Charge and discharge control method for charge and discharge element, and charge and discharge control device for charge and discharge element

Abstract

This charge / discharge control method for a charging / discharging element receives a frequency adjustment capacity request value (Pfr) in accordance with the system frequency (f) of a power system (10), said request value (Pfr) being broadcasted to a plurality of charging / discharging elements (EV1, EV2, EV3,...) connected to an electric wire (12) of the power system (10), determines the charging / discharging output characteristics with respect to the system frequency (f) on the basis of a priority (β) and the received request value (Pfr), said priority (β) indicating a degree in which charging or discharging of the charging / discharging element (EV1) is prioritized over charging or discharging of the other charging / discharging elements (EV2, EV3,...), corrects the output characteristics so as to increase the upper limit value or the lower limit value of an output range as the priority (β) is higher, and performs charging or discharging with the output determined on the basis of the difference (△f) between the system frequency (f) measured at a connection end connected to the power system (10) and a reference frequency (fref) and the corrected output characteristics.

Description

Technical Field

[0001] The present invention relates to a method for controlling charge and discharge of a charge and discharge element, and a charge and discharge control device for a charge and discharge element.

Background Art

[0002] Patent Document 1 describes a technique for a frequency stabilization system of a power system. In this technique, on the power system side, the system frequency is measured, and the frequency adjustment capacity of the power system is calculated based on the deviation between the measured system frequency and the reference frequency. Further, information corresponding to the calculated frequency adjustment capacity is transmitted all at once from the power system side to a plurality of power reception amount control loads connected to the power system. Each power reception amount control load measures the system frequency by itself, and controls the power reception amount of each power reception amount control load based on the measured system frequency, the information received from the power system side, and the reference frequency.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, an electric vehicle is cited as an example of an optimal power reception amount control load. In an electric vehicle, the charge and discharge output characteristics of the battery may be set according to its own priority. The own priority indicates the degree to which the charge and discharge of its own battery is prioritized over the charge and discharge of the batteries of other electric vehicles connected to the same power system.

[0005] When an electric vehicle sets the charge-discharge output characteristics of its battery according to its own priority, an electric vehicle with a lower priority will have charge-discharge output characteristics with a narrower output range set than an electric vehicle with a higher priority. In an electric vehicle with a narrow output range of charge-discharge output characteristics, the frequency adjustment capacity obtained by power reception control is smaller than that of an electric vehicle with a wide output range of charge-discharge output characteristics. For this reason, in the technology of Patent Document 1, for example, when performing power reception control with the battery of an electric vehicle as a power reception control load, due to the influence of the priority set for the electric vehicle, the system side may not be able to sufficiently secure the frequency adjustment capacity calculated.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to enable the charge-discharge element side to sufficiently secure the frequency adjustment capacity calculated by the power system side.

Means for Solving the Problems

[0007] In order to solve the above-described problems, in a charge-discharge control method for a charge-discharge element according to one aspect of the present invention, charge-discharge elements connected in plurality to an electric wire of a power system receive a required value of a frequency adjustment capacity corresponding to the system frequency of the power system, which has been broadcast to all charge-discharge elements. The charge-discharge output characteristics with respect to the system frequency determined based on the priority indicating the degree to which its own charging or discharging is prioritized over other charge-discharge elements and the received required value are corrected so that the upper limit value or the lower limit value of the output range increases as the priority is higher, and charging or discharging is performed with the output determined based on the deviation between the system frequency measured at the connection end to the power system and the reference frequency of the power system and the corrected output characteristics.

Effects of the Invention

[0008] According to the present invention, the charge-discharge element side can sufficiently secure the frequency adjustment capacity calculated by the power system side.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8

[0010] With reference to the drawings, embodiments, variations thereof, and specific examples to which the embodiments or variations thereof are applied will be described. In the description of the drawings, the same reference numerals are given to the same parts and the description thereof is omitted.

[0011] (Power System) Referring to FIG. 1, the configuration of an electric vehicle equipped with a charge / discharge control device according to an embodiment and a power system to which the electric vehicle is connected will be described.

[0012] Electric vehicles EV1 to EV3 (an example of charge / discharge elements) are each equipped with a charge / discharge control device according to an embodiment and are electrically connected to a power grid 11 via a common electric wire 12. Other power consumption elements are also connected to the electric wire 12. The other power consumption elements and the electric vehicles EV1 to EV3 are elements that constitute a load group to which power is supplied from the power system 10.

[0013] The electric vehicles EV1 to EV3 can receive power (charge) from the power grid 11 and transmit power (discharge) to the power grid 11 via the electric wire 12. Each of the charge / discharge control devices autonomously controls the power (charge / discharge power) for charging and discharging of the electric vehicles EV1 to EV3 on which it is mounted. The number of electric vehicles (EV) connected to the electric wire 12 and autonomously controlling the charge / discharge power is not limited to the three shown in FIG. 1.

[0014] The electric wire 12 is connected to the power grid 11 via a current measurement device 15 and a transformer 14. The electric vehicles EV1 to EV3 receive power from the current measurement device 15 side and transmit power toward the current measurement device 15 side. As an example of the transformer 14, a pole transformer that changes the voltage applied to a high-voltage distribution line to a voltage used in a home, office, etc. can be mentioned.

[0015] The current measurement device 15 measures the current flowing through the electric wire 12, and based on the measured current and the voltage of the electric wire 12, calculates the current value (Pall_now) of the total charge / discharge power with which the electric vehicles EV1 to EV3 as a whole are charging or discharging via the electric wire 12. Further, the current measurement device 15 measures the system frequency (f) of the power system 10 based on the measured current. The system frequency (f) is the frequency of the current flowing through the electric wire 12.

[0016] In the power system 10, when the power supply and demand are balanced, the system frequency (f) becomes the reference frequency (fref). When the power supply and demand balance in the power system 10 is disrupted, the system frequency (f) fluctuates from the reference frequency (fref). For example, when the power demand in the power system 10 is less than the supply, the system frequency (f) rises above the reference frequency (fref). When the power demand in the power system 10 exceeds the supply, the system frequency (f) drops below the reference frequency (fref).

