JP2022122662A - Charging-discharging control method for charge-discharge element, and charging-discharging control apparatus for charge-discharge element - Google Patents

Abstract

To keep a charge-discharge element that is charging and a charge-discharge element that is discharging from being present together in a power system.SOLUTION: A charging-discharging control method for charge-discharge elements includes: receiving a surplus amount (ΔPall fmax) of maximum power amount of charge and discharge by a plurality of charge-discharge elements (EV1, EV2, EV3 ...) connected to an electric wire (12) of a power system (10) and a surplus amount (ΔPall freq) of a frequency adjustment capacity corresponding to a system frequency of the power system; determining output characteristics corresponding to a level of priority (β) of charge and discharge relative to a system frequency (f) of which a value of the system frequency (f) that defines a boundary between charging and discharging remains the same regardless of the level of priority (β), on the basis of the level of priority and two received surplus amounts (ΔPall fmax), (ΔPall freq), where the level of priority (β)represents the degree to which charging or discharging of a charge-discharge element itself (EV1) is given higher priority than the other charge-discharge elements (EV2, EV3, ...); and charging or discharging at an output calculated on the basis of the determined output characteristics.SELECTED DRAWING: Figure 8

Description

The present invention relates to a charge/discharge control method for charge/discharge elements and a charge/discharge control device for charge/discharge elements.

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

In the technique disclosed in Patent Document 1, the information that is simultaneously transmitted from the power system side to the received power amount control load is determined based on the frequency response characteristics of the received power amount controlled load. The frequency response characteristic of the received power amount controlled load is the response characteristic of the received power amount of the received power amount controlled load with respect to the fluctuation of the system frequency.

Patent Literature 1 also describes that the frequency response characteristic of the received power amount control load may be shifted in parallel so that the charge power at the reference frequency decreases during the time period when the power demand reaches its peak.

Japanese Patent No. 5598896

In Patent Literature 1, an electric vehicle is given as an example of an optimal power receiving amount control load. In an electric vehicle, the charging/discharging output characteristics of the battery may be set according to its own priority. The own priority indicates the degree to which charging and discharging of the battery of the vehicle is prioritized over charging and discharging of the batteries of other electric vehicles connected to the same power system.

In the technique of Patent Document 1, as described in relation to the parallel shift of the frequency response characteristic, the base capacity corresponding to the power consumption of the load on the power system is set separately from the frequency adjustment capacity set according to the fluctuation of the system frequency. is set according to power demand.

If the base power is set separately from the frequency adjustment capacity, the power consumption of the electric vehicle fluctuates according to the priority when the electric vehicle is used as the power reception amount control load. When the power consumption of the electric vehicle fluctuates, the base capacity fluctuates, and the boundary frequency between the charge output region and the discharge output region in the frequency response characteristics fluctuates. If the boundary frequency changes according to the priority of the electric vehicle, for example, when a plurality of electric vehicles with different priorities are connected to the power system, the electric vehicle whose battery is to be charged and the electric vehicle whose battery is to be discharged will be separated from the power system. mixed on top. This mixture is a factor that lowers the charging/discharging efficiency of the battery.

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent a charging/discharging element that charges and a charging/discharging state that discharges from being mixed in an electric power system.

In order to solve the above-described problems, in a charging/discharging control method for a charging/discharging element according to one aspect of the present invention, a plurality of charging/discharging elements connected to electric wires of an electric power system can be charged/discharged by the plurality of charging/discharging elements. The margin of the maximum power amount and the margin of the frequency adjustment capacity according to the system frequency of the power system are received. Based on the priority indicating the degree to which the own charging or discharging is prioritized over other charging/discharging elements and the two margins received, the value of the system frequency that is the boundary between charging and discharging depends on the priority. First, the same output characteristic is determined according to the priority of charging and discharging with respect to the system frequency, and charging or discharging is performed with the output calculated based on the output characteristic.

Advantageous Effects of Invention According to the present invention, it is possible to prevent a charging/discharging element that charges and a charging/discharging state that discharges from being mixed in an electric power system.

