Power management system

Abstract

To facilitate implementation of required energy management using a plurality of electric vehicles that learns current sensor offset values.SOLUTION: A power management system includes a vehicle group including a plurality of electric vehicles and a control device that controls the vehicle group. Each of the plurality of electric vehicles includes a power storage device and a current sensor that detects a charge and discharge current of the power storage device, and sets the charge and discharge current to zero at predetermined timing to learn an offset value of the current sensor (S11 to S15). When causing the vehicle group to execute energy management through charging or discharging of the power storage device, the control device estimates power reduction due to the learning with regard to charging power or discharging power of the vehicle group, and determines a power command value to the vehicle group for energy management on the basis of the estimated power reduction (S22).SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Japanese Patent Application Laid-Open No. 2009-171666 (Patent Document 1) discloses a control device that temporarily suspends charging at predetermined time intervals after starting charging of an electricity storage device mounted on an electric vehicle, and performs learning (offset value learning) for correcting the output of a current sensor provided in the charge / discharge path of the electricity storage device. [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, it has been proposed to perform energy management of a power system using multiple electric vehicles equipped with power storage devices. However, when multiple electric vehicles are made to perform energy management by charging or discharging the power storage devices, if at least one of the electric vehicles executes the above-mentioned learning of the offset value of the current sensor, the charge / discharge current of the power storage device in that electric vehicle becomes zero (0 A), and there is a possibility that the charging power or discharging power will be insufficient for the requested energy management.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to make it easier to execute required energy management using multiple electric vehicles that learn offset values ​​of current sensors. [Means for solving the problem]

[0006] An energy management system according to an embodiment of the present disclosure includes a vehicle group including a plurality of electric vehicles, and a control device that controls the vehicle group. Each of the plurality of electric vehicles has a power storage device and a current sensor that detects a charge / discharge current of the power storage device, and is configured to set the charge / discharge current to zero at a predetermined timing to learn an offset value of the current sensor. When causing the vehicle group to perform energy management by charging or discharging the power storage device, the control device estimates a power reduction due to learning regarding the charging power or discharging power of the vehicle group, and determines a power command value for the vehicle group for energy management based on the estimated power reduction. Effect of the Invention

[0007] According to the present disclosure, it is easier to implement the required energy management using a plurality of electric vehicles that learn the offset values ​​of the current sensors. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an overview of a power management system according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a diagram for explaining an energy management method according to an embodiment of the present disclosure. [Diagram 3] FIG. 11 is a diagram illustrating a comparison of actual adjusted power according to an embodiment, a modified example, and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 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 characters and will not be described repeatedly.

[0010] FIG. 1 is a diagram showing an overview of a power management system according to an embodiment of the present disclosure. Referring to FIG. 1, the power management system according to the embodiment executes energy management of a power system PG. The power management system includes a vehicle group 10G including a plurality of vehicles 10, a vehicle group 20G including a plurality of vehicles 20, a supply and demand management system 100 (hereinafter, referred to as "system 100"), a resource management system 200 (hereinafter, referred to as "system 200"), an electric vehicle management system 300 (hereinafter, referred to as "system 300"), a plurality of power supply facilities 510, and a plurality of power supply facilities 520. The system 300 includes a processor 310 and a storage device 320. Although not shown in the figure, the systems 100 and 200 also include a processor and a storage device, similar to the system 300.

[0011] The power system PG is a power network constructed by power transmission and distribution facilities. A plurality of power plants are connected to the power system PG. Each of the power supply facilities 510 and 520 is electrically connected to the power system PG and receives power supply from the power system PG. Each of the vehicles 10 and 20 is an electric vehicle (xEV) equipped with a power storage device, and is configured to be able to run using discharged power from the power storage device. When the vehicles 10 and 20 are electrically connected to the power supply facilities 510 and 520, respectively (plugged-in state), they can charge their on-board batteries (power storage devices) using power (power from outside the vehicles) supplied from the power system PG through the power supply facilities 510 and 520.

