JP7764302B2 - Virtual Power Plant Power Management System - Google Patents

Description

The present invention relates to a power management system for a virtual power plant (VPP) that controls the charging and discharging operations of the onboard batteries of each vehicle to follow the output power demands and instantaneous output demands for a fleet of vehicles.

Patent Document 1 describes an energy management system that includes a prediction means for predicting changes in the power supply-demand gap for each microgrid, an acquisition means for acquiring vehicle information including at least the remaining charge of the secondary battery for electric vehicles located within the area corresponding to each microgrid, and a distribution means for distributing information regarding the charging and discharging of the secondary battery to electric vehicles based on the prediction results of the prediction means and the vehicle information acquired by the acquisition means, where the distribution means distributes information to designated electric vehicles encouraging them to charge and discharge the secondary battery so as to equalize the power supply-demand gap in each microgrid.

Japanese Patent Application Laid-Open No. 2020-114090

In recent years, there has been growing interest in operating electric vehicles as part of a virtual power plant (VPP) by linking their battery functions with the power infrastructure and optimizing the charge/discharge amount and timing of the vehicle's onboard batteries. This VPP has two uses: adjusting power supply and demand by controlling output power (kWh) and adjusting frequency by controlling instantaneous power (kW). Simultaneous control of output power and instantaneous power is required to effectively utilize limited battery resources. For this reason, a method has been proposed in which the instantaneous power control request is proportionally allocated to each electric vehicle and superimposed on the output power control command for each electric vehicle. However, when this method is used, a tracking delay may occur when switching between onboard battery charging and discharging operations, as the output power control command may be switched to a discharging command despite being a charging command for the onboard battery, or the power control command may be switched to a charging command despite being a discharging command for the onboard battery. Therefore, there is a need for technology that can suppress tracking delays when switching between onboard battery charging and discharging operations.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a power management system for a virtual power plant that can suppress tracking delays when switching between charging and discharging operations of an onboard battery.

The virtual power plant power management system of the present invention controls the charging and discharging operations of each vehicle's onboard battery to follow the output power demands and instantaneous output demands for the vehicle group. It calculates the minimum value of the discharge limit output power of each vehicle's onboard battery, the output power demands until charge/discharge switching, and the charge limit output power demands as the output power demands of each vehicle. If the sum of the calculated output power demands of each vehicle is greater than the instantaneous output demand value for the vehicle group, the instantaneous output demand value is allocated to each vehicle according to the magnitude of each vehicle's output power demand, and the charging and discharging operations of each vehicle's onboard battery are controlled according to the allocated instantaneous output demand value.

The power management system for a virtual power plant according to the present invention is characterized in that, in the above invention, if the sum of the available power output of each vehicle is less than or equal to the instantaneous output required value for the vehicle group, the control server calculates the sum of the available power output of each vehicle until the charge/discharge switching of its onboard battery; and if the sum of the available power output of each vehicle until the charge/discharge switching of its onboard battery is greater than the instantaneous output required value for the vehicle group, the control server sets the available power output of each vehicle until the charge/discharge switching of its onboard battery. This allows the vehicle to follow the instantaneous output request without switching the battery's charge/discharge operation.

The virtual power plant power management system of the present invention is characterized in that, in the above invention, the control server calculates the sum of the smaller of the discharge limit output power and charge limit output power of each vehicle's onboard battery when the sum of the available output power of each vehicle's onboard battery up to the charge/discharge switch is less than the instantaneous output required value for the vehicle group; and, when the sum of the smaller of the discharge limit output power and charge limit output power of each vehicle's onboard battery is greater than the instantaneous output required value for the vehicle group, sets the available output power of each vehicle to the smaller of the discharge limit output power and charge limit output power of each vehicle's onboard battery. This allows the instantaneous output required to be met while maintaining symmetry between the charge and discharge sides.

The virtual power plant power management system of the present invention is characterized in that, in the above invention, when the sum of the smaller of the discharge limit output power capacity and the charge limit output power capacity of the onboard battery of each vehicle is less than or equal to the instantaneous output request value for the vehicle group, if the instantaneous output request value for the vehicle group is greater than 0, the control server sets the discharge limit output power capacity of the onboard battery of each vehicle to the output power capacity of each vehicle, and if the instantaneous output request value for the vehicle group is less than or equal to 0, the control server sets the charge limit output power capacity of the onboard battery of each vehicle to the output power capacity of each vehicle. This makes it possible to comply with large instantaneous output requests.