FIG. 1 is a diagram showing the configuration of a power system including charge/discharge elements to which a charge/discharge control method according to an embodiment of the present invention is applied. FIG. 2 is a block diagram showing the configuration of the charge/discharge control device for the electric vehicle of FIG. 1 and its peripheral devices. FIG. 3 is a graph showing charge/discharge output characteristics according to the priority of the electric vehicle determined by the characteristic determining unit of FIG. 2 . FIG. 4 is a graph showing charge/discharge output characteristics according to the priority of an electric vehicle according to a comparative example in which a frequency range in which electric vehicles that are charged and electric vehicles that are discharged are mixed occurs. FIG. 5 is a flowchart in which processing steps executed by the charge/discharge control device of FIG. 1 are arranged in time series. FIG. 6 is a graph showing that the higher the priority, the higher the discharge output in the discharge region, in the charge/discharge output characteristics according to the priority of the electric vehicle determined by the characteristic determining unit of FIG. FIG. 7 is a graph showing output characteristics of charging corrected by the characteristics correction unit of FIG. 2 . FIG. 8 shows the charging/discharging output characteristics according to the priority of the electric vehicle according to the comparative example, in which the output characteristics in which the charging output exceeds the maximum charging electric energy are shifted so that the charging output falls below the maximum charging electric energy. is a graph showing FIG. 9 shows the output characteristics determined by the characteristic determining unit in FIG. 10 is a graph showing output characteristics of charge/discharge according to the priority of the electric vehicle, which are made to be the same as the output characteristics of the priority of .

Embodiments, modifications thereof, and specific examples to which the embodiments or modifications are applied will be described with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals, and the description thereof is omitted.

(power system)
With reference to FIG. 1, a 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.

Electric vehicles EV1 to EV3 (an example of charging/discharging elements) are each equipped with the charging/discharging control device according to the embodiment, and are electrically connected to a power grid 11 via a common electric wire 12 . Other power consuming elements are also connected to the line 12 . Other power consuming elements and electric vehicles EV1 to EV3 are elements forming a load group to which power is supplied from power system .

The electric vehicles EV1 to EV3 can receive (charge) power from the power grid 11 and transmit (discharge) power to the power grid 11 via the electric wire 12 . Each of the charge/discharge control devices autonomously controls the electric power (charge/discharge power) charged/discharged by the electric vehicles EV1 to EV3 in which it is mounted. The number of electric vehicles (EV) that are connected to the electric wire 12 and that autonomously control charging/discharging power is not limited to the three shown in FIG.

The electric wire 12 is connected to the power grid 11 via the current measuring device 15 and the transformer 14 . The electric vehicles EV1 to EV3 receive power from the current measuring device 15 side and transmit power to the current measuring device 15 side. An example of the transformer 14 is a pole-mounted transformer (pole transformer) that changes the voltage applied to a high-voltage distribution line to the voltage used in homes, offices, and the like.

The current measuring device 15 measures the current flowing through the wire 12, and based on the measured current and the voltage of the wire 12, the total charge/discharge power charged or discharged by the entire electric vehicle EV1 to EV3 via the wire 12. The current value (Pall_now) of is calculated. Also, the current measuring 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 .

A power system 10 is a power system in which the flow of power can be controlled and optimized from both the supply side and the demand side. The power system 10 is a concept including a smart grid, a smart community, and a microgrid or MEMS (Mansion Energy Management System) that manages end consumption from energy supply sources in a limited range such as offices and factories with a communication network. is. The power system 10 includes the power network 11, the electric wire 12, the transformer 14, and the current measuring device 15 shown in FIG. The electric power network 11 includes various power plants such as thermal, nuclear, and hydraulic power plants, and substations for transforming voltage from hundreds of thousands of volts (V) to thousands of volts.

In an embodiment, power system 10 further includes information transmitter 16 . The information transmission device 16 is a computer or server that controls and optimizes 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 measuring device 15 via the power network 11 .

The information transmission device 16 includes a calculation unit 17 that generates a signal requesting charging or discharging of the entire electric vehicles EV1 to EV3 based on various types of power information supplied from the power system 10, and a signal generated by the calculation unit 17. to the electric vehicles EV1 to EV3.

The signal generated by the calculator 17 includes a charge or discharge request for the electric vehicles EV1 to EV3 as a whole, ie, a “system request”. The system requirement is, for example, the differential power (ΔPall fmax) at the maximum frequency (fmax) of the power system 10, which will be described later.

