Storage battery control system, storage battery control method, storage battery control program, and integrated controller

Abstract

The battery control system of the present disclosure includes a first inverter, a second inverter, and an integrated controller, wherein the integrated controller switches operation of the first inverter and the second inverter between GFL control and GFM control based on characteristic values ​​of the first storage battery and the second storage battery or temperatures of the first inverter and the second inverter, and adjusts the operating state of the current source based on changes in amplitude and frequency in the AC voltage generated by the voltage source.

Description

[Technical field]

[0001] The present disclosure relates to a storage battery control system, a storage battery control method, a storage battery control program, and an integrated controller. [Background technology]

[0002] Patent Document 1 discloses a distributed power system including multiple distributed power sources and a control device. Each distributed power source is used as either a current source or a voltage source. The current source is operated in synchronization with the voltage and frequency output by the voltage source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-278700 A Summary of the Invention [Problem to be solved by the invention]

[0004] When using storage batteries as distributed power sources, applying the disclosure of Patent Document 1 results in the existence of storage batteries used as voltage sources and storage batteries used as current sources. In this case, the load on each storage battery is biased, and there is a possibility that deterioration of a particular storage battery progresses.

[0005] In view of the above circumstances, the present disclosure aims to provide a storage battery control system, a storage battery control method, a storage battery control program, and an integrated controller that can suppress the progression of deterioration of a specific storage battery. [Means for solving the problem]

[0006] One embodiment of the battery control system according to the present disclosure is a battery control system for controlling a plurality of storage batteries, comprising: a first inverter for converting DC power from a first storage battery into AC power; a second inverter for converting DC power from a second storage battery into AC power; and an integrated controller for controlling the first inverter and the second inverter, wherein the first inverter is capable of switching its operation between GFM control for causing the first storage battery to function as a voltage source and GFL control for causing the first storage battery to function as a current source, and the second inverter is capable of switching its operation between GFM control for causing the second storage battery to function as a voltage source and GFL control for causing the second storage battery to function as a current source, and the integrated controller switches the operation of the first inverter and the second inverter between the GFL control and the GFM control based on characteristic values ​​of the first storage battery and the second storage battery or the temperatures of the first inverter and the second inverter, and the operating state of the current source is adjusted based on changes in amplitude and frequency in the AC voltage generated by the voltage source.

[0007] One aspect of the storage battery control method of the present disclosure includes the steps of switching operation of the first inverter and the second inverter between GFL control and GFM control based on characteristic values ​​of a first storage battery and a second storage battery, or temperatures of a first inverter that converts DC power from the first storage battery into AC power and a second inverter that converts DC power from the second storage battery into AC power, and adjusting the operating state in the GFL control based on changes in amplitude and frequency in the AC voltage generated based on the GFM control, wherein the GFM control is control for causing the first storage battery or the second storage battery to function as a voltage source, and the GFL control is control for causing the first storage battery or the second storage battery to function as a current source.

[0008] A storage battery control program according to the present disclosure causes a computer to execute the steps of switching the operation of the first inverter and the second inverter between GFL control and GFM control based on characteristic values ​​of a first storage battery and a second storage battery, or temperatures of a first inverter that converts DC power from the first storage battery into AC power and a second inverter that converts DC power from the second storage battery into AC power, and adjusting the operating state in the GFL control based on changes in amplitude and frequency in the AC voltage generated based on the GFM control, wherein the GFM control causes the first storage battery or the second storage battery to function as a voltage source, and the GFL control causes the first storage battery or the second storage battery to function as a current source.

