.

[0016] The server 200 is a computer that manages a plurality of electric vehicles 10, and is managed by a resource aggregator. The server 200 corresponds to an example of a "charge / discharge instruction means" in the present disclosure. Each of the plurality of electric vehicles 10 is, for example, a BEV (Battery Electric Vehicle), and includes a power storage device 11. Each of the electric vehicles 10 is used as a power adjustment resource, and is configured to be capable of performing external charging and external discharging.

[0017] FIG. 2 is a schematic diagram of an electric vehicle 10. The electric vehicle 10 includes a motor generator (MG) 1, a power transmission gear 2, drive wheels 3, and a power control unit (PCU) 4. The electric vehicle 10 also includes a system main relay (SMR) 5, a power storage device 11, a monitoring unit 8, and an ECU (Electronic Control Unit) 9, which is a control device. The MG1 is, for example, an IPM motor, and has a function as an electric motor and a function as a generator. The output torque of the MG1 is transmitted to the drive wheels 3 via the power transmission gear 2, which includes a reduction gear, a differential device, and the like. When braking the electric vehicle 10, the MG1 is driven by the drive wheels 3, the MG1 operates as a generator, and regenerative power generated by regenerative braking force is stored in the power storage device 11. The PCU 4 is a power conversion device that converts power bidirectionally between the MG1 and the power storage device 11.

[0018] The SMR 5 is electrically connected to a power line connecting the power storage device 11 and the PCU 4. When the SMR 5 is closed (ON) in response to a control signal from the ECU 9, power can be exchanged between the power storage device 11 and the PCU 4. On the other hand, when the SMR 5 is open (OFF), the electrical connection between the power storage device 11 and the PCU 4 is cut off.

[0019] The power storage device 11 is a rechargeable DC power source (secondary battery) and is configured by stacking a plurality of single batteries (battery cells) and, for example, electrically connecting them in series. The monitoring unit 8 includes a voltage sensor 81, a current sensor 82, and a temperature sensor 83. The current sensor 82 detects a current (charge / discharge current) IB input / output to / from the power storage device 11. Detection signals from each sensor are input to the ECU 9.

[0020] The electric vehicle 10 includes an inlet 6, and the power storage device 11 is capable of external charging and external power supply (external discharging) via a charging / discharging facility 20. A charging / discharging relay 7 is electrically connected to a power line connecting the inlet 6 and the power storage device 11, and switches between supplying and cutting off power between the inlet 6 and the power storage device 11. When a connector (plug) 22 provided at the end of a charging / discharging cable 21 of the charging / discharging facility 20 is connected to the inlet 6 and the charging / discharging relay 7 is closed (ON), the power storage device 11 is charged (external charging) from a power system PG (external power source) via the charging / discharging facility 20. In addition, the power stored in the power storage device 11 is supplied (discharged) to an external load (for example, an electrical device in a facility 30) via the charging / discharging facility 20.

[0021] The ECU 9 calculates an offset value of the current sensor 82 when the power storage device 11 is being externally charged or externally fed. When external charging or external power feeding starts, the ECU 9 opens (turns off) the charge / discharge relay 7 and the SMR 5 to set the input / output current of the power storage device 11 to zero, and obtains an offset value of the current sensor 82 and stores it in a memory (not shown). Obtaining the offset value of the current sensor 82 and storing it in a memory is also referred to as "offset learning." The offset learning corresponds to an example of the "specific control" of the present disclosure.

[0022] In this embodiment, the ECU 9 executes offset learning in different modes in the electric vehicle 10A and the electric vehicle 10B. When the ECU 9 of the electric vehicle 10A starts external charging or external power feeding, the ECU 9 opens (OFF) the charge / discharge relay 7 and the SMR 5 for a set time tm (for example, 5 seconds) at every predetermined time P0 (for example, every 15 minutes) to set the input / output current of the power storage device 11 to zero and executes offset learning. As long as the input / output current of the power storage device 11 can be set to zero, the states of the charge / discharge relay 7 and the SMR 5 may be any. In this way, the offset learning is executed at a constant frequency in the electric vehicle 10A. The electric vehicle 10A corresponds to the "first vehicle" in this disclosure.