[0012] The vehicle 10 and the power supply equipment 510 are respectively an electric vehicle and a power supply equipment of a V1G type (a type that receives power unilaterally from the power grid PG). The power supply equipment 510 is, for example, a power supply equipment of a socket type. The vehicle 20 and the power supply equipment 520 are respectively an electric vehicle and a power supply equipment of a V2G type (a type that exchanges power in both directions with the power grid PG). The power supply equipment 520 is, for example, a power supply equipment of an integrated cable type. Each of the vehicles 10 and 20 is, for example, a BEV (electric vehicle). However, this is not limited thereto, and the type of electric vehicles (xEVs) included in each of the vehicle groups 10G and 20G is arbitrary.

[0013] The system 300 is configured to be able to communicate with each electric vehicle included in the vehicle groups 10G, 20G. The system 300 may communicate with the vehicles 10, 20 via wired communication via power supply equipment 510, 520, respectively, or may communicate directly with each of the vehicles 10, 20 by wireless communication. In addition, a user of each electric vehicle carries a user terminal 30. The system 300 also communicates with the user terminal 30. The user terminal 30 is, for example, a smartphone, but may be another terminal.

[0014] Each electric vehicle and each power supply facility shown in FIG. 1 are registered in the system 300. The storage device 320 stores information about each registered electric vehicle (such as specifications, location, and state) by distinguishing it by the identification information of the electric vehicle (vehicle ID). The user terminal 30 of each electric vehicle is also linked to the vehicle ID and registered in the system 300. For example, when a user inputs a driving plan or charging plan for an electric vehicle into the user terminal 300, the plan is linked to the identification information of the electric vehicle and registered in the system 300. The storage device 320 also stores information about each registered power supply facility (such as specifications, location, and state) by distinguishing it by the identification information of the power supply facility.

[0015] Hereinafter, all electric vehicles managed by the system 300 are collectively referred to as "electric vehicle resources." The system 300 obtains, for the electric vehicle resources, charge / discharge power (reference value) when not adjusted and the amount of power (chargeable / dischargeable amount) that the electric vehicle resources can adjust with respect to the reference value, and transmits them to the system 200. The system 200 manages a plurality of distributed energy resources (hereinafter, referred to as "DERs") including the electric vehicle resources. Hereinafter, all DERs managed by the system 200 are collectively referred to as "EM resources." The EM resources further include DERs other than the electric vehicle resources (e.g., stationary power storage devices). The system 200 obtains, for the EM resources, charge / discharge power (reference value) when not adjusted and the amount of power (chargeable / dischargeable amount) that the EM resources can adjust with respect to the reference value, and transmits them to the system 100. The system 100 performs transactions in the electricity market based on the reference value and the chargeable / dischargeable amount received from the system 200. The system 100 performs settlement for electricity transactions and manages transaction records. Below, we will explain tertiary control reserve-2 as an example of a product traded in the electricity market.

[0016] The tertiary control reserve-2 is traded in the supply and demand adjustment market. In the supply and demand adjustment market, the tertiary control reserve-2 is traded, for example, by a bidding method, for each of eight blocks that divide a day into three-hour units. The system 100 makes a bid in the supply and demand adjustment market during the period from 12:00 to 14:00 on the day before the target block. Specifically, the system 100 transmits bidding information including a product (for example, the tertiary control reserve-2), a block (one of the eight blocks), a reference value, and a bid amount to a market system (not shown). Thereafter, the system 100 is notified of the result at 15:00 on the day of the bid. When the bid product is successful, a contract is reached. A person who wins a bid for the tertiary control reserve-2 in the supply and demand adjustment market is obligated (contractual obligation) to adjust power within the range (contract adjustment range) from the reference value (kW) to the contract amount (kW).