The maximum value of total charge/discharge power (Pall_max) is the maximum amount of power that can be charged or discharged by the electric vehicles EV1 to EV3 as a whole via the electric wire 12. FIG. The maximum value (Pall_max) of the total charge/discharge power is predetermined. The current value of the total charge/discharge power (Pall_now) is the current value of the amount of power being charged or discharged by the electric vehicles EV1 to EV3 as a whole via the electric wire 12. FIG. The charge/discharge control device according to the embodiment is based on the constraint of the maximum value (Pall_max) of the total charge/discharge power, so that the current value (Pall_now) of the total charge/discharge power does not exceed the maximum value (Pall_max) of the power. It controls the charge/discharge output of electric vehicles EV1 to EV3.

The information transmitting device 16 receives the system frequency (f) of the power system 10 and the current value (Pall_now) of the total charge/discharge power measured by the current measuring device 15 via the computer network or the power network 11 . The information transmitting device 16 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 and data indicating the maximum value (Pall_max) of the total charge/discharge power. Have a device.

The calculation unit 17 calculates the output characteristics of the total charge/discharge output with respect to the system frequency (f) of the power system 10 from the system frequency (f) measured by the current measuring device 15 and the calculated current value (Pall_now) of the total charge/discharge power. Calculate Further, the calculation unit 17 calculates the total electric vehicles EV1 to EV3 at the maximum frequency (fmax) in the adjustment range of the system frequency (f) from the calculated output characteristics and the system frequency (f) measured by the current measuring device 15. An estimated value of the total charge/discharge power (Pall_fmax) is calculated. The adjustment range of the grid frequency (f) can be ±0.2 Hz when the reference frequency (fref) of the power grid 10 is 50 Hz.

The calculation unit 17 subtracts the estimated value of the total charge/discharge power at the maximum frequency (fmax) from the maximum value of the total charge/discharge power (Pall_max), as shown in equation (1), to obtain the difference at the maximum frequency (fmax). Calculate the power (ΔPall fmax). In a situation where the electric power system 10 requests charging of the electric vehicles EV1 to EV3, the calculation unit 17 calculates the differential power of charging at the maximum frequency (fmax). The differential power for charging at the maximum frequency (fmax) is calculated from the maximum value of the total charging power that the wire 12 can transmit to all of the electric vehicles EV1 to EV3 via the wire 12 at the maximum frequency (fmax). Calculated by subtracting the estimated value of the total charging power transmitted to the entire EV3.

On the other hand, in a situation where the electric power system 10 requests the electric vehicles EV1 to EV3 to discharge, the calculator 17 calculates the differential power of the discharge at the maximum frequency (fmax). The differential power of the discharge at the maximum frequency (fmax) is calculated from the maximum value of the total discharge power that the wire 12 can receive from all of the electric vehicles EV1 to EV3 via the wire 12 at the maximum frequency (fmax). ˜Calculate by subtracting the estimated value of the total charging power received from the entire EV3. The differential power (ΔPall fmax) at the maximum frequency (fmax) is a positive value equal to or greater than 0, and is a concept including the charge differential power and the discharge differential power at the maximum frequency (fmax).

The situation in which the power system 10 requests charging or discharging of the electric vehicles EV1 to EV3 changes according to the power supply and demand balance in the power system 10 . The information transmission device 16 uses the data indicating the maximum value (Pall_max) of the total charge/discharge power read from the storage device and the differential power (ΔPall fmax) at the maximum frequency (fmax) calculated by the calculation unit 17 to calculate the maximum The difference power (ΔPall fmax) at the frequency (fmax) is calculated as a value indicating the margin of the maximum power amount for charge/discharge. As a method of calculating the differential power (ΔPall fmax) at the maximum frequency (fmax), the current value of the total charge/discharge power (Pall_now) from the maximum value of the total charge/discharge power (Pall_max) disclosed in International Publication No. 2020/194010 ) to calculate the difference power (ΔP) can be applied.

Further, the calculation unit 17 calculates the difference (ΔPall freq) of the frequency adjustment capacity as a value indicating the margin of the frequency adjustment capacity. The frequency adjustment capacity difference (ΔPall freq) is the frequency adjustment capacity (Pall freq) obtained from the minimum frequency to the maximum frequency (fmax) in the adjustment range of the system frequency (f) based on the basic output characteristics read from the storage device. From the theoretical value of, the actual value of the frequency adjustment capacity (Pall freq) obtained as a result between the minimum frequency and the maximum frequency (fmax) of the adjustment range of the system frequency (f) by the output characteristics calculated by the calculation unit 17 This is the reduced difference.