[0017] The power system 10 is a power system that can control and optimize the power flow from both the supply side and the demand side. The power system 10 is a concept that includes a smart grid, a smart community, and a microgrid or MEMS (Mansion Energy Management System) that manages the end - consumption part from an energy source to a limited range such as a business office or a factory through a communication network. The power system 10 includes the power grid 11, the electric wire 12, the transformer 14, and the current measurement device 15 shown in FIG. 1. The power grid 11 includes various power plants such as thermal power plants, nuclear power plants, and hydroelectric power plants, and substations that transform the voltage from hundreds of thousands of volts (V) to thousands of volts.

[0018] In an embodiment, the power system 10 further includes an information transmission device 16. The information transmission device 16 is a computer or a server that controls and optimizes the power flow from both the supply side and the demand side, and is connected to the current measurement device 15 via a computer network. Alternatively, various power information may be acquired from the current measurement device 15 via the power grid 11.

[0019] The information transmission device 16 includes a calculation unit 17 that generates a signal for requesting charging or discharging to the entire electric vehicles EV1 to EV3 based on various power information supplied from the power system 10, and a broadcast transmission unit 18a and a broadcast transmission device 18b that broadcast - transmit the signal generated by the calculation unit 17 to the electric vehicles EV1 to EV3.

[0020] When the system frequency (f) input from the current measurement device 15 varies from the reference frequency (fref), the calculation unit 17 generates a signal that requests charging or discharging for the entire electric vehicles EV1 to EV3. What is requested for the entire electric vehicles EV1 to EV3 by the generated signal is charging or discharging to return the system frequency (f) to the reference frequency (fref).

[0021] The signal generated by the calculation unit 17 includes a request for charging or discharging for the entire electric vehicles EV1 to EV3, that is, a "system request". The system request is, for example, the differential power (ΔP) obtained by subtracting the current value of the total charge-discharge power (Pall_now) from the maximum value of the total charge-discharge power (Pall_max).

[0022] The maximum value of the total charge-discharge power (Pall_max) is the maximum value of the amount of electric power that the entire electric vehicles EV1 to EV3 can charge or discharge via the electric wire 12. The current value of the total charge-discharge power (Pall_now) is the current value of the amount of electric power that the entire electric vehicles EV1 to EV3 are charging or discharging via the electric wire 12. The differential power (ΔP) obtained by subtracting the current value of the total charge-discharge power (Pall_now) from the maximum value of the total charge-discharge power (Pall_max) becomes the required value (Pfr) of the frequency adjustment capacity for balancing the power supply and demand of the electric power system 10 by making the system frequency (f) coincide with the reference frequency (fref).

[0023] The information transmission device 16 receives the system frequency (f) of the electric power system 10 measured by the current measurement device 15 via a computer network or the power grid 11. The information transmission device 16 includes a storage device that stores data indicating the basic output characteristics of the total charge-discharge power (Pall) with respect to the system frequency (f) of the electric power system 10. The calculation unit 17 calculates the maximum value (Pall_max) of the total charge-discharge power using the system frequency (f) received from the current measurement device 15 and the data of the basic output characteristics read from the storage device.

[0024] As shown in equation (1), the calculation unit 17 calculates the differential power (ΔP) by subtracting the current value (Pall_now) of the total charge-discharge power from the maximum value (Pall_max) of the total charge-discharge power. In a situation where the power grid 10 requests charging from the electric vehicles EV1 to EV3, the calculation unit 17 calculates the differential power for charging. The differential power for charging is calculated by subtracting the current value of the total charging power being transmitted to the electric vehicles EV1 to EV3 via the wire 12 from the maximum value of the total charging power that the wire 12 can transmit to the electric vehicles EV1 to EV3 as a whole.

[0025] On the other hand, in a situation where the power grid 10 requests discharging from the electric vehicles EV1 to EV3, the calculation unit 17 calculates the differential power (ΔP) for discharging. The differential power for discharging is calculated by subtracting the current value of the total discharging power being received from the electric vehicles EV1 to EV3 via the wire 12 from the maximum value of the total discharging power that the wire 12 can receive from the electric vehicles EV1 to EV3 as a whole. The differential power (ΔP) is a positive value of 0 or more and is a concept that includes the differential power for charging and the differential power for discharging.

[0026] Note that the situation where the power grid 10 requests charging or discharging from the electric vehicles EV1 to EV3 changes according to the power supply-demand balance in the power grid 10. The information transmission device 16 includes a storage device that stores in advance data indicating the maximum value (Pall_max) of the total charge-discharge power, and the calculation unit 17 calculates the differential power (ΔP) using the data indicating the maximum value (Pall_max) of the total charge-discharge power read from the storage device. As a method for calculating the differential power (ΔP), the method disclosed in International Publication No. 2020 / 194010 can be used.

Equation

[0027] The broadcast transmission unit 18a uses the broadcast transmission device 18b to broadcast (send a broadcast) an electrical signal indicating the required value (Pfr) of the frequency adjustment capacity calculated by the calculation unit 17 as the differential power (ΔP) to all electric vehicles EV1 to EV3. Further, after the broadcast transmission of the required value (Pfr), the broadcast transmission unit 18a uses the broadcast transmission device 18b to broadcast (send a broadcast) an electrical signal indicating the excess or deficiency capacity (ΔPfr) of the frequency adjustment capacity to all electric vehicles EV1 to EV3.

