Power management system

Abstract

To provide a power management system which can suppress significant change of a power adjustment amount when a plurality of electric vehicles for calibrating a current sensor participate in power adjustment.SOLUTION: A power management system comprises: a plurality of electric vehicles 10; and a server 200 (power transmission instruction device. A part of the plurality of electric vehicles 10 calibrates a current sensor 12 by using current flowing by external discharge (power transmission) as zero for every period T1 (predetermined period). The server 200 makes power (W2) to be transmitted in the external discharge by the electric vehicle 10 by which the current sensor 12 is calibrated smaller than power (W1) to be transmitted in the external discharge by the electric vehicle 10 by which the current sensor 12 is not calibrated.SELECTED DRAWING: Figure 2

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) discloses that during external charging of a plug-in hybrid vehicle (PHEV), the current flowing to a battery (energy 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 (hereinafter referred to as calibration of the current sensor). [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 a virtual power plant (VPP) that uses electric vehicles as an energy resource. For example, during periods when the supply of electricity is greater than the demand for electricity, electricity is stored in an electricity 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 electricity 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, power adjustment may not be performed well if the current sensor is calibrated by setting the current flowing through the power storage device to zero at predetermined time intervals as described in Patent Document 1. For example, there is a concern that the amount of charge or discharge due to power adjustment may be significantly reduced due to the current becoming zero when the current sensor is calibrated.

[0006] An object of the present disclosure is to provide a power management system capable of suppressing large changes in the amount of power adjustment when multiple electric vehicles that calibrate current sensors are participating in power adjustment. [Means for solving the problem]

[0007] A power management system according to one aspect of the present disclosure uses a plurality of electric vehicles each equipped with a power storage device as a power adjustment resource, and includes the plurality of electric vehicles and a power transmission instruction device that instructs each of the plurality of electric vehicles to perform power transmission including at least one of charging and discharging. Each of the plurality of electric vehicles includes a current sensor that detects a current flowing due to the power transmission. Some of the plurality of electric vehicles are configured to calibrate the current sensor at predetermined intervals during the power transmission period by setting the current flowing due to the power transmission to zero, and the remaining portion of the plurality of electric vehicles are configured not to perform calibration. The power transmission instruction device makes the power transmitted in the power transmission by the electric vehicle that performs calibration among the plurality of electric vehicles smaller than the power transmitted in the power transmission by the electric vehicle that does not perform calibration among the plurality of electric vehicles.

[0008] In the power management system according to one aspect of the present disclosure, as described above, the power transmitted by the electric vehicle that performs calibration is set to be smaller than the power transmitted by the electric vehicle that does not perform calibration. As a result, since the power transmitted by the electric vehicle that performs calibration is set relatively low, it is possible to prevent a large decrease in the power adjustment amount due to the electric vehicle that performs calibration. As a result, when multiple electric vehicles that perform current sensor calibration participate in power adjustment, it is possible to prevent a large change in the power adjustment amount. Effect of the Invention

[0009] According to the present disclosure, when a plurality of electric vehicles that perform calibration of current sensors participate in power adjustment, it is possible to suppress a large change in the amount of power adjustment. [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; [Diagram 2] Fig. 2(A) is a diagram showing the discharge sequence and total resource power of each vehicle according to a comparative example, and Fig. 2(B) is a diagram showing the discharge sequence and total resource power of each vehicle according to this embodiment. [Diagram 3] FIG. 4 is a diagram illustrating a control sequence of a server in a power management system according to an 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. Note that the server 200 is an example of the "power transmission instruction device" of the present disclosure.

[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. 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 able to perform external charging and external discharging. In this embodiment, each of the electric vehicles 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. Each of the external charging and external discharging is an example of "power transmission" in the present disclosure.

[0015] Each of the multiple electric vehicles 10 includes a current sensor 12 that detects a current flowing due to external charging and external discharging. Some of the multiple electric vehicles 10 (vehicles A and B in FIG. 2(A)) calibrate the current sensor 12 every predetermined period T (see FIG. 2(A)) by setting the current flowing due to external charging and external discharging to zero. Meanwhile, the remaining some of the multiple electric vehicles 10 (vehicles C and D in FIG. 2(A)) do not calibrate the current sensor 12. Note that the period T is an example of a "predetermined period" in the present disclosure.

[0016] 1 again, 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.

[0017] 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.

[0018] 2A, when the electric vehicle 10 is used as a power adjustment resource, if the current sensor 12 is calibrated at predetermined time intervals, the power adjustment may not be performed well. For example, there is a concern that the amount of charge or discharge due to the power adjustment may be significantly reduced due to the current becoming zero when the current sensor 12 is calibrated.

[0019] 2A, the total resource power (discharge amount in this embodiment) falls below the lower limit of the allowable range centered on the contract amount of the power adjustment due to the fact that the calibration timings of the current sensor 12 overlap in vehicles A and B. The allowable range is, for example, within ±10% of the contract amount.