The broadcast transmission unit 18a uses the broadcast transmission device 18b to transmit an electrical signal indicating the differential power (ΔPall fmax) at the maximum frequency (fmax) calculated by the calculation unit 17 and the difference in frequency adjustment capacity (ΔPall freq). , to all electric vehicles EV1 to EV3. The differential power (ΔPall fmax) at the maximum frequency (fmax) and the difference (ΔPall freq) between the frequency adjustment capacity indicated by the electric signal broadcasted by the broadcast transmission unit 18a is Updated.

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

In the embodiment, “electric vehicles EV1 to EV3” are examples of “charging/discharging elements” that charge/discharge electric power via electric wires 12 . The charging/discharging element stores the received power in a battery (including a secondary battery, a storage battery, and a rechargeable battery). "Charging and discharging elements" include all equipment and devices with batteries, such as vehicles (including electric vehicles, hybrid vehicles, construction machinery, and agricultural machinery), railway vehicles, playground equipment, tools, household products, and daily necessities. In the embodiments, an electric vehicle (EV) that runs using electricity as an energy source and a motor as a power source is given as an example of the charging/discharging element. However, it is not intended to limit the charging/discharging element in the present invention to an electric vehicle (EV).

A “charge/discharge element” indicates a unit configuration of charge/discharge control by the charge/discharge control device according to the embodiment. That is, the charge/discharge control according to the embodiment is performed in units of charge/discharge elements. For example, charge/discharge control is performed independently and in parallel for each of the plurality of electric vehicles EV1 to EV3.

(Electric car)
With reference to FIG. 2, the configuration of the charge/discharge control device 23 and its peripheral devices mounted on each of the electric vehicles EV1 to EV3, . Of the electric vehicles EV1 to EV3, . be able to.

The electric vehicle EV1 is equipped with a receiver 21 (receiving unit), a vehicle state acquisition device 22, a charge/discharge device 24, a motor 26, and a battery 25 as peripheral devices of the charge/discharge control device 23. FIG.

The receiver 21 is a device that receives an electric signal (radio signal) broadcasted from the broadcast transmitter 18b. The electrical signal received by the receiver 21 includes a signal requesting charging or discharging of the electric vehicles EV1 to EV3 as a whole. This signal includes a signal indicating the required value (Pfr) of the frequency adjustment capacity of the electric power system 10 and a signal indicating excess/deficiency (ΔPfr) of the frequency adjustment capacity, as an example of system requirements.

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 state of charge 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. Numerical values representing the demands of the user of the electric vehicle EV1 are, for example, the target value (SOCgoal) of the charging rate of the battery 25 and the time to end charging/discharging of the electric vehicle EV1 (charging/discharging end time Td). The remaining time (T) until the end time Td is the remaining time during which the electric vehicle EV1 can charge and discharge.

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

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

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

The charge/discharge control device 23 can be implemented using a microcomputer having a CPU (central processing unit), memory, and an input/output unit. A computer program for causing the microcomputer to function as the charge/discharge control device 23 is installed in the microcomputer and executed. Thereby, the microcomputer can function as a plurality of information processing units (31 to 38) included in the charge/discharge control device 23. FIG. Here, an example of realizing the charge/discharge control device by software is shown, but of course, it is also possible to configure the charge/discharge control device 23 by preparing dedicated hardware for executing each information processing. Specialized hardware includes devices such as application specific integrated circuits (ASICs) and conventional circuitry arranged to perform the functions described in the embodiments.

Although the charging/discharging control device 23, the receiving device 21, the vehicle state acquiring device 22, and the charging/discharging device 24 have been described as different members, it is of course possible to configure two or more arbitrarily selected devices as one device. good. Alternatively, the plurality of information processing units (31 to 38) may be divided and configured using two or more different devices. Furthermore, all or part of the plurality of information processing units (31 to 37) may be configured using another ECU (Electronic Control Unit) mounted on the electric vehicle EV1.

The charge/discharge control device 23 performs the power reception control disclosed in International Publication No. 2020/194010 for processes related to charge/discharge control of the electric vehicle EV1 other than the process related to the correction of the priority (β) described below. The processing performed by the device can be applied.

The charge/discharge control device 23 includes, as a plurality of information processing units (31 to 37), 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 charging A discharge power calculator 36 and a charge/discharge controller 37 are provided.

The charge/discharge request acquisition unit 31 obtains information indicating the differential power (ΔPall fmax) at the maximum frequency (fmax) of the power system 10 as an example of the system request from the electric signal received by the receiving device 21, and the difference in the frequency adjustment capacity. Information indicating (ΔPall freq) is acquired.

