Control device for power converter, power conversion system, program, and control method for power converter

Abstract

This control device (16 to 19) is applied to a power conversion system (10) comprising a plurality of electricity storage unit modules (30, 60, 90, 130, 160, 190, 230, 260, 290) which have electricity storage units (31, 61, 91, 131, 161, 191, 231, 261, 291) and power converters (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the electricity storage units and each of which is electrically connected in parallel. The control device comprises: a control unit (16a) that performs switching processing of each power converter so that the electricity storage amount of each electricity storage unit approaches a target value; and an adjustment unit (16b) that performs adjustment processing. The adjustment processing is switching processing for adjusting a module current flowing through at least one of the electricity storage unit modules so as to prevent the magnitude of the terminal voltage in at least one of the power converters from exceeding an upper limit voltage.

Description

Power converter control device, power conversion system, program, and power converter control method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-014492 filed on February 1, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power converter control device, a power conversion system, a program, and a power converter control method.

[0003] A power conversion system having a power converter and a plurality of storage batteries is known. The power converter converts power between the storage batteries. An example of such a technology is disclosed in Patent Document 1.

[0004] JP 2022-23722 A

[0005] In some cases, power storage modules each having a power storage unit and a power converter are electrically connected in parallel. In such cases, it is desirable to appropriately realize a power conversion system in which the power storage modules are electrically connected in parallel.

[0006] The present disclosure has been made to solve the above-mentioned problems, and its main purpose is to provide a power converter control device, a power conversion system, a program, and a power converter control method that appropriately realize a power conversion system in which each storage unit is electrically connected in parallel.

[0007] The present disclosure provides a system including a plurality of power storage modules, each having a power storage unit and a power converter electrically connected to the power storage unit, in a power converter control device applied to a power conversion system in which the power storage modules are electrically connected in parallel, the system including: a control unit that performs switching processing on each power converter so that the amount of power stored in each power storage unit approaches a target value; and an adjustment unit that performs adjustment processing, wherein the adjustment processing is a switching processing that adjusts a module current flowing in at least one of the power storage modules so as to prevent the magnitude of the terminal voltage in at least one of the power converters from exceeding an upper limit voltage.

[0008] In a configuration in which multiple power storage modules are electrically connected in parallel, each power storage module shares the power required for the power conversion system. In this case, if the sharing of the power required is inappropriate, there is a concern that the power storage modules may not be used appropriately or that an overvoltage may be applied to at least one of the power converters. In this case, there is a concern that the power conversion system in which the power storage modules are electrically connected in parallel may not be properly implemented.

[0009] Therefore, in the present disclosure, switching processing of each power converter is performed so that the amount of power stored in each power storage unit approaches a target value. The target value can be set arbitrarily for each power storage unit within a range that can meet the requirements for the power conversion system. Therefore, the amount of power stored in each power storage unit can be controlled, and each power storage unit can be used appropriately.

[0010] A switching process is then performed to adjust the module current flowing through at least one of the power storage modules so as to prevent the terminal voltage of at least one of the power converters from exceeding the upper limit voltage, thereby preventing overvoltage from being applied to the power converters.

[0011] According to the present disclosure described above, it is possible to appropriately use the power storage unit while suppressing the application of an overvoltage to the power converter, thereby appropriately realizing a power conversion system in which the power storage unit modules are electrically connected in parallel.

[0012] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a configuration diagram of a power conversion system according to a first embodiment, Fig. 2 is a diagram showing an example of a power converter, Fig. 3 is a flowchart showing a procedure for current distribution control, Fig. 4 is a diagram showing an example of adjustment processing, Fig. 5 is a diagram showing an example of adjustment processing, Fig. 6 is a diagram showing an example of adjustment processing, Fig. 7 is a diagram showing an example of adjustment processing, Fig. 8 is a diagram showing an example of redistribution processing, Fig. 9 is a diagram showing an example of redistribution processing, Fig. 10 is a diagram showing an example of reduction processing, Fig. 11 is a flowchart showing a procedure for overvoltage suppression control, and Fig. 12 is a flowchart showing a procedure for overcurrent suppression control. FIG. 13 is a flowchart showing an example of a change process executed in the switching control according to the second embodiment, FIG. 14 is a diagram showing an example of the change process, FIG. 15 is a flowchart showing the processing procedure of the switching control, FIG. 16 is a configuration diagram of a power conversion system according to the third embodiment, FIG. 17 is a configuration diagram of a power conversion system according to another embodiment, FIG. 18 is a configuration diagram of a power conversion system according to another embodiment, FIG. 19 is a configuration diagram of a power conversion system according to another embodiment, FIG. 20 is a diagram showing an example of a power converter, and FIG. 21 is a diagram showing an example of a power converter.

[0013] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0014] A first embodiment of a control device according to the present disclosure will now be described with reference to the drawings. In this embodiment, the control device constitutes a power conversion system mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0015] FIG. 1 shows a configuration diagram of a power conversion system 10 mounted on a vehicle. The power conversion system 10 includes a plurality of storage battery modules (corresponding to "power storage module"), and in this embodiment, includes three modules: a first storage battery module 30, a second storage battery module 60, and a third storage battery module 90. Each storage battery module 30, 60, 90 includes a storage battery 31, 61, 91 (corresponding to "power storage module"). Each storage battery 31, 61, 91 is, for example, a battery pack configured as a series connection of battery cells serving as single cells. The battery cells may be, for example, secondary batteries such as lithium-ion batteries.

[0016] A load 21 is electrically connected to a high-potential side terminal 11 and a low-potential side terminal 12 of the power conversion system 10. The high-potential side terminal 11 is electrically connected to the positive electrode sides of the storage battery modules 30, 60, and 90 via a high-potential side path 13 such as a bus bar. The low-potential side terminal 12 is electrically connected to the negative electrode sides of the storage battery modules 30, 60, and 90 via a low-potential side path 14 such as a bus bar. As a result, the storage battery modules 30, 60, and 90 are electrically connected in parallel to the load 21.

[0017] Specifically, the load 21 is a three-phase inverter 22 and a rotating electric machine 23 having armature windings corresponding to the number of phases and electrically connected to the inverter 22. The inverter 22 controls the current flowing through the windings of each phase. The rotating electric machine 23 is an on-board main engine, and a rotor of the rotating electric machine 23 is capable of transmitting power voltage to the drive wheels of the vehicle. The rotating electric machine 23 is, for example, a permanent magnet synchronous machine.

[0018] The high-potential side path 13 is electrically connected to the positive electrode side of the inverter 22, and the low-potential side path 14 is electrically connected to the negative electrode side of the inverter 22. This enables current to flow between the power conversion system 10 and the load 21. The inverter 22 converts DC power supplied from the power conversion system 10 into AC power and supplies the power to each phase winding of the rotating electric machine 23. In this case, the rotating electric machine 23 serves as a power source for running the vehicle. The rotating electric machine 23 also generates regenerative power using rotational force applied to the rotor. The inverter 22 converts the generated AC power into DC power and outputs it to the power conversion system 10.

[0019] Each storage battery module 30, 60, 90 includes a power converter 40, 70, 100. In each storage battery module 30, 60, 90, the power converter 40, 70, 100 is electrically connected to the storage battery 31, 61, 91 and the load 21. Hereinafter, the storage battery 31 and the power converter 40 of the first storage battery module 30 will be referred to as the "first storage battery 31" and the "first power converter 40," the storage battery 61 and the power converter 70 of the second storage battery module 60 will be referred to as the "second storage battery 61" and the "second power converter 70," and the storage battery 91 and the power converter 100 of the third storage battery module 90 will be referred to as the "third storage battery 91" and the "third power converter 100."

[0020] Next, a specific description will be given of the connection relationships between the storage batteries 31, 61, 91, the power converters 40, 70, 100, and the load 21 in each of the storage battery modules 30, 60, 90. First, the first storage battery module 30 will be described as an example.

[0021] The first power converter 40 includes a primary-side positive terminal 41 and a primary-side negative terminal 42 that constitute a primary-side terminal pair, and a secondary-side positive terminal 43 and a secondary-side negative terminal 44 that constitute a secondary-side terminal pair. The primary-side positive terminal 41 of the first power converter 40 is electrically connected to the positive electrode side of the first storage battery 31. The primary-side negative terminal 42 of the first power converter 40 and the negative electrode side of the first storage battery 31 are electrically connected to the inverter 22 via the low-potential-side path 14. In other words, the primary-side terminal pair of the first power converter 40 is electrically connected in parallel to the first storage battery 31. In this case, the voltage of the first storage battery 31 is applied to the primary-side terminal pair of the first power converter 40.