[0017] When the system 100 wins a bid for a product, it registers a reference value in the market system by the submission deadline (e.g., one hour before the start time of the target block for which it has won). The system 100 sequentially receives market request signals from the market system requesting energy management during the target block for which it has won (contract period). The market request signal indicates a power request value that is arbitrarily requested by the market system within the contract adjustment range. The system 100 performs energy management during the contract period so that the actual adjusted power follows the power request value.

[0018] The market system checks every frame (30 minutes) whether the system 100 (successful bidder) is adjusting (response performance) according to the command (market demand signal) within the contract adjustment range during the contract period. If the power demand value is changed during the contract period, the successful bidder changes the output to that value within the response time of the product requirements. However, the output may deviate from the power demand value as long as it is within the allowable range. Also, if the power demand value continues at the same value during the contract period, the successful bidder continues the output according to the power demand value for at least the duration of the product requirements. For tertiary adjustment capacity-2, the response time is within 45 minutes and the duration is 3 hours (6 frames). If the successful bidder performs energy management using a power storage device, the successful bidder's output is charging (increased demand) or discharging (increased supply) corresponding to the requested energy management (product). If non-compliance with the requirements is found, a specified penalty fee is imposed on the successful bidder.

[0019] In the example shown in FIG. 1, the period from time t1 to time t2 corresponds to the contract period, and the range from the reference value to the contract amount Y corresponds to the contract adjustment range. Line L10 shows the transition of the power request value. Line L11 shows a power value (lower limit of the tolerance range) that is smaller than the power request value by the tolerance range. Line L12 shows a power value (upper limit of the tolerance range) that is larger than the power request value by the tolerance range. The tolerance range is, for example, 10% of the contract amount Y. The market system transmits a market request signal to the successful bidder at time t0, which is the response time (45 minutes) before time t1. In the example shown in FIG. 1, the initial power request value is the contract amount Y, and the power request value is changed at time t3. The range from time t0 to the time the response time has elapsed (response tolerance A), the range from time t3 to the time the response time has elapsed (response tolerance B), and the range corresponding to the tolerance range shown by lines L11 and L12 (increase / decrease tolerance) correspond to the range that satisfies the requirements (tolerance range).

[0020] When the system 100 receives a market request signal, it obtains an adjustment amount (upper command amount) required to execute the energy management required by the market request signal, and determines a power request value (resource command amount) to be requested of the EM resource based on the obtained upper command amount. Then, the system 100 transmits a first request signal indicating the contract requirement (contract amount, contract period, tolerance range, etc.) and the resource command amount to the system 200. When the system 200 receives the first request signal, it obtains an adjustment amount (required charge / discharge amount) required for the resource command amount, and obtains a power request value (vehicle group command amount) to be requested of the electric vehicle resource based on the obtained required charge / discharge amount. Then, the system 200 transmits a second request signal indicating the contract requirement and the vehicle group command amount to the system 300. The system 300 controls the electric vehicle resource so that the energy management required by the second request signal is executed by the process shown in FIG. 2 described later. According to such a hierarchical structure (tree structure), it is possible to request energy management from many consumers. The EM resource may function as a VPP (virtual power plant).

[0021] 2 is a diagram for explaining the energy management method according to this embodiment. "S" in the flowchart indicates a step.

[0022] 2, each of the vehicles 10, 20 includes a battery 51 (driving battery), an ECU (electronic control unit) 52, a current sensor 53 that detects a current flowing through the battery 51, and a voltage sensor 54 and a temperature sensor 55 that detect the voltage and temperature of the battery 51, respectively. The detection results of each sensor are input to the ECU 52. The ECU 52 includes a processor and a storage device (not shown), and records the detection results of each sensor in the storage device. In each of the vehicles 10, 20, when charging / discharging of the battery 51 (more specifically, charging of the battery 51 with power from outside the vehicle or discharging of the battery 51 to the outside of the vehicle) is started, the ECU 52 starts a process flow of S11 to S15 described below.

[0023] In S11, ECU 52 determines whether or not a learning timing has arrived. In this embodiment, learning for correcting the output of current sensor 53 is periodically executed. The learning timing arrives every time a predetermined time has elapsed during charging / discharging of battery 51. When the learning timing arrives (YES in S11), learning is executed by the processes of S12 to S14.