The current information acquiring unit 32 acquires a current value of the electric wire 12 measured by the ammeter 24 a of the charging/discharging device 24 at the connection end of the electric vehicle EV<b>1 to the electric wire 12 .

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 .

Based on the numerical value representing the request of the user of the electric vehicle EV1 and the state of the electric vehicle EV1, the priority calculation unit 34 prefers charging the own EV1 over charging or discharging other electric vehicles (EV2, EV3, . . . ). Alternatively, the priority (β) of the electric vehicle EV1, which indicates the degree of priority given to discharging, is calculated. Specifically, the priority calculation unit 34 calculates the priority (β) from the remaining time (T) from the current time (To) to the charging/discharging end time (Td) using the equation (2). In the formula (2), N indicates the total number of electric vehicles that charge and discharge. The method disclosed in International Publication No. 2020/194010 can be used as a method of calculating the priority (β) using the current value (SOCnow) of the charging rate and the target value (SOCgoal) of the charging rate.

The total number of electric vehicles (N) may be statistical data (quantity data) obtained by investigating the past charge/discharge history of the load group of the electric power system 10 including the electric vehicles connected to the electric wire 12, It is also possible to roughly estimate the total number of electric vehicles (N) from the current value of total charge/discharge power (Pall_now). The total number (N) is broadcast from the information transmitting device 16 or a device attached to the information transmitting device 16, like the differential power (ΔP). Alternatively, the total number (N) may be specified by location information or an identification signal of the charging system of the electric vehicle.

The characteristic determining unit 35 determines the priority (β) calculated by the priority calculating unit 34, the differential power (ΔPall fmax) at the maximum frequency (fmax) of the power system 10 received by the receiving device 21, and the difference in frequency adjustment capacity ( ΔPall freq), the charging/discharging output characteristics of the electric vehicle EV1 with respect to the system frequency (f) are determined. This output characteristic defines the charge/discharge output of the electric vehicle EV1 at each frequency within the adjustment range of the system frequency (f).

The characteristic determining unit 35 determines the charging/discharging output characteristic of the electric vehicle EV1 according to the priority (β).

If, as in the output characteristics of the comparative example shown in FIG. ), there occurs a frequency region in which electric vehicles that are charged and electric vehicles that are discharged are mixed due to the output characteristics according to the priority (β). In this frequency range, electric power discharged from one electric vehicle is charged to another electric vehicle, resulting in a large charging/discharging loss and a decrease in charging/discharging efficiency of the entire electric vehicle.

Therefore, the characteristic determination unit 35 determines that the boundary between the charging region and the discharging region is different from each other regardless of the priority (β), such as the output characteristics of the high, medium, and low priorities (β) shown in FIG. The output characteristic with the same system frequency (f) is determined as the output characteristic of the electric vehicle EV1.

The maximum frequency (fmax ), the differential power (ΔPall fmax) available to all electric vehicles EV1 to EV3, and the frequency adjustment capacity (Pall freq) supplied by all electric vehicles EV1 to EV3, are both It suffices if it can be distributed according to the priority (β) of EV1. The differential power (ΔPall fmax) is the intercept on the charge/discharge output axis of the output characteristic, and the frequency adjustment capacity (Pall freq) is the slope of the output characteristic.

If the power and slope used at the maximum frequency are distributed so as to have a proportional relationship with the priority (β) of the electric vehicle EV1, the charge/discharge output will be zero in the output characteristics of each priority (β). system frequency (f) is inevitably one. Expressed in a general formula, the charging/discharging output Pi at the system frequency (f) of each electric vehicle EVi is given by Equation (3) as a function of the system frequency (f).

Here, the suffix (lower right character) “i” in the formula (3) indicates each of the electric vehicles EV1 to EV3, . . .

In equation (3), if the differential power (ΔPall) of the entire electric vehicle and the frequency adjustment capacity (Pfreq) are distributed according to the priority βi of the electric vehicle i, then the element differential power (ΔPall ,i) and the element frequency adjustment capacity (Pfreq,i) are expressed by equation (4). In the equation (4), "Btotal" is the total priority βi of the electric vehicle i.

Applying the equation (4) to the differential power (ΔPall) and the frequency adjustment capacity (Pfreq) in the equation (3) yields the equation (5). In this equation, if the portion on the right side excluding βi/Btotal becomes "0" (zero), the charge/discharge output Pi of the electric vehicle i becomes "0" (zero) regardless of the value of the priority βi. Therefore, the characteristic determining unit 35 determines the charging/discharging output characteristics of the electric vehicle EV1 in which the boundary between the charging region and the discharging region has the same system frequency (f) regardless of the priority (β), using equation (3). to decide.

