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] This disclosure relates to a power management system.

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2009-171666 (Patent Document 1) discloses calculating an offset value of a current sensor that detects a battery current by setting the current flowing through a battery (power storage device) to zero at regular intervals during external charging of a plug-in hybrid vehicle (PHEV) (hereinafter referred to as calibration of the current sensor).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, a virtual power plant (VPP) that uses electric vehicles as energy resources has been used to balance power supply and demand. For example, during a period when power supply is greater than power demand, power is stored in the power storage device of the electric vehicle, and during a period when power demand is greater than power supply, power stored in the power storage device of the electric vehicle is discharged to balance power supply and demand.

[0005] When an electric vehicle is used as a power adjustment resource, as described in Patent Document 1, if the current sensor is calibrated by setting the current flowing through the power storage device to zero at regular intervals, power adjustment may not be successfully performed. 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 during calibration of the current sensor.

[0006] ​The purpose of this disclosure is to provide a power management system that can suppress large changes in the amount of power adjustment when multiple electric vehicles that perform current sensor calibration are participating in power adjustment. [Means for solving the problem]

[0007] A power management system according to one aspect of this disclosure is a power management system that uses a plurality of electric vehicles, each equipped with an energy storage device, as a power adjustment resource, and comprises a 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 the current flowing through power transmission. Some of the plurality of electric vehicles are configured to calibrate their current sensors by setting the current flowing through power transmission to zero at predetermined intervals during the power transmission period, while the remaining portion of the plurality of electric vehicles are configured not to perform calibration. The power transmission instruction device makes the power transmitted by the electric vehicles that are calibrated during power transmission less than the power transmitted by the electric vehicles that are not calibrated during power transmission.

[0008] In a power management system relating to one aspect of this disclosure, as described above, the power transmitted by the electric vehicle performing calibration is set to be less than the power transmitted by the electric vehicle that does not perform calibration. As a result, since the power transmitted by the electric vehicle performing calibration is set to a relatively low level, it is possible to suppress a large decrease in the power adjustment amount caused by the electric vehicle performing calibration. Consequently, when multiple electric vehicles performing current sensor calibration participate in power adjustment, it is possible to suppress large changes in the power adjustment amount. [Effects of the Invention]

[0009] According to this disclosure, when multiple electric vehicles performing current sensor calibration participate in power adjustment, it is possible to suppress large changes in the amount of power adjustment. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows a schematic overall configuration of a power management system according to one embodiment. [Figure 2] Figure 2(A) shows the discharge sequence and total resource power of each vehicle according to the comparative example. Figure 2(B) shows the discharge sequence and total resource power of each vehicle according to this embodiment. [Figure 3] This figure shows the control sequence of a server in a power management system according to one embodiment. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0012] Figure 1 is a diagram showing a schematic overall configuration of the power management system according to this embodiment. Referring to Figure 1, the power management system 1 includes a power grid PG, a plurality of electric vehicles 10, a server 100, and a server 200. Note that server 200 is an example of the "power transmission instruction device" of this disclosure.

[0013] The power grid (PG) is a power network constructed by power plants and transmission / distribution facilities (not shown), and is maintained and managed by the power company. The power company is equivalent to the administrator of the power grid (PG). Server 100 is a server managed by the aggregation coordinator, and distributes power adjustment amounts to the resource aggregator at the request of the power company.

[0014] Server 200 is a computer that manages multiple electric vehicles 10 and is managed by a resource aggregator. Each of the multiple electric vehicles 10 is, for example, a BEV (Battery Electric Vehicle) and is equipped with a power storage device 11. Each electric vehicle 10 is used as a power adjustment resource and is configured to perform external charging and external discharging. In this embodiment, each electric vehicle 10 included in the power management system 1 is assumed to have the same configuration. However, the power management system 1 may include multiple types of vehicles having different configurations. Note that external charging and external discharging are examples of "power transmission" as defined in this disclosure.

[0015] Each of the multiple electric vehicles 10 includes a current sensor 12 that detects the current flowing due to external charging and external discharging. Some of the multiple electric vehicles 10 (vehicles A and B in Figure 2(A)) undergo calibration of the current sensor 12 by setting the current flowing due to external charging and external discharging to 0 at predetermined intervals T (see Figure 2(A)). On the other hand, the remaining part of the multiple electric vehicles 10 (vehicles C and D in Figure 2(A)) do not undergo calibration of the current sensor 12. Note that period T is an example of a “predetermined period” in this disclosure.

[0016] Referring again to Figure 1, each charging / discharging device 20 is a charging / discharging device installed on the premises of a facility 30 (for example, a residence and commercial facility). The charging / discharging device 20 may be, for example, a V2H device. Each charging / discharging device 20 charges the energy storage device 11 with power supplied from the power grid PG and supplies (discharges) the power stored in the energy storage device 11 to the electrical loads of the residence and each facility.

[0017] Server 200 includes a control device 210, a storage device 220, and a communication device 230, and is configured to communicate with Server 100 and each electric vehicle 10 via a network NW. When Server 200 receives a power adjustment request from Server 100, it creates a charge / discharge plan for each electric vehicle 10 and issues charging / discharging instructions to each electric vehicle 10 based on the charge / discharge plan. Each electric vehicle 10 performs charging and discharging in cooperation with the charging / discharging equipment 20 based on the charging / discharging instructions from Server 200.