[0028] The excess or deficiency capacity (ΔPfr) of the frequency adjustment capacity is the difference between the theoretical value and the actual value of the charge / discharge output by all electric vehicles EV1 to EV3. The theoretical value of the charge / discharge output by all electric vehicles EV1 to EV3 can be calculated by the calculation unit 17 from the deviation (Δf) of the system frequency (f) (actual measurement value) of the electric wire 12 to which all electric vehicles EV1 to EV3 are connected with respect to the reference frequency (fref), measured by the current measurement device 15 after the broadcast transmission of the required value (Pfr), and the data of the basic output characteristics read from the storage device of the information transmission device 16. The actual value of the charge / discharge output by all electric vehicles EV1 to EV3 can be set as the current value (Pall_now) of the total charge / discharge power by all electric vehicles EV1 to EV3, calculated by the current measurement device 15 after the broadcast transmission of the required value (Pfr).

[0029] As a method of broadcast transmission, a wireless LAN (Local Area Network) such as Wi-Fi (registered trademark) or Bluetooth (registered trademark) can be used.

[0030] In an embodiment, "electric vehicles EV1 to EV3" are an example of a "charge / discharge element" that charges and discharges electric power via an electric wire 12. The charge / discharge element stores the received electric power in a battery (including a secondary battery, a storage battery, and a rechargeable battery). The "charge / discharge element" includes all devices and apparatuses equipped with a battery, such as vehicles (including electric vehicles, hybrid vehicles, construction machines, and agricultural machines), railway vehicles, playground equipment, tools, household products, and daily necessities. In an embodiment, as an example of the charge / discharge element, an electric vehicle (EV) that uses electricity as an energy source and a motor as a power source to run is mentioned. However, it is not intended to limit the charge / discharge element in the present invention to an electric vehicle (EV).

[0031] The "charge / discharge element" indicates a unit configuration of charge / discharge control by a charge / discharge control device according to an embodiment. That is, the charge / discharge control according to the embodiment is performed in units of charge / discharge elements. For example, for each of a plurality of electric vehicles EV1 to EV3, charge / discharge control is performed independently and in parallel with each other.

[0032] (Electric vehicle) Referring to FIG. 2, the configuration of a charge / discharge control device 23 and its peripheral devices mounted on each of electric vehicles EV1 to EV3,... connected to the electric wire 12 will be described. Hereinafter, among electric vehicles EV1 to EV3,..., electric vehicle EV1 will be taken as an example for explanation, but other electric vehicles EV2, EV3,... also have the same configuration and can operate in the same manner.

[0033] On electric vehicle EV1, as peripheral devices of the charge / discharge control device 23, a receiving device 21 (receiving unit), a vehicle state acquisition device 22, a charge / discharge device 24, a motor 26, and a battery 25 are mounted.

[0034] The receiving device 21 is a device that receives an electrical signal (radio signal) synchronously transmitted from the synchronous transmission device 18b. The electrical signal received by the receiving device 21 includes a signal that requests charging or discharging for the entire electric vehicles EV1 to EV3. This signal includes a signal indicating a required value (Pfr) of the frequency adjustment capacity of the power system 10 and a signal indicating an excess or deficiency capacity (ΔPfr) of the frequency adjustment capacity, as an example of a system requirement.

[0035] The vehicle state acquisition device 22 acquires information representing the state of the electric vehicle EV1. For example, the "state of the electric vehicle EV1" includes the current value (SOCnow) of the charge rate of the battery 25 provided in the electric vehicle EV1 and a numerical value representing the request of the user of the electric vehicle EV1. The numerical value representing the request of the user of the electric vehicle EV1 is, for example, the target value (SOCgoal) of the charge rate of the battery 25 and the time (end time Td of charging and discharging) when the charging and discharging of the electric vehicle EV1 ends. The remaining time (T) until the end time Td is the remaining time during which the electric vehicle EV1 can perform charging and discharging.

[0036] The charging and discharging device 24 is an on-board charger (OBC), and under the control of the charging and discharging control device 23, it executes the charging and discharging of the battery 25 via the electric wire 12. The charging and discharging device 24 stores the received power in the battery 25. Alternatively, the charging and discharging device 24 may directly transmit the received power to the motor 26 as a drive source without storing it in the battery 25. On the other hand, the charging and discharging device 24 discharges the power stored in the battery 25 or the power generated by the motor 26 to the power grid 11 via the electric wire 12.

[0037] The charging and discharging device 24 is provided with an ammeter 24a. The ammeter 24a measures the current flowing through the electric wire 12 at the position on the electric wire 12 to which the electric vehicle EV1 is connected. The position on the electric wire 12 to which the electric vehicle EV1 is connected is called the "power receiving end" of the electric vehicle EV1. The charging and discharging device 24 can measure the system frequency (f) of the power system 10 at the power receiving end of the electric vehicle EV1.

[0038] The battery 25 includes a secondary battery, a storage battery, and a rechargeable battery that store the power received by the power charging / discharging device 24. The motor 26 is a drive source of the electric vehicle EV1 that is driven based on the electrical energy or power stored in the battery 25.

[0039] The charge / discharge control device 23 can be realized by using a microcomputer including a CPU (Central Processing Unit), a memory, and an input / output unit. A computer program for causing the microcomputer to function as the charge / discharge control device 23 is installed and executed in the microcomputer. Thereby, the microcomputer can function as a plurality of information processing units (31 to 38) included in the charge / discharge control device 23. Here, an example of realizing the charge / discharge control device by software is shown. Of course, it is also possible to prepare dedicated hardware for executing each information process and configure the charge / discharge control device 23. The dedicated hardware includes devices such as an application-specific integrated circuit (ASIC) arranged to execute the functions described in the embodiment and conventional circuit components.

[0040] Although the charge / discharge control device 23, the reception device 21, the vehicle state acquisition device 22, and the charge / discharge device 24 have been described as different members, of course, two or more arbitrarily selected devices may be configured as one device. Alternatively, the plurality of information processing units (31 to 38) may be divided and configured using two or more different devices. Further, all or part of the plurality of information processing units (31 to 38) may be configured using other ECUs (Electronic Control Units) mounted on the electric vehicle EV1.