The charging/discharging power calculator 36 calculates the elemental charging/discharging output of the electric vehicle EV1. Equation (6) can be used to calculate the element charge/discharge output. Formula (6) is an update formula for obtaining the updated value (Pt+1) of the charge/discharge power (Pt) by a plurality of charge/discharge elements connected to the power system from the differential power (ΔP) as the “system request”. In the equation (6), the differential power (ΔP) is a value obtained 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 of the electric power system.

In the equation (6), the element differential power (βi×ΔP) is calculated by multiplying the differential power (ΔP) by the priority (βi) of the electric vehicle. Then, the element difference power (β×ΔP) is added to the element charge/discharge power (Pt) in the previous processing cycle, and a constant power correction value (α×Pt ), the updated value (Pt+1) of the element charge/discharge power (Pt) can be obtained. The suffixes (lower right letters) 't' and 't+1' of the symbol 'P' indicating charge/discharge power indicate the number of repetitions of the 'processing cycle'. t is a positive integer including zero. By subtracting a constant power correction value (α×Pt) when updating the element charge/discharge power (Pt), it is possible to make the differential power (ΔP) less likely to become zero. An electric vehicle that wants to newly start receiving power can start receiving power early.

By substituting the difference power (ΔPall fmax) at the maximum frequency (fmax) received by the receiving device 21 and the difference in the frequency adjustment capacity (ΔPall freq) for the charge/discharge power (Pt) in the equation (6), the charging The discharge power calculation unit 36 calculates an updated value (ΔPt+1, all fmax) of the element differential power (ΔPt, all fmax) at the maximum frequency (fmax) according to the priority (β) of the electric vehicle (EV1), An updated value (ΔPt+1,all freq) of the difference (ΔPt,all freq) of the element frequency adjustment capacitances can be calculated.

The charge/discharge power calculation unit 36 calculates the calculated updated value of the element difference power (ΔPt+1, all fmax), the calculated update value of the difference of the element frequency adjustment capacity (ΔPt+1, all freq), and the charge/discharge device 24 From the measured system frequency (f), using the equation (3), the element charge/discharge output of the self EV1 is calculated.

The charge/discharge control unit 37 controls the charge/discharge device 24 so that the electric vehicle EV1 is charged or discharged with the element charge/discharge output calculated by the charge/discharge power calculation unit 36 . In this way, the charging/discharging control device 23 controls the charging/discharging power (P), which is the power charged/discharged by the electric vehicle EV1, by repeating the processing cycles (a) to (f) shown below.
(a) obtaining information indicating the differential power (ΔPt,all fmax) at the maximum frequency (fmax) and the difference in the frequency adjustment capacity (ΔPt,all freq);
(b) Calculate the priority (β),
(c) Calculate the updated value (ΔPt+1, all fmax) (ΔPt+1, all freq) of the differential power (ΔPt, all fmax) at the maximum frequency (fmax) and the difference in the frequency adjustment capacitance (ΔPt, all freq) , determine the charge-discharge output characteristics according to the priority (β),
(d) measuring the grid frequency (f) at the connection end;
(e) Updated values (ΔPt+1, all fmax) (ΔPt+1, all freq) of the measured system frequency (f), the differential power (ΔPt, all fmax), and the difference in the frequency adjustment capacity (ΔPt, all freq) ) to determine the element charge/discharge output,
(f) Control the charging/discharging device 24 to charge/discharge with the determined element charging/discharging output.

An example of the charge/discharge control method by the charge/discharge control device 23 of FIG. 2 will be described with reference to the flowchart of FIG. This charging/discharging control method is executed by the charging/discharging control device 23 of each electric vehicle EV1 to EV3, . . . A person 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 function of the charge/discharge control device 23 in FIG. Therefore, here, as a charge/discharge control method by the charge/discharge control device 23 of FIG. omitted because

First, in step S201, the priority calculation unit 34 calculates the charge/discharge priority (β) from the current value (SOCnow) of the charging rate of the battery 25 acquired by the vehicle state acquisition device 22, the scheduled departure time, and the like. .

Proceeding to step S202, the charge/discharge power calculation unit 36 calculates the update value (ΔPt+1 , all fmax) and the updated value (ΔPt+1, all freq) of the difference (ΔPt, all freq) of the element frequency adjustment capacitances.

