Power management system

Abstract

To prevent a power adjustment amount from being significantly changed even if an offset value of a current sensor is calculated in an electric vehicle participating in power adjustment.SOLUTION: A server 200 of a power management system divides electric vehicles participating in power adjustment into a plurality of vehicle groups (S10). The server 200 allocates initial time τ for offset value learning, which is set to different values for each vehicle group (S12), or allocates a different learning cycle T to each vehicle group (S13). Since learning timing of an offset value differs for each vehicle group when power is adjusted, a large increase in the number of learning vehicles is suppressed and a large decrease in a charge amount or a discharge amount by power adjustment can be suppressed.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] For example, in Japanese Patent Laid-Open Publication No. 2009-171666 (Patent Document 1), during external charging of a plug-in hybrid vehicle (PHEV), the current flowing to a battery (electricity storage device) is set to zero at regular time intervals, and an offset value of a current sensor that detects the battery current is calculated. [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, during 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 during 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] In this way, when an electric vehicle is used as a power adjustment resource, 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 as described in Patent Document 1, the power adjustment may not be performed well. For example, if the control specifications of multiple electric vehicles participating in the power adjustment are the same, the cycle for calculating the offset value of the current sensor will be approximately the same, and the timing for setting the current flowing through the power storage device to zero will be approximately the same for multiple electric vehicles. For this reason, the number of electric vehicles participating in the power adjustment that simultaneously have the current flowing through the power storage device become zero will increase, and there is a concern that the amount of charge or discharge due to the power adjustment will be significantly reduced.

[0006] An object of the present disclosure is to prevent the amount of power adjustment from changing significantly even if an offset value of a current sensor is calculated in an electric vehicle participating in power adjustment. [Means for solving the problem]

[0007] The power management system disclosed herein uses an electric vehicle equipped with a power storage device as a power adjustment resource. The electric vehicle has a current sensor that detects a charge / discharge current of the power storage device and a control device, and the control device is configured to set the charge / discharge current to zero at predetermined intervals and obtain an offset value of the current sensor when the electric vehicle is not participating in power adjustment. The power management system includes a charge / discharge instruction means that instructs the electric vehicle to charge / discharge, and the charge / discharge instruction means instructs a vehicle participating in power adjustment on the timing to calculate the offset value of the current sensor.

[0008] According to this configuration, the control device for the electric vehicle is configured to set the charge / discharge current to zero at predetermined intervals and obtain an offset value for the current sensor when the electric vehicle is not participating in power adjustment. The power management system includes a charge / discharge instruction means for instructing charging / discharging of the electric vehicle. The charge / discharge instruction means instructs the timing for calculating the offset value for the current sensor to the vehicle participating in power adjustment. Since the charge / discharge instruction means instructs the timing for calculating the offset value for the current sensor to the vehicle participating in power adjustment, the timing for calculating the offset value for the current sensor can be appropriately instructed so that the amount of power adjustment (amount of charge or discharge due to power adjustment) does not decrease significantly. Effect of the Invention

[0009] According to the present disclosure, even if an offset value of a current sensor is calculated in an electrically powered vehicle participating in power adjustment, it is possible to prevent the amount of power adjustment from changing significantly. [Brief description of the drawings]

[0010] [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] 6A to 6D are diagrams illustrating a sequence of an offset value learning timing instruction according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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.

[0012] 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 10, a server 100, and a server 200.

[0013] 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.

[0014] 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 electric vehicle 10 is used as a power adjustment resource, and is configured to be able to perform external charging and external discharging. In this embodiment, each electric vehicle 10 included in the power management system 1 has the same configuration. However, the power management system 1 may include a plurality of types of vehicles having different configurations.

[0015] 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 MG 1 is, for example, an IPM motor, and has a function as an electric motor (motor) and a function as a generator (generator). The output torque of the MG 1 is transmitted to the drive wheels 3 via the power transmission gear 2, which includes a reduction gear, a differential device, and the like.

[0016] When braking the electric vehicle 10, the MG1 is driven by the drive wheels 3 and operates as a generator. This allows the MG1 to function as a braking device that performs regenerative braking to convert the kinetic energy of the electric vehicle 10 into electric power. Regenerative power generated by the regenerative braking force in the MG1 is stored in the power storage device 11. The PCU 4 is a power conversion device that converts electric power in both directions between the MG1 and the power storage device 11.

[0017] 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.

[0018] 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 connecting them electrically in series, for example. The single batteries may be lithium-ion batteries. 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.

[0019] 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.

