Power system and storage battery system

Abstract

To provide a power system which can equalize a charging rate of each storage battery system without receiving power from a power system.SOLUTION: A power system F1 including a plurality of storage battery systems B includes: a storage battery 21; a communication part 247 communicating with another device; a charging rate acquisition part 243 for acquiring a charging rate of the storage battery 21; an average value detection part 244 for detecting a charging average being an arithmetic average value of each charging rate of the plurality of storage battery systems B; and an inverter 22 for charging and discharging the storage battery 21. The average value detection part 244 detects the charging average by performing communication with the other device through the communication part 247. The inverter 22 performs discharging in a first state in which a self-charging rate being the charging rate acquired by the charging rate acquisition part 243 is larger than the charging average, and performs charging in a second state in which the self-charging rate is smaller than the charging average.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power system and a battery system. [Background technology]

[0002] In recent years, power systems that manage multiple power devices connected to a power grid and control the power transmitted and received between the power grid are becoming widespread. Among such power systems, there are power systems equipped with multiple battery storage systems and specialized in supplying power according to transactions in power trading markets such as the wholesale power market, the capacity market, and the supply and demand adjustment market. The power system supplies power according to the contract during the supply period in which a transaction is concluded in the power trading market. Normally, the charging rates of the batteries in each battery storage system (hereinafter, abbreviated as "charging rates of the battery storage systems") are approximately the same, but when some of the battery storage systems are stopped, the charging rates may become uneven. The charging rate, also known as SOC (State Of Charge), is an index indicating the charging state, and is expressed as a percentage of the remaining charge relative to the capacity when fully charged. Due to uneven charging rates, the power system may not be able to supply power according to the contract during the supply period.

[0003] FIG. 4(a) is a time chart showing the change in the charge rate of each storage battery system when a power system equipped with four storage battery systems outputs 400 kW during a two-hour supply period. The rated power of each storage battery system is 100 kW, and the capacity of each storage battery is 400 kWh. As shown in FIG. 4(a), at the start of the supply period, the charge rate of storage battery system B1 is 100%, the charge rate of storage battery system B2 is 50%, the charge rate of storage battery system B3 is 40%, and the charge rate of storage battery system B4 is 10%. In this case, during the supply period, the charge rate of storage battery system B4 becomes 0%, and the output power of the power system becomes 300 kW. After that, the charge rate of storage battery system B3 becomes 0%, and the output power of the power system becomes 200 kW. Therefore, the power system cannot maintain an output of 400 kW during the supply period. In reality, the storage batteries are not used until the charge rate reaches 100% or 0%, but for convenience, this is ignored in the explanation of FIG. 4.

[0004] If the contracted power cannot be supplied in the middle of the contracted provision period, a large penalty will be imposed. In order to prevent this, it is necessary to set a preparation period before the contracted provision period and increase the charging rate of the storage battery system, which may have a shortage of charging rate. For example, Patent Document 1 discloses a charging and discharging system that inputs and outputs power for frequency control according to transactions in a frequency adjustment market. The charging and discharging system charges or discharges the storage battery so that the SOC of the storage battery becomes an appropriate value by the start time of the service provision period. The charging and discharging system charges for SOC adjustment by charging from a power grid or a generator.

[0005] As shown in FIG. 4(b), if the storage battery systems B2, B3, and B4 are charged to a charging rate of 100% during the preparation period before the contracted provision period, an output of 400 kW can be maintained during the provision period. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-233096 A [Patent Document 2] JP 2015-166901 A [Patent Document 3] JP 2018-121189 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, receiving power from the power grid to charge the storage battery incurs extra costs for receiving the power, and receiving power from the power grid may adversely affect the power grid or disrupt the supply-demand balance.

[0008] The present invention has been devised in light of the above-mentioned circumstances, and has an object to provide a power system that can equalize the charging rates of each storage battery system without receiving power from the power grid. [Means for solving the problem]

[0009] A power system provided by a first aspect of the present invention is a power system comprising a plurality of storage battery systems, each of which comprises a storage battery, a communication unit that communicates with other devices, a charging rate acquisition unit that acquires the charging rate of the storage battery, an average value detection unit that detects a charging average which is an arithmetic average value of the charging rates of the plurality of storage battery systems, and an inverter that charges and discharges the storage battery, wherein the average value detection unit detects the charging average by communicating with the other devices via the communication unit, and the inverter discharges when the self-charging rate, which is the charging rate acquired by the charging rate acquisition unit, is greater than the charging average in a first state, and charges when the self-charging rate is in a second state where the self-charging rate is smaller than the charging average.

[0010] In a preferred embodiment of the present invention, the rated power of each inverter of the multiple storage battery systems is the same as that of the other inverters, and each storage battery system further includes a number detection unit that detects a first number, which is the number of storage battery systems in the first state, and a second number, which is the number of storage battery systems in the second state, and when the first number is less than or equal to the second number, the inverter discharges at the rated power when in the first state, and charges at a calculated charging power obtained by multiplying the first number by the rated power and dividing the result by the second number when in the second state, and when the first number is greater than the second number, charges at the rated power when in the second state, and discharges at a calculated discharging power obtained by multiplying the second number by the rated power and dividing the result by the first number when in the first state.

[0011] In a preferred embodiment of the present invention, each of the storage battery systems further includes a number detection unit that detects a first number, which is the number of storage battery systems in the first state, and a second number, which is the number of storage battery systems in the second state, and a rated average detection unit that detects a first rated average, which is an arithmetic mean value of the rated power of the storage battery systems in the first state, and a second rated average, which is the arithmetic mean value of the rated power of the storage battery systems in the second state, and the inverter discharges at rated power when in the first state if a first overall rating obtained by multiplying the first number and the first rated average is equal to or less than a second overall rating obtained by multiplying the second number and the second rated average, and charges at a calculated charging power obtained by dividing the first overall rating by the second number when in the second state, and charges at rated power when in the second state if the first overall rating is greater than the second overall rating, and discharges at a calculated discharging power obtained by dividing the second overall rating by the first number when in the first state.

[0012] In a preferred embodiment of the present invention, the number detection unit sets a first value or a second value as an initial internal value, transmits the internal value to at least one of the other storage battery systems via the communication unit, and generates an internal value using a calculation result based on the internal value received by the communication unit from at least one of the other storage battery systems and the generated internal value, thereby converging, and when in the first state, performs a calculation based on the internal value received from the storage battery system in the first state and the generated internal value, detects the reciprocal of the converged internal value received from the storage battery system in the second state as the second number, and when in the second state, performs a calculation based on the internal value received from the storage battery system in the second state and the generated internal value, detects the reciprocal of the converged internal value as the second number, and detects the reciprocal of the converged internal value received from the storage battery system in the first state as the first number.

[0013] In a preferred embodiment of the present invention, the average value detection unit transmits the generated internal average value to at least one of the other storage battery systems via the communication unit, and generates an internal average value using a calculation result based on the internal average value received by the communication unit from the at least one of the other storage battery systems and the generated internal average value, and detects the converged internal average value as the charging average by repeating this process.