The virtual power plant power management system of the present invention calculates the output power capacity of each vehicle as the minimum of the discharge limit output power capacity of each vehicle's onboard battery, the output power capacity until charge/discharge switching, and the charge limit output power capacity.If the sum of the calculated output power capacity of each vehicle is greater than the instantaneous output demand value for the vehicle group, the instantaneous output demand value is allocated to each vehicle according to the size of each vehicle's output power capacity, and the charge/discharge operation of each vehicle's onboard battery is controlled according to the allocated instantaneous output demand value, thereby reducing tracking delays when switching between onboard battery charge/discharge operations.

FIG. 1 is a block diagram showing the configuration of a virtual power plant according to an embodiment of the present invention. FIG. 2 is a flowchart showing the flow of power management processing according to an embodiment of the present invention. FIG. 3 is a diagram showing the output power amount tracking instruction value, the discharge limit of the available output power amount, the available output power amount until switching between charge and discharge, and the charge limit of the available output power amount.

Below, we will explain in detail the power management system for a virtual power plant (VPP), one embodiment of the present invention, with reference to the drawings.

〔composition〕
First, the configuration of a VPP according to an embodiment of the present invention will be described with reference to FIG.

Figure 1 is a schematic diagram showing the configuration of a VPP, one embodiment of the present invention. As shown in Figure 1, the VPP 1, one embodiment of the present invention, is a system that adjusts the balance of power supply and demand within a power transmission and distribution network by controlling the charging and discharging operations of batteries installed in vehicles 2. In this embodiment, the VPP 1 mainly comprises multiple vehicles 2, a power company 3, and a control server 4, and each component is configured to be able to communicate information with each other via telecommunications lines 5, such as the Internet or power lines.

Vehicle 2 is composed of a vehicle such as an HV (Hybrid Vehicle), EV (Electric Vehicle), or FCEV (Fuel Cell Electric Vehicle). Vehicle 2 is equipped with a battery that can be charged and discharged via a power transmission and distribution network, and is configured to be able to transmit various vehicle data via telecommunications line 5. The vehicle data includes information such as the vehicle 2's identification number (such as a VIN number), the battery's SOC (State of Charge), and the upper and lower limits of the battery's output power. When vehicle 2 is connected to a charging station 6 that charges the battery, it may connect to telecommunications line 5 via the charging station 6 to transmit vehicle data.

Power company 3 supplies electricity generated at well-known power plants such as hydroelectric power plants, thermal power plants, and nuclear power plants to consumers and demand facilities via the power transmission and distribution network, and also purchases surplus electricity supplied by consumers and demand facilities via the power transmission and distribution network.

The control server 4 is composed of a well-known information processing device such as a workstation. The control server 4 acquires output power requests and instantaneous output requests for the vehicle group, as well as vehicle data for the vehicles 2 that make up the vehicle group, via the telecommunications line 5. The control server 4 then controls the charging and discharging operations of the batteries installed in the vehicles 2 based on the acquired information.

In a VPP 1 configured as described above, the control server 4 executes the power management process described below to prevent tracking delays when switching between charging and discharging the battery installed in the vehicle 2. Below, we will explain the operation of the control server 4 when executing the power management process, with reference to Figure 2.

[Power management processing]
Figure 2 is a flowchart showing the flow of power management processing according to one embodiment of the present invention. The flowchart shown in Figure 2 begins when the control server 4 acquires, via the telecommunications line 5, an output power request and an instantaneous output request for the vehicle group, as well as vehicle data for the vehicles 2 that make up the vehicle group, and inputs a command to execute the power management processing to the control server 4. The power management processing then proceeds to step S1. The operation of the control server 4 described below is realized by the control server 4 executing a computer program.

In the process of step S1, the control server 4 calculates the output power (kWh) tracking instruction value P base (i) (indicated by a star in FIG. 3 ) for the vehicle i (= 1 to N (total number of vehicles)) to be controlled, based on the output power request for the vehicle group in response to the adjustment of the _balance between supply and demand of electricity. This completes the process of step S1, and the power management process proceeds to the process of step S2.