[0022] A secondary-side negative terminal 44 of the first power converter 40 is electrically connected to the positive electrode side of the first storage battery 31. A secondary-side positive terminal 43 of the first power converter 40 is electrically connected to the inverter 22 via the high-potential-side path 13. In other words, the secondary-side terminal pair of the first power converter 40 is electrically connected in series to the first storage battery 31 on the positive electrode side of the first storage battery 31.

[0023] The second power converter 70 includes a primary-side positive terminal 71 and a primary-side negative terminal 72 that constitute a primary-side terminal pair, and a secondary-side positive terminal 73 and a secondary-side negative terminal 74 that constitute a secondary-side terminal pair. The third power converter 100 includes a primary-side positive terminal 101 and a primary-side negative terminal 102 that constitute a primary-side terminal pair, and a secondary-side positive terminal 103 and a secondary-side negative terminal 104 that constitute a secondary-side terminal pair. In the second and third storage battery modules 60 and 90, the connections between the terminals 71 to 74 and 101 to 104 of the corresponding power converters 70 and 100, the corresponding storage batteries 61 and 91, and the load 21 are similar to those in the first storage battery module 30, although detailed description will be omitted. In other words, the storage battery modules 30, 60, and 90 are electrically connected in parallel to the load 21.

[0024] In each storage battery module 30, 60, 90, the secondary-side terminal voltages Vo1, Vo2, and Vo3 applied to the secondary-side terminal pairs of the power converters 40, 70, and 100 are the differential voltages between the voltages between the paths 13 and 14 (specifically, the voltages supplied to the inverter 22) and the voltages Vbat1, Vbat2, and Vbat3 of the corresponding storage batteries 31, 61, and 91. The secondary-side terminal voltages Vo1, Vo2, and Vo3 of each storage battery module 30, 60, and 90 are lower than the rated voltages (e.g., 400 V) of the corresponding storage batteries 31, 61, and 91. Therefore, the rated secondary voltages on the secondary sides of the power converters 40, 70, and 100 are set lower than the rated voltages of the corresponding storage batteries 31, 61, and 91, e.g., 16 V. This allows the power converters 40, 70, and 100 to be miniaturized.

[0025] FIG. 2 shows an example of a first power converter 40. The first power converter 40 is an isolated DC-DC converter. The first power converter 40 includes first to eighth switches S1 to S8, a primary-side capacitor 51, a secondary-side capacitor 52, and a transformer 53. In this embodiment, voltage-controlled semiconductor switching elements, more specifically, N-channel MOSFETs, are used as the first to eighth switches S1 to S8. In this case, the high-potential side terminal of each switch S1 to S8 is the drain, and the low-potential side terminal is the source. Each switch S1 to S8 also has a body diode.

[0026] The drain of the first switch S1 and the drain of the third switch S3 are electrically connected to the primary-side positive terminal 41 and a first end of the primary-side capacitor 51. The source of the first switch S1 is connected to the drain of the second switch S2, and the source of the third switch S3 is connected to the drain of the fourth switch S4. The sources of the second switch S2 and the fourth switch S4 are electrically connected to the primary-side negative terminal 42 and the second end of the primary-side capacitor 51.

[0027] The drain of the fifth switch S5 and the drain of the seventh switch S7 are electrically connected to the secondary-side positive terminal 43 and the first end of the secondary-side capacitor 52. The source of the fifth switch S5 is connected to the drain of the sixth switch S6, and the source of the seventh switch S7 is connected to the drain of the eighth switch S8. The sources of the sixth switch S6 and the eighth switch S8 are electrically connected to the secondary-side negative terminal 44 and the second end of the secondary-side capacitor 52.

[0028] The transformer 53 includes a primary winding 53a and a secondary winding 53b, which are wound around a common core. As a result, the primary winding 53a and the secondary winding 53b are magnetically coupled by the common core. When the potential at the first end of the primary winding 53a becomes higher relative to the second end, an induced voltage is generated such that the potential at the first end of the secondary winding 53b becomes higher than the potential at the second end. On the other hand, when the potential at the second end of the primary winding 53a becomes higher relative to the first end, an induced voltage is generated such that the potential at the second end of the secondary winding 53b becomes higher than the potential at the first end.

[0029] A first end of the primary winding 53a is electrically connected to the connection point of the first switch S1 and the second switch S2, a second end of the primary winding 53a is electrically connected to the connection point of the third switch S3 and the fourth switch S4, a first end of the secondary winding 53b is connected to the connection point of the seventh switch S7 and the eighth switch S8, and a second end of the secondary winding 53b is electrically connected to the connection point of the fifth switch S5 and the sixth switch S6.

[0030] The second power converter 70 and the third power converter 100 are isolated DC-DC converters, and similar to the first power converter 40, each of them includes first to eighth switches, a primary-side capacitor, a secondary-side capacitor, and a transformer. In this embodiment, the first power converter 40, the second power converter 70, and the third power converter 100 have basically the same configuration, and therefore detailed description of the second power converter 70 and the third power converter 100 will be omitted.

[0031] The power conversion system 10 includes battery monitoring devices 32, 62, and 92. The battery monitoring devices 32, 62, and 92 are provided corresponding to the respective storage batteries 31, 61, and 91. For example, the first battery monitoring device 32 detects the terminal voltage, current, internal resistance, SOC, and the like of each battery cell constituting the first storage battery 31, and monitors the state of the first storage battery 31. The second battery monitoring device 62 monitors the state of the second storage battery 61, similar to the first battery monitoring device 32. The third battery monitoring device 92 monitors the state of the third storage battery 91, similar to the first battery monitoring device 32. The detected values ​​detected by the battery monitoring devices 32, 62, and 92 are input to the control device 16 provided in the power conversion system 10.

[0032] The power conversion system 10 includes voltage sensors 45, 75, 105 and current sensors 46, 76, 106. The voltage sensors 45, 75, 105 and current sensors 46, 76, 106 are provided corresponding to each storage battery module 30, 60, 90. Each voltage sensor 45, 75, 105 detects a secondary-side terminal voltage Vo1, Vo2, Vo3 of the corresponding power converter 40, 70, 100. Each current sensor 46, 76, 106 detects a secondary-side current Io1, Io2, Io3 flowing through the secondary side of the corresponding power converter 40, 70, 100. Specifically, taking the first power converter 40 as an example, as shown in FIG. 2 , the voltage sensor 45 detects the voltage of the secondary-side capacitor 52. The current sensor 46 detects a current flowing between the secondary-side positive terminal 43 and the first end of the secondary-side capacitor 52. The detected values ​​of the sensors 45 , 46 , 75 , 76 , 105 , and 106 are input to the control device 16 .

[0033] The control device 16 is an ECU (electronic control unit) primarily composed of a microcomputer equipped with a CPU and various memories. The functions provided by the microcomputer can be provided by software stored in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof. For example, when the microcomputer is provided by hardware electronic circuits, the functions can be provided by digital circuits including numerous logic circuits or analog circuits. For example, the microcomputer executes programs stored in a non-transitory tangible storage medium serving as its own storage unit. The programs include, for example, programs for the processes shown in Figures 3, 11, 12, and 15. Execution of the programs results in the execution of the corresponding methods. The storage unit is, for example, a non-volatile memory. The programs stored in the storage unit can be downloaded and updated via a communication network such as the Internet, for example, via OTA (Over the Air).

[0034] In the power conversion system 10, the storage battery modules 30, 60, and 90 share the power required for the power conversion system 10. In this case, the control device 16 drives the first to eighth switches of the power converters 40, 70, and 100.

[0035] However, if the required power distribution to the power conversion system 10 is not appropriate, there is a concern that the storage batteries 31, 61, 91 may not be used appropriately, or that an overvoltage may be applied to at least one of the power converters 40, 70, 100. In this case, there is a concern that the power conversion system 10 in which the storage battery modules 30, 60, 90 are electrically connected in parallel may not be properly realized.

[0036] Therefore, the control device 16 performs switching processing of each power converter 40, 70, 100 to control the module current flowing through each storage battery module 30, 60, 90. In this embodiment, the module current is the secondary current Io1, Io2, Io3 of the power converter 40, 70, 100 corresponding to each storage battery module 30, 60, 90. The switching processing performed by the control device 16 will be described in detail below.