[0014] A storage battery system provided by a second aspect of the present invention is a storage battery system included in a power system having a plurality of storage battery systems, and comprises a storage battery, a communication unit that communicates with other devices, a charging rate acquisition unit that acquires the charging rate of the storage battery, an average value detection unit that detects a charging average which is the arithmetic average of the charging rates of the plurality of storage battery systems, and an inverter that charges and discharges the storage battery, wherein the average value detection unit detects the charging average by communicating with the other devices via the communication unit, and the inverter discharges when the self-charging rate, which is the charging rate acquired by the charging rate acquisition unit, is greater than the charging average in a first state, and charges when the self-charging rate is in a second state where the charging rate is smaller than the charging average. Effect of the Invention

[0015] According to the present invention, the inverter of each storage battery system discharges when the self-charging rate is higher than the charging average, and charges when the self-charging rate is lower than the charging average. The storage battery system with a self-charging rate higher than the charging average discharges, and the storage battery system with a self-charging rate lower than the charging average charges the discharged power, so there is no need to receive power from the power grid. Furthermore, each storage battery system charges and discharges until its self-charging rate reaches the charging average. In this way, the power system according to the present invention can equalize the charging rates of each storage battery system without receiving power from the power grid. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram for explaining a power system according to a first embodiment, where (a) is a block diagram showing the overall configuration, and (b) is a block diagram showing the internal configuration of a storage battery system. [Diagram 2] FIG. 4A is a block diagram showing an example of the internal configuration of an average value detection unit, and FIG. 4B is a block diagram showing an example of the internal configuration of a number of vehicles detection unit. [Diagram 3] 5 is an example of a flowchart showing a charging rate uniform process performed by a control board according to the first embodiment. [Figure 4] 4 is a time chart showing changes in the charging rate of the storage batteries in each storage battery system. [Diagram 5] FIG. 11 is a block diagram showing an internal configuration of a control board according to a second embodiment. [Figure 6] 4 is a block diagram showing an example of an internal configuration of an average rating detection unit. FIG. [Figure 7] 10 is an example of a flowchart showing a charging rate uniform process performed by a control board according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] Fig. 1 and Fig. 2 are diagrams for explaining a power system F1 according to a first embodiment. Fig. 1(a) is a block diagram showing the overall configuration of the power system F1. Fig. 1(b) is a block diagram showing the internal configuration of a storage battery system. Fig. 2(a) is a block diagram showing an example of the internal configuration of an average value detection unit. Fig. 2(b) is a block diagram showing an example of the internal configuration of a number detection unit.

[0019] As shown in FIG. 1(a), the power system F1 includes a centralized control device A and a plurality of storage battery systems B. In the power system F1, the plurality of storage battery systems B are connected to a power system K via a connection point X1. In the power system F1, all of the plurality of storage battery systems B may be operated by one business operator, or the plurality of storage battery systems B may be operated by a plurality of business operators. The centralized control device A may be operated by a business operator that operates at least one of the plurality of storage battery systems B, or may be operated by an aggregator that bundles the plurality of business operators. In this embodiment, the case where the power system F1 includes four storage battery systems B1 to B4 will be described, but the number of storage battery systems B is not limited. The power system F1 is connected to the power system K via a connection point X2. The power system F1 can transmit and receive power from the power system K via the connection point X2.

[0020] The centralized control device A manages the entire power system F1. The centralized control device A measures the power at the connection point X2 with the power system K (hereinafter referred to as "connection point power") using a power meter. The centralized control device A may receive detection values ​​of the input / output power detected by each storage battery system B, and use a total value calculated from these detection values ​​as the connection point power. The centralized control device A commands each storage battery system B to set targets for the input / output power so that the connection point power becomes the target power. The centralized control device A may command an individual target for each storage battery system B, or may command a common index so that each storage battery system B calculates a target based on the index. The method of communication between the centralized control device A and each storage battery system B is not limited.

[0021] The centralized management device A trades in an energy trading market with the power output from the multiple storage battery systems B as the trading object. The energy trading market may be any of a wholesale power market, a capacity market, and a supply and demand adjustment market. The centralized management device A sets a target power so as to supply a predetermined power during a supply period in which a transaction is concluded in the energy trading market. The centralized management device A also transmits a measurement result of the connection point power measured by a power meter during the supply period as a performance report to an operator of the energy trading market D. In this embodiment, the centralized management device A also commands each storage battery system B to start a preparation period before the supply period in which a transaction is concluded. When each storage battery system B receives a command to start the preparation period, it starts a charging rate uniform process, which will be described later.

[0022] Each of the multiple storage battery systems B is connected to a power system K via a connection point X1. Each of the multiple storage battery systems B is capable of outputting power to the connection point X1. In the example shown in FIG. 1, a transformer is connected between the connection point X1 and the connection point X2, but this transformer is not necessary. In this case, the connection point X1 and the connection point X2 are the same. As shown in FIG. 1(b), each of the multiple storage battery systems B includes a storage battery 21, an inverter 22, and a control board 24. Note that the configuration of each storage battery system B is not limited to the example shown in FIG. 1(b).

[0023] The storage battery 21 is, for example, a secondary battery or a capacitor. In FIG. 1(b), each storage battery system B includes one storage battery 21, but may include multiple storage batteries 21. In this embodiment, the storage batteries 21 of the multiple storage battery systems B have the same specifications and the same storage battery capacity and rated power. Note that the storage batteries 21 of each storage battery system B may have different storage battery capacities or rated powers.

[0024] The inverter 22 is connected to the storage battery 21 and charges and discharges the storage battery 21. The inverter 22 is connected to a connection point X1. The inverter 22 charges the storage battery 21 by converting AC power input from the connection point X1 into DC power and supplying it to the storage battery 21. The inverter 22 also converts DC power stored in the storage battery 21 into AC power and outputs it to the connection point X1, thereby discharging the storage battery 21. The charging and discharging performed by the inverter 22 is controlled by a control board 24 (a control unit 242 described below). In this embodiment, the inverters 22 of the multiple storage battery systems B have the same specifications and have the same rated power, which is equal to or less than the rated power of the storage battery 21.

[0025] The control board 24 controls each component of the storage battery system B. The control board 24 includes at least one or more ICs (Integrated Circuits) and memories. As shown in Fig. 1(b), the control board 24 includes, as its functional components, a target value setting unit 241, a control unit 242, a charging rate acquisition unit 243, an average value detection unit 244, a charging rate comparison unit 245, a unit number detection unit 246, and a communication unit 247. Each unit may be configured with a digital circuit or an analog circuit.

[0026] The target value setting unit 241 sets an output target value, which is a target value of the output power of the device itself, in response to a command from the centralized management device A. When the centralized management device A commands an individual target for each storage battery system B, the target value setting unit 241 sets the received target value as the output target value. When the centralized management device A commands a common index, the target value setting unit 241 uses the received index to calculate and set an output target value based on a preset optimization problem. The target value setting unit 241 outputs the set output target value to the control unit 242. When the storage battery system B receives a command to start a preparation period from the centralized management device A, the target value setting unit 241 sets an output target value for equalizing the charging rates based on a charging rate equalization process. The charging rate equalization process will be described in detail later.