[0009] One embodiment of the integrated controller according to the present disclosure is an integrated controller that controls a first inverter that converts DC power from a first storage battery into AC power and a second inverter that converts DC power from a second storage battery into AC power, wherein the integrated controller outputs an operation switching signal that switches the operation of the first inverter and the second inverter between GFL control and GFM control based on characteristic values ​​of the first storage battery and the second storage battery or temperatures of the first inverter and the second inverter, the GFM control causes the first storage battery or the second storage battery to function as a voltage source, and the GFL control causes the first storage battery or the second storage battery to function as a current source, and the operating state of the current source is adjusted based on changes in amplitude and frequency in the AC voltage generated by the voltage source. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a storage battery control system, a storage battery control method, a storage battery control program, and an integrated controller that are capable of suppressing deterioration of a storage battery. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a microgrid according to the present disclosure. [Diagram 2] FIG. 1 is a diagram illustrating GFM control according to the present disclosure. [Diagram 3] FIG. 2 is a diagram illustrating GFL control according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments, and may be modified as desired within the scope of the technical concept of the present disclosure.

[0013] Embodiment 1 Fig. 1 is a schematic diagram illustrating a microgrid in a first embodiment. As shown in Fig. 1, the microgrid 1 includes a power generation facility 2, a plurality of power receiving and distributing facilities 4, a plurality of storage batteries 5, a power transmission and distribution network 6, and a battery control system 10. The battery control system 10 includes an integrated controller 11 and a plurality of PCSs (Power Conditioning Systems) 12. The microgrid 1 is connected to a power system 3 by the power transmission and distribution network 6. In addition, the components in the microgrid 1 are connected to each other by the power transmission and distribution network 6.

[0014] The power generation facility 2 is, for example, a wind power plant, a solar cell, a hydroelectric power plant, etc. Other types of power generation facilities 2 may be used. Furthermore, a combination of a plurality of types of power generation facilities 2 may be used. The microgrid 1 is configured to charge and discharge a plurality of storage batteries 5 according to the supply and demand situation of power. For example, in a situation where the demand for power is low, the plurality of storage batteries 5 are charged using the power generated by the power generation facility 2. In addition, in a situation where the demand for power is high, the power generated by the power generation facility 2 and the power of the plurality of storage batteries 5 are combined and output to the power system 3. Alternatively, the combined power may be supplied to a load in the microgrid 1.

[0015] A switch (not shown) may be provided between the microgrid 1 and the power grid 3. The switch is switchable between a closed state and an open state. When the switch is in the closed state, the microgrid 1 and the power grid 3 are disconnected. This state is called an island mode. In the island mode, the microgrid 1 generates and consumes power independently. When the switch is in the open state, the microgrid 1 and the power grid 3 are connected. This state is called a grid-connected mode.

[0016] Each storage battery 5 may be, for example, a lithium ion battery, a NAS battery, a redox flow battery, or the like. Other types of storage batteries 5 may also be used. Each PCS 12 has a built-in inverter INV that controls the charging and discharging of each storage battery 5. Each PCS 12 also has a control unit C that controls the inverter INV, a communication unit T that communicates with the integrated controller 11, and the like.

[0017] In the following description, any two of the multiple PCSs 12 are referred to as the first PCS 12a and the second PCS 12b. Any two of the multiple storage batteries 5 are referred to as the first storage battery 5a and the second storage battery 5b. The first PCS 12a controls the charging and discharging of the first storage battery 5a, and the second PCS 12b controls the charging and discharging of the second storage battery 5b. The inverter INV included in the first PCS 12a is referred to as the "first inverter." The inverter INV included in the second PCS 12b is referred to as the "second inverter."

[0018] The first PCS 12a and the second PCS 12b can switch between GFL (Grid Following) control and GFM (Grid Forming) control. GFL control is an operation that causes the corresponding storage battery 5 to function as a current source. GFM control is an operation that causes the corresponding storage battery 5 to function as a voltage source. In other words, the first PCS 12a can switch whether the first storage battery 5a functions as a voltage source or a current source. Similarly, the second PCS 12b can switch whether the second storage battery 5b functions as a voltage source or a current source.

[0019] The integrated controller 11 switches the operation of the first PCS 12a and the second PCS 12b between GFL control and GFM control. Specifically, the integrated controller 11 outputs an operation switching signal to the first PCS 12a and the second PCS 12b. The operation switching signal is a signal for switching the operation between GFL control and GFM control.