[0024] In S12, the ECU 52 stops (interrupts) the charging and discharging of the battery 51. As a result, the charging and discharging current of the battery 51 becomes zero (0 A). Next, in S13, the ECU 52 learns (acquires and records) the offset value (output value when no current flows) of the current sensor 53. Then, the ECU 52 corrects (calibrates) the detection error of the current sensor 53 based on the obtained offset value. The ECU 52 may set a correction coefficient in the current sensor 53. Thereafter, the ECU 52 resumes the charging and discharging of the battery 51 in S14.

[0025] When the above learning (S12 to S14) is performed, the process proceeds to S15. The process also proceeds to S15 while the learning timing has not arrived (NO in S11). In S15, the ECU 52 determines whether or not charging / discharging of the battery 51 has been completed. If charging / discharging of the battery 51 continues (NO in S15), the process returns to S11. On the other hand, when charging / discharging of the battery 51 is completed (YES in S15), the above process flow (S11 to S15) ends.

[0026] When the system 300 receives a second request signal requesting the start of EM (energy management), the system 300 starts the process flow of S21 to S25. The system 300 causes the electric vehicle resource (a vehicle group including a plurality of electric vehicles) to charge or discharge the power storage device (battery 51) corresponding to the energy management requested by the second request signal in the manner described below.

[0027] In S21, the system 300 judges whether or not the instruction timing has arrived. The instruction timing arrives when the EM starts. Thereafter, the instruction timing arrives every time a predetermined time (for example, one minute) has elapsed. Then, when the instruction timing arrives (YES in S21), the system 300 estimates the power reduction caused by the above-mentioned learning (calibration of the current sensor 53) for the vehicle group power (charging power or discharging power of the vehicle group) in S22, and determines a power command value for the vehicle group for EM (energy management) based on the estimated power reduction. As will be described in detail later, the system 300 determines the power command value for the vehicle group so that the vehicle group power falls within an allowable range set for the power request value. Then, the system 300 transmits a control command to each electric vehicle used for EM so that the vehicle group power becomes the above-mentioned power command value. The system 300 may apportion the power command value for the vehicle group to each electric vehicle. Each electric vehicle executes charging or discharging of the power storage device according to the control command from the system 300. However, when the above-mentioned learning timing arrives, each electric vehicle executes the above-mentioned learning (S12 to S14) regardless of the control command. That is, in each electric vehicle, the above-mentioned learning control takes priority over the control command.

[0028] In the next step S23, the system 300 determines whether the detection timing has arrived. When the detection timing arrives (YES in S23), the system 300 detects the power value of the electric vehicle resource (vehicle group power) in S24. The system 300 may obtain the power value from each electric vehicle or from a power meter (e.g., a smart meter) at each charging / discharging station. The detection timing arrives every time a predetermined time (e.g., one minute) has elapsed since the start of EM.

[0029] In the next S25, the system 300 determines whether EM (energy management) has ended. For example, when the contract period (time t1 to time t2) has elapsed, EM ends. If EM continues (NO in S25), the process returns to S21. When the contract period ends (YES in S25), the above process flow (S21 to S25) ends.

[0030] In the embodiment shown in FIG. 2, the electric vehicle resource (vehicle group) executes EM corresponding to the contract amount Y. Line L20 indicates the transition of the power request value requested by the second request signal. Line L21 indicates the actual adjusted power by the vehicle group (vehicle group power). In this example, a plurality of electric vehicles executes learning of the offset value of the current sensor 53 at the same timing. In S22, the system 300 estimates the amount of power reduction caused by the above-mentioned learning. Then, the system 300 makes the power command value to the vehicle group higher than the power request value according to the estimated amount of power reduction. The system 300 makes the power command value to the vehicle group higher than the power request value (for example, contract amount Y) according to the amount of power reduction, so that both the power value Y1 (power value reduced by learning) indicating the vehicle group power at the time of learning and the power value Y2 (power value according to the power command value) indicating the vehicle group power at the time of non-learning fall within the allowable range. The difference between the power value Y2 and the power value Y1 shown in FIG. 2 corresponds to the above-mentioned amount of power reduction.