[0027] The control unit 242 controls the inverter 22. The control unit 242 controls the output power of the inverter 22 to the output target value input from the target value setting unit 241. Specifically, the control unit 242 controls the output power of the inverter 22 to the output target value by adjusting the switching of the inverter 22 based on the difference between the output target value and a detection value of the output power of the inverter 22 detected by a sensor. Note that, for example, when the input output target value is a positive value, the control unit 242 causes the inverter 22 to discharge the storage battery 21. Conversely, when the input output target value is a negative value, the control unit 242 causes the inverter 22 to charge the storage battery 21.

[0028] The charging rate acquisition unit 243, the average value detection unit 244, the charging rate comparison unit 245, the number of devices detection unit 246, and the communication unit 247 are components for performing the charging rate uniform process.

[0029] The communication unit 247 communicates with another storage battery system B. The communication unit 247 receives the internal average value X generated by the average value detection unit 244. i , and the internal value Y1 generated by the number detection unit 246 i ,Y2 i ,Y3 i is input and transmitted to another battery storage system B. Note that the internal average value X i and the internal value Y1 i ,Y2 i ,Y3 i The communication unit 247 also receives the internal average value X j to the average value detection unit 244, and the internal value Y1 received from the other storage battery system B j ,Y2 j ,Y3 j to the number detection unit 246. The communication method is not limited, and may be wired communication or wireless communication. In this embodiment, the communication unit 247 communicates with all the other storage battery systems B.

[0030] The charging rate acquisition unit 243 acquires the charging rate of the storage battery 21. The charging rate acquisition unit 243 acquires the charging rate by estimating it using a well-known method such as a current integration method or an OCV method. The method of acquiring the charging rate by the charging rate acquisition unit 243 is not limited. The charging rate acquisition unit 243 outputs the acquired charging rate to the average value detection unit 244 and the charging rate comparison unit 245 as a self-charging rate.

[0031] The average value detection unit 244 detects a charge average, which is an arithmetic mean value of the self-charging rates of each of the multiple storage battery systems B. The average value detection unit 244 detects the charge average by communicating with the other storage battery systems B via the communication unit 247. There are no limitations on the method by which the average value detection unit 244 detects the charge average, but for example, the average value generation method disclosed in Patent Document 2 may be used.

[0032] The average value detection unit 244 detects the internal average value X i to at least one of the other storage battery systems B, and an internal average value X j The internal average value is an arithmetic mean value of the self-charging rate of each battery system B, which is provisionally calculated within each battery system B. The internal average value X i is an internal average value generated in the target battery system B (i-th battery system B), where i is a natural number from 1 to n (n=4 in this embodiment). j is an internal average value received from the j-th storage battery system B among the other storage battery systems B, where j is a natural number from 1 to n (n=4 in this embodiment). i and the received internal average value X j The internal average value X is calculated using the calculation result based on i Generate the internal mean value X i and the internal mean value X j Even if the internal average value X is different from the internal average value X, the calculation process in the average value detection unit 244 is repeated. i and the internal mean value X j2(a), average value detection section 244 includes a change amount calculation section 31, a calculation section 32, a multiplier 33, an adder , an integrator 35, and a convergence detection section .

[0033] The change amount calculation unit 31 calculates the amount of change in the self-charging rate input from the charging rate acquisition unit 243. The change amount calculation unit 31 sets the amount of change to "0" while the self-charging rate input from the charging rate acquisition unit 243 has not been updated, and when the self-charging rate is updated, calculates the difference between the self-charging rate after the update and the self-charging rate before the update as the amount of change.

[0034] The calculation unit 32 performs calculation based on the following formula (1). That is, the calculation unit 32 receives each internal average value X j From the internal average value X generated by the average value detection unit 244, i The result of subtracting each of these and adding up all the subtracted results is u i is output to the multiplier 33.

number

[0035] The multiplier 33 multiplies the calculation result u i is multiplied by a predetermined coefficient ε and output to the adder 34. The coefficient ε is 0<ε<1 / d max It is a value that satisfies and is set in advance. max is the number of other storage battery systems B with which the communication unit 247 communicates, d i Among these, the battery storage system B in the power system F1 is the largest. In other words, among the battery storage systems B, the battery storage system B that communicates with the largest number of other battery storage systems B has an internal average value X j The coefficient ε is the internal mean value X i In order to suppress the fluctuation of u i Therefore, when the processing in the average value detection unit 244 is a continuous time processing, there is no need to provide the multiplier 33.

[0036] The adder 34 adds the amount of change calculated by the change amount calculation unit 31 to the input from the multiplier 33, and outputs the result to the integrator 35. Since the amount of change is "0" while the self-charging rate is not updated, the input from the multiplier 33 is output to the integrator 35 as is. On the other hand, when the self-charging rate is updated, the amount of change in the self-charging rate before and after the update is added to the input from the multiplier 33, and the result is output to the integrator 35. The integrator 35 integrates the value input from the adder 34 (i.e., multiplies the previously generated internal average value X i The internal average value X i Generate and output the internal average value X i is output to the communication unit 247, the calculation unit 32, and the convergence detection unit .

[0037] The calculation process is repeated by the average value detection unit 244 in each storage battery system B, and the internal average value X i is the common convergence value X α Converges to the convergence value X α is the internal average value X of each battery storage system B i The average value detection unit 244 calculates the self-charging rate initially acquired by the charging rate acquisition unit 243 by dividing the self-charging rate by the internal average value X i The initial value is updated when the self-charging rate of any of the storage battery systems B is updated. In the storage battery system B whose self-charging rate has been updated, the amount of change is added by the adder 34, so that the internal average value X i becomes the updated initial value, and in the battery storage system B where the self-charging rate was not updated, the internal average value X i becomes the initial value.

[0038] The convergence detection unit 36 ​​detects the internal average value X i When the internal average value X i Specifically, the convergence detection unit 36 ​​determines that the internal average value X i and the previous internal average value X i If the difference is within a predetermined error range, the internal average value Xi has not changed. If this state continues for a predetermined time, it is determined that convergence has occurred. In this embodiment, the number of calculations in the calculation unit 32 is used as the predetermined time. The configuration of the convergence detection unit 36 ​​is not limited, and it is sufficient if it can determine that convergence has occurred. For example, the convergence detection unit 36 ​​takes into consideration the time required for convergence and detects the internal average value X i The convergence detection unit 36 ​​may determine that the internal average value X i When it is judged that convergence has been reached, the internal average value X i The convergence value X α is output as the charging average to the charging rate comparison unit 245. Note that the configuration of the average value detection unit 244 is not limited to the one described above.

[0039] The charging rate comparison unit 245 compares the self-charging rate acquired by the charging rate acquisition unit 243 with the charging average detected by the average detection unit 244. The multiple storage battery systems B are divided into a first group in a first state where the self-charging rate is higher than the charging average, a second group in a second state where the self-charging rate is lower than the charging average, and a third group in a third state where the self-charging rate is equal to the charging average. The charging rate comparison unit 245 determines which group its own storage battery system B belongs to based on the comparison result, and outputs affiliation information indicating the group to which the storage battery system B belongs to the number detection unit 246 and the target value setting unit 241.