[0020] Therefore, in this embodiment, the server 200 sets the power transmitted during external discharging (or external charging) by an electric vehicle 10 in which the current sensor 12 is calibrated among the multiple electric vehicles 10 to be smaller than the power transmitted by an electric vehicle 10 in which the current sensor 12 is not calibrated. Note that the transmitted power is the power transmitted per unit time.

[0021] Specifically, in the comparative example shown in FIG. 2(A), the discharge power (W) in the external discharge by the vehicles A to D is the same as each other, that is, power W1. In contrast, in the example of the present embodiment shown in FIG. 2(B), the discharge power (W2) by the vehicles A and B on which calibration is performed (vehicles subject to calibration) is set to be smaller than the discharge power (W1) by the vehicles C and D on which calibration is not performed (vehicles not subject to calibration). This makes it possible to reduce the discharge power (W2) reduced by the calibration in each of the vehicles A and B. As a result, even if the timing of calibration overlaps in the vehicles A and B, for example, it is possible to suppress the reduction in the total resource power. Note that the discharge power W2 is set to a value such that the product of the discharge power W2 and the number (total number) of the electric vehicles 10 on which calibration is performed is equal to or smaller than the difference between the contract amount and the lower limit (1 / 2 of the above allowable range).

[0022] In the example shown in Fig. 2, the discharge power during normal times (timings other than calibration) is constant for each vehicle, but this is not limited to the above example. As long as the relationship is maintained in which the discharge power of the electric vehicle 10 on which calibration is performed is lower than the discharge power of the electric vehicle 10 on which calibration is not performed, the discharge power may change over time. In this case, the amount of change in the discharge power of the electric vehicle 10 on which calibration is performed may be limited to be equal to or less than a predetermined threshold value. The amount of change in the discharge power of the electric vehicle 10 on which calibration is not performed may not be limited as described above.

[0023] <Server control flow> Next, a control flow by the server 200 will be described with reference to Fig. 3. Note that the control flow shown in Fig. 3 is performed every time external discharging for power adjustment is performed.

[0024] In step S1, the server 200 (control device 210) acquires, via the communication device 230, information regarding whether or not the current sensor 12 in each electric vehicle 10 has been calibrated.

[0025] In step S2, the server 200 determines whether or not there are electric vehicles 10 whose current sensors 12 are to be calibrated and electric vehicles 10 whose current sensors 12 are not to be calibrated, based on the information in step S1. If there are electric vehicles 10 whose current sensors 12 are to be calibrated and electric vehicles 10 whose current sensors 12 are not to be calibrated (Yes in S2), the process proceeds to step S3. If there are only either electric vehicles 10 whose current sensors 12 are to be calibrated or electric vehicles 10 whose current sensors 12 are not to be calibrated (No in S2), the process ends.

[0026] In step S3, the server 200 sets (adjusts) the discharge power of each electric vehicle 10 so that the discharge power (W2) of the electric vehicle 10 in which the current sensor 12 is calibrated is smaller than the discharge power (W1) of the electric vehicle 10 in which the calibration is not performed. The server 200 may appropriately adjust each of the power W1 and the power W2 based on the number of electric vehicles 10 in which the calibration is performed, the number of electric vehicles 10 in which the calibration is not performed, the total resource power required, the length of time for external discharge, and the like. Also, each of the power W1 and the power W2 may be a fixed value set in advance. The process then ends.

[0027] As described above, in this embodiment, the server 200 sets the discharge power of the electric vehicle 10 in which the current sensor 12 is calibrated to be smaller than the discharge power of the electric vehicle 10 in which the current sensor 12 is not calibrated. As a result, the discharge power of the electric vehicle 10 in which calibration is performed is set small in advance, so that the effect of the calibration of the current sensor 12 on the total resource power can be made relatively small.

[0028] In the above embodiment, an example in which the discharge power in the external discharge is adjusted has been described, but the present disclosure is not limited to this. The charging power in the external charging may be adjusted based on whether or not the current sensor 12 has been calibrated.

[0029] The configurations of the above-described embodiment and the above-described modified examples may be combined with each other.

[0030] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure 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]

[0031] 1 Power management system, 10 Electric vehicle, 11 Power storage device, 12 Current sensor, 200 Server (power transmission instruction device), T period (predetermined period), W1 power (discharge power of vehicle without calibration), W2 power (discharge power of vehicle with calibration).

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: The plurality of electric vehicles; a power transmission instruction device that instructs each of the plurality of electric vehicles to transmit power including at least one of charging and discharging; each of the plurality of electric vehicles includes a current sensor that detects a current flowing due to the power transmission; some of the plurality of electric vehicles are configured to calibrate the current sensor at predetermined intervals during the power transmission by setting the current flowing due to the power transmission to zero, and the remaining portion of the plurality of electric vehicles are configured not to perform the calibration; The power transmission instruction device makes the power transmitted in the power transmission by an electric vehicle among the plurality of electric vehicles that performs the calibration smaller than the power transmitted in the power transmission by an electric vehicle among the plurality of electric vehicles that does not perform the calibration.

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