[0037] The control device 16 includes a control unit 16a and an adjustment unit 16b as components for performing switching processing. The control unit 16a performs switching processing to control the secondary currents Io1, Io2, and Io3 of each storage battery module 30, 60, and 90 so that the amount of stored power in each storage battery 31, 61, and 91 approaches a target value. Here, the target value is a value for controlling the amount of stored power in each storage battery 31, 61, and 91 after a predetermined time. The control unit 16a can arbitrarily set the target value for each storage battery module 30, 60, and 90 within a range that can meet the demands of the load 21.

[0038] For example, in order to power the rotating electric machine 23, a request may arise to discharge at least one of the storage batteries 31, 61, 91 and to flow current from the power conversion system 10 to the rotating electric machine 23. In this case, the control unit 16a can set a value smaller than the current amount of electricity stored in each of the storage batteries 31, 61, 91 as the target value.

[0039] For example, in order to regeneratively drive the rotating electric machine 23, a request may arise to charge at least one of the storage batteries 31, 61, 91 and to flow current from the rotating electric machine 23 to the power conversion system 10. In this case, the control unit 16a can set a value greater than the current amount of electricity stored in each of the storage batteries 31, 61, 91 as the target value.

[0040] For example, a request may arise to power the rotating electric machine 23 or regenerate the electric power and to control the amount of electricity stored in each of the storage batteries 31, 61, 91 by discharging some of the storage batteries 31, 61, 91 and charging the remaining ones, thereby exchanging electric power between the rotating electric machine 23 and each of the storage batteries 31, 61, 91. In this case, the control unit 16a can set a target value for the storage battery 31, 61, 91 to be discharged to a value smaller than the current amount of electricity stored. The control unit 16a can set a target value for the storage battery 31, 61, 91 to be charged to a value larger than the current amount of electricity stored.

[0041] The adjustment unit 16b performs an adjustment process. The adjustment process is a switching process that adjusts the secondary-side currents Io1, Io2, and Io3 of the storage battery modules 30, 60, and 90 so as to prevent the secondary-side terminal voltages Vo1, Vo2, and Vo3 of the power converters 40, 70, and 100 from exceeding an upper limit voltage VT. The upper limit voltage VT is determined according to the secondary-side rated voltage of the power converters 40, 70, and 100, and is set to a value between 80% and 90% or between 90% and 100% of the secondary-side rated voltage, for example.

[0042] In this embodiment, switching processes are performed so that the amount of stored power in each storage battery 31, 61, 91 approaches a target value. This allows the amount of stored power in each storage battery 31, 61, 91 to be controlled. Therefore, each storage battery 31, 61, 91 can be used appropriately. Furthermore, switching processes are performed to adjust the secondary-side currents Io1, Io2, Io3 of each storage battery module 30, 60, 90 so as to prevent the secondary-side terminal voltages Vo1, Vo2, Vo3 of each power converter 40, 70, 100 from exceeding the upper limit voltage VT. This prevents overvoltage from being applied to each power converter 40, 70, 100. Therefore, while ensuring appropriate use of each storage battery 31, 61, 91, it is possible to prevent overvoltage from being applied to each power converter 40, 70, 100. As a result, it is possible to appropriately realize the power conversion system 10 in which each storage battery module 30, 60, 90 is electrically connected in parallel.

[0043] In each storage battery module 30, 60, 90, the primary terminal pairs of the power converters 40, 70, 100 are electrically connected in parallel to the storage batteries 31, 61, 91, and the secondary terminal pairs are electrically connected in series to the storage batteries 31, 61, 91. In this configuration, the rated voltage of each power converter 40, 70, 100 may be set lower than the voltage of each storage battery 31, 61, 91, or the secondary terminal voltages Vo1, Vo2, Vo3 of each power converter 40, 70, 100 may be affected by the voltage of the corresponding storage battery 31, 61, 91. In this case, there is a relatively high possibility that an overvoltage will be applied to the secondary terminal pairs of each power converter 40, 70, 100. Furthermore, when current command values ​​for the secondary currents Io1, Io2, and Io3 are set for each of the power converters 40, 70, and 100, there is a relatively high possibility that an overvoltage will be applied to the secondary terminal pairs of each of the power converters 40, 70, and 100. Therefore, there is a great advantage in providing the adjustment unit 16b as a configuration for executing the switching process.

[0044] Next, the control performed by the control unit 16a, the adjustment unit 16b, etc. will be specifically described. The acquisition unit 16c, the voltage determination unit 16d, the current determination unit 16e, and the distribution determination unit 16f provided in the control device 16, the control unit 16a, and the adjustment unit 16b perform current distribution control. The current distribution control sets current command values ​​I1*, I2*, and I3* for the secondary currents Io1, Io2, and Io3 in the storage battery modules 30, 60, and 90, and performs switching processing of the power converters 40, 70, and 100 based on the set current command values ​​I1*, I2*, and I3*. The current command values ​​I1*, I2*, and I3* set in the current distribution control are current command values ​​to be used in the switching processing of the power converters 40, 70, and 100.

[0045] The procedure for the current distribution control is shown in Fig. 3. This control is repeatedly executed at intervals of updating the target values ​​for the amounts of stored electricity in the storage batteries 31, 61, and 91, for example, at intervals of several minutes to several hours.

[0046] In step S10, the acquisition unit 16c acquires the amount of stored power of each storage battery 31, 61, 91. The acquisition unit 16c acquires the remaining power or SOC as the amount of stored power of each storage battery 31, 61, 91. For example, the remaining power of each storage battery 31, 61, 91 can be calculated based on the detected voltage and detected current of the corresponding battery monitoring device 32, 62, 92. Furthermore, for example, the SOC of each storage battery 31, 61, 91 can be calculated based on the detected value of the corresponding battery monitoring device 32, 62, 92. By acquiring the remaining power or SOC as the amount of stored power of each storage battery 31, 61, 91, the amount of stored power of each storage battery 31, 61, 91 can be appropriately determined. In this embodiment, the remaining power and SOC of each storage battery 31, 61, 91 correspond to "power storage parameters."

[0047] In step S11, the control unit 16a sets a target value for the amount of stored power in each of the storage batteries 31, 61, and 91. For example, when the control unit 16a acquires the amount of remaining power as the amount of stored power in each of the storage batteries 31, 61, and 91, the control unit 16a sets a target amount of remaining power. Also, for example, when the control unit 16a acquires the SOC as the amount of stored power in each of the storage batteries 31, 61, and 91, the control unit 16a sets a target SOC. In this embodiment, the target amount of remaining power and the target SOC correspond to "target parameters."

[0048] The control unit 16a may set the target value of each of the storage batteries 31, 61, 91 based on the acquired current amount of power stored in each of the storage batteries 31, 61, 91 and the power required for the power conversion system 10. The control unit 16a may also set the target value of each of the storage batteries 31, 61, 91 based on a command from the higher-level control device 25 to the control device 16.

[0049] The control unit 16a can arbitrarily set the target value of each of the storage batteries 31, 61, and 91 within a range of the amount of power storage that can be controlled during the period from the current time to the next update timing of the target value. In this embodiment, the control unit 16a sets the target value of each of the storage batteries 31, 61, and 91 to the same or equivalent values ​​in order to equalize the amount of power storage of each of the storage batteries 31, 61, and 91. For example, the target SOC of each of the storage batteries 31, 61, and 91 is set to an equivalent value when the target SOC of each of the storage batteries 31, 61, and 91 is set so that the difference between the target SOC of the second and third storage batteries 61 and 91 and the target SOC of the first storage battery 31 falls within a range of several percent (e.g., 1% to 4%, or 2% to 3%). For example, when the target remaining energy amounts of each storage battery 31, 61, 91 are set to the same value, the target remaining energy amounts of each storage battery 31, 61, 91 are set so that the difference between the target remaining energy amounts of the second and third storage batteries 61, 91 and the target remaining energy amount of the first storage battery 31 is within a range of a few percent when converted into a ratio (percentage) of the remaining energy amount of the first storage battery 31 in a fully charged state.

[0050] In step S12, the control unit 16a sets the current command values ​​I1*, I2*, and I3* for the storage battery modules 30, 60, and 90. As a result, the share of the requested current for the power conversion system 10 is distributed to the storage battery modules 30, 60, and 90.

[0051] In this embodiment, the control unit 16a sets the magnitude of the current command value for a storage battery module 30, 60, or 90 in which the deviation between the acquired stored power amount and the set target value is large to be larger than the magnitude of the current command value for a storage battery module in which the deviation value is small. This allows the stored power amount of the storage battery in the storage battery module 30, 60, or 90 in which the deviation value is large to quickly approach the target value. Therefore, a configuration suitable for appropriate use of the storage batteries 31, 61, or 91 can be realized.