[0041] For the processes related to the charge / discharge control of the electric vehicle EV1 other than the processes related to the correction of the following priority (β), the processes performed by the power reception control device disclosed in International Publication No. 2020 / 194010 can be applied to the charge / discharge control device 23.

[0042] The charge / discharge control device 23 includes, as a plurality of information processing units (31 to 38), a charge / discharge request acquisition unit 31, a current information acquisition unit 32, a system frequency measurement unit 33, a priority calculation unit 34, a characteristic determination unit 35, a characteristic correction unit 36, a charge / discharge power determination unit 37, and a charge / discharge control unit 38.

[0043] The charge / discharge request acquisition unit 31 acquires information indicating a required value (Pfr) of the frequency adjustment capacity of the power system 10 as an example of the system request and information indicating the excess / deficiency capacity (ΔPfr) of the frequency adjustment capacity from the electrical signal received by the receiving device 21.

[0044] The current information acquisition unit 32 acquires the current value of the electric wire 12 measured by the ammeter 24a of the charge / discharge device 24 at the connection end of the electric vehicle EV1 to the electric wire 12.

[0045] The system frequency measurement unit 33 measures the system frequency (f) of the electric wire 12 using the current value of the electric wire 12 acquired by the current information acquisition unit 32.

[0046] The priority calculation unit 34 calculates the priority (β) of the electric vehicle EV1 indicating the degree to which the charge / discharge of its own EV1 is prioritized over the charge / discharge of other electric vehicles (EV2, EV3,...) based on a numerical value representing the request of the user of the electric vehicle EV1 (the state of the electric vehicle EV1). This priority (β) can be set for each of the charging side and the discharging side.

[0047] The priority calculation unit 34 calculates the priority (β) of the electric vehicle EV1, which indicates the degree to which the charging or discharging of the self-EV1 is prioritized over the charging or discharging of other electric vehicles (EV2, EV3, ···), based on the numerical value representing the request of the user of the electric vehicle EV1 and the state of the electric vehicle EV1. Specifically, the priority calculation unit 34 calculates the priority (β) from the remaining time (T) from the current time (To) to the end time (Td) of charging and discharging using Equation (2). In Equation (2), N represents the total number of electric vehicles performing charging and discharging. As a method for calculating the priority (β) using the current value of the state of charge (SOCnow) and the target value of the state of charge (SOCgoal), the method disclosed in International Publication No. 2020 / 194010 can be used. [Number]

[0048] Based on the priority (β) calculated by the priority calculation unit 34 and the frequency adjustment capacity (Pfr) received by the receiving device 21, the characteristic determination unit 35 determines the charging and discharging output characteristics of the electric vehicle EV1 with respect to the system frequency (f). This output characteristic defines the charging and discharging output of the electric vehicle EV1 at each frequency within the adjustment range of the system frequency (f) centered on the reference frequency (fref). For example, when the reference frequency (fref) is 50 Hz, the adjustment range of the system frequency (f) can be set to ±0.2 Hz.

[0049] The characteristic determination unit 35 sets the value obtained by dividing the frequency adjustment capacity (Pfr) by the total number (N) of electric vehicles as the output range of the system frequency (f) in the reference characteristics of the charging and discharging of the electric vehicle EV1. The output range of the charging and discharging of the electric vehicle EV1 within the adjustment range of the system frequency (f) becomes the element frequency adjustment capacity (Pfr / N) obtained on the electric wire 12 due to the charging and discharging of the electric vehicle EV1. The reference characteristics of charging and discharging are, for example, linear characteristics with an output of zero at the reference frequency (fref), as shown by the solid line in FIG. 3. In the reference characteristics, the output upper limit value on the charging side is defined at the highest frequency within the adjustment range of the system frequency (f), and the output upper limit value on the discharging side is defined at the lowest frequency within the adjustment range.

[0050] The total number (N) of electric vehicles may be statistical data (quantity data) obtained by investigating the past charge and discharge history in the load group of the power system 10 including the electric vehicles connected to the electric wire 12, or it is also possible to estimate the approximate total number (N) of electric vehicles from the current value (Pall_now) of the total charge and discharge power. The total number (N) is transmitted in the same way as the differential power (ΔP) from the information transmission device 16 or a device associated with the information transmission device 16. Alternatively, the total number (N) may be specified by the position information, identification signal, etc. of the charging system of the electric vehicle.

[0051] The characteristic determination unit 35 corrects the reference characteristics of charge and discharge according to the priority (β) of the electric vehicle EV1 to determine the output characteristics of charge and discharge of the electric vehicle EV1. For example, when the priority calculation unit 34 calculates the priority on the charging side and the priority on the discharging side respectively, the characteristic determination unit 35 corrects the output upper limit value on the charging side according to the priority on the charging side, and corrects the output upper limit value on the discharging side according to the priority on the discharging side.

[0052] In FIG. 3, the output characteristics obtained by correcting the reference characteristics according to the priority (β) of the electric vehicle EV1 are respectively shown by broken lines. The broken line with the shortest pitch shows the output characteristics after correction when the priority on the charging side is 0.5 and the priority on the discharging side is 1. The broken line with the longest pitch shows the output characteristics after correction when the priority on the charging side is 1 and the priority on the discharging side is 0.5. The broken line with an intermediate length pitch shows the output characteristics after correction when both the priority on the charging side and the priority on the discharging side are 0.5.

[0053] When the reference characteristics are corrected according to the priority (β), the output range of charge and discharge of the electric vehicle EV1 in the adjustment range of the system frequency (f) becomes narrower than before. That is, by correcting the reference characteristics according to the priority (β) of the electric vehicle EV1, the element frequency adjustment capacity obtained on the electric wire 12 by the charge and discharge of the electric vehicle EV1 decreases compared with before.