[0018] Here, as shown in FIG. 2(A), when the electric vehicle 10 is used as a power adjustment resource, if the current sensor 12 is calibrated every predetermined time, power adjustment may not be successfully executed. For example, there is a concern that the amount of charge or discharge due to power adjustment may significantly decrease because the current becomes zero during calibration of the current sensor 12.

[0019] Specifically, in the comparative example shown in FIG. 2(A), due to the calibration timings of the current sensor 12 overlapping in vehicles A and B, the total resource power (discharge amount in this embodiment) is below the lower limit value of the allowable range centered around the approximate amount of power adjustment. The allowable range is, for example, within ±10% of the approximate amount.

[0020] Therefore, in this embodiment, the server 200 makes the power transmitted by the electric vehicle 10 in which the current sensor 12 is calibrated among the plurality of electric vehicles 10 during external discharge (or external charging) smaller than the power transmitted by the electric vehicle 1 which the current sensor 12 is not calibrated. The transmitted power described above is the power transmitted per unit time.

[0021] Specifically, in the comparative example shown in FIG. 2(A), the discharge powers (W) in external discharge by vehicles A to D are the same as each other at power W1. In contrast, in the example of this embodiment shown in FIG. 2(B), the discharge powers (W2) by vehicles A and B for which calibration is performed (the vehicles to be calibrated) are made smaller than the discharge powers (W1) by vehicles C and D for which calibration is not performed (the non-target vehicles for calibration). Thereby, the discharge power (W2) that decreases due to calibration in each of vehicles A and B can be reduced. As a result, even if the calibration timings overlap in vehicles A and B, for example, a decrease in the total resource power can be suppressed. The discharge power W2 is set to a value such that the product with the number (total number) of electric vehicles 10 to be calibrated is not more than the difference between the approximate amount and the lower limit value (1 / 2 of the allowable range).

[0022] In the example shown in FIG. 2, an example is shown where the discharge power during normal times (timing other than calibration) is constant for each vehicle. However, the present invention is not limited to the above example. As long as the relationship that the discharge power of the electric vehicle 10 during which calibration is performed is lower than the discharge power of the electric vehicle 10 during which calibration is not performed is maintained, the discharge power may change over time. In this case, the amount of change in the discharge power when the discharge power of the electric vehicle 10 during which calibration is performed changes may be restricted to be below a predetermined threshold value. Note that no such restriction need be provided for the amount of change in the discharge power of the electric vehicle 10 during which calibration is not performed.

[0023] <Server Control Flow> Next, referring to FIG. 3, the control flow by the server 200 will be described. Note that the control flow shown in FIG. 3 is performed each time external discharge for power adjustment is executed.

[0024] In step S1, the server 200 (control device 210) acquires information regarding the presence or absence of calibration of the current sensor 12 in each electric vehicle 10 through the communication device 230.

[0025] In step S2, the server 200 determines whether there are electric vehicles 10 in which the current sensor 12 is calibrated and electric vehicles 10 in which the current sensor 12 is not calibrated based on the information in step S1. If there are electric vehicles 10 in which calibration is performed and electric vehicles 10 in which calibration is not performed (Yes in S2), the process proceeds to step S3. If only either one of the electric vehicles 10 in which calibration is performed and the electric vehicles 10 in which calibration is not performed exists (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 whose current sensor 12 is being calibrated is also small, as is the discharge power (W1) of the electric vehicle 10 whose current sensor 12 is not being calibrated. The server 200 may appropriately adjust power W1 and power W2 based on the number of electric vehicles 10 whose current sensor 12 is being calibrated, the number of electric vehicles 10 whose current sensor 12 is not being calibrated, the total required resource power, and the length of time for which external discharge is performed. Alternatively, power W1 and power W2 may each be fixed values ​​set in advance. After that, the process ends.

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

[0028] The above embodiment shows an example in which the discharge power in external discharge is adjusted, but the disclosure is not limited thereto. The charging power by external charging may be adjusted based on whether or not the current sensor 12 is calibrated.

[0029] Furthermore, the configurations of the above embodiments and each of the above modified examples may be combined with each other.

[0030] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0031] 1 Power management system, 10 Electric vehicle, 11 Energy storage device, 12 Current sensor, 200 Server (Power transmission instruction device), T Period (predetermined period), W1 Power (discharge power of uncalibrated vehicle), W2 Power (discharge power of calibrated vehicle).

Claims

[Claim 1] A power management system that uses multiple electric vehicles, each equipped with an energy storage device, as power adjustment resources, The aforementioned multiple electric vehicles, Each of the aforementioned plurality of electric vehicles is provided with a power transmission instruction device that instructs power transmission including at least one of charging and discharging, Each of the aforementioned multiple electric vehicles includes a current sensor for detecting the current flowing through the power transmission, Some of the aforementioned electric vehicles are configured to perform calibration of the current sensor by setting the current flowing through the power transmission to zero at predetermined intervals during the power transmission period, while the remaining portion of the aforementioned electric vehicles are configured not to perform the calibration. The power transmission instruction device is a power management system that makes the power transmitted in the power transmission by the electric vehicle that performs calibration among the plurality of electric vehicles less than the power transmitted by the electric vehicle that does not perform calibration among the plurality of electric vehicles.

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