[0052] In step S13, the adjuster 16b calculates each secondary-side terminal voltage Vo1, Vo2, Vo3. Specifically, the adjuster 16b calculates the voltage of each storage battery 31, 61, 91 when the storage battery 31, 61, 91 is discharged or charged at each set current command value I1*, I2*, I3*. The adjuster 16b calculates, as each secondary-side terminal voltage Vo1, Vo2, Vo3, the differential voltage between the voltage between each path 13, 14 and the calculated voltage of each storage battery 31, 61, 91 when the storage battery 31, 61, 91 is discharged or charged.

[0053] For example, the adjustment unit 16b calculates the voltage of each storage battery 31, 61, 91 when it is discharged or charged based on the set current command values ​​I1*, I2*, I3* and the internal resistance of each storage battery 31, 61, 91. For example, the detected value of each battery monitoring device 32, 62, 92 can be used as the internal resistance of each storage battery 31, 61, 91. Furthermore, for example, the voltage applied to the DC side of the inverter 22 can be used as the voltage between each path 13, 14. The voltage applied to the DC side of the inverter 22 can be obtained, for example, from the control device 24 that controls the switching of the inverter 22.

[0054] In step S14, the voltage determination unit 16d determines whether or not there is an overvoltage module. An overvoltage module is a storage battery module among the storage battery modules 30, 60, 90 whose secondary terminal voltages Vo1, Vo2, Vo3 exceed the upper limit voltage VT. Here, the voltage determination unit 16d determines whether or not there is an overvoltage module based on the calculated secondary terminal voltages Vo1, Vo2, Vo3. If a negative determination is made in step S14, the process proceeds to step S15.

[0055] In step S15, the current determination unit 16e determines whether or not there is an excess current module. An excess current module is a storage battery module among the storage battery modules 30, 60, and 90 whose secondary currents Io1, Io2, and Io3 exceed the upper limit current IT. Here, the current determination unit 16e determines whether or not there is an excess current module based on the set current command values ​​I1*, I2*, and I3*. The upper limit current IT is determined according to the secondary rated current of each power converter 40, 70, and 100, and is set to, for example, a value between 80% and 90% or between 90% and 100% of the secondary rated current. If a negative determination is made in step S15, the switching process of each power converter 40, 70, and 100 is performed based on the currently set current command values ​​I1*, I2*, and I3*. When it is determined that there is no overvoltage module and no overcurrent module, the switching process of each power converter 40, 70, 100 is performed based on the current command values ​​I1*, I2*, I3*, thereby suppressing the occurrence of overvoltage and overcurrent.

[0056] If the determination in step S14 is affirmative, the process proceeds to step S16. In step S16, the adjustment unit 16b performs an adjustment process. Here, as the adjustment process, the adjustment unit 16b resets the current command values ​​I1*, I2*, and I3* to be used in the switching process of each power converter 40, 70, and 100 from now on. As a result, the burden of the requested current is redistributed to each storage battery module 30, 60, and 90. The process in step S14 corresponds to a "first adjustment process."

[0057] The adjustment process for each state of the storage batteries 31, 61, and 91 will be described in detail below.

[0058] 4 to 7 compare the module currents flowing through the storage battery modules 30, 60, and 90 and the secondary terminal voltages Vo1, Vo2, and Vo3 before and after the adjustment process. Before the adjustment process, the secondary terminal voltages Vo1 and Vo3 of the first and third storage battery modules 30 and 90 are equal to or lower than the upper limit voltage VT, and the secondary terminal voltage Vo2 of the second storage battery module 60 exceeds the upper limit voltage VT. In other words, of the storage battery modules 30, 60, and 90, the second storage battery module 60 is an over-voltage module.

[0059] Here, possible causes of an overvoltage module include differences in the voltage and other characteristics of the storage batteries 31, 61, and 91. Specifically, in a storage battery module 30, 60, and 90 in which the storage battery 31, 61, and 91 has a low voltage, the differential voltage between the voltage across the paths 13 and 14 and the voltage of the storage battery 31, 61, and 91 is high. In this case, the secondary terminal voltage of a storage battery module 30, 60, and 90 in which the differential voltage is high may exceed the upper limit voltage VT. The voltages of the storage batteries 31, 61, and 91 may differ from each other in their initial states or due to changes in internal resistance caused by deterioration of the storage batteries 31, 61, and 91. For example, a storage battery 31, 61, and 91 with a high internal resistance will have a lower voltage during discharge than a storage battery with a low internal resistance, even when the same amount of discharge current is flowing.

[0060] 4 assumes a case where a request has been made to power the rotating electric machine 23. In this case, the storage battery modules 30, 60, and 90 share and output the current flowing from the power conversion system 10 to the inverter 22. Therefore, the storage batteries 31, 61, and 91 are discharged.

[0061] The adjustment unit 16b resets the current command value I2* so as to reduce the magnitude of the secondary current Io2 in the second storage battery module 60 by the adjustment amount ΔIo. When the switching process is performed based on the reset current command value I2*, the discharge current of the second storage battery 61 is reduced. In this case, the amount of voltage drop due to the internal resistance of the second storage battery 61 during discharge is reduced, and the voltage of the second storage battery 61 is increased. Therefore, the differential voltage between the voltage between each of the paths 13 and 14 and the voltage of the second storage battery 61 is reduced. Therefore, after the adjustment process is performed, the secondary terminal voltage Vo2 of the second storage battery module 60 is reduced by ΔVo2 and becomes equal to or lower than the upper limit voltage VT.

[0062] Furthermore, the adjustment unit 16b resets the current command value I1* so as to increase the magnitude of the secondary current Io1 in the first storage battery module 30 by the adjustment amount ΔIo. This makes it possible to maintain the magnitude of the current supplied from the power conversion system 10 to the inverter 22 before and after the adjustment process. Therefore, in the switching process for discharging each of the storage batteries 31, 61, 91, it is possible to suppress the occurrence of overvoltage while performing the power running drive of the rotating electric machine 23 in the same manner as before the adjustment process.

[0063] The adjuster 16b may reset the current command value I3* to increase the magnitude of the secondary current Io3 in the third storage battery module 90, in order to compensate for the adjustment amount ΔIo (specifically, the reduction amount) of the secondary current Io2 in the second storage battery module 60. The adjuster 16b may reset the current command values ​​I1*, I3* to increase the magnitude of the secondary currents Io1, Io3 in both the first and third storage battery modules 30, 90, in order to compensate for the adjustment amount ΔIo of the secondary current Io2 in the second storage battery module 60.

[0064] 5 assumes a case where a request has been made to regeneratively drive the rotating electric machine 23. In this case, the storage battery modules 30, 60, and 90 share the current flowing from the inverter 22 to the power conversion system 10 and receive the power. As a result, the storage batteries 31, 61, and 91 are charged.

[0065] The adjustment unit 16b resets the current command value I2* so as to increase the magnitude of the secondary current Io2 in the second storage battery module 60 by the adjustment amount ΔIo. When a switching process is performed based on the reset current command value I2*, the charging current of the second storage battery 61 is increased. In this case, the amount of voltage drop across the internal resistance of the second storage battery 61 during charging is increased, and the voltage of the second storage battery 61 is increased. As a result, the differential voltage between the voltages across the paths 13 and 14 and the voltage of the second storage battery 61 is reduced. Therefore, after the adjustment process is performed, the secondary terminal voltage Vo2 of the second storage battery module 60 is reduced by ΔVo2 and becomes equal to or lower than the upper limit voltage VT.

[0066] Furthermore, the adjustment unit 16b resets the current command value I1* so as to reduce the magnitude of the secondary current Io1 in the first storage battery module 30 by the adjustment amount ΔIo. This makes it possible to maintain the magnitude of the current flowing from the inverter 22 to the power conversion system 10 before and after the adjustment process. Therefore, in the switching process for charging each of the storage batteries 31, 61, 91, it is possible to suppress the occurrence of overvoltage while performing regenerative driving of the rotating electric machine 23 in the same manner as before the adjustment process.

[0067] The adjuster 16b may reset the current command value I3* to reduce the magnitude of the secondary current Io3 in the third storage battery module 90, in order to compensate for the adjustment amount ΔIo (specifically, the increase) of the secondary current Io2 in the second storage battery module 60. The adjuster 16b may reset the current command values ​​I1*, I3* to reduce the magnitude of the secondary currents Io1, Io3 in both the first and third storage battery modules 30, 90, in order to compensate for the adjustment amount ΔIo of the secondary current Io2 in the second storage battery module 60.

