Power management system

Abstract

To provide a power management system which can suppress significant change of a power adjustment amount when a plurality of electronic vehicles which calibrate a current sensor participate in power adjustment.SOLUTION: A power management system 1 comprises: a plurality of electric vehicles 10; and a server 200 (power transmission instruction device). Each of the plurality of electric vehicles 10 comprises a current sensor 12 which detects current which flows by external discharge (power transmission) and calibrates the current sensor 12 for every predetermined period. The server 200 adjusts start timing of the external discharge by at least a part of the plurality of electric vehicles 10 so that timing of calibration of the plurality of electric vehicles 10 deviates when it is predicted that resource total power (the total amount of a power amount to be exchanged by the power transmission) becomes smaller than a lower limit value (predetermined threshold) of an allowable range resulting from overlap of the timing of calibration of the plurality of electric vehicles 10.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, if the current sensor is calibrated by setting the current flowing through the power storage device to zero every predetermined time as described in Patent Document 1, power adjustment may not be performed well. For example, if the calibration of the current sensor is performed simultaneously in multiple electric vehicles, the timing at which the current flowing through the power storage device is set to zero will be the same for the multiple electric vehicles. For this reason, there is a concern that the amount of charge or discharge due to power adjustment will be significantly reduced.

[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] According to one aspect of the present disclosure, there is provided a power management system that uses a plurality of electric vehicles, each of which includes a power storage device, as a power adjustment resource, and that 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, and calibrates the current sensor by setting the current flowing due to the power transmission to zero at predetermined intervals during the power transmission. When it is predicted that the total amount of power exchanged by the plurality of electric vehicles through power transmission will be smaller than a predetermined threshold due to overlapping of the calibration timings of the plurality of electric vehicles, the power transmission instruction device adjusts the start timing of power transmission by the plurality of electric vehicles so that the calibration timings of the plurality of electric vehicles are shifted from each other.

[0008] In the power management system according to the above aspect, when it is predicted that the total amount of power exchanged by the multiple electric vehicles through power transmission will be smaller than a predetermined threshold due to overlapping calibration timings of the multiple electric vehicles, the start timings of power transmission by the multiple electric vehicles are adjusted so that the calibration timings of the multiple electric vehicles are shifted from each other. This makes it possible to suppress a decrease in the total amount of power exchanged through power transmission due to overlapping calibration timings of the multiple electric vehicles. As a result, when multiple electric vehicles that calibrate their current sensors participate in power adjustment, it is possible to suppress 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 first diagram showing the discharge sequence and total resource power of each vehicle before and after the discharge start timing is adjusted. Fig. 2(B) is a first diagram showing the discharge sequence and total resource power of each vehicle after the discharge start timing is adjusted. [Diagram 3] Fig. 3(A) is a second diagram showing the discharge sequence and total resource power of each vehicle before and after the discharge start timing is adjusted. Fig. 3(B) is a second diagram showing the discharge sequence and total resource power of each vehicle after the discharge start timing is adjusted. [Figure 4] 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. Each of the multiple electric vehicles 10 calibrates the current sensor 12 every predetermined period T1 (see FIG. 2(A)) by setting the current flowing due to external charging and external discharging to zero. Note that there is a period T2 (see FIG. 2(A)) between the start of external charging or external discharging and the first calibration. As shown in FIG. 2(A), the period T2 is longer than the period T1. Note that the period T2 may be shorter than or equal to the period T1. The period T1 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 calibration of the current sensor 12 is performed simultaneously in a plurality of electric vehicles 10, the timing at which the current flowing due to external charging or external discharging becomes zero is the same for the plurality of electric vehicles 10. For this reason, there is a concern that the amount of charging or discharging due to power adjustment may be significantly reduced.

[0019] Specifically, in the example shown in FIG. 2(A), the calibration timing of the current sensor 12 overlaps in vehicles A to D, causing the total resource power (discharge amount in this embodiment) to fall below the lower limit of the allowable range centered on the contract amount of the power adjustment. The total resource power is an example of the "total amount of power exchanged by power transmission" in the present disclosure. The lower limit of the allowable range is an example of the "predetermined threshold" in the present disclosure. The allowable range is, for example, ±10% of the contract amount.

[0020] Therefore, in this embodiment, when the total resource power is expected to be smaller than the lower limit of the allowable range due to overlapping of the calibration timings of the multiple electric vehicles 10, the server 200 adjusts the start timing of external discharging (and external charging) by the multiple electric vehicles 10 so that the calibration timings of the multiple electric vehicles 10 are shifted. At a predetermined timing, the server 200 determines whether the total resource power will be smaller than the lower limit of the allowable range due to overlapping of the calibration timings of the respective vehicles. Note that in FIG. 2(A) and later-described FIGS. 2(A), 3(A) and (B), the period during which each of the vehicles A to D is performing external discharging is indicated by a solid line in the column to the right of the portion labeled vehicles A to D.