[0054] In FIG. 4, the frequency adjustment capacity obtained by summing the element frequency adjustment capacities obtained from each electric vehicle EV1 to EV3, ··· that has performed charge and discharge with the reference characteristics is shown by the ideal output profile of the broken line. Also, the sum of the element frequency adjustment capacities when each electric vehicle EV1 to EV3, ··· performs charge and discharge with the output characteristics corresponding to their respective priorities (β) is shown by the actual output profile of the solid line.

[0055] The maximum value of the ideal output profile is the value obtained by summing the charge and discharge output ranges of each electric vehicle EV1 to EV3, ··· in the reference characteristics. This sum value becomes the required value (Pfr) of the frequency adjustment capacity.

[0056] The maximum value of the actual output profile is the value obtained by summing the charge and discharge output ranges of each electric vehicle EV1 to EV3, ··· in the output characteristics determined by the characteristic determination unit 35. Since the output range of the output characteristics determined by the characteristic determination unit 35 is narrower than the output range of the reference characteristics, the actual output profile cannot obtain the frequency adjustment capacity as required (Pfr).

[0057] When the priority (β) calculated by the priority calculation unit 34 is high, for example, when it is above a certain height, the characteristic correction unit 36 corrects the charge and discharge output characteristics of the electric vehicle EV1 determined by the characteristic determination unit 35 according to the excess or deficiency capacity (ΔPfr) of the received frequency adjustment capacity when the receiving device 21 receives the excess or deficiency capacity (ΔPfr) of the frequency adjustment capacity.

[0058] As shown in FIG. 5, the characteristic correction unit 36 corrects the charge and discharge output characteristics of the electric vehicle EV1 so that, for example, when the excess or deficiency capacity (ΔPfr) is large on the charging side, the output upper limit value on the charging side is increased, and when the excess or deficiency capacity (ΔPfr) is large on the discharging side, the output upper limit value on the discharging side is increased. In the corrected output characteristics, the output upper limit value on the charging side or the output upper limit value on the discharging side approaches the respective output upper limit values in the reference characteristics compared to the output characteristics before correction. Therefore, the output range expands compared to before correction and approaches the output range of the reference characteristics.

[0059] The charge / discharge power determination unit 37 calculates a deviation (Δf) of the system frequency (f) of the electric wire 12 measured by the system frequency measurement unit 33 from a reference frequency (fref) using the current value of the electric wire 12 measured by the ammeter 24a. The charge / discharge power determination unit 37 determines the element charge / discharge output of the electric vehicle EV1 from the deviation (Δf) and the charge / discharge output characteristics determined by the characteristic determination unit 35.

[0060] The charge / discharge control unit 38 controls the charge / discharge device 24 so that the electric vehicle EV1 charges or discharges with the element charge / discharge output determined by the charge / discharge power determination unit 37. In this way, the charge / discharge control device 23 controls the charge / discharge power (P), which is the power for the electric vehicle EV1 to charge / discharge, by repeating the following processing cycles (a) to (h). (a) Obtain information indicating the differential power (ΔP = required value Pfr of the frequency adjustment capacity), (b) Calculate the priority (β), (c) Determine the charge / discharge output characteristics according to the priority (β) from the required value (Pfr) of the frequency adjustment capacity, (d) Determine the element charge / discharge output based on the charge / discharge output characteristics according to the priority (β) from the deviation (Δf) between the system frequency (f) measured at the connection end and the reference frequency (fref), (e) Control the charge / discharge device 24 to charge / discharge with the determined element charge / discharge output, (f) Receive information indicating the excess / deficiency capacity (ΔPfr), which is the difference between the theoretical value and the actual value of the total charge / discharge output, (g) Correct the charge / discharge output characteristics according to the priority (β) from the received excess / deficiency capacity (ΔPfr), and (h) Control the charge / discharge device 24 to charge / discharge with the element charge / discharge output determined based on the corrected charge / discharge output characteristics.

[0061] With reference to the flowchart of FIG. 6A, an example of the main processing operations performed by the information transmission device 16 of FIG. 1 will be described.

[0062] First, in step S101, the information transmission device 16 determines the frequency adjustment capacity (Pfr) required for all electric vehicles EV1 to EV3, ···, and broadcasts it to all electric vehicles EV1 to EV3, ···.

[0063] Proceed to step S102. After the broadcast of the requested value (Pfr), the current measurement device 15 measures the system frequency (f) of the wire 12 to which all electric vehicles EV1 to EV3, ··· are connected, and the calculation unit 17 calculates the deviation (Δf) of the measured system frequency (f) from the reference frequency (fref).

[0064] Proceed to step S103. Based on the deviation (Δf) calculated by the current measurement device 15 and the data of the basic output characteristics read from the storage device of the information transmission device 16, the calculation unit 17 calculates the theoretical value of the charge / discharge output assumed for all electric vehicles EV1 to EV3, ··· after the broadcast of the requested value (Pfr).

[0065] Proceed to step S104. After the broadcast of the requested value (Pfr), the current measurement device 15 calculates the current value (Pall_now) of the total charge / discharge power by all electric vehicles EV1 to EV3, ··· as the actual value of the charge / discharge output by all electric vehicles EV1 to EV3, ···. Then, the information transmission device 16 broadcasts the difference between the theoretical value of the charge / discharge output calculated by the calculation unit 17 in step S103 to all electric vehicles EV1 to EV3, ··· as the excess / deficiency capacity (ΔPfr) of the frequency adjustment capacity.

[0066] With reference to the flowchart of FIG. 6B, an example of the charge / discharge control method by the charge / discharge control device 23 in FIG. 2 will be described. This charge / discharge control method is executed by the charge / discharge control devices 23 of each electric vehicle EV1 to EV3, ···. Those skilled in the art can easily understand the specific procedure of the charge / discharge control method by the charge / discharge control device 23 from the description of the specific configuration and functions of the charge / discharge control device 23 in FIG. 2. Therefore, here, as the charge / discharge control method by the charge / discharge control device 23 in FIG. 2, the main processing operations of the charge / discharge control device 23 will be described, and the description of the detailed processing operations is omitted because it overlaps with the description with reference to FIG. 2.