In the process of step S2, the control server 4 calculates the discharge limit output power amount P _ub (i) (see FIG. 3), the output power amount P O (i) (see FIG. 3) until charge/discharge switching, and the charge limit output power amount P _lb (i) (see FIG. 3) from the power amount tracking instruction value P _base (i) calculated in the process of step S1 and the upper and lower limit values of the output power amount of the _battery mounted on the vehicle i to be controlled (upper and lower limit outputs shown in FIG. 3). This completes the process of step S2, and the power management process proceeds to the process of step S3.

In the process of step S3, the control server 4 calculates the minimum value of the discharge limit output power amount P _ub (i), the output power amount P _O (i) until charge/discharge switching, and the charge limit output power amount P _lb (i) calculated in the process of step S2 as the output power amount P(i) of the vehicle i to be controlled. This completes the process of step S3, and the power management process proceeds to the process of step S4.

In the process of step S4, the control server 4 calculates the sum of the available output amounts of energy P(i) of each vehicle i calculated in the process of step S3, and determines whether the sum of the available output amounts of energy P(i) is greater than the instantaneous power (kW) demand amount _PfleetkW for the vehicle fleet. If the result of the determination is that the sum of the available output amounts of energy P(i) is greater than the instantaneous power demand amount _PfleetkW for the vehicle fleet (step S4: Yes), the control server 4 proceeds with the power management process to the process of step S12. On the other hand, if the sum of the available output amounts of energy P(i) is equal to or less than the instantaneous power demand amount _PfleetkW for the vehicle fleet (step S4: No), the control server 4 proceeds with the power management process to the process of step S5.

In the process of step S5, the control server 4 sets the available output power P( _i ) of the vehicle i to the available output power P(i) calculated in the process of step S2 until the charge/discharge switching. This completes the process of step S5, and the power management process proceeds to the process of step S6.

In the process of step S6, the control server 4 calculates the sum of the available output amounts of energy P(i) of each vehicle i set in the process of step S5, and determines whether the sum of the available output amounts of energy P(i) is greater than the instantaneous power (kW) demand amount _PfleetkW for the vehicle fleet. If the result of the determination is that the sum of the available output amounts of energy P(i) is greater than the instantaneous power demand amount _PfleetkW for the vehicle fleet (step S6: Yes), the control server 4 proceeds with the power management process to the process of step S12. On the other hand, if the sum of the available output amounts of energy P(i) is equal to or less than the instantaneous power demand amount _PfleetkW for the vehicle fleet (step S6: No), the control server 4 proceeds with the power management process to the process of step S7.

In the process of step S7, the control server 4 sets the smaller of the discharge limit output power amount P _ub (i) and the charge limit output power amount P _lb (i) calculated in the process of step S2 as the output power amount P(i) of the vehicle i to be controlled. This completes the process of step S7, and the power management process proceeds to the process of step S8.

In the process of step S8, the control server 4 calculates the sum of the available output amounts of energy P(i) of each vehicle i set in the process of step S7, and determines whether the sum of the available output amounts of energy P(i) is greater than the instantaneous power demand _PfleetkW for the vehicle fleet. If the result of the determination is that the sum of the available output amounts of energy P(i) is greater than the instantaneous power demand _PfleetkW for the vehicle fleet (step S8: Yes), the control server 4 proceeds with the power management process to the process of step S12. On the other hand, if the sum of the available output amounts of energy P(i) is equal to or less than the instantaneous power demand _PfleetkW for the vehicle fleet (step S8: No), the control server 4 proceeds with the power management process to the process of step S9.

In the process of step S9, the control server 4 determines whether the instantaneous power demand P _{fleet kW} for the vehicle fleet is greater than 0. If the determination result shows that the instantaneous power demand P _{fleet kW} is greater than 0 (step S9: Yes), the control server 4 proceeds with the power management process to the process of step S10. On the other hand, if the instantaneous power demand P _{fleet kW} is equal to or less than 0 (step S9: No), the control server 4 proceeds with the power management process to the process of step S11.