[0031] FIG. 3 is a graph showing the transition of the vehicle group power according to the embodiment and the modified example (lines L21, L21A) in comparison with a graph showing the transition of the vehicle group power according to the comparative example (line L22).

[0032] 3, in the comparative example, a power command value for the vehicle group is determined according to the power request value indicated by the second request signal. As a result, as shown by line L22, the actual adjusted power (vehicle group power) is lower than the allowable range due to the power reduction caused by the above-mentioned learning. In contrast, in the embodiment, the system 300 sets the power command value for the vehicle group higher than the power request value in accordance with the power reduction caused by the above-mentioned learning (S22). As a result, as shown by line L21, the vehicle group power falls within the allowable range during the contract period.

[0033] As described above, the power management system according to this embodiment includes a vehicle group (vehicle group 10G, 20G) including a plurality of electric vehicles, and a control device (system 300) that controls the vehicle group. Each of the plurality of electric vehicles has an electric storage device (battery 51) and a current sensor 53 that detects a charge / discharge current of the electric storage device, and learns an offset value of the current sensor 53 by setting the charge / discharge current to zero at a predetermined timing (S11 to S15). When the control device causes the vehicle group to perform energy management by charging or discharging the electric storage device, the control device estimates a power reduction caused by learning with respect to the charging power or discharging power of the vehicle group, and determines a power command value for the vehicle group for energy management based on the estimated power reduction (S22). With this configuration, even if the charging power or discharging power of the vehicle group decreases due to the learning, the power command value for the vehicle group is increased to compensate for the power reduction, thereby preventing a shortage of charging power or discharging power for the requested energy management. Therefore, it becomes easier to perform the requested energy management using the plurality of electric vehicles.

[0034] In the above embodiment, if the power request value does not change, the power command value to the electric vehicle resource (vehicle group) is not changed. In contrast, in the modified example shown in FIG. 3, the system 300 predicts the output reduction caused by the above-mentioned learning and estimates the amount of power reduction caused by the learning. Then, during the non-learning period, the system 300 determines the power command value to the vehicle group according to the power request value indicated by the second request signal. Furthermore, during the learning period, the system 300 sets the power command value to the vehicle group higher than the power request value according to the estimated amount of power reduction. That is, even if the power request value does not change, the system 300 controls the vehicle group based on different power command values ​​in the non-learning period and the learning period. Even with this modified example, it is possible to keep the vehicle group power within the allowable range during the contract period, as shown by the line L21A. When increasing the output according to the output reduction, a V2H (Vehicle to Home) function that can change the output linearly may be utilized.

[0035] Alternatively, a TSO (system operator) may request energy management instead of the power market. Each of the systems 100, 200, and 300 is implemented by an on-premise server, but may also be implemented on the cloud. The functions of each system may be included in a single device.

[0036] 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]

[0037] 10,20 Vehicle, 51 Battery, 52 ECU, 53 Current sensor, 100 Supply and demand management system, 200 Resource management system, 300 Electric vehicle management system, 510,520 Power supply equipment, PG power system.

Claims

[Claim 1] A power management system including a vehicle group including a plurality of electric vehicles and a control device that controls the vehicle group, each of the plurality of electric vehicles has a power storage device and a current sensor that detects a charge / discharge current of the power storage device, and is configured to set the charge / discharge current to zero at a predetermined timing and learn an offset value of the current sensor; The control device is a power management system that, when causing the vehicle group to perform energy management by charging or discharging the storage device, estimates a power reduction in the charging power or discharging power of the vehicle group due to the learning, and determines a power command value for the vehicle group for the energy management based on the estimated power reduction.

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