[0040] The number detection unit 246 detects a first number, which is the number of storage battery systems B belonging to a first group, a second number, which is the number of storage battery systems B belonging to a second group, and a third number, which is the number of storage battery systems B belonging to a third group. The number detection unit 246 detects the first number, the second number, and the third number by communicating with other storage battery systems B via the communication unit 247. The number detection unit 246 outputs the detected first number, the second number, and the third number to the target value setting unit 241. The method by which the number detection unit 246 detects the first number, the second number, and the third number is not limited, and may use, for example, a configuration number search method disclosed in Patent Document 3.

[0041] As shown in FIG. 2B, the number detection unit 246 detects an internal value Y i and an internal value generator 4 for generating an internal value Y i Set the initial value to and the converged internal value Y i The internal value Y i are provisionally calculated within each storage battery system B, and the three internal values ​​Y1 i ,Y2 i ,Y3 i Contains the internal value Y1 i is an internal value for detecting the first number of units. Internal value Y2 i is an internal value for detecting the second number of units. Internal value Y3 i is an internal value for detecting the third number.

[0042] The internal value generator 4 receives the internal value Y i to at least one of the other storage battery systems B, and the internal value Y j Receive the internal value Y i (Y1 i ,Y2 i ,Y3 i ) is an internal value generated in the target battery system B (the i-th battery system B), where i is a natural number from 1 to n (n=4 in this embodiment). j (Y1 j ,Y2 j ,Y3 j ) is an internal value received from the j-th storage battery system B among the other storage battery systems B, where j is a natural number from 1 to n (n=4 in this embodiment). The internal value generation unit 4 generates the internal value Y i and the received internal value Y j The internal value Y is calculated using the result of the calculation based on i Generates the internal value Y i and the internal value Y j Even if the internal value Y is different from the internal value Y, the internal value Y can be obtained by repeating the calculation process in the internal value generating unit 4. i and the internal value Y j and converge to a common value.

[0043] The internal value generator 4 generates the internal value Y i The internal value Y1 contained in i , internal value Y2 i , and the internal value Y3 i Among them, only the internal value Y corresponding to the affiliation information input from the charging rate comparison unit 245 is calculated, and the internal value Y corresponding to the affiliation information is not calculated. i (Y1 i ,Y2 i ,Y3 i ) and the internal value Y received from the battery storage system B having the same affiliation information. j (Y1 j ,Y2 j ,Y3 j The internal value Y i (Y1 i ,Y2 i ,Y3 i When the belonging information indicates the first group (first state), the internal value generating unit 4 generates an internal value Y1 i Only the calculation of the internal value Y2 i and the internal value Y3 i When the belonging information indicates the second group (second state), the internal value generating unit 4 does not perform the calculation of the internal value Y2 i Only the calculation of the internal value Y3 i and the internal value Y1 i When the belonging information indicates the third group (third state), the internal value generating unit 4 does not perform the calculation of the internal value Y3 i Only the calculation of the internal value Y1 i and the internal value Y2 i 2(b), the internal value generating unit 4 includes a calculation unit 41, a multiplier 42, and an integrator 43.

[0044] The calculation unit 41 performs the same calculation as the calculation unit 32. The multiplier 42 performs the same calculation as the multiplier 33. The integrator 43 performs the same calculation as the integrator 35 on the value input from the multiplier 42. The internal value Y iis output to the communication unit 247, the calculation unit 41, and the convergence detection unit 53 via the switching unit 51. As described above, the calculation unit 41, the multiplier 42, and the integrator 43 output the internal value Y i The internal value Y1 contained in i , internal value Y2 i , and the internal value Y3 i Only the calculations corresponding to the affiliation information are performed.

[0045] The internal value generating unit 4 of each storage battery system B repeats the calculation process, and the internal value Y i (Y1 i ,Y2 i ,Y3 i ) are the common convergence values ​​Y α (Y1 α ,Y2 α ,Y3 α ) converges to the convergence value Y1 α is the internal value Y1 of the battery storage system B in the first state. i The convergence value Y2 α is the internal value Y2 of the battery storage system B in the second state. i The arithmetic mean of the initial values ​​is the convergence value Y3 α is the internal value Y3 of the battery storage system B in the third state. i It becomes the arithmetic mean of the initial values.

[0046] The number search unit 5 calculates the internal value Y i (Y1 i ,Y2 i ,Y3 i 2(b), the number of vehicles searching unit 5 includes a switching unit 51, a timing generating unit 52, a convergence detecting unit 53, and a number calculating unit 54.

[0047] The switching unit 51 selects an internal value Y i (Y1 i ,Y2 i ,Y3 i The switching unit 51 sets an initial value for the internal value Y iis input, and the internal value Y i is output as is to the communication unit 247, the calculation unit 41, and the convergence detection unit 53. However, when an instruction to input an initial value is input from the timing generation unit 52, "0" or "1" is input to the internal value Y1 i ,Y2 i ,Y3 i The initial value is basically set to "0", but in one of the storage battery systems B in the first state, the internal value Y1 i is set to “1”, and in any one of the storage battery systems B in the second state, the internal value Y2 i is set to “1”, and in any one of the storage battery systems B in the third state, the internal value Y3 i The initial value set to "1" may be any one of the storage battery systems B.

[0048] The timing generation unit 52 outputs an instruction to input an initial value to the switching unit 51 at a predetermined timing. The predetermined timing is not limited and is set in advance as a timing at which the number of units is to be searched. For example, the predetermined timing may be set to the timing at which the average value detection unit 244 detects the average charging rate.

[0049] The convergence detector 53 detects the internal value Y i Detects that convergence has occurred and returns the converged internal value Y i (Y1 i ,Y2 i ,Y3 i ) the convergence value Y α (Y1 α ,Y2 α ,Y3 α ) to the number calculation unit 54. The convergence detection unit 53 detects convergence in the same manner as the convergence detection unit 36.

[0050] The number calculation unit 54 calculates the convergence value Y α (Y1 α ,Y2 α ,Y3 α) The first number, the second number, and the third number are calculated based on the convergence value Y1 α (Y2 α ,Y3 α ) is the internal value Y1 of the battery system B in the first (2,3) state. i (Y2 i ,Y3 i The internal value Y1 of each battery system B is the arithmetic mean value of the initial value. i ,Y2 i ,Y3 i The initial value of each is set to "1" for only one, and "0" for the rest, so the sum of the initial values ​​is "1". Therefore, if the first number is N1, the second number is N2, and the third number is N3, the convergence value Y1 α ,Y2 α ,Y3 α are 1 / N1, 1 / N2, and 1 / N3, respectively. Therefore, the first number N1, the second number N2, and the third number N3 are the convergence values ​​Y1 α ,Y2 α ,Y3 α Reciprocal of (N1=1 / Y1 α , N2=1 / Y2 α , N3=1 / Y3 α The number calculation unit 54 calculates the convergence value Y α The reciprocals of these are calculated and output to target value setting section 241 as first number N1, second number N2, and third number N3.