[0020] The integrated controller 11 may output an operation switching signal to the first PCS 12a and the second PCS 12b based on the temperatures of the first inverter and the second inverter. In this case, the temperatures of the first inverter and the second inverter are input to the integrated controller 11. The integrated controller 11 outputs an operation switching signal to the first PCS 12a and the second PCS 12b so that the temperature difference between the first inverter and the second inverter is reduced.

[0021] For example, assume that an inverter performing GFM control has a tendency to have a higher temperature than an inverter performing GFL control. Also assume that a first inverter performs GFM control and a second inverter performs GFL control. The integrated controller 11 calculates the temperature difference between the first inverter and the second inverter. When this temperature difference exceeds a threshold, the integrated controller 11 outputs an operation switching signal to the first PCS 12a to perform GFL control. Furthermore, the integrated controller 11 outputs an operation switching signal to the second PCS 12b to perform GFM control.

[0022] This reduces the temperature difference between the first inverter and the second inverter, making it possible to prevent only a specific inverter included in the microgrid 1 from becoming too hot. In other words, it becomes possible to level the loads of the multiple inverters included in the microgrid 1.

[0023] Furthermore, the integrated controller 11 may output an operation switching signal to the first PCS 12a and the second PCS 12b based on the characteristic values ​​of the first storage battery 5a and the second storage battery 5b. In this case, the characteristic values ​​of the first storage battery 5a and the second storage battery 5b are input to the integrated controller 11. The characteristic values ​​are, for example, parameters such as temperature, SOC (State of charge), SOH (State of health), etc. Also, these parameters may be used in combination. The integrated controller 11 outputs the operation switching signal to the first PCS 12a and the second PCS 12b so that the difference between the characteristic values ​​of the first storage battery 5a and the second storage battery 5b is reduced.

[0024] For example, assume that the storage battery under GFM control tends to deteriorate more than the storage battery under GFL control. Also assume that the first inverter undertakes GFM control and the second inverter undertakes GFL control. The integrated controller 11 calculates the difference between the characteristic values ​​of the first storage battery 5a and the second storage battery 5b. If this difference exceeds a threshold, the integrated controller 11 outputs an operation switching signal to the first PCS 12a to perform GFL control. Furthermore, the integrated controller 11 outputs an operation switching signal to the second PCS 12b to perform GFM control.

[0025] This reduces the difference in the characteristic values ​​of the first storage battery 5a and the second storage battery 5b. This makes it possible to suppress the progression of deterioration only in a specific storage battery included in the microgrid 1. In other words, it becomes possible to level out the degree of deterioration of the multiple storage batteries included in the microgrid 1. The above-mentioned "threshold value" is determined in advance, for example, by a preliminary experiment, and is stored in the memory of the integrated controller 11, etc.

[0026] The integrated controller 11 has a calculation unit, a communication unit, etc. The calculation unit is a CPU or the like, and performs calculations to realize the functions of the integrated controller 11 described above. The communication unit communicates with each PCS 12 wirelessly or via wire. For example, an operation switching signal generated by the calculation unit is transmitted to each PCS 12 via the communication unit.

[0027] In this embodiment, the operating state of the storage battery and inverter as a current source is adjusted based on the change in amplitude and frequency of the AC voltage generated by the storage battery and inverter as a voltage source. The "operating state" refers to, for example, the magnitude of the active power and reactive power. In the following description, an inverter that performs GFL control is referred to as a "current source inverter". Similarly, an inverter that performs GFM control is referred to as a "voltage source inverter". An example of GFM control and GFL control will be described below with reference to Figs. 2 and 3.

[0028] FIG. 2 is a diagram illustrating an example of GFM control. The "power supply target" shown in FIG. 2 is a target to which power is supplied by the multiple storage batteries 5. For example, when the multiple storage batteries 5 supply power to the power system 3, the power line connecting the microgrid 1 and the power system 3 is the "power supply target." At least one of the multiple storage batteries 5 included in the microgrid 1 is used as a voltage source. In other words, at least one inverter of the multiple PCSs 12 included in the microgrid 1 performs GFM control.