[0067] First, in step S201, the priority calculation unit 34 calculates the charging / discharging priority (β) from the current value of the battery charge rate (SOCnow) acquired by the vehicle state acquisition device 22, the scheduled departure time, and the like.

[0068] Proceeding to step S202, the characteristic determination unit 35 determines the charging / discharging output characteristics of the electric vehicle EV1 with respect to the system frequency (f) based on the priority (β) calculated by the priority calculation unit 34 in step S201 and the frequency adjustment capacity (Pfr) received by the receiving device 21. The frequency adjustment capacity (Pfr) received by the receiving device 21 is the one broadcasted by the information transmitting device 16 in step S101 of FIG. 6A.

[0069] Proceeding to step S203, the charging / discharging power determination unit 37 calculates the deviation (Δf) of the system frequency (f) of the electric wire 12 measured by the system frequency measurement unit 33 with respect to the reference frequency (fref) using the current value of the electric wire 12 measured by the ammeter 24a.

[0070] Proceeding to step S204, the charging / discharging power determination unit 37 determines the element charging / discharging output of the electric vehicle EV1 from the deviation (Δf) calculated in step S203 and the charging / discharging output characteristics determined in step S202.

[0071] Proceeding to step S205, the characteristic correction unit 36 corrects the charging / discharging output characteristics of the electric vehicle EV1 determined by the characteristic determination unit 35 in step S202 so that the excess / deficiency capacity (ΔPfr) of the frequency adjustment capacity received by the receiving device 21 becomes smaller. The excess / deficiency capacity (ΔPfr) of the frequency adjustment capacity received by the receiving device 21 is the one broadcasted by the information transmitting device 16 in step S104 of FIG. 6A.

[0072] According to the embodiment of the present invention, the following operational effects can be obtained.

[0073] When the information transmission device 16 of the power system 10 broadcasts and transmits a required value (Pfr) of the frequency adjustment capacity according to the deviation (Δf) of the system frequency (f) with respect to the reference frequency (fref), in each electric vehicle EV1 to EV3, ···, the charge / discharge output characteristics are respectively determined corresponding to the required value (Pfr). Each electric vehicle EV1 to EV3, ··· corrects the determined charge / discharge output characteristics according to their respective priorities (β). When the output range of the corrected charge / discharge output characteristics becomes narrower than before correction, the frequency adjustment capacity obtained by summing up the charge / discharge outputs of each electric vehicle EV1 to EV3, ··· will not reach the required value (Pfr) of the frequency adjustment capacity.

[0074] Since the information transmission device 16 only has a unidirectional communication function for each electric vehicle EV1 to EV3, ···, on the power system 10 side, it is impossible to know the corrected charge / discharge output characteristics of each electric vehicle EV1 to EV3, ··· corrected by the priority (β).

[0075] In this embodiment, in the charge / discharge output of each electric vehicle EV1 to EV3, ···, on the power system 10 side, the calculation unit 17 calculates the assumed theoretical value for the charge / discharge output assumed for all electric vehicles EV1 to EV3, ···, and the ammeter 15 calculates the actual value. Then, the information transmission device 16 broadcasts and transmits the difference between the actual value and the theoretical value as the excess / deficiency capacity (ΔPfr) of the frequency adjustment capacity to all electric vehicles EV1 to EV3, ···.

[0076] In each electric vehicle EV1 to EV3, ···, the charge / discharge control device 23 receives the excess / deficiency capacity (ΔPfr) of the frequency adjustment capacity broadcast and transmitted, and corrects the charge / discharge output characteristics of the electric vehicle EV1 determined by the characteristic determination unit 35 so that the excess / deficiency capacity (ΔPfr) becomes smaller. In the example shown in FIG. 5, for the side with the larger excess / deficiency capacity (ΔPfr) among the charging side and the discharging side, the charge / discharge output characteristics are corrected so that the excess / deficiency capacity (ΔPfr) becomes smaller.

[0077] As the excess / deficit power capacity (ΔPfr) decreases and approaches zero, the actual values of the charge / discharge output by all-electric vehicles EV1 to EV3, ··· approach the theoretical values, and the system frequency (f) approaches the reference frequency (fref). Therefore, according to the magnitude relationship between the actual value and the theoretical value indicated by the sign of the excess / deficit power capacity (ΔPfr), by correcting the output characteristics of the charge / discharge output and increasing or decreasing the actual value, the frequency regulation capacity obtained by summing the charge / discharge outputs of each all-electric vehicle EV1 to EV3, ··· can be made to approach the required value (Pfr) of the frequency regulation capacity. As a result, the frequency regulation capacity calculated by the power grid 10 side can be sufficiently ensured by the control performed on the side of each all-electric vehicle EV1 to EV3, ···.

[0078] (First Modified Example) In the above embodiment, when the receiving device 21 receives the excess / deficit power capacity (ΔPfr) of the frequency regulation capacity, the characteristic correction unit 36 corrects the charge / discharge output characteristics of the all-electric vehicle EV1 determined by the characteristic determination unit 35 according to the received excess / deficit power capacity (ΔPfr) of the frequency regulation capacity. Instead, the characteristic correction unit 36 may calculate the rate of change over time ((ΔPfrt + 1 - ΔPfrt) / Δt) per unit time (Δt) of the excess / deficit power capacity (ΔPfr) received by the receiving device 21. In that case, the characteristic correction unit 36 Rate of change over time can correct the charge / discharge output characteristics of the all-electric vehicle EV1 determined by the characteristic determination unit 35 according to ((ΔPfrt + 1 - ΔPfrt) / Δt).

[0079] The rate of change over time ((ΔPfrt + 1 - ΔPfrt) / Δt) of the excess / deficit power capacity (ΔPfr) becomes a positive (+) value when the excess / deficit power capacity (ΔPfr) increases over time, and becomes a negative (-) value when the excess / deficit power capacity (ΔPfr) decreases.