[0068] 6 assumes a case where a request arises to power the rotating electric machine 23 and increase the amount of electricity stored in the third storage battery 91. In this case, the first and second storage battery modules 30, 60 share and output the current supplied to the inverter 22 and the third storage battery module 90. Therefore, the first and second storage batteries 31, 61 are discharged, and the third storage battery 91 is charged.

[0069] The adjuster 16b resets the current command value I2* so as to reduce the magnitude of the secondary current Io2 in the second storage battery module 60 by the adjustment amount ΔIo. As a result, the secondary terminal voltage Vo2 becomes equal to or lower than the upper limit voltage VT, as in the case described with reference to FIG.

[0070] Furthermore, the adjustment unit 16b resets the current command value I3* so as to reduce the magnitude of the secondary current Io3 in the third storage battery module 90 by the adjustment amount ΔIo. This makes it possible to maintain the magnitude of the current flowing from the power conversion system 10 to the inverter 22 before and after the adjustment process. Therefore, in the switching process of discharging the first and second storage batteries 31, 61 and charging the third storage battery 91, it is possible to suppress the occurrence of overvoltage while performing the power running drive of the rotating electric machine 23 in the same manner as before the adjustment process.

[0071] The adjuster 16b may reset the current command value I1* so as to increase the magnitude of the secondary current Io1 in the first storage battery module 30, in order to compensate for the adjustment amount ΔIo (specifically, the reduction amount) of the secondary current Io2 in the second storage battery module 60. Furthermore, the adjuster 16b may reset the current command values ​​I1*, I3* so as to increase the magnitude of the secondary current Io1 in the first storage battery module 30 and reduce the magnitude of the secondary current Io3 in the third storage battery module 90, in order to compensate for the adjustment amount ΔIo of the secondary current Io2 in the second storage battery module 60.

[0072] 7 assumes a case where a request arises to power the rotating electric machine 23 and increase the amount of electricity stored in the second storage battery 61. In this case, the first and third storage battery modules 30, 90 share and output the current supplied to the inverter 22 and the second storage battery module 60. Therefore, the first and third storage batteries 31, 91 are discharged, and the second storage battery 61 is charged.

[0073] The adjuster 16b resets the current command value I2* so as to increase the magnitude of the secondary current Io2 in the second storage battery module 60 by the adjustment amount ΔIo. As a result, the secondary terminal voltage Vo2 is set to be equal to or lower than the upper limit voltage VT, as in the case described with reference to FIG.

[0074] Furthermore, the adjuster 16b resets the current command value I3* so as to increase the magnitude of the secondary current Io3 in the third storage battery module 90 by the adjustment amount ΔIo. This makes it possible to maintain the magnitude of the current flowing from the power conversion system 10 to the inverter 22 before and after the adjustment process. Therefore, in the switching process of discharging the first and third storage batteries 31, 91 and charging the second storage battery 61, it is possible to suppress the occurrence of overvoltage while performing the power running drive of the rotating electric machine 23 in the same manner as before the adjustment process.

[0075] The adjustment unit 16b may reset the current command value so as to increase the secondary current in at least one of the first and third battery modules 30, 90 to compensate for the adjustment amount ΔIo (specifically, the increase amount) of the secondary current Io2 in the second battery module 60.

[0076] 4 to 7, the secondary-side terminal voltage increases (see ΔVo1 and ΔVo3) in one of the first and third storage battery modules 30 and 90. Therefore, the adjuster 16b may select the storage battery module with the lower calculated secondary-side terminal voltage Vo1 or Vo3 from the first and third storage battery modules 30 and 90, and reset the current command value for the selected storage battery module. This allows the adjustment process to be performed by appropriately selecting the storage battery module with the increased secondary-side terminal voltage.

[0077] 3 , if the current determination unit 16e determines in step S15 that an excess current module is present, the process proceeds to step S17. For example, when an adjustment process is performed to suppress the occurrence of an overvoltage, the magnitude of the secondary current in one of the storage battery modules 30, 60, 90 may be increased to compensate for the adjustment of the secondary current for the excess voltage module. In this case, the current determination unit 16e may determine that an excess current module is present.

[0078] Therefore, in the present embodiment, when it is determined that there is an excess current module, the adjusting unit 16b performs a redistribution process. The redistribution process is a switching process in which the excess current of the secondary side current in the excess current module over the upper limit current IT is distributed to the storage battery modules 30, 60, and 90 other than the excess current module in order to suppress the occurrence of an overcurrent.

[0079] In step S17, the distribution determination unit 16f determines whether or not the secondary-side terminal voltages Vo1, Vo2, and Vo3 are likely to exceed the upper limit voltage VT as a result of the redistribution process. The distribution determination unit 16f performs the determination process of step S17 based on the calculated secondary-side terminal voltages Vo1, Vo2, and Vo3. Here, the secondary-side terminal voltages Vo1, Vo2, and Vo3 can be changed between their current values ​​and the upper limit voltage VT. Therefore, in this embodiment, the distribution determination unit 16f calculates a voltage margin for the calculated secondary-side terminal voltages Vo1, Vo2, and Vo3 to reach the upper limit voltage VT. Based on the calculated voltage margin, the distribution determination unit 16f determines whether or not the redistribution process can be performed so that the secondary-side terminal voltages Vo1, Vo2, and Vo3 do not exceed the upper limit voltage VT.

[0080] For example, when the distribution determination unit 16f determines that a voltage margin exists (for example, the voltage margin is higher than 0) in a storage battery module in which the magnitude of the secondary-side terminal voltage is increased by executing the redistribution process among the storage battery modules 30, 60, 90, the distribution determination unit 16f makes a negative determination in step S17. On the other hand, when the distribution determination unit 16f determines that a voltage margin does not exist (for example, the voltage margin is 0) in a storage battery module in which the magnitude of the secondary-side terminal voltage is increased by executing the redistribution process among the storage battery modules 30, 60, 90, the distribution determination unit 16f makes a positive determination in step S17.

[0081] If a negative determination is made in step S17, the process proceeds to step S18. In step S18, the distribution determination unit 16f determines whether the secondary currents Io1, Io2, and Io3 are allocable. The distribution determination unit 16f executes the determination process of step S18 based on the set current command values ​​I1*, I2*, and I3*. Here, the current command values ​​I1*, I2*, and I3* are adjustable between their current values ​​and the upper limit current IT. Therefore, in this embodiment, the distribution determination unit 16f calculates an adjustable current until the magnitude of each of the set current command values ​​I1*, I2*, and I3* reaches the upper limit current IT. The distribution determination unit 16f determines whether the current current command values ​​I1*, I2*, and I3* are allocable based on the calculated adjustable currents.

[0082] For example, when the distribution determination unit 16f determines that a storage battery module, of which the magnitude of the current command value is increased by executing the redistribution process, has an adjustable current (for example, the adjustable current is greater than 0), it makes a positive determination in step S18. On the other hand, when the distribution determination unit 16f determines that a storage battery module, of which the magnitude of the current command value is increased by executing the redistribution process, does not have an adjustable current (for example, the adjustable current is 0), it makes a negative determination in step S18.

[0083] If the determination in step S18 is affirmative, the distribution determination unit 16f determines that the redistribution process will be executed, and the process proceeds to step S19. If the determination in step S17 is affirmative, or if the determination in step S18 is negative, the distribution determination unit 16f determines that the redistribution process will not be executed, and the process proceeds to step S20. Note that the distribution determination unit 16f may determine that the redistribution process will be executed if the determination in step S17 is negative without performing the process in step S18.

[0084] In step S19, the adjuster 16b executes a redistribution process to suppress the occurrence of an overcurrent. As the redistribution process, the adjuster 16b resets the current command values ​​I1*, I2*, and I3* to be used in the switching processes of the power converters 40, 70, and 100.

[0085] In step S20, the adjuster 16b executes a reduction process. The reduction process is a switching process that reduces the total current of the secondary-side currents Io1, Io2, and Io3. As the reduction process, the adjuster 16b resets the current command values ​​I1*, I2*, and I3* to be used in the switching processes of the power converters 40, 70, and 100.

[0086] After the processes of steps S16, S19, and S20, the process returns to step S13. In this case, the processes of step S13 and subsequent steps are executed again based on the current command values ​​I1*, I2*, and I3* reset by the processes of steps S16, S19, and S20.