[0029] Qmeasure shown in Fig. 2 is the actual measurement value of reactive power Q supplied to the power supply target. Pmeasure is the actual measurement value of active power P supplied to the power supply target. The actual measurement value Qmeasure and the actual measurement value Pmeasure are measured, for example, by a measuring device attached to the power line to which power is supplied. The measured actual measurement value Qmeasure and actual measurement value Pmeasure are subjected to zero order hold (ZOH) and input to the PCS 12 which performs GFM control. The processing in the control unit C of the PCS 12 will be explained below.

[0030] Qref is a command value for reactive power Q. Pref is a command value for active power P. The command value Pref and the command value Qref may be calculated, for example, by the integrated controller 11. The command value Pref and the command value Qref are input to the control unit C of the PCS 12 that performs GFM control.

[0031] The control unit C that performs GFM control calculates the deviation dQ between the command value Qref and the measured value Qmeasure for reactive power Q. The control unit C performs Qv control in the control block B11 of FIG. 2. In the "Qv control", the amplitude of the AC voltage that the voltage source inverter outputs to the power supply target is calculated based on the command value Qref. The Qv control is a feedback control for bringing the deviation dQ closer to zero. This feedback control may be, for example, PI control. The control unit C also adds the rated voltage Vm [V] to the output in the control block B11. The value obtained by the addition becomes the output amplitude Vv of the voltage that the voltage source inverter outputs to the power supply target.

[0032] The control unit C that performs the GFM control performs virtual synchronous generator control as shown by the control block B12 in FIG. 2. The virtual synchronous generator control is a control that imparts characteristics simulating a synchronous generator when the voltage source inverter converts the DC power of the storage battery 5 into AC power. The virtual synchronous generator control is also called VSG (Virtual Synchronous Generator) control. By performing the VSG control, it is possible to impart inertia to the AC power generated using the storage battery 5 and improve stability against load fluctuations. The control block B12 shown in FIG. 2 represents a specific example of the VSG control.

[0033] The control unit C that performs the VSG control calculates the deviation dP between the command value Pref and the measured value Pmeasure with respect to the active power P. The control unit C also calculates the deviation df with respect to the frequency based on the deviation dP. When calculating the deviation df, a transfer function that simulates the damper component D and the inertia component M of the actual synchronous generator is set. The control unit C adds the rated frequency fn [Hz] to the deviation df that is the output in the control block B12. The value obtained by the addition becomes the output frequency fv that the voltage source inverter outputs to the power supply target. The control unit C also performs governor control as shown in the control block B13. Governor control is a control that imitates a speed governor for keeping the rotation speed of the synchronous generator constant.

[0034] The voltage source inverter supplies an AC voltage with an output amplitude Vv and an output frequency fv to a power supply target. The above is the operation of the PCS 12 performing GFM control as a voltage source. Next, the operation of the PCS 12 performing GFL control as a current source will be described.

[0035] Fig. 3 is a diagram for explaining an example of GFL control. In Fig. 3, V and f are actual measurement values ​​of AC voltage supplied from a voltage source inverter. V and f are a set of actual measurement values ​​of voltage amplitude V and frequency f. A measured current value Imeasure is an actual measurement value of a current supplied to a power supply target. Note that when the voltage amplitude corresponding to the frequency component of frequency f, which is the actual measurement value, is the main component of the voltage waveform, the control described below may be performed using an effective voltage value instead of the above-mentioned actual measurement value of voltage amplitude V.