[0080] When the sign of the rate of change over time ((ΔPfrt+1 - ΔPfrt) / Δt) is positive, in order to change the increase in the rate of change over time ((ΔPfrt+1 - ΔPfrt) / Δt) with the passage of time to a decrease, the value of the frequency adjustment capacity (Pfr), which is too large as it is, is decreased. When the sign of the rate of change over time ((ΔPfrt+1 - ΔPfrt) / Δt) is negative, in order to accelerate the decrease in the rate of change over time ((ΔPfrt+1 - ΔPfrt) / Δt) with the passage of time, the value of the frequency adjustment capacity (Pfr) is increased compared to the current value. Thereby, the followability of the actual value with respect to the required value of the frequency adjustment capacity (Pfr) can be improved.

[0081] (Second Modified Example) Further, the characteristic correction unit 36 may calculate the rate of change of the excess / deficiency capacity (ΔPfr) received by the receiving device 21 due to the deviation (Δf) between the system frequency (f) and the reference frequency (fref) as the frequency deviation rate of change ((ΔPfrf+1 - ΔPfrf) / Δf). In that case, the characteristic correction unit 36 can correct the charge / discharge output characteristics of the electric vehicle EV1 determined by the characteristic determination unit 35 according to the frequency deviation rate of change ((ΔPfrf+1 - ΔPfrf) / Δf).

[0082] When the excess / deficiency capacity (ΔPfr) increases due to an increase in the deviation (Δf) between the system frequency (f) and the reference frequency (fref), the frequency deviation rate of change ((ΔPfrf+1 - ΔPfrf) / Δf) becomes a positive (+) value indicating that the system frequency is higher than the reference frequency. When the excess / deficiency capacity (ΔPfr) decreases due to an increase in the deviation (Δf) between the system frequency (f) and the reference frequency (fref), the frequency deviation rate of change ((ΔPfrf+1 - ΔPfrf) / Δf) becomes a negative (-) value indicating that the system frequency is lower than the reference frequency.

[0083] When the sign of the frequency deviation rate of change ((ΔPfrf+1 - ΔPfrf) / Δf) is positive, in order to bring the system frequency ( f ) closer to a reference frequency (fref) that is lower than it, the value of the frequency adjustment capacity (Pfr), which is too large as it is, is decreased. When the sign of the frequency deviation rate of change ((ΔPfrf+1 - ΔPfrf) / Δf) is negative, the system frequency (f ) To make it closer to a higher reference frequency (fref), increase the value of the frequency adjustment capacitance (Pfr) which is currently too small as it is. By doing this, the rapidity when returning the fluctuating system frequency (f) to the reference frequency (fref) can be improved.

[0084] (Third Modification Example) In the above embodiments and the first and second modification examples, the information transmission device 16 broadcasted the required value of the frequency adjustment capacitance (Pfr) to all the electric vehicles EV1 to EV3 as being for the total charge-discharge power with respect to the entire electric vehicles EV1 to EV3. However, the information transmission device 16 may broadcast the required value of the frequency adjustment capacitance (Pfr) separately as being for the total charge power and for the total discharge power with respect to the entire electric vehicles EV1 to EV3 to all the electric vehicles EV1 to EV3. In that case, the receiving device 21 of the charge-discharge control device 23 separately receives the required value of the frequency adjustment capacitance on the charging side and the required value of the frequency adjustment capacitance on the discharging side respectively.

[0085] When the required value of the frequency adjustment capacitance (Pfr) is distributed separately as the required value on the charging side and the required value on the discharging side, the charge-discharge control device 23 can individually determine the output characteristics on the charging side and the output characteristics on the discharging side of each electric vehicle EV1 to EV3, ···. For this reason, the correction of the output characteristics according to the priority (β) can be separately and individually performed on the charging side and the discharging side, and it can be made easier to perform the correction process of the output characteristics.

[0086] (Fourth Modification Example) In the above embodiments and the first to third modification examples, as shown in FIG. 5, the upper limit value of the output range in the output characteristics on the charging side and the discharging side was corrected to be increased to an even higher value according to the priority (β) of each electric vehicle EV1, EV2, EV3, ···. However, when performing the correction according to the priority (β), instead of increasing the upper limit value of the output range in the output characteristics on the charging side and the discharging side, the lower limit value may be increased.

[0087] For example, in the case of the output characteristics on the charging side shown in FIG. 7A, the amount of decrease of the lower limit value with respect to the upper limit value of the output range existing only on the charging side is made smaller as the priority (β) is higher, and larger as the priority (β) is lower. Also, when the characteristic correction unit 36 corrects the charge and discharge output characteristics of the electric vehicle EV1 determined by the characteristic determination unit 35 according to the excess / deficiency capacity (ΔPfr) of the frequency adjustment capacitance received by the receiving device 21, the amount of reduction of the amount of decrease of the lower limit value with respect to the upper limit value of the output range on the charging side is made larger as the excess / deficiency capacity (ΔPfr) is larger, and smaller as the excess / deficiency capacity (ΔPfr) is smaller.

[0088] Even in this case, electric vehicles EV1, EV2, EV3, ··· with a high priority (β) can be charged with high power regardless of the high or low system frequency (f).

[0089] (Fifth Modification Example) In the fourth modification example, the slope of the output characteristics on the charging side becomes larger for electric vehicles EV1, EV2, EV3, ··· with a lower priority (β). Also, the upper limit value of the output range on the charging side becomes lower for electric vehicles EV1, EV2, EV3, ··· with a lower priority (β). For this reason, the lower limit value of the output characteristics on the charging side may become lower than the base power (Pbase) constantly supplied from the battery 25 to the dark current load as the priority (β) is lower.