Proceeding to step S203, 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 measured by the ammeter 24a. Proceeding to step S204, the charge/discharge power calculation unit 36 calculates the updated value (ΔPt+1, all fmax) of the element differential power (ΔPt, all fmax) at the maximum frequency (fmax) and the difference in the element frequency adjustment capacity (ΔPt, all freq) update value (ΔPt+1, all freq), the system frequency (f) of the electric wire 12 measured by the system frequency measurement unit 33, and the charge/discharge output characteristics determined by the characteristic determination unit 35, the electricity Determine the element charge/discharge output of the vehicle EV1.

Proceeding to step S<b>205 , the charge/discharge control unit 37 controls the charge/discharge device 24 so that the electric vehicle EV<b>1 is charged or discharged with the element charge/discharge output calculated by the charge/discharge power calculation unit 36 .

According to the embodiment of the present invention, the following effects can be obtained.

The information transmitting device 16 of the power system 10 calculates the differential power (ΔPall fmax) at the maximum frequency (fmax) in the adjustment range of the system frequency (f) as a value indicating the margin of the maximum power amount for charging and discharging in the power system 10. , electric vehicles EV1 to EV3, . Then, each of the electric vehicles EV1 to EV3, . are determined as the output characteristics of . . .

Therefore, electric vehicles of any priority (β) are uniformly charged or discharged at the same system frequency (f). Therefore, the output characteristic according to the priority (β) suppresses the occurrence of a frequency range in which electric vehicles that are charged and electric vehicles that are discharged are mixed even at the same system frequency (f). It is possible to suppress the deterioration of the overall charging/discharging efficiency of the automobiles EV1 to EV3 due to the charging/discharging loss.

(First modification)
In the above embodiment, the characteristic determining unit 35 determines the linear output characteristic across the charge region and the discharge region as shown in FIG. 3 according to the priority (β). In this output characteristic, the higher the priority (β) in the charging region, the higher the charging output. growing. In this case, electric vehicles EV1 to EV3, . Therefore, the priority (β) calculated by the priority calculator 34 may be made different between the charge region and the discharge region.

For example, as shown in FIG. 7, all the priority (β) electric vehicles EV1 to EV3, . can be reversed. In this case, the electric vehicles EV1 to EV3, . Conversely, the electric vehicles EV1 to EV3, . . . with low priority (β) in the charging region have high priority (β) in the discharging region. Therefore, electric vehicles EV1 to EV3, .

In addition, the change to a different priority (β) may be changed discontinuously at the timing when the system frequency (f) changes across the boundary between the charging region and the discharging region, and continuously through a plurality of stages. can be changed to

Then, the charging/discharging output characteristics of each electric vehicle EV1 to EV3, . Since there is no restriction on the priority (β), even if the priority (β) is different between the charging region and the discharging region, the overall charging and discharging efficiency of the electric vehicles EV1 to EV3 in the electric power system 10 is improved. Decrease can be suppressed.

(Second modification)
In the above embodiment, the slope of the output characteristic determined by the characteristic determining unit 35 according to the priority (β) increases as the priority (β) increases, as shown in FIG. For this reason, depending on the magnitude of the slope of the output characteristics, for example, the charging output on the maximum frequency side of the output characteristics corresponding to the high priority (β) may be the maximum charging power amount of the electric vehicles EV1 to EV3, . may exceed.

In this case, for example, an upper limit value is set for the priority (β) of the output characteristics in which the charging output exceeds the maximum charging power amount, and the priority (β) of the output characteristics corresponding to the high priority (β) in the comparative example shown in FIG. Thus, it is conceivable to shift the charge output so that the charge output falls below the maximum charge power amount. However, the system frequency (f), which is the boundary between the charging region and the discharging region of the shifted high priority (β) output characteristics, is a different frequency from the output characteristics of other priorities (β). .

Therefore, the priority calculation unit 34 sets the upper limit value to the priority (β) of the output characteristic in which the charging output exceeds the maximum charging power amount, and sets the high priority (β) in which the charging output exceeds the maximum charging power amount. As shown in FIG. 9, the corresponding output characteristics are such that the charging output falls below the maximum charging power amount and the boundary between the charging region and the discharging region of the output characteristics is the same frequency as the output characteristics of other priorities. good too. This upper limit can be determined, for example, by an upper limit setting formula represented by formula (7).