[0023] When the ECU 9 of the electrically powered vehicle 10B starts external charging or external power feeding, the ECU 9 sets the charge / discharge current of the power storage device 11 to zero for a set time tm every predetermined time P1 (e.g., every minute) for a predetermined period S (e.g., 10 minutes) after the start of the external charging or external power feeding, and executes offset learning. Then, after the predetermined period S has elapsed, the ECU 9 sets the input / output current of the power storage device 11 to zero for a set time tm every predetermined time P0, and executes offset learning. The predetermined time P1 is shorter than the predetermined time P0, and in the electrically powered vehicle 10B, the frequency of offset learning is higher during the predetermined period S from the start of charging / discharging compared to after the predetermined period S has elapsed. The electrically powered vehicle 10B corresponds to the "second vehicle" in this disclosure.

[0024] Each charging / discharging equipment 20 is a charging / discharging equipment installed on the premises of a facility 30 (for example, a house, a commercial facility, etc.). The charging / discharging equipment 20 may be, for example, a V2H device. Each charging / discharging equipment 20 charges an electricity storage device 11 with power supplied from a power system PG, and supplies (discharges) the power stored in the electricity storage device 11 to an electrical load in the house or each facility. Each charging / discharging equipment 20 is also capable of supplying (reverse power flow) the power stored in the electricity storage device 11 to the power system PG. A charging / discharging cable 21 connected to the charging / discharging equipment 20 is connected to an inlet 6 of the electric vehicle 10, thereby enabling power to be exchanged between the charging / discharging equipment 20 and the electric vehicle 10.

[0025] The server 200 includes a control device 210, a storage device 220, and a communication device 230, and is configured to be able to communicate with the server 100 and each electric vehicle 10 via the network NW. When the server 200 receives a request for power adjustment from the server 100, the server 200 creates a charge / discharge plan for each electric vehicle 10, and issues instructions to each electric vehicle 10 to charge / discharge based on the charge / discharge plan. Each electric vehicle 10 charges / discharges in cooperation with the charge / discharge facility 20 based on the charge / discharge instructions from the server 200.

[0026] Fig. 3 is a diagram for explaining a sequence of a charge / discharge start timing instruction according to this embodiment. As shown in Fig. 3(A), when the server 200 receives a request for power adjustment from the server 100, the server 200 invites electric vehicles 10 that can participate in the power adjustment together with information such as the type of power adjustment (charging or discharging (power supply)), the power adjustment time, and the amount of power to be adjusted, and extracts target vehicles that will participate in the power adjustment (S10). When the target vehicles that will participate in the power adjustment are extracted, the participating vehicles are divided into a vehicle group of electric vehicles 10A and electric vehicles 10B (S11). Information (ID, etc.) of each electric vehicle 10 is stored in the storage device 220.

[0027] Next, the server 200 sets the timing to start charging / discharging for the electric vehicles 10 (S12). The server 200 sets the timing to start charging / discharging for each electric vehicle 10 so that the number of electric vehicles 10 that execute offset learning at the same timing is equal to or less than a predetermined number. At the same time, the server 200 sets the timing to start charging / discharging for each electric vehicle 10B so that offset learning for electric vehicle 10B is executed at least once within the response time of power adjustment. The response time is the allowable period from when a command for power adjustment is received until the commanded adjustment amount (instruction amount) is achieved.