[0036] The voltage amplitude V, frequency f, and current actual value Imeasure of the AC voltage are measured, for example, by a measuring device attached to the power line to which power is supplied. The measured actual values ​​V, f, and current actual value Imeasure are zero-order held (ZOH) and input to the PCS 12 that performs GFL control. The control unit C of the PCS 12 performs fP control and vQ control shown in the control block B21 of FIG. 3. In the "fP control", the control unit C calculates a target value Ptarget of the active power P based on the actual measured value of the frequency f. In the "vQ control", the control unit C calculates a target value Qtarget of the reactive power Q based on the actual measured value of the voltage amplitude V. For example, consider a case in which the control unit C has a set value fr of the frequency f and a set value Vr of the voltage amplitude V. In this case, the control unit C calculates the target value Ptarget so that the difference between the set value fr and the actual measured value of the frequency f becomes small. Moreover, the control unit C calculates the target value Qtarget so that the difference between the set value Vr and the voltage amplitude V, which is the actual measured value, becomes small.

[0037] Next, current conversion is performed as shown in control block B22 in Fig. 3. That is, the control unit C of the PCS 12 converts the target value Ptarget and the target value Qtarget into a current command value Iref. The control unit C also calculates the deviation ΔI between the current command value Iref and the current measurement value Imeasure. The control unit C performs feedback control in a control block B23 using the deviation ΔI as an input. The transfer function in the control block B23 is set so that the deviation ΔI approaches zero. This feedback control may be, for example, PI control.

[0038] The control unit C performs addition based on the voltage amplitude V, which is an actual measurement value, to the output of the control block B23. Based on the result of this addition, the current source inverter supplies power to the power supply target. The above is the operation of the PCS 12 that performs GFM control as a current source.

[0039] As described above, in GFM control, the storage battery 5 and the inverter INV function as a voltage source, generating an output amplitude Vv and an output frequency fv in AC voltage. In GFL control, the storage battery 5 and the inverter INV function as a current source, supplying current (active power P, reactive power Q) based on the actual measured values ​​V and f. This allows the active power and reactive power supplied by the voltage source inverter to the power supply target to be shared by the current source inverter.

[0040] The functions of the integrated controller 11 and the PCS 12 described above are realized by a processor such as a CPU (Central Processing Unit) executing a program stored in a program memory. Some or all of these functions may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array), or may be realized by a combination of software and hardware.

[0041] The program for realizing the functions of the PCS 12 and integrated controller 11 described above is recorded, for example, on a computer-readable recording medium. The program recorded on this recording medium may be read into a computer and executed to perform the processing in the PCS 12 and integrated controller 11 described above. Here, "reading a program recorded on a recording medium into a computer and executing it" includes installing the program into a computer. The term "computer" here includes an OS and hardware such as peripheral devices.

[0042] Furthermore, a "computer" may include multiple computer devices connected via a network including the Internet or communication lines such as a WAN, LAN, or leased line. Furthermore, a "computer-readable recording medium" refers to portable media such as a flexible disk, optical magnetic disk, ROM, or CD-ROM, and storage devices such as a hard disk built into a computer. Thus, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM.

[0043] The recording medium also includes a recording medium installed inside or outside the computer and accessible from a distribution server to distribute the program. The program may be divided into a plurality of parts, each of which may be downloaded at a different timing, and then combined by the PCS 12 and the integrated controller 11. The divided programs may be distributed by different distribution servers. Furthermore, the "computer-readable recording medium" includes a recording medium that holds a program for a certain period of time, such as a volatile memory (RAM) inside a computer that becomes a server or a client when a program is transmitted via a network. The program may be a recording medium for implementing part of the above-mentioned functions. Furthermore, the program may be a recording medium that can realize the above-mentioned functions in combination with a program already recorded in the computer, that is, a so-called difference file (difference program).