[0087] An example of the redistribution process is shown in Figures 8 and 9. In Figures 8 and 9, the first battery module 30 among the battery modules 30, 60, and 90 is the excess current module. Figure 8 assumes a situation in which the batteries 31, 61, and 91 are being discharged. Figure 9 assumes a situation in which the batteries 31, 61, and 91 are being charged.

[0088] In Fig. 8, the distribution determination unit 16f determines that the second and third storage battery modules 60 and 90 have voltage margins Va2 and Va3, respectively, and makes a negative determination in step S17 in Fig. 3. The distribution determination unit 16f also determines that the second and third storage battery modules 60 and 90 have adjustable currents Ia2 and Ia3, respectively, and makes a positive determination in step S18 in Fig. 3. Therefore, the adjustment unit 16b executes the redistribution process.

[0089] In the redistribution process, the adjuster 16b resets the current command value I1* so as to reduce the magnitude of the secondary current Io1 in the first storage battery module 30 by an adjustment amount ΔIo. The adjuster 16b adjusts the secondary current Io1 in the first storage battery module 30 within a range in which the secondary terminal voltages Vo2, Vo3 of the second and third storage battery modules 60, 90 do not exceed the upper limit voltage VT. Here, the adjuster 16b resets the current command value I1* so that the adjustment amount ΔIo of the secondary current Io1 in the first storage battery module 30 is greater than the amount by which the secondary current Io1 exceeds the upper limit current IT. Therefore, after the redistribution process is executed, the magnitude of the secondary current Io1 in the first storage battery module 30 is equal to or less than the upper limit current IT.

[0090] Furthermore, in the redistribution process, the adjuster 16b distributes the adjustment amount ΔIo of the secondary-side current Io1 in the first storage battery module 30 to the second storage battery module 60. In other words, the adjuster 16b resets the current command value I2* so that the magnitude of the secondary-side current Io2 in the second storage battery module 60 is increased by the adjustment amount ΔIo. Accordingly, the secondary-side terminal voltage Vo2 increases by ΔVo2. In FIG. 8 , the increase amount ΔVo2 of the secondary-side terminal voltage Vo2 in the second storage battery module 60 is lower than the voltage margin Va2, and the adjustment amount ΔIo of the secondary-side current Io2 is smaller than the adjustable current Ia2. Therefore, in the second storage battery module 60 after the redistribution process is executed, the secondary-side terminal voltage Vo2 is set to be equal to or lower than the upper limit voltage VT, and the magnitude of the secondary-side current Io2 is set to be equal to or lower than the upper limit current IT. The adjusting unit 16b may distribute the adjustment amount ΔIo of the secondary current Io1 in the first storage battery module 30 to the third storage battery module 90, or to both the second and third storage battery modules 60, 90.

[0091] In Fig. 9, the distribution determination unit 16f determines that the first storage battery module 30 has a voltage margin Vb1, and makes a negative determination in step S17 in Fig. 3. The distribution determination unit 16f also determines that the second and third storage battery modules 60 and 90 have adjustable currents Ib2 and Ib3, and makes a positive determination in step S18 in Fig. 3. Therefore, the adjustment unit 16b executes the redistribution process.

[0092] In the redistribution process, the adjuster 16b resets the current command value I1* so as to reduce the magnitude of the secondary current Io1 in the first storage battery module 30 by an adjustment amount ΔIo. In FIG. 9 , the adjuster 16b resets the current command value I1* so that the adjustment amount ΔIo of the secondary current Io1 in the first storage battery module 30 is greater than the amount by which the secondary current Io1 exceeds the upper limit current IT. Therefore, after the redistribution process is executed, the magnitude of the secondary current Io1 in the first storage battery module 30 is equal to or less than the upper limit current IT. Furthermore, the adjuster 16b adjusts the secondary current Io1 in the first storage battery module 30 within a range in which the secondary terminal voltage Vo1 of the first storage battery module 30 does not exceed the upper limit voltage VT. In FIG. 9 , the increase ΔVo1 of the secondary terminal voltage Vo1 in the first storage battery module 30 is lower than the voltage margin Vb1. Therefore, after the redistribution process is executed, the secondary side terminal voltage Vo1 of the first storage battery module 30 is set to be equal to or lower than the upper limit voltage VT.

[0093] In the redistribution process, the adjuster 16b distributes the adjustment amount ΔIo of the secondary current Io1 in the first storage battery module 30 to the second storage battery module 60. In other words, the adjuster 16b resets the current command value I2* so as to increase the magnitude of the secondary current Io2 in the second storage battery module 60 by the adjustment amount ΔIo. In FIG. 9 , in the second storage battery module 60, the adjustment amount ΔIo of the secondary current Io2 is smaller than the adjustable current Ib2. Therefore, after the redistribution process is executed, the magnitude of the secondary current Io2 is set to be equal to or less than the upper limit current IT. Note that the adjuster 16b may distribute the adjustment amount ΔIo of the secondary current Io1 in the first storage battery module 30 to the third storage battery module 90, or may distribute it to both the second and third storage battery modules 60, 90.

[0094] According to this embodiment, in addition to the adjustment process, redistribution control is also performed, which makes it possible to suppress the occurrence of overvoltage and overcurrent in each of the storage battery modules 30, 60, and 90. As a result, it is possible to appropriately suppress the occurrence of problems during the switching process.

[0095] In Fig. 10 , the distribution determination unit 16f determines that the second and third storage battery modules 60 and 90 have no voltage margins Vc2 and Vc3, and makes a positive determination in step S17 of Fig. 3 . Therefore, the adjustment unit 16b executes the reduction process. Note that in Fig. 10 , the distribution determination unit 16f determines that the second and third storage battery modules 60 and 90 have no adjustable currents Ic2 and Ic3, and makes a negative determination in step S18 of Fig. 3 . Even in this case, the adjustment unit 16b executes the reduction process.

[0096] In the reduction process, the adjuster 16b resets the current command value I1* so as to reduce the magnitude of the secondary current Io1 in the first storage battery module 30 by the excess amount ΔIo relative to the upper limit current IT. The adjuster 16b also maintains the current current command values ​​I2* and I3* in the second and third storage battery modules 60 and 90.

[0097] According to this embodiment, the total value of the secondary currents Io1, Io2, and Io3 in each of the storage battery modules 30, 60, and 90 is reduced. As a result, even when it is determined that the redistribution process should not be performed, the magnitude of the secondary current in the excess current module can be kept below the upper limit current IT. Therefore, a configuration suitable for suppressing the occurrence of overcurrent can be realized.

[0098] Based on the current command values ​​I1*, I2*, I3* set by the current distribution control described above, the switching process of each of the power converters 40, 70, 100 is performed. In this case, for example, the voltages Vbat1, Vbat2, Vbat3 of the storage batteries 31, 61, 91 may change during the period between execution intervals of the current distribution control, and there is a concern that the actual magnitudes of the secondary-side terminal voltages Vo1, Vo2, Vo3 may exceed the upper limit voltage VT.

[0099] Therefore, in this embodiment, the control device 16 executes overvoltage suppression control. In the overvoltage suppression control, the secondary currents Io1, Io2, and Io3 flowing through the storage battery modules 30, 60, and 90 are adjusted so as to prevent the magnitudes of the current secondary terminal voltages Vo1, Vo2, and Vo3 during the switching process from exceeding the upper limit voltage VT. The control device 16 executes the overvoltage suppression control in parallel with the current distribution control, and executes the overvoltage suppression control at an execution interval shorter than the execution interval of the current distribution control. The execution interval of the overvoltage suppression control is, for example, several msec to several tens of msec.

[0100] FIG. 11 shows a procedure for the overvoltage suppression control executed by the control device 16.

[0101] In step S30, the acquisition unit 16c acquires the current secondary-side terminal voltages Vo1, Vo2, and Vo3 of the storage battery modules 30, 60, and 90. For example, the acquisition unit 16c acquires the detected voltages of the voltage sensors 45, 75, and 105 as the secondary-side terminal voltages Vo1, Vo2, and Vo3 of the storage battery modules 30, 60, and 90.

[0102] The acquisition unit 16c may acquire calculated values ​​of the secondary-side terminal voltages Vo1, Vo2, Vo3 of the storage battery modules 30, 60, 90, instead of the detected voltages of the voltage sensors 45, 75, 105. The calculation of the secondary-side terminal voltages Vo1, Vo2, Vo3 of the storage battery modules 30, 60, 90 can use detected values ​​of the corresponding battery monitoring devices 32, 62, 92, specifically, the voltages Vbat1, Vbat2, Vbat3, currents Ibat1, Ibat2, Ibat3, internal resistances, SOCs, etc. of the storage batteries 31, 61, 91.