[0028] As shown in FIG. 3(B), the charge / discharge start timing of each of the electric vehicles 10B is set so that offset learning (see ● in FIG. 3(B)) is performed at least once within the response time of the power adjustment (time t0 to time t1), so that the charge / discharge start timing of the vehicle group B is preferably set earlier than the charge / discharge start timing of the vehicle group A. As shown in FIG. 3(B), by each of the electric vehicles 10 sequentially starting charge / discharge, it is possible to reduce the number of electric vehicles 10 that perform offset learning at the same time to a predetermined value or less. In addition, because offset learning of the electric vehicle 10B is performed at least once within the response time, it is possible to reduce the frequency with which offset learning is performed simultaneously during power adjustment (adjustment period: after the response time has elapsed) (it is possible to reduce the frequency with which currents flowing through a plurality of power storage devices 11 become zero simultaneously).

[0029] Once the charge / discharge start timing is set, it is transmitted to the electric vehicles 10 (S13). Upon receiving the charge / discharge start timing, each electric vehicle 10 sets the charge / discharge timing for each electric vehicle 10, and starts charging / discharging the electricity storage device 11 when the charge / discharge start timing arrives.

[0030] FIG. 3(C) is a diagram showing the transition of the number of vehicles undergoing offset learning during power adjustment. In FIG. 3(C), the dashed line indicates the number of electric vehicles 10 participating in power adjustment. The dashed line indicates the transition of the number of vehicles undergoing learning in the prior art, and indicates a case in which the timing at which each electric vehicle starts charging and discharging is approximately the same. The electric vehicles 10 participating in power adjustment start offset learning approximately at the same time. For this reason, as indicated by the dashed line, the number of vehicles undergoing learning increases significantly. During offset learning, the charge and discharge current of the power storage device 11 is set to zero, and so there is a concern that the amount of charge or discharge due to power adjustment may decrease significantly.

[0031] In this embodiment, the timings for starting charge / discharge for the electric vehicles 10 participating in power adjustment are set so that the number of electric vehicles 10 performing offset learning at the same timing is equal to or less than a predetermined value. Therefore, as shown by the solid line in Fig. 3(C), a large increase in the number of learned vehicles is suppressed, and a large decrease in the charge amount or discharge amount due to power adjustment can be suppressed.

[0032] In Fig. 3(B), the dashed line indicates the command amount of power adjustment, and the solid line indicates the actual amount of power adjustment. Since the charge amount or discharge amount due to power adjustment does not decrease significantly, the actual amount falls within the allowable range indicated by the dashed line. By providing a slope to the command amount (dashed line) during the response time, the timing at which charging / discharging begins for electric vehicles 10 participating in power adjustment can be set so that the number of electric vehicles 10 performing offset learning at the same time is equal to or less than a predetermined value.

[0033] In addition, when a vehicle that does not execute offset learning is included among the electrically powered vehicles 10 participating in the power adjustment, the timing for starting charging / discharging of the vehicle may be set to start after vehicle group A.

[0034] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0035] 1 Power management system, 8 Monitoring unit, 9 ECU, 10 Vehicle, 11 Energy storage device, 20 Charging / discharging equipment, 30 Facilities, 81 Current sensor, 100,200 Server, NW network, PG power system.

Claims

[Claim 1] A power management system using a plurality of electric vehicles, each of which is equipped with a power storage device, as a power adjustment resource, comprising: Each of the plurality of electric vehicles has a control device, the control device is configured to execute specific control by setting a charge / discharge current of the power storage device to zero at a predetermined frequency; the plurality of electric vehicles include a first vehicle having a constant frequency and a second vehicle having a frequency higher than the constant frequency for a predetermined period from a start of charging / discharging of the power storage device, The power management system includes a charge / discharge instruction means for instructing charging / discharging of the plurality of electric vehicles, The charge / discharge instruction means is during power adjustment, instructing a charge / discharge start timing for each of the plurality of electric vehicles so that the number of electric vehicles that execute the specific control at the same timing is equal to or less than a predetermined number; and a power management system that instructs the second vehicle to execute the specific control at least once within a response time of the power adjustment.

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