[0021] In the example shown in FIG. 2(B), the server 200 starts external discharge for the vehicles A to D simultaneously, and then stops the external discharge for the vehicles A to D in that order. Furthermore, the server 200 starts (resumes) external discharge for the vehicles A to D in that order. This distributes the start timings of external discharge for the vehicles A to D. Since the calibration timing is uniquely determined based on the start timing of external discharge, the calibration timings for the vehicles A to D are shifted from each other. As a result, a decrease in the total resource power is suppressed. This keeps the total resource power within an allowable range. The server 200 may make the above determination, for example, before (or at the time of starting) the external discharge for the vehicles A to D simultaneously.

[0022] 2B, the server 200 does not have to simultaneously start external discharging of the vehicles A to D. For example, the start timing of external discharging of at least one of the vehicles A to D may be adjusted from the beginning of the agreed section of the power adjustment.

[0023] Fig. 3(A) is a diagram showing a case where the external discharge of vehicle D ends in the middle of the contracted section after the start timings of external discharge of vehicles A to D are adjusted as in Fig. 2(B). In this case, external discharge of vehicle E is started instead of vehicle D. In the example shown in Fig. 3(A), the calibration timings of vehicle B and vehicle E overlap.

[0024] In this case, in the example shown in FIG. 3(B), the server 200 adjusts the discharge start timing of the vehicle E to prevent the calibration timings of the vehicles B and E from overlapping. For example, when the calibration timings overlap by starting the external discharge of the vehicle E immediately after the external discharge of the vehicle D is ended (see FIG. 3(A)), the server 200 delays the start timing of the external discharge of the vehicle E by time t. Specifically, the vehicle E starts the external discharge immediately after the external discharge of the vehicle D is ended, and then stops the external discharge. Then, the vehicle E resumes the external discharge after time t from the time when the external discharge of the vehicle D is ended. This prevents the calibration timings of the vehicles B and E from overlapping. The time t may be calculated by the server 200 based on the calibration timing of the other electric vehicle 10, or may be a fixed value set in advance. The server 200 may perform the above determination, for example, at the timing when the external discharge of the vehicle D is ended.

[0025] <Server control flow> Next, a control flow by the server 200 will be described with reference to Fig. 4. In step S1, the server 200 (control device 210) calculates the amount of reduction in the total resource power due to the future calibration of the current sensor 12.

[0026] In step S2, the server 200 determines whether the future total resource power is smaller than the lower limit of the above-mentioned allowable range based on the reduction amount of the total resource power calculated in step S1. If the future total resource power is smaller than the lower limit (Yes in S2), the process proceeds to step S3. If the future total resource power will not fall below the lower limit (No in S2), the process ends. Note that in step S2, the determination may be made based on the magnitude relationship between the reduction amount of the total resource power itself and a predetermined threshold value.

[0027] In step S3, the server 200 judges whether the total resource power after the current (at the time of the above judgment, t1) period T1 (calibration interval) is below the lower limit value. If the total resource power at the time (t1+T1) is not below the lower limit value (Yes in S3), the process proceeds to step S4. If the total resource power at the time (t1+T1) is below the lower limit value (No in S3), the process ends. Note that the process of step S3 does not have to be performed. Furthermore, in step S3, the judgment may be made based on the magnitude relationship between the amount of decrease in the total resource power at the time (t1+T1) itself and a predetermined threshold value.

[0028] In step S4, the server 200 selects the electric vehicle 10 that is causing the decrease in the total resource power, and adjusts (changes) the discharge start timing of the selected electric vehicle 10. Then, the process ends.

[0029] As described above, in this embodiment, when it is predicted that the total resource power will be smaller than the lower limit of the allowable range due to overlapping calibration timings of the multiple electric vehicles 10, the server 200 adjusts the start timings of external discharging (external charging) by the multiple electric vehicles 10 so as to stagger the calibration timings of the multiple electric vehicles 10. As a result, the calibration timings are adjusted in conjunction with the adjustment of the start timings of external discharging (external charging), and therefore overlapping calibration timings of the multiple electric vehicles 10 can be easily eliminated.

[0030] In the above embodiment, the period T1, which is the calibration cycle, and the period T2 from the start of discharging (charging) to the first calibration are the same for each of the multiple electric vehicles 10, but the present disclosure is not limited to this. The period T1 (T2) may be different for each vehicle.

[0031] In the above embodiment, the discharge start timing is adjusted during power adjustment by external discharging, but the present disclosure is not limited to this. The charge start timing may be adjusted during power adjustment by external charging.

[0032] The configurations of the above-described embodiment and the above-described modified examples may be combined with each other.

[0033] 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]

[0034] 1 power management system, 10 electric vehicle, 11 power storage device, 12 current sensor, 200 server (power transmission instruction device), T1 period (predetermined period).

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 for detecting a current flowing due to the power transmission, calibrating the current sensor by setting the current flowing due to the power transmission to zero at predetermined intervals during the power transmission period; The power transmission instruction device is When it is predicted that a total amount of electric power exchanged by the power transmission between the plurality of electric vehicles will be smaller than a predetermined threshold due to overlapping of the calibration timings of the plurality of electric vehicles, and adjusting a timing at which the plurality of electric vehicles start transmitting power such that timings at which the calibrations are performed for the plurality of electric vehicles are shifted from one another.

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