In the process of step S10, the control server 4 sets the available output power P(i) of the vehicle 2 to be controlled to the discharge limit available output power P _ub (i) calculated in the process of step S2. This completes the process of step S10, and the power management process proceeds to the process of step S12.

In the process of step S11, the control server 4 sets the available output power P(i) of the vehicle 2 to be controlled to the charging limit available output power P _lb (i) calculated in the process of step S2. This completes the process of step S11, and the power management process proceeds to the process of step S12.

In the process of step S12, the control server 4 calculates a proportional distribution value P final (i) of the instantaneous power demand P _{fleet kW} for the controlled vehicle 2 by multiplying the value obtained by dividing the instantaneous power demand P _{fleet kW} by the _sum ΣP(i) of the available output power P(i) of each controlled vehicle i by the available output power P(i) of the controlled vehicle i. Here, the available output power P(i) of each vehicle i is a value set in any one of the processes of steps S3, S5, S7, S10, and S11. This completes the process of step S12, and the power management process proceeds to the process of step S13.

In the process of step S13, the control server 4 calculates an instruction value for the vehicle i to be controlled by superimposing the proportional allocation value P _final (i) of the instantaneous power demand P _fleetkW calculated in the process of step S12 on the output power amount tracking instruction value P _base (i) calculated in the process of step S1. The control server 4 then controls the charging and discharging operation of the battery by transmitting the calculated charging and discharging instruction value to the vehicle i to be controlled. This completes the process of step S13, and the series of power management processes ends.

As is clear from the above description, in the VPP1 according to one embodiment of the present invention, the control server 4 calculates the available output power _P (i) for each vehicle 2 as the minimum of the discharge limit available output power P _ub (i), the available output power P O (i) until charge/discharge switching, and the available output power P _lb (i) for the battery of each vehicle 2. If the sum of the calculated available output power P(i) for each vehicle 2 is greater than the instantaneous output request value P _{fleet kW} for the vehicle fleet, the control server 4 allocates the instantaneous output request value P _{fleet kW} to each vehicle 2 according to the magnitude of the available output power P(i), and controls the charging and discharging operation of the onboard battery of each vehicle 2 according to the allocated instantaneous output request value P _{fleet kW} . This prevents a tracking delay when switching the charging and discharging operation of the battery installed in each vehicle 2. Furthermore, since the waveform of the original instantaneous output request is kept symmetrical between the charging side and the discharging side, the instantaneous output request can be tracked.

Furthermore, in the VPP1 according to one embodiment of the present invention, if the sum of the available output power P(i) of each vehicle 2 is equal to or less than the instantaneous output request value _PfleetkW for the vehicle group, the control server 4 calculates the sum of the available output power P _O (i) of each vehicle 2 until the battery charging/discharging switching, and if the sum of the available output power P _O (i) of each vehicle 2 until the battery charging/discharging switching is greater than the instantaneous output request value _PfleetkW for the vehicle group, the control server 4 sets the available output power P _O (i) of each vehicle 2 until the battery charging/discharging switching as the available output power P(i) of each vehicle 2. This makes it possible to follow the instantaneous output request without switching the battery charging/discharging operation.

Furthermore, in the VPP1 according to one embodiment of the present invention, if the sum of the available output power P _O (i) of the battery of each vehicle 2 up to the charge/discharge switching is equal to or less than the instantaneous output request value P _{fleet kW} for the vehicle group, the control server 4 calculates the sum of the smaller of the discharge limit available output power P _ub (i) and the charge limit available output power P _lb (i) of the battery of each vehicle 2, and if the sum of the smaller of the discharge limit available output power P _ub (i) and the charge limit available output power P _lb (i) of the battery of each vehicle 2 is greater than the instantaneous output request value P _{fleet kW} , the control server 4 sets the smaller of the discharge limit available output power P _lb (i) and the charge limit available output power P _ub (i) of the battery of each vehicle 2 as the available output power P(i) of each vehicle 2. This makes it possible to follow the instantaneous output request while maintaining symmetry between the charge side and the discharge side.