[0051] When the storage battery system B receives a command to start the preparation period from the centralized management device A, the target value setting unit 241 sets an output target value based on the first number N1, the second number N2, and the third number N3 input from the number detection unit 246 and the belonging information input from the charging rate comparison unit 245. The target value setting unit 241 compares the first number N1 with the second number N2. When the first number N1 is equal to or less than the second number N2, the target value setting unit 241 sets the rated power (positive value) as the output target value when the belonging information indicates the first group (first state), and sets the calculated charging power (negative value) as the output target value when the belonging information indicates the second group (second state). The calculated charging power is a power value calculated by multiplying the first number N1 by the rated power and dividing by the second number N2. As a result, the inverter 22 discharges at the rated power when in the first state, and charges at the calculated charging power when in the second state. On the other hand, when the first number N1 is greater than the second number N2, the target value setting unit 241 sets the rated power (negative value) as the output target value when the affiliation information indicates the second group (second state), and sets the calculated discharging power (positive value) as the output target value when the affiliation information indicates the first group (first state). The calculated discharging power is a power value calculated by multiplying the second number N2 by the rated power and dividing by the first number N1. As a result, the inverter 22 charges at the rated power when in the second state, and discharges at the calculated discharging power when in the first state. Note that the target value setting unit 241 sets "0" as the output target value when the affiliation information indicates the third group (third state). As a result, the inverter 22 does not charge or discharge. It should be noted that the third number N3 is not necessary for the processing in the target value setting unit 241, and therefore the number calculation unit 54 does not need to detect the third number N3.

[0052] 3 is an example of a flowchart showing the charging rate equalization process performed by the control board 24. The charging rate equalization process is executed at predetermined time intervals from when a command to start a preparation period is input from the centralized management device A until the self-charging rates of the storage battery systems B become uniform.

[0053] First, the charge average (convergence value X αSpecifically, the self-charging rate SOC acquisition unit 243 acquires the self-charging rate SOC, and the average value detection unit 244 detects the internal average value X based on the self-charging rate SOC. i By communicating with other battery storage system B, the charge average (convergence value X α ) to detect.

[0054] Next, the self-charging rate SOC is the charging average (convergence value X α It is determined whether the self-charging rate SOC is greater than the charging average (convergence value X α If the self-charging rate SOC is greater than the charging average (convergence value X α ) or less (S2: NO), the self-charging rate SOC is the charging average (convergence value X α It is determined whether the self-charging rate SOC is smaller than the charging average (convergence value X α If the self-charging rate SOC is smaller than the charging average (convergence value X α ) or more (S4: NO), the self-charging rate SOC is the charging average (convergence value X α ), and the belonging information G is set to "3" indicating the third group (S6). Specifically, in steps S2 to S6, the charging rate comparison unit 245 compares the self charging rate SOC with the charging average (convergence value X α )

[0055] Next, the number of storage battery systems B belonging to each group is detected (S7). Specifically, the number detection unit 246 detects the first number N1, the second number N2, and the third number N3 by communicating with the other storage battery systems B via the communication unit 247.

[0056] Next, it is determined whether the first number N1 is equal to or smaller than the second number N2 (S8). If the first number N1 is equal to or smaller than the second number N2 (S8: YES), it is determined whether the battery belongs to the first group (the affiliation information G is "1") (S9). If the battery belongs to the first group (S9: YES), the rated power is discharged (S10). Specifically, the target value setting unit 241 sets the rated power (positive value) as the output target value. If the battery does not belong to the first group (S9: NO), it is determined whether the battery belongs to the second group (the affiliation information G is "2") (S11). If the battery belongs to the second group (S11: YES), the charging power is calculated (S12), and the calculated charging power is charged (S13). Specifically, the target value setting unit 241 calculates the calculated charging power, and sets the calculated charging power (negative value) as the output target value. If the battery does not belong to the second group (S11: NO), the battery is determined to belong to the third group and charging / discharging is not performed. Specifically, the target value setting unit 241 sets "0" as the output target value.

[0057] In step S8, if the first number N1 is greater than the second number N2 (S8: NO), it is determined whether or not the battery belongs to the first group (the belonging information G is "1") (S14). If the battery belongs to the first group (S14: YES), the discharge power is calculated (S15), and the calculated discharge power is discharged (S16). Specifically, the target value setting unit 241 calculates the calculated discharge power, and sets the calculated discharge power (positive value) as the output target value. If the battery does not belong to the first group (S14: NO), it is determined whether or not the battery belongs to the second group (the belonging information G is "2") (S17). If the battery belongs to the second group (S17: YES), charging of the rated power is performed (S16). Specifically, the target value setting unit 241 sets the rated power (negative value) as the output target value. If the battery does not belong to the second group (S17: NO), it is determined that the battery belongs to the third group, and charging and discharging are not performed. Specifically, the target value setting unit 241 sets the output target value to "0." Note that the process shown in the flowchart of Fig. 3 is an example, and the charging rate uniform process performed by the control board 24 is not limited to the above.

[0058] 4 is a time chart showing the change in the self-charging rate of each storage battery system B when the power system F1 outputs 400 kW in a two-hour supply period. The rated power of each storage battery system B is 100 kW, and the capacity of each storage battery 21 is 400 kWh. The self-charging rate of storage battery system B1 is 100%, the self-charging rate of storage battery system B2 is 50%, the self-charging rate of storage battery system B3 is 40%, and the self-charging rate of storage battery system B4 is 10%.

[0059] Fig. 4(a) shows a case where power provision is started without performing the charging rate uniformity process. In this case, in the middle of the provision period, the self-charging rate of the storage battery system B4 becomes 0%, and the output power of the power system F1 becomes 300kW. After that, the self-charging rate of the storage battery system B3 becomes 0%, and the output power of the power system F1 becomes 200kW. Therefore, the power system F1 cannot maintain an output of 400kW during the provision period.

[0060] FIG. 4(b) shows a case where, during the preparation period before the supply period, the self-charging rates of the battery storage systems B2, B3, and B4 are charged to 100% instead of using the uniform charging rate processing. In this case, the power system F1 can maintain an output of 400 kW during the supply period. However, receiving power from power system K to charge the battery storage systems B2, B3, and B4 incurs extra costs for receiving power. In addition, receiving power from power system K may have a negative impact on power system K and disrupt the supply and demand balance.

[0061] FIG. 4(c) shows a case where the charging rate uniformity process is performed during the preparation period before the provision period. The average charging rate of the storage battery systems B1 to B4 is 50 (= (100 + 50 + 40 + 10) / 4)%. Therefore, at the start of the preparation period, the storage battery system B1 is in the first state and discharges at a rated power of 100 kW. On the other hand, the storage battery systems B3 and B4 are in the second state and each charges at a calculated charging power of 50 (= 100 / 2) kW. The storage battery system B2 is in the third state and does not charge or discharge. The self-charging rate of the storage battery system B1 decreases, and the self-charging rates of the storage battery systems B3 and B4 increase. Then, at time t1 in the middle of the preparation period, the self-charging rate of the storage battery system B3 is 50%. The charging rate uniformity process is performed periodically, and after time t1, the storage battery system B3 is determined to be in the third state. Then, only the storage battery system B4 enters the second state and performs charging with a calculated charging power of 100 = (100 / 1) kW. The storage battery system B3 is in the third state and does not perform charging or discharging. Then, at time t2, when the self-charging rates of the storage battery systems B1 to B4 become uniform, the charging rate uniformity process is no longer performed. At this time, the self-charging rates of the storage battery systems B1 to B4 are all 50%. After that, the supply period begins, and the power system F1 maintains an output of 400 kW during the supply period.