[0103] In step S31, the voltage determination unit 16d determines whether or not there is an overvoltage module. Here, the voltage determination unit 16d determines whether or not there is an overvoltage module based on the acquired secondary-side terminal voltages Vo1, Vo2, and Vo3. If the determination in step S31 is negative, the process proceeds to step S32. On the other hand, if the determination in step S31 is positive, the process proceeds to step S33.

[0104] In step S32, the adjuster 16b maintains the current command values ​​I1*, I2*, and I3* used in the current switching process. In this case, the current secondary currents Io1, Io2, and Io3 are maintained in the storage battery modules 30, 60, and 90. This allows the state in which no overvoltage occurs to continue.

[0105] In step S33, the adjuster 16b performs an adjustment process. The process of step S33 can be executed in the same manner as the process of step S16 in FIG. 3 . Here, as the adjustment process, the adjuster 16b resets the current command values ​​I1*, I2*, and I3* used in the current switching process. For example, the adjuster 16b performs the adjustment process as described above with reference to FIGS. 4 to 7 . This changes the current secondary currents Io1, Io2, and Io3 flowing through the storage battery modules 30, 60, and 90, thereby suppressing the occurrence of overvoltage in the overvoltage module. The process of step S33 corresponds to a "second adjustment process."

[0106] When the adjustment process in the overvoltage suppression control is performed and the magnitude of the secondary current in any of the storage battery modules 30, 60, 90 increases, the actual magnitude of each secondary current Io1, Io2, Io3 may exceed the upper limit current IT. Therefore, the control device 16 performs overcurrent suppression control. In the overcurrent suppression control, the current secondary currents Io1, Io2, Io3 during the switching process are adjusted to suppress the occurrence of overcurrent. The control device 16 performs the overcurrent suppression control in parallel with the current distribution control and the overvoltage suppression control, and performs the overcurrent suppression control at intervals shorter than the execution interval of the current distribution control. The execution interval of the overcurrent suppression control is, for example, several msec to several tens of msec.

[0107] FIG. 12 shows a procedure for the overcurrent suppression control executed by the control device 16.

[0108] In step S40, the acquiring unit 16c acquires the secondary-side terminal voltages Vo1, Vo2, Vo3 of the storage battery modules 30, 60, 90 and the secondary-side currents Io1, Io2, Io3 of the storage battery modules 30, 60, 90. The secondary-side currents Io1, Io2, Io3 of the storage battery modules 30, 60, 90 are specifically the currents detected by the current sensors 46, 76, 106.

[0109] In step S41, the current determination unit 16e determines whether or not there is a current exceedance module. Here, the current determination unit 16e determines whether or not there is a current exceedance module based on the acquired secondary currents Io1, Io2, and Io3. If the determination in step S41 is negative, the process proceeds to step S42. If the determination in step S41 is positive, the process proceeds to step S43.

[0110] In step S42, the adjuster 16b maintains the current command values ​​I1*, I2*, and I3* used in the current switching process. In this case, the current secondary currents Io1, Io2, and Io3 are maintained in the storage battery modules 30, 60, and 90. This allows a state in which no overcurrent occurs to continue. Note that even if the process of maintaining the secondary currents Io1, Io2, and Io3 is performed in step S42, if a positive determination is made in step S31 of FIG. 11 , an adjustment process is performed to suppress the occurrence of an overvoltage, and the current command values ​​I1*, I2*, and I3* may be changed.

[0111] In step S43, the distribution determination unit 16f determines whether or not there is a possibility that each of the secondary-side terminal voltages Vo1, Vo2, and Vo3 will exceed the upper limit voltage VT as a result of the execution of the redistribution process. The distribution determination unit 16f executes the determination process of step S43 based on each of the acquired secondary-side terminal voltages Vo1, Vo2, and Vo3. The process of step S43 can be executed in the same manner as the process of step S17 in FIG. 3 .

[0112] If the determination in step S43 is negative, the process proceeds to step S44. In step S44, the distribution determination unit 16f determines whether the secondary currents Io1, Io2, and Io3 are allocable. The distribution determination unit 16f executes the determination process of step S44 based on the acquired secondary currents Io1, Io2, and Io3. The process of step S44 can be executed in the same manner as the process of step S18 in FIG. 3 .

[0113] If the determination in step S44 is affirmative, the distribution determination unit 16f determines to execute the redistribution process, and the process proceeds to step S45. If the determination in step S43 is affirmative or if the determination in step S44 is negative, the distribution determination unit 16f determines not to execute the redistribution process, and the process proceeds to step S46. Note that if the determination in step S43 is negative without performing the process in step S44, the distribution determination unit 16f may determine to execute the redistribution process to suppress the occurrence of an overcurrent.

[0114] In step S45, the adjuster 16b executes a redistribution process. The process of step S45 is executed in the same manner as the process of step S19 in FIG. 3 . For example, the adjuster 16b executes the redistribution process as described above with reference to FIGS. 8 and 9 . Here, as the redistribution process, the adjuster 16b resets the current command values ​​I1*, I2*, and I3* used in the current switching process, and performs switching processes based on the reset current command values ​​I1*, I2*, and I3*. This changes the current secondary-side currents Io1, Io2, and Io3 flowing through the storage battery modules 30, 60, and 90. This makes it possible to suppress the occurrence of overcurrent in the excess current module.

[0115] In step S46, the adjuster 16b executes a reduction process. The process of step S46 can be executed in the same manner as the process of S20 in FIG. 3 . For example, the adjuster 16b can execute the reduction process as described above with reference to FIG. 10 . Here, as the reduction process, the adjuster 16b resets the current command values ​​I1*, I2*, and I3* used in the current switching process, and performs switching processes based on the reset current command values ​​I1*, I2*, and I3*. This reduces the total current of the secondary currents Io1, Io2, and Io3. This makes it possible to suppress the occurrence of overcurrent in the excess current module.

[0116] In this embodiment, when it is determined that an overvoltage module exists, the current command values ​​I1*, I2*, and I3*, which are set so that the amount of electricity stored in each of the storage batteries 31, 61, and 91 approaches the target value, are reset by adjustment processing in the current distribution control or the overvoltage suppression control. In this case, suppressing the occurrence of overvoltage in the overvoltage module takes priority over bringing the amount of electricity stored in each of the storage batteries 31, 61, and 91 closer to the target value. Therefore, the amount of electricity stored in each of the storage batteries 31, 61, and 91 can be controlled while ensuring the reliability of the power conversion system 10.

[0117] Furthermore, even if it is determined that an excess current module exists, the current command values ​​I1*, I2*, and I3*, which are set so that the storage amounts of the storage batteries 31, 61, and 91 approach their target values, are reset in the redistribution process or reduction process. This makes it possible to suppress the occurrence of overvoltage and overcurrent in the excess voltage module. This allows for a configuration that is suitable for ensuring the reliability of the power conversion system 10.

[0118] The overvoltage suppression control is performed at an interval shorter than the execution interval of the current distribution control. This allows for prompt adjustment processing when it is determined that an overvoltage module exists between execution intervals of the current distribution control. This allows for accurate suppression of overvoltage. As a result, a configuration suitable for ensuring the reliability of the power conversion system 10 can be realized.

[0119] Moreover, the overcurrent suppression control is also performed at an interval shorter than the execution interval of the current distribution control. This allows for the rapid execution of redistribution or reduction processing when it is determined that there is a current-excess module between execution intervals of the current distribution control. This allows for the occurrence of overcurrent to be accurately suppressed, thereby realizing a configuration suitable for ensuring the reliability of the power conversion system 10.

[0120] <Modification of First Embodiment> In the adjustment process in the current distribution control and the overvoltage suppression control, the adjuster 16b may suppress application of an overvoltage to one or two secondary-side terminal pairs of the power converters 40, 70, and 100. In this case, the adjuster 16b may calculate the secondary-side terminal voltages of one or two of the storage battery modules 30, 60, and 90 in step S13 of FIG. 3 . Furthermore, the acquirer 16c may acquire the current secondary-side terminal voltages of one or two of the storage battery modules 30, 60, and 90 in step S30 of FIG. 11 .

[0121] In the redistribution process in the current distribution control and the overcurrent suppression control, the adjuster 16b only needs to suppress an overcurrent from flowing to at least one secondary-side terminal pair of each of the power converters 40, 70, and 100. In this case, the acquirer 16c only needs to acquire the secondary-side current Io1, Io2, and Io3 of at least one of the storage battery modules 30, 60, and 90 in step S40 of FIG.