[0044] As described above, the battery control system 10 according to the present embodiment is a battery control system 10 that controls a plurality of storage batteries 5, and includes a first inverter that converts DC power from the first storage battery 5a into AC power, a second inverter that converts DC power from the second storage battery 5b into AC power, and an integrated controller 11 that controls the first inverter and the second inverter. The first inverter can switch between GFM control for making the first storage battery 5a function as a voltage source and GFL control for making the first storage battery 5 function as a current source. The second inverter can switch between GFM control for making the second storage battery 5b function as a voltage source and GFL control for making the second storage battery 5b function as a current source. The integrated controller 11 switches the operations of the first inverter and the second inverter between GFL control and GFM control based on the characteristic values ​​of the first storage battery 5a and the second storage battery 5b or the temperatures of the first inverter and the second inverter. Based on the change in amplitude V and frequency f of the AC voltage generated by the voltage source, the operating state of the current source (active power P, reactive power Q) is adjusted.

[0045] According to the storage battery control system 10, it is possible to equalize the degree of deterioration of the multiple storage batteries 5, and to prevent deterioration from progressing only in a specific storage battery 5. Alternatively, it is possible to equalize the load of the multiple inverters, and to prevent only a specific inverter from becoming too hot.

[0046] Furthermore, the "characteristic value" may be at least one of temperature, SOC, and SOH. For example, when temperature is used as the characteristic value, the temperatures of the multiple storage batteries 5 can be equalized. When SOC is used as the characteristic value, the SOCs of the multiple storage batteries 5 can be equalized. When SOH is used as the characteristic value, the SOHs of the multiple storage batteries 5 can be equalized.

[0047] The present disclosure proposes a storage battery control method as follows. That is, the storage battery control method includes a step of switching the operation of the first inverter and the second inverter between GFL control and GFM control based on the characteristic values ​​of the first storage battery 5a and the second storage battery 5b, or the temperatures of the first inverter that converts DC power from the first storage battery 5a to AC power and the second inverter that converts DC power from the second storage battery 5b to AC power, and a step of adjusting the operating state in the GFL control based on changes in the amplitude V and frequency f of the AC voltage generated based on the GFM control. In this control method, the GFM control is control for making the first storage battery 5a or the second storage battery 5b function as a voltage source, and the GFL control is control for making the first storage battery 5a or the second storage battery 5b function as a current source.

[0048] The present disclosure also proposes a storage battery control program as follows. That is, the storage battery control program causes a computer to execute a step of switching the operation of the first inverter and the second inverter between GFL control and GFM control based on the characteristic values ​​of the first storage battery 5a and the second storage battery 5b, or the temperatures of the first inverter that converts DC power from the first storage battery 5a to AC power and the second inverter that converts DC power from the second storage battery 5b to AC power, and a step of adjusting the operating state in the GFL control based on changes in amplitude and frequency in the AC voltage generated based on the GFM control. The GFM control is control for making the first storage battery 5a or the second storage battery 5b function as a voltage source, and the GFL control is control for making the first storage battery 5a or the second storage battery 5b function as a current source.

[0049] Embodiment 2 Next, a description will be given of the microgrid 1 and the battery control system 10 according to the embodiment 2. The microgrid 1 and the battery control system 10 according to the embodiment have the same basic configuration as the embodiment 1, so the description will focus on the differences.

[0050] In this embodiment, the integrated controller 11 assigns reference power to each of the multiple PCSs 12. The "reference power" is set so that the multiple PCSs 12 generate power using the multiple storage batteries 5 and the combined power matches the power demand. For example, in GFM control, the values ​​of Qref and Pref shown in Fig. 2 are set to values ​​that reflect the reference power. Also, in GFL control, the values ​​of Qtarget and Ptarget shown in Fig. 3 are set to values ​​that reflect the reference power.

[0051] In this manner, the integrated controller 11 sets the reference power for each PCS 12 (that is, each inverter INV), so that the loads on the multiple storage batteries 5 can be leveled.

[0052] The technical scope of the present disclosure is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure.

[0053] For example, the GFM control and GFL control shown in Figures 2 and 3 are merely examples. GFM control is sufficient if the electrical energy of the storage battery 5 can be extracted as a voltage source. Also, GFL control is sufficient if the electrical energy of the storage battery 5 can be extracted as a current source.