[0062] Next, the operation and effects of the power system F1 according to this embodiment will be described.

[0063] According to this embodiment, the average value detection unit 244 detects the charge average, which is the arithmetic mean value of the self-charging rates of the plurality of storage battery systems B. The charge rate comparison unit 245 compares the self-charging rate acquired by the charge rate acquisition unit 243 with the charge average detected by the average value detection unit 244 to acquire affiliation information indicating the group to which the storage battery system B belongs. The number detection unit 246 detects the first number N1, the second number N2, and the third number N3 of each group. The target value setting unit 241 sets an output target value based on the first number N1, the second number N2, and the third number N3 input from the number detection unit 246 and the affiliation information input from the charge rate comparison unit 245. The inverter 22 discharges when it belongs to the first group (the self-charging rate is higher than the charge average) according to the set output target value, and charges when it belongs to the second group (the self-charging rate is lower than the charge average). Since the storage battery system B with a self-charging rate higher than the charging average discharges and the storage battery system B with a self-charging rate lower than the charging average charges this power, there is no need to receive power from the power grid K. Also, each storage battery system B charges and discharges until its self-charging rate reaches the charging average. This allows the power system F1 to equalize the charging rates of each storage battery system B without receiving power from the power grid K.

[0064] Moreover, according to this embodiment, when the first number N1 is equal to or less than the second number N2, the target value setting unit 241 sets the rated power (positive value) as the output target value when the vehicle belongs to the first group, and sets the calculated charging power (negative value) as the output target value when the vehicle belongs to the second group. Moreover, when the first number N1 is greater than the second number N2, the target value setting unit 241 sets the rated power (negative value) as the output target value when the vehicle belongs to the second group, and sets the calculated discharging power (positive value) as the output target value when the vehicle belongs to the first group. Therefore, the power system F1 can match the total discharging power and the total charging power, and maximize the total discharging power and the total charging power.

[0065] Moreover, according to this embodiment, the average value detection unit 244 detects the charging average by communicating with the other storage battery systems B via the communication unit 247. Furthermore, the number detection unit 246 detects the first number N1, the second number N2, and the third number N3 by communicating with the other storage battery systems B via the communication unit 247. In the charging rate uniformity processing, the centralized management device A does not transmit, receive, or process information with each storage battery system B. Therefore, the power system F1 can reduce the processing burden on the centralized management device A.

[0066] According to the present embodiment, the average value detection unit 244 receives the internal average value X i to at least one of the other storage battery systems B, and an internal average value X j The average value detection unit 244 receives the generated internal average value X i and the received internal average value X j The internal average value X is calculated using the calculation result based on i The calculation process is repeated by the average value detection unit 244 in each storage battery system B, whereby the internal average value X i is the common convergence value X α Converges to the convergence value X α is the internal average value X of each battery storage system B i Therefore, the average value detection unit 244 can appropriately detect the charge average.

[0067] According to the present embodiment, the internal value generation unit 4 receives the internal value Y i to at least one of the other storage battery systems B, and the internal value Y j The internal value generator 4 receives the generated internal value Y i and the received internal value Y j The internal value Y is calculated using the result of the calculation based on i The internal value generator 4 of each storage battery system B repeats the calculation process, and the internal value Yi is the common convergence value Y α The number of vehicles search unit 5 converges to the internal value Y i The initial value is set to , and the number calculation unit 54 calculates the convergence value Y α Therefore, the number detection unit 246 can appropriately detect the first number N1, the second number N2, and the third number N3.

[0068] In this embodiment, the switching unit 51 of the number detection unit 246 sets the internal value Y i (Y1 i ,Y2 i ,Y3 i In the above description, the initial value set in the unit 54 is a combination of "0" and "1", but this is not limited to this. The initial value set by the switching unit 51 may be another combination of numerical values. However, when the initial value is another combination of numerical values, the calculation method in the unit number calculation unit 54 differs. Setting the initial value to a combination of "0" and "1" is desirable because it most simplyifies the calculation method in the unit number calculation unit 54.

[0069] In the present embodiment, the case where each storage battery system B communicates with all other storage battery systems B has been described, but this is not limited to the case. i (Internal value Y1 i ,Y2 i ,Y3 i ) converges, each member of a group (first to third groups) consisting of storage battery systems B having the same affiliation information must be in communication with at least one of all members, and a communication path must exist between any two members (hereinafter, this state will be referred to as a "connected state"). If each group is in a connected state, there is no restriction on which storage battery system B each storage battery system B communicates with, and each storage battery system B does not have to communicate with all other storage battery systems B.

[0070] In the present embodiment, the case has been described in which the average value detection unit 244 detects the charge average by communicating with another storage battery system B via the communication unit 247, but this is not limited to the above. For example, the average value detection unit 244 may obtain the charge average by receiving it from the centralized management device A, the charge average being detected by the centralized management device A.

[0071] In the present embodiment, the case has been described in which the number detection unit 246 detects the first number N1, the second number N2, and the third number N3 by communicating with another storage battery system B via the communication unit 247, but this is not limited to the above. For example, the number detection unit 246 may obtain the first number N1, the second number N2, and the third number N3 detected by the centralized management device A by receiving them from the centralized management device A.

[0072] In the present embodiment, the power system F1 is described as having only a plurality of storage battery systems B as power devices, but the present invention is not limited to this. The power system F1 may also have other power devices including solar cells or loads that consume power. In this case, however, in the charging rate uniformity process, it is necessary to set the output target value of each storage battery system B taking into account the input / output power of the other power devices and the power consumption of the load.

[0073] 5 and 6 are diagrams for explaining a power system F2 according to a second embodiment. FIG. 5 is a block diagram showing an internal configuration of a control board 24 according to the second embodiment. FIG. 6 is a block diagram showing an example of an internal configuration of a rated average detection unit. In FIG. 5 and FIG. 6, elements that are the same as or similar to those in the power system F1 according to the first embodiment are given the same reference numerals, and duplicated explanations are omitted. The power system F2 according to this embodiment differs from the power system F1 according to the first embodiment in that it can also accommodate cases where the rated power of the inverters 22 of each storage battery system B is different.

[0074] The power system F1 according to the first embodiment is for a case where the rated power of the inverters 22 of each storage battery system B is the same. Therefore, if the rated power of the inverters 22 of each storage battery system B is different, the charging rate equalization process may not function properly. The power system F2 according to the second embodiment is configured to also accommodate a case where the rated power of the inverters 22 of each storage battery system B is different. The rated power of the inverter 22 of the storage battery system B is equal to or less than the rated power of the storage battery 21, so it becomes the rated power of the storage battery system B.