[0122] The control device 16 may not execute the processes of steps S15 and S17 to S20 in the current distribution control and may not execute the overcurrent suppression control. In other words, the control device 16 may control the amount of electricity stored in each storage battery 31, 61, 91 and suppress only the occurrence of overvoltages among the occurrence of overvoltages and overcurrents in each storage battery module 30, 60, 90.

[0123] The control device 16 does not need to execute steps S13 to S20 in FIG. 3 during the current distribution control. Even in this case, the amount of electricity stored in each storage battery 31, 61, 91 can be controlled, and each storage battery 31, 61, 91 can be used appropriately. By executing overvoltage suppression control in parallel with the current distribution control, it is possible to suppress the occurrence of overvoltage in each storage battery module 30, 60, 90. By executing overcurrent suppression control in parallel with the current distribution control, it is possible to suppress the occurrence of overcurrent in each storage battery module 30, 60, 90. As a result, it is possible to appropriately implement the power conversion system 10 in which the storage battery modules 30, 60, 90 are electrically connected in parallel.

[0124] The control device 16 may execute only the current distribution control among the current distribution control, the overvoltage suppression control, and the overcurrent suppression control. In this case, it is still possible to control the amount of electricity stored in each storage battery 31, 61, 91 and to suppress the occurrence of overvoltage and overcurrent in each storage battery module 30, 60, 90.

[0125] The control device 16 may perform a switching process to control the secondary currents Io1, Io2, and Io3 of one or two of the storage battery modules 30, 60, and 90 and control the secondary terminal voltages of the remaining storage battery modules, instead of performing a switching process to control the secondary currents Io1, Io2, and Io3 of the storage battery modules 30, 60, and 90. For example, the control device 16 may perform a switching process to control the secondary terminal voltage Vo1 of the first storage battery module 30 and a switching process to control the secondary currents Io2 and Io3 of the second and third storage battery modules 60 and 90. In this case, the control device 16 may perform a switching process of the first power converter 40 in the first storage battery module 30 so that the secondary terminal voltage Vo1 becomes the required voltage of the rotating electric machine 23.

[0126] When voltage control is performed on some of the storage battery modules 30, 60, and 90 and current control is performed on the remaining ones, the control unit 16a can perform switching processing of the power converters in the storage battery modules that perform voltage control so that the amount of electricity stored in the storage battery approaches a target value. Specifically, the control unit 16a can control the secondary current of the storage battery modules that perform current control among the storage battery modules 30, 60, and 90, thereby controlling the proportion of the secondary current that is shared by the storage battery modules that perform voltage control relative to the current required by the load 21. Therefore, in the storage battery modules that perform voltage control, the storage battery can be charged or discharged so that the amount of electricity stored in the storage battery approaches a target value.

[0127] An overcurrent in each of the storage battery modules 30, 60, 90 can also occur due to a sudden change in the demand for the power conversion system 10 from the rotating electric machine 23. Specifically, if the demand for power from the rotating electric machine 23 suddenly increases, the increased demand for power may be borne by the storage battery module that is subjected to voltage control among the storage battery modules 30, 60, 90, causing an increase in the secondary current. In this case, there is a concern that an overcurrent may flow in the storage battery module that is subjected to voltage control among the storage battery modules 30, 60, 90.

[0128] Even if one of the storage battery modules 30, 60, and 90 undergoing voltage control becomes an excess current module, the redistribution process in step S45 of FIG. 12 is performed to prevent overcurrent from occurring in the excess current module. In this case, the adjuster 16b increases the magnitude of the secondary current in the storage battery modules 30, 60, and 90 other than the excess current module and undergoing current control. This reduces the share of the required power in the excess current module, thereby reducing the magnitude of the secondary current Io1 in the excess current module. This prevents overcurrent from occurring in the storage battery modules 30, 60, and 90 undergoing voltage control.

[0129] 3 in the current distribution control, except for steps S14 and S16, and may execute only the overcurrent suppression control out of the overvoltage suppression control and the overcurrent suppression control. In other words, the control device 16 may control the amount of electricity stored in each storage battery 31, 61, 91 to a target value, and may suppress only the occurrence of overcurrent out of the overvoltage and overcurrent in each storage battery module 30, 60, 90.

[0130] When the operation of the power converter in a specific storage battery module, which is one of the storage battery modules 30, 60, and 90, is stopped, the control device 16 may perform only the overcurrent suppression control out of the overvoltage suppression control and the overcurrent suppression control on the specific storage battery module. In this case, in step S14 of FIG. 3 , the voltage determination unit 16d may not determine whether the specific storage battery module is an overvoltage module. In step S30 of FIG. 11 , the acquisition unit 16c may not acquire the secondary-side terminal voltage of the specific storage battery module. In step S31, the voltage determination unit 16d may not determine whether the specific storage battery module is an overvoltage module.

[0131] The operation of the power converter in the specific battery module may be stopped if the voltage of the battery in the specific battery module is higher than the sum of the voltages of the batteries in the other battery modules (30, 60, 90) and the secondary terminal voltage. In this case, the switching operation for power conversion in the power converter of the specific battery module may be stopped. When the power converter in the specific battery module is stopped, the secondary terminal voltage may be set to 0 V. Furthermore, the voltage between paths 13 and 14 may be set to the voltage of the battery in the specific battery module.

[0132] For example, in the isolated DC-DC converter described above with reference to FIG. 2 , the operation of the power converter is stopped with the first to eighth switches fixed off. In this case, the body diodes of the fifth to eighth switches are conductive, which can cause the storage battery of a specific storage battery module to be in a discharging state. Furthermore, for example, the operation of the power converter is stopped with the first to fourth switches fixed off and the fifth to eighth switches fixed on. In this case, the fifth to eighth switches are conductive, which can cause the storage battery of a specific storage battery module to be in a charging or discharging state. Note that, instead of the fifth to eighth switches being fixed on, the operation of the power converter can be stopped with only the fifth and sixth switches of the fifth to eighth switches fixed on, or with only the seventh and eighth switches fixed on.

[0133] When the control unit 16a stops the operation of the power converter in one of the storage battery modules 30, 60, and 90 and performs voltage control on the remaining storage battery modules, the control unit 16a can perform switching processing on the power converter in the storage battery module where voltage control is performed so that the amount of stored power in the storage battery approaches a target value. Specifically, the control unit 16a sets the voltage command value for the secondary terminal voltage of each storage battery module 30, 60, and 90 where voltage control is performed to the same value and performs switching processing based on the set voltage command value. In this case, when the characteristics of the batteries in the storage battery modules where voltage control is performed, such as the SOC and internal resistance, are consistent, the magnitude of the secondary current flowing through each storage battery module where voltage control is performed is equivalent. Therefore, the amount of stored power in the storage batteries in the storage battery modules where voltage control is performed can be made to approach a common target value for each storage battery.

[0134] In the present embodiment, the control device 16 may perform the switching process for controlling the amount of stored power described above, and may execute only the overcurrent suppression control out of the overvoltage suppression control and the overcurrent suppression control. That is, the control device 16 may control the amount of stored power in the storage battery to a target value in the storage battery module in which voltage control is performed among the storage battery modules 30, 60, 90, and suppress only the occurrence of overcurrent out of the overvoltage and overcurrent in each storage battery module.

[0135] Even if an overcurrent occurs in a storage battery module undergoing voltage control and it is determined in step S41 of FIG. 12 that there is an excess current module, the redistribution process in step S45 is performed to prevent the occurrence of the overcurrent in the excess current module. In this case, for example, the adjustment unit 16b performs a switching process to distribute the excess module current in the excess current module over the upper limit current to a specific storage battery module whose power converter has stopped operating among the power storage modules. This prevents the occurrence of an overcurrent in the storage battery module undergoing voltage control among the storage battery modules 30, 60, 90.

[0136] In addition to repeatedly executing the current distribution control at the target value update interval, the control device 16 may execute the current distribution control when it is determined that the discharging state or the charging state has switched in each of the storage batteries 31, 61, 91. This allows the target value to be updated in response to the switching of the state of each of the storage batteries 31, 61, 91. As a result, the amount of stored power in each of the storage batteries 31, 61, 91 can be suitably controlled.

[0137] In step S10, the acquisition unit 16c may acquire the voltage (specifically, the open circuit voltage) of each storage battery 31, 61, 91 instead of the amount of power stored in each storage battery 31, 61, 91. For example, the voltage of each storage battery 31, 61, 91 may