[0020] The ECU 9 calculates an offset value of the current sensor 82 when the power storage device 11 is externally charged or externally fed. When the ECU 9 starts external charging or external power feeding, the ECU 9 opens (OFF) the charge / discharge relay 7 and the SMR 5 for a predetermined time tm (for example, 5 seconds) at every predetermined period P (for example, every 15 minutes) to set the input / output current of the power storage device 11 to zero, obtains an offset value of the current sensor 82, and stores the offset value in a memory (not shown). Hereinafter, obtaining the offset value of the current sensor 82 and storing the offset value in a memory is also referred to as "learning the offset value." As long as the input / output current of the power storage device 11 can be set to zero, the charge / discharge relay 7 and the SMR 5 may be in any state. In this embodiment, it is assumed that each electric vehicle 10 included in the power management system 1 has the same configuration. However, the power management system 1 may include a plurality of types of vehicles having different configurations.

[0021] 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.

[0022] 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.

[0023] Fig. 3 is a diagram for explaining the offset value learning timing instruction sequence according to the present 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 (grouped) into a plurality of vehicle groups (S11). The number of groups may be any number, and may be, for example, 10 groups or 100 groups, and may be set according to the number of participating vehicles.

[0024] Next, the server 200 sets the timing of learning the offset value for each vehicle group (for each group). For example, the server 200 assigns a first time τ, which is the timing for first executing learning of the offset value from the start of the power adjustment, to each vehicle group (S12). As shown in FIG. 3(B), when the first time τ has elapsed from the start of the power adjustment, learning of the offset value is executed in the electric vehicle 10, and thereafter, learning of the offset value is executed for each learning cycle T. In this case, the learning cycle T may be a cycle equivalent to a predetermined period P (for example, 15 minutes) set by the ECU 9. The first time τ is set to a different value for each vehicle group (for each group), and is a value different from the predetermined period P. Alternatively, the server 200 assigns a different learning cycle T to each vehicle group (for each group) as shown in FIG. 3(C) (S13). In this case, the learning cycle T is set to a value different from the predetermined period P (for example, 15 minutes) set by the ECU 9 and different from each vehicle group.

[0025] When the initial time τ or the learning cycle T is assigned with a different value for each vehicle group, the assigned initial time τ or learning cycle T is transmitted to the electric vehicles 10 (S14). When each electric vehicle 10 receives the assigned initial time τ or learning cycle T, it sets the learning timing using the received initial time τ or learning cycle T, and executes offset learning when the learning timing occurs during power adjustment.

[0026] FIG. 3(D) is a diagram showing the transition of the number of vehicles for which offset values ​​have been learned during power adjustment. In FIG. 3(D), the dashed line indicates the number of electric vehicles 10 participating in the power adjustment. The dashed line indicates the transition of the number of vehicles for which offset learning has been performed in the prior art, in the case where offset learning is performed every predetermined period P set by the ECU 9. When the control specifications of the electric vehicles 10 are the same, the predetermined period P is the same value, so that the electric vehicles 10 participating in the power adjustment start offset learning almost simultaneously. Therefore, as shown by the dashed line, the number of vehicles for which offset learning has been performed increases significantly. During offset learning, the charge / discharge current of the power storage device 11 is set to zero, so there is a concern that the charge amount or discharge amount due to the power adjustment may decrease significantly.

[0027] In this embodiment, the server 200 sets the timing of learning the offset value for each vehicle group (group) of electric vehicles 10 participating in the power adjustment. For example, an initial time τ set to a different value for each vehicle group (group) is assigned to each vehicle group (S12), or a different learning period T is assigned to each vehicle group (group) (S13). Therefore, during power adjustment, the timing of learning the offset value differs for each vehicle group (group) at the instruction of the server 200, so that a large increase in the number of learned vehicles is suppressed, and a large decrease in the charge amount or discharge amount due to the power adjustment can be suppressed, as shown by the solid line in Fig. 3(D).

[0028] In the above embodiment, a different initial time τ or a different learning period T is assigned to each vehicle group, but a different initial time τ or a different learning period T may be assigned to each electric vehicle 10 participating in the power adjustment.

[0029] 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]

[0030] 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 that uses an electric vehicle equipped with a power storage device as a power adjustment resource, the electric vehicle has a current sensor that detects a charge / discharge current of the power storage device and a control device; the control device is configured to, when the electric vehicle is not participating in power adjustment, set the charge / discharge current to zero at predetermined intervals and calculate an offset value of the current sensor; The power management system includes a charge / discharge instruction means for instructing charging / discharging of the electric vehicle, The charge / discharge instruction means instructs the vehicles participating in the power adjustment as to the timing for calculating the offset value of the current sensor.

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