Accordingly, it is possible to prevent the charge output from exceeding the maximum charge power amount, and suppress the decrease in the charge/discharge efficiency of the electric vehicles EV1 to EV3, . . . Also, the electric vehicles EV1 to EV3, . It is possible to easily avoid different frequencies between the output characteristics of (β) and the output characteristics of other priorities.

It should be noted that setting the upper limit value for the priority (β) in the second modification is particularly effective when the term ΔP in the equation (6) approaches zero. That is, as shown in FIG. 3, the characteristic determination unit 35 originally tries to increase the slope of the output characteristics of the electric vehicles EV1 to EV3, . Therefore, when the ΔP term in the equation (6) approaches zero and the charging output of the electric vehicles EV1 to EV3, . EV3, .

Therefore, when the ΔP term in the equation (6) approaches zero, the priority calculation unit 34 sets an upper limit value for the priority (β) so that the electric vehicles EV1 to EV3 that are difficult to be charged , .

Note that the above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and even if it is a form other than this embodiment, as long as it does not deviate from the technical idea according to the present invention, according to design etc. Of course, various modifications are possible.

REFERENCE SIGNS LIST 10 electric power system 12 electric wire 21 receiving device 34 priority calculation unit 35 characteristic determination unit 37 charge/discharge control unit EV1, EV2, EV3, ... electric vehicle

Claims (9)

Receive the margin of the maximum power amount for charging and discharging by a plurality of charging and discharging elements connected to the electric power system and the margin of the frequency adjustment capacity according to the system frequency of the power system,
Based on the priority indicating the degree to which self-charging or discharging is prioritized over charging or discharging of other charging/discharging elements, and the received margin of the maximum power amount of charging and discharging and the margin of the frequency adjustment capacity. determining an output characteristic according to the priority of charging and discharging with respect to the system frequency, wherein the value of the system frequency, which is the boundary between charging and discharging, is the same regardless of the priority;
Charging or discharging with an output calculated based on the output characteristics,
A charging/discharging control method for a charging/discharging element. 2. The charging/discharging control method of a charging/discharging element according to claim 1, wherein the maximum power amount for charging/discharging and the frequency adjustment capacity in the output characteristics are proportional to each other between the output characteristics having different priorities. The output of charging or discharging based on the output characteristics is the current charging/discharging power Pt, the priority βi, the margin of the maximum charging/discharging power amount ΔP, and the correction coefficient for the current charging/discharging power α , the following update formula

3. The charging/discharging control method of the charging/discharging element according to claim 1 or 2, wherein updating is performed using The charge/discharge control method for charge/discharge elements according to any one of claims 1 to 3, wherein the output characteristics are determined based on the different priorities for charging and discharging. The charge/discharge control method for charge/discharge elements according to any one of claims 1 to 4, wherein the output characteristics are determined based on the priority levels reversed between charging and discharging. 3. The charge/discharge control method for charge/discharge elements according to claim 1, wherein an upper limit value is set for the priority when the charge output calculated based on the output characteristics reaches the maximum charge power of the power system. The output of charging or discharging based on the output characteristics is the current charging/discharging power Pt, the priority βi, the margin of the maximum charging/discharging power amount ΔP, and the correction coefficient for the current charging/discharging power α , the following update formula

to update the upper limit with the following upper limit setting formula

The charging/discharging control method of the charging/discharging element according to claim 6, provided by: estimating the priority of the other charging/discharging element based on the value of the margin ΔP of the maximum power amount of the charging/discharging in the updating formula, and based on the estimated priority of the other charging/discharging element 8. The charge/discharge control method for a charge/discharge element according to claim 7, wherein an upper limit value is set. a receiving unit that receives the margin of the maximum power amount for charging/discharging by a plurality of charging/discharging elements connected to the electric wires of the electric power system and the margin of the frequency adjustment capacity according to the system frequency of the electric power system;
a priority calculation unit that calculates a priority indicating the degree of priority given to self-charging or discharging over charging or discharging of other charge-discharge elements;
Based on the priority, the margin of the maximum power amount of charging and discharging, and the margin of the frequency adjustment capacity, the value of the system frequency, which is the boundary between charging and discharging, is the same regardless of the priority. , a characteristic determination unit that determines output characteristics according to the priority of charging and discharging with respect to the system frequency;
A control unit that controls the output of charging or discharging in the power system with the output calculated based on the output characteristics;
A charge/discharge control device for a charge/discharge element.

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