[0054] Furthermore, the microgrid 1 may be completely independent from the power system 3. In other words, the microgrid 1 may be configured to supply power from the storage batteries 5 only to loads (e.g., houses in rural areas) included in the microgrid 1. In this case as well, the effect of suppressing deterioration of the multiple storage batteries 5 can be obtained.

[0055] In the above embodiment, the inverter INV of the PCS 12 that performs GFL control adjusts the operating state (active power P and reactive power Q) of the current source based on the change in amplitude V and frequency f of the AC voltage generated by the voltage source. However, the present invention is not limited to this, and for example, the integrated controller 11 may adjust the operating state of the current source.

[0056] In addition, the above-described embodiments and modifications may be combined as appropriate. [Explanation of symbols]

[0057] 5a...first storage battery 5b...second storage battery 10...storage battery control system 11...integrated controller

Claims

1. A battery control system for controlling a plurality of batteries, a first inverter that converts DC power from the first storage battery into AC power; a second inverter that converts DC power from the second storage battery into AC power; an integrated controller that controls the first inverter and the second inverter, The first inverter is capable of switching an operation between a GFM control for causing the first storage battery to function as a voltage source and a GFL control for causing the first storage battery to function as a current source; The second inverter is capable of switching an operation between GFM control for causing the second storage battery to function as a voltage source and GFL control for causing the second storage battery to function as a current source; the integrated controller switches operations of the first inverter and the second inverter between the GFL control and the GFM control based on temperatures of the first storage battery and the second storage battery, or temperatures of the first inverter and the second inverter, or a characteristic value representing a degree of deterioration of the first storage battery and the second storage battery; A battery control system in which the operating state of the current source is adjusted based on changes in amplitude and frequency in the AC voltage generated by the voltage source.

2. The battery control system of claim 1 , wherein the integrated controller sets a reference power for the first inverter and the second inverter.

3. the operating conditions are active and reactive powers of the current sources; The battery control system of claim 1 , wherein the first inverter or the second inverter performing the GFL control adjusts the active power and the reactive power of the current source based on the changes in the amplitude and the frequency.

4. switching operations of the first inverter and the second inverter between GFL control and GFM control based on temperatures of a first storage battery and a second storage battery, or temperatures of a first inverter that converts DC power from the first storage battery into AC power and a second inverter that converts DC power from the second storage battery into AC power, or a characteristic value that represents a degree of deterioration of the first storage battery and the second storage battery; and adjusting an operating state in the GFL control based on a change in amplitude and frequency in the AC voltage generated based on the GFM control. the GFM control is control for causing the first storage battery or the second storage battery to function as a voltage source, A method for controlling a storage battery, wherein the GFL control is control for causing the first storage battery or the second storage battery to function as a current source.

5. On the computer, switching operations of the first inverter and the second inverter between GFL control and GFM control based on temperatures of a first storage battery and a second storage battery, or temperatures of a first inverter that converts DC power from the first storage battery into AC power and a second inverter that converts DC power from the second storage battery into AC power, or a characteristic value that represents a degree of deterioration of the first storage battery and the second storage battery; and adjusting an operating state in the GFL control based on a change in amplitude and frequency in an AC voltage generated based on the GFM control; The GFM control causes the first storage battery or the second storage battery to function as a voltage source; The GFL control is a battery control program that causes the first storage battery or the second storage battery to function as a current source.

6. An integrated controller that controls a first inverter that converts DC power from a first storage battery into AC power and a second inverter that converts DC power from a second storage battery into AC power, the integrated controller outputs an operation switching signal for switching the operation of the first inverter and the second inverter between GFL control and GFM control based on the temperatures of the first storage battery and the second storage battery, or the temperatures of the first inverter and the second inverter, or a characteristic value representing a degree of deterioration of the first storage battery and the second storage battery; The GFM control causes the first storage battery or the second storage battery to function as a voltage source; The GFL control causes the first storage battery or the second storage battery to function as a current source, An integrated controller that adjusts the operating state of the current source based on changes in amplitude and frequency in the AC voltage generated by the voltage source.

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