Furthermore, in the VPP1 according to one embodiment of the present invention, when the sum of the smaller of the discharge limit output power P _ub (i) and the charge limit output power P _lb (i) of the battery of each vehicle 2 is equal to or less than the instantaneous output request value P _{fleet kW} for the vehicle group, the control server 4 sets the discharge limit output power P _ub (i) of the battery of each vehicle 2 as the output power P(i) of each vehicle 2 if the instantaneous output request value P _{fleet kW} for the vehicle group is greater than 0, and sets the charge limit output power P _lb (i) of the battery of each vehicle 2 as the output power P(i) of each vehicle 2 if the instantaneous output request value P fleet kW for the vehicle group is equal to or less than 0. This makes it possible to comply with large instantaneous output requests.

The above describes an embodiment of the invention developed by the inventors, but the present invention is not limited to the descriptions and drawings that form part of the disclosure of the present invention according to this embodiment. In other words, all other embodiments, examples, and operational techniques that are developed by those skilled in the art based on this embodiment are included in the scope of the present invention.

1. Virtual Power Plant (VPP)
2 Vehicle 3 Electric power company 4 Control server 5 Telecommunication line 6 Charging station

Claims (4)

A power management system for a virtual power plant that controls the charging and discharging operation of an on-board battery of each vehicle so as to follow an output power amount request and an instantaneous output request for a group of vehicles,
A power management system for a virtual power plant, characterized by comprising a control server that calculates the output power of each vehicle as the minimum value of the discharge limit output power of the onboard battery of each vehicle, the output power until charge/discharge switching, and the charge limit output power of the onboard battery of each vehicle, and if the sum of the calculated output power of each vehicle is greater than the instantaneous output required value for the vehicle group, allocates the instantaneous output required value to each vehicle according to the size of the output power of each vehicle, and controls the charging and discharging operation of the onboard battery of each vehicle according to the allocated instantaneous output required value. 2. The power management system for a virtual power plant according to claim 1, wherein the control server calculates the sum of the amount of power that can be output by each vehicle until the charging/discharging switching of its onboard battery when the sum of the amount of power that can be output by each vehicle until the charging/discharging switching of its onboard battery is less than or equal to the instantaneous output required value for the vehicle group, and when the sum of the amount of power that can be output by each vehicle until the charging/discharging switching of its onboard battery is greater than the instantaneous output required value for the vehicle group, sets the amount of power that can be output by each vehicle until the charging/discharging switching of its onboard battery, calculates a proportional allocation value of the instantaneous power required amount for each vehicle according to the set amount of power that can be output by each vehicle, and controls the charging/discharging operation of the onboard battery of each vehicle according to the calculated proportional allocation value of the instantaneous power required amount. 3. The power management system for a virtual power plant according to claim 2, wherein the control server calculates the sum of the smaller of the discharge limit output power and the charge limit output power of the onboard battery of each vehicle when the sum of the output power that can be output until the charge/discharge switching of the onboard battery of each vehicle is equal to or less than the instantaneous output required value for the vehicle group; and when the sum of the smaller of the discharge limit output power and the charge limit output power of the onboard battery of each vehicle is greater than the instantaneous output required value for the vehicle group , sets the smaller of the discharge limit output power and the charge limit output power of the onboard battery of each vehicle as the output power of each vehicle, calculates a proportional distribution value of the instantaneous power required for each vehicle according to the set output power of each vehicle, and controls the charge/discharge operation of the onboard battery of each vehicle according to the calculated proportional distribution value of the instantaneous power required. 4. The power management system for a virtual power plant according to claim 3, wherein, when the sum of the smaller of the discharge limit output power amount and the charge limit output power amount of the onboard battery of each vehicle is equal to or less than the instantaneous output request value for the vehicle group, if the instantaneous output request value for the vehicle group is greater than 0, the control server sets the discharge limit output power amount of the onboard battery of each vehicle to the output power amount of each vehicle , and if the instantaneous output request value for the vehicle group is equal to or less than 0, the control server sets the charge limit output power amount of the onboard battery of each vehicle to the output power amount of each vehicle, calculates a proportional distribution value of the instantaneous power request amount of each vehicle according to the set output power amount of each vehicle, and controls the charging and discharging operation of the onboard battery of each vehicle according to the calculated proportional distribution value of the instantaneous power request amount .