[0090] When electric vehicles EV1 to EV3, ··· are charge control elements whose output range of output characteristics exists only on the charging side, if the lower limit value of the charging output is set to a value lower than the base power (Pbase) constantly supplied from the battery 25 to the dark current load, the charging output interrupts the base power Pbase on the lowest frequency side in the adjustment range of the system frequency (f). In this state, it is not possible to charge the battery 25 to obtain the element frequency adjustment capacitance (Pfr / N).

[0091] Therefore, when the lower limit value of the output characteristics of the charging side with a low priority (β) is set to a value lower than the base power (Pbase), as shown in FIG. 7B, the characteristic determination unit 35 may determine the output characteristics with the lower limit value set to a value equal to or higher than the base power (Pbase). In that case, in order to compensate for the insufficient charging-side element frequency adjustment capacity (Pfr / N) by setting the lower limit value of the output characteristics of the charging side with a low priority (β) to a value equal to or higher than the base power (Pbase), the characteristic determination unit 35 may determine the output characteristics of the charging side with a high or medium priority.

[0092] FIG. 8 is a graph schematically showing a state in which the output characteristics corresponding to the system frequency (f) having a value equal to or lower than the base power (Pbase) of electric vehicles EV1, EV2, EV3,... with low priority (β) whose output characteristics are set only on the charging side, determined by the characteristic determination unit 35, are supplemented by the charge-discharge output characteristics of other electric vehicles EV1, EV2, EV3,... set across the charging side and the discharging side.

[0093] Thereby, the continuity of the frequency adjustment capacity with respect to the deviation (Δf) between the system frequency (f) and the reference frequency (fref) can be ensured.

[0094] Note that the above-described embodiment is an example of the present invention. Therefore, the present invention is not limited to the above-described embodiment, and various modifications can be made according to the design and the like without departing from the technical idea of the present invention even in forms other than this embodiment.

Explanation of Reference Numerals

[0095] 10 Power grid 12 Electric wire 21 Receiver 34 Priority calculation unit 35 Characteristic determination unit 36 Characteristic correction unit 38 Charge-discharge control unit EV1, EV2, EV3,... Electric vehicle

Claims

1. receiving a required value of a frequency adjustment capacity corresponding to a system frequency of the power system, which is broadcast to a plurality of charge / discharge elements connected to an electric wire of the power system; determining an output characteristic indicating a charge / discharge output of the own charge / discharge element with respect to the system frequency based on a priority indicating a degree of priority of charging or discharging of the own charge / discharge element over charging or discharging of other charge / discharge elements among the plurality of charge / discharge elements and the received required value; correcting the output characteristic so as to increase an upper limit value or a lower limit value of an output range in the output characteristic as the priority is higher; performing charging or discharging of the own charge / discharge element with an output determined based on a deviation between the system frequency measured at a connection end to the power system and a reference frequency of the power system and the corrected output characteristic; A method for controlling charge / discharge of a charge / discharge element.

2. Receiving, by broadcast to the plurality of charge / discharge elements, a difference between a theoretical value of a total charge / discharge output of the plurality of charge / discharge elements and an actual value of a total charge / discharge output of the plurality of charge / discharge elements measured in the power system, according to a deviation between an actual measurement value of the system frequency and the reference frequency when the plurality of charge / discharge elements are each charging or discharging with the determined output characteristic; correcting the output characteristic such that the frequency adjustment capacity decreases when the received difference indicates that the actual value is higher than the theoretical value, and the frequency adjustment capacity increases when the received difference indicates that the actual value is lower than the theoretical value; The method for controlling charge / discharge of a charge / discharge element according to Claim 1.

3. Calculating a time change rate of the received difference, and correcting the output characteristic such that the frequency adjustment capacity decreases when the sign of the calculated time change rate is positive, and the frequency adjustment capacity increases when the sign of the time change rate is negative; The method for controlling charge / discharge of a charge / discharge element according to Claim 2.

4. Calculate a frequency deviation change rate, which is the change rate of the received difference due to the deviation between the measured value of the system frequency and the reference frequency. When the sign of the calculated frequency deviation change rate is positive, correct the output characteristics so that the frequency adjustment capacity decreases; when the sign of the frequency deviation change rate is negative, correct the output characteristics so that the frequency adjustment capacity increases. The charge and discharge control method for a charge and discharge element according to claim 2.

5. Receive the requested values that are broadcast separately to the charging side and the discharging side, and based on the received requested values for the charging side and the discharging side, perform the determination and correction of the output characteristics separately for the charging side and the discharging side. Charge the self charge and discharge element with the output determined based on the output characteristics of the charging side after correction, and discharge the self charge and discharge element with the output determined based on the output characteristics of the discharging side after correction. The charge and discharge control method for a charge and discharge element according to any one of claims 1 to 4.

6. When the output range in the output characteristics of each of the plurality of charge and discharge elements exists only on the charging side, determine the output characteristics such that the lower limit value of each output range is a value equal to or greater than the base power constantly supplied to the dark current load of each of the plurality of charge and discharge elements, based on the priority and the received requested value. The charge and discharge control method for a charge and discharge element according to any one of claims 1 to 5.

7. A receiving unit that receives a requested value of a frequency adjustment capacity corresponding to the system frequency of the power system, which is broadcast to a plurality of charge and discharge elements connected to the electric wire of the power system; A priority calculation unit that calculates a priority indicating the degree to which the charging or discharging of the self charge and discharge element is prioritized over the charging or discharging of other charge and discharge elements among the plurality of charge and discharge elements; A characteristic determination unit that determines output characteristics indicating the charge and discharge output of the self charge and discharge element with respect to the system frequency, based on the priority and the requested value; A characteristic correction unit that corrects the output characteristics such that the upper limit value or the lower limit value of the output range in the output characteristics increases as the priority increases. Based on the deviation between the system frequency measured at the connection end with the electric wire and the reference frequency of the power system, and the output determined based on the corrected output characteristics, a control unit that controls the charging or discharging output of the self-charging / discharging element in the power system; A charging / discharging control device for a charging / discharging element comprising the above.

Images