[0075] The control board 24 of the storage battery system B according to the second embodiment further includes a rated average detection unit 248. The rated average detection unit 248 detects a first rated average P1, which is an arithmetic mean value of the rated power of the storage battery system B belonging to the first group, a second rated average P2, which is an arithmetic mean value of the rated power of the storage battery system B belonging to the second group, and a third rated average P3, which is an arithmetic mean value of the rated power of the storage battery system B belonging to the third group. The rated average detection unit 248 detects the first rated average P1, the second rated average P2, and the third rated average P3 by communicating with the other storage battery systems B via the communication unit 247. The rated average detection unit 248 outputs the detected first rated average P1, the second rated average P2, and the third rated average P3 to the target value setting unit 241. There are no limitations on the method by which the rated average detection unit 248 detects the first rated average P1, the second rated average P2, and the third rated average P3, but they may be detected in a similar manner to the average detection unit 244.

[0076] As shown in FIG. 6, the rated average detection unit 248 detects an internal average value Z i to at least one of the other storage battery systems B, and the internal average value Z j The internal average value Z i is calculated provisionally within each storage battery system B, and the three internal average values ​​Z1 i ,Z2 i ,Z3 i Contains the internal mean value Z1 iis the internal average value for detecting the first rated average value P1. The internal average value Z2 i is the internal average value for detecting the second rated average P2. The internal average value Z3 i is the internal mean value for detecting the third rated mean P3. The internal mean value Z i (Z1 i ,Z2 i ,Z3 i ) is an internal average value generated in the target battery system B (i-th battery system B), where i is a natural number from 1 to n (n=4 in this embodiment). j (Z1 j ,Z2 j ,Z3 j ) is an internal average value received from the j-th storage battery system B among the other storage battery systems B, where j is a natural number from 1 to n (n=4 in this embodiment). The rated average detection unit 248 generates the internal average value Z i and the received internal average value Z j The internal average value Z i Generate the internal mean value Z i and the internal mean value Z j Even if the internal average value Z is different, the calculation process in the rated average detection unit 248 is repeated, and the internal average value Z i and the internal mean value Z j and converge to a common value.

[0077] The rated average detector 248 detects the internal average value Z i The internal average value Z1 included in i , internal mean value Z2 i , and the internal mean value Z3 i Among them, only the internal average value Z corresponding to the affiliation information input from the charging rate comparison unit 245 is calculated, and the internal average value Z corresponding to the affiliation information is not calculated. i (Z1 i ,Z2 i ,Z3 i ) and the internal average value Z received from the battery storage system B having the same affiliation information j (Z1 j ,Z2 j ,Z3j The internal average value Z i (Z1 i ,Z2 i ,Z3 i When the affiliation information indicates the first group (first state), the rated average detection unit 248 generates an internal average value Z1 i Only the calculation of the internal average value Z2 i and the internal mean value Z3 i When the affiliation information indicates the second group (second state), the rated average detection unit 248 does not calculate the internal average value Z2 i Only the calculation of the internal average value Z3 i and the internal mean value Z1 i When the affiliation information indicates the third group (third state), the rated average detection unit 248 does not calculate the internal average value Z3 i Only the calculation of the internal average value Z1 i and the internal mean value Z2 i 6, the rated average detection unit 248 includes a calculation unit 62, a multiplier 63, an integrator 65, and a convergence detection unit 66.

[0078] The calculation unit 62 performs the same calculation as the calculation unit 32. The multiplier 63 performs the same calculation as the multiplier 33. The integrator 65 performs the same calculation as the integrator 35 on the value input from the multiplier 63. The internal average value Z i is output to the communication unit 247, the calculation unit 62, and the convergence detection unit 66. As described above, the calculation unit 62, the multiplier 63, and the integrator 65 calculate the internal average value Z i The internal average value Z1 included in i , internal mean value Z2 i , and the internal mean value Z3 i Only the calculation corresponding to the affiliation information is performed.

[0079] The rated average detection unit 248 in each storage battery system B repeats the calculation process, and the internal average value Z i (Z1 i ,Z2 i ,Z3i ) are the common convergence values ​​Z α (Z1 α ,Z2 α ,Z3 α ) converges to the convergence value Z1 α is the internal average value Z1 of the battery storage system B in the first state. i The arithmetic mean of the initial values ​​of Z2 α is the internal average value Z2 of the battery storage system B in the second state. i The arithmetic mean of the initial values ​​is the convergence value Z3 α is the internal average value Z3 of the battery storage system B in the third state. i The rated power detection unit 248 calculates the rated power of the battery storage system B by the internal average value Z i Set this as the initial value.

[0080] The convergence detector 66 detects the internal average value Z i Detects that convergence has occurred and calculates the converged internal mean value Z i (Z1 i ,Z2 i ,Z3 i ) the convergence value Z α (Z1 α ,Z2 α ,Z3 α ) as the first rated average P1, the second rated average P2, and the third rated average P3 to the target value setting unit 241. The convergence detection unit 66 detects convergence in the same manner as the convergence detection unit 36.

[0081] The target value setting unit 241 according to the second embodiment further uses the first rating average P1, the second rating average P2, and the third rating average P3 input from the rating average detection unit 248 in setting the output target value when a command to start the preparation period is received. The target value setting unit 241 compares a first overall rating obtained by multiplying the first number N1 and the first rating average P1 with a second overall rating obtained by multiplying the second number N2 and the second rating average P2. When the first overall rating is equal to or less than the second overall rating, if the belonging information indicates the first group (first state), the target value setting unit 241 sets the rated power (positive value) as the output target value, and if the belonging information indicates the second group (second state), the target value setting unit 241 sets the second calculated charging power (negative value) as the output target value. The second calculated charging power is a power value calculated by dividing the first overall rating by the second number N2. As a result, the inverter 22 discharges at the rated power when in the first state, and charges at the second calculated charging power when in the second state. On the other hand, when the first overall rating is greater than the second overall rating, the target value setting unit 241 sets the rated power (negative value) as the output target value when the affiliation information indicates the second group (second state), and sets the second calculated discharging power (positive value) as the output target value when the affiliation information indicates the first group (first state). The second calculated discharging power is a power value calculated by dividing the second overall rating by the first number N1. As a result, the inverter 22 charges at the rated power when in the second state, and discharges at the second calculated discharging power when in the first state. Note that the target value setting unit 241 sets "0" as the output target value when the affiliation information indicates the third group (third state). As a result, the inverter 22 does not charge or discharge. It should be noted that the third number N3 is not necessary for the processing in the target value setting unit 241, and therefore the number calculation unit 54 does not need to detect the third number N3.

[0082] Fig. 7 is an example of a flowchart showing a charging rate uniform process performed by the control board 24 according to the second embodiment. In Fig. 7, steps performing the same or similar processes as those in the flowchart shown in Fig. 3 are given the same step numbers, and duplicated explanations will be omitted.

[0083] Steps S1 to S7 are the same as those in the flowchart shown in FIG. 3. Next, the rated average of the storage battery system B belonging to each group is detected (S21). Specifically, the rated average detection unit 248 detects the first rated average P1, the second rated average P2, and the third rated average P3 by communicating with the other storage battery systems B via the communication unit 247. Next, it is determined whether the first overall rating is equal to or less than the second overall rating (S22). If the first overall rating is equal to or less than the second overall rating (S22: YES), the process proceeds to step S9. On the other hand, if the first overall rating is greater than the second overall rating (S22: NO), the process proceeds to step S14.

[0084] Steps S9 to S18 are almost the same as those in the flowchart shown in Fig. 3. However, in step S12, the second calculated charging power is calculated by dividing the first overall rating by the second number N2, and in step S15, the second calculated discharging power is calculated by dividing the second overall rating by the first number N1. Note that the process shown in the flowchart in Fig. 7 is an example, and the charging rate uniformity process performed by the control board 24 is not limited to the one described above.

[0085] In this embodiment, the inverter 22 also discharges when the battery belongs to the first group (the self-charging rate is higher than the charging average) and charges when the battery belongs to the second group (the self-charging rate is lower than the charging average) according to the set output target value. Therefore, the power system F2 can make the charging rates of the storage battery systems B uniform without receiving power from the power grid K.

[0086] Moreover, according to this embodiment, when the first overall rating is equal to or less than the second overall rating, the target value setting unit 241 sets the rated power (positive value) as the output target value when the battery belongs to the first group, and sets the second calculated charging power (negative value) as the output target value when the battery belongs to the second group. Moreover, when the first overall rating is greater than the second overall rating, the target value setting unit 241 sets the rated power (negative value) as the output target value when the battery belongs to the second group, and sets the second calculated discharging power (positive value) as the output target value when the battery belongs to the first group. Therefore, the power system F2 can match the total discharging power and the total charging power, and maximize the total discharging power and the total charging power. Moreover, since the target value setting unit 241 compares the first overall rating with the second overall rating, the power system F2 can also handle cases where the rated power of the inverter 22 of each storage battery system B is different.

[0087] Moreover, the power system F2 has the same configuration as the power system F1, and thus has the same effects as the power system F1. Furthermore, according to this embodiment, the rated average detection unit 248 transmits the internal average value Z i to at least one of the other storage battery systems B, and the internal average value Z j The rated average detection unit 248 receives the generated internal average value Z i and the received internal average value Z j The internal average value Z i The rated average detection unit 248 in each storage battery system B repeats the calculation process to generate an internal average value Z i is the common convergence value Z α Converges to the convergence value Z α is the internal average value Z of each battery storage system B i Therefore, the rated average detection unit 248 can appropriately detect the first rated average P1, the second rated average P2, and the third rated average P3.

[0088] In the present embodiment, the rated average detection unit 248 detects the first rated average P1, the second rated average P2, and the third rated average P3 by communicating with another storage battery system B via the communication unit 247, but this is not limited to the above. For example, the rated average detection unit 248 may obtain the first rated average P1, the second rated average P2, and the third rated average P3 detected by the centralized management device A by receiving them from the centralized management device A.

[0089] The power system and the storage battery system according to the present invention are not limited to the above-described embodiment. The specific configurations of the components of the power system and the storage battery system according to the present invention can be freely designed in various ways. [Explanation of symbols]

[0090] S1, S2: power system, B, B1 to B4: battery system, 21: battery, 22: inverter, 243: charging rate acquisition unit, 244: average value detection unit, 246: number of units detection unit, 247: communication unit, 248: average output detection unit

Claims

1. A power system including a plurality of storage battery systems, Each of the storage battery systems includes: A storage battery, A communication unit for communicating with other devices; A charging rate acquisition unit that acquires a charging rate of the storage battery; an average value detection unit that detects a charging average that is an arithmetic mean value of the charging rates of the plurality of storage battery systems; An inverter that charges and discharges the storage battery; Equipped with The average value detection unit detects the charging average by communicating with the other device via the communication unit; The inverter performs discharging when a self-charging rate, which is the charging rate acquired by the charging rate acquisition unit, is in a first state in which the self-charging rate is greater than the charging average, and performs charging when the self-charging rate is in a second state in which the self-charging rate is smaller than the charging average. Power system.

2. The rated power of each inverter of the plurality of storage battery systems is the same as each other, Each of the storage battery systems includes: a number detection unit that detects a first number that is the number of storage battery systems in the first state and a second number that is the number of storage battery systems in the second state, The inverter is When the first number is equal to or less than the second number, discharging is performed at a rated power in the first state, and charging is performed at a calculated charging power obtained by multiplying the first number by the rated power and dividing the result by the second number in the second state. When the first number is greater than the second number, charging is performed at a rated power when in the second state, and discharging is performed at a calculated discharging power obtained by multiplying the second number by the rated power and dividing the result by the first number when in the first state. The power system of claim 1 .

3. Each of the storage battery systems includes: a number detection unit that detects a first number that is the number of storage battery systems in the first state and a second number that is the number of storage battery systems in the second state; a rated average detection unit that detects a first rated average, which is an arithmetic mean value of the rated power of the storage battery system in the first state, and a second rated average, which is an arithmetic mean value of the rated power of the storage battery system in the second state; Further preparation, The inverter is When a first overall rating obtained by multiplying the first number of units and the first rating average is equal to or less than a second overall rating obtained by multiplying the second number of units and the second rating average, discharging is performed at a rated power when in the first state, and charging is performed at a calculated charging power obtained by dividing the first overall rating by the second number of units when in the second state; When the first overall rating is greater than the second overall rating, charging is performed at a rated power when in the second state, and discharging is performed at a calculated discharge power obtained by dividing the second overall rating by the first number when in the first state. The power system of claim 1 .

4. The number detection unit a first value or a second value is set as an initial internal value, the internal value is transmitted to at least one of the other battery systems via the communication unit, and an internal value is generated by using a calculation result based on the internal value received by the communication unit from the at least one of the other battery systems and the generated internal value, and this process is repeated until convergence occurs; When in the first state, a calculation is performed based on an internal value received from the storage battery system in the first state and the generated internal value, and a reciprocal of the converged internal value is detected as the first number, and a reciprocal of the converged internal value received from the storage battery system in the second state is detected as the second number, When in the second state, a calculation is performed based on an internal value received from the storage battery system in the second state and the generated internal value, and a reciprocal of the converged internal value is detected as the second number, and a reciprocal of the converged internal value received from the storage battery system in the first state is detected as the first number. The power system according to claim 2 or 3.

5. The average value detection unit the generated internal average value is transmitted to at least one of the other storage battery systems via the communication unit, and an internal average value is generated using a calculation result based on the internal average value received by the communication unit from the at least one of the other storage battery systems and the generated internal average value; and the converged internal average value is detected as the charge average by repeating this process. The power system of claim 1 .

6. A storage battery system included in a power system having a plurality of storage battery systems, A storage battery, A communication unit for communicating with other devices; A charging rate acquisition unit that acquires a charging rate of the storage battery; an average value detection unit that detects a charging average that is an arithmetic mean value of the charging rates of the plurality of storage battery systems; An inverter that charges and discharges the storage battery; Equipped with The average value detection unit detects the charging average by communicating with the other device via the communication unit; The inverter performs discharging when a self-charging rate, which is the charging rate acquired by the charging rate acquisition unit, is in a first state in which it is greater than the charging average, and performs charging when the self-charging rate is in a second state in which it is smaller than the charging average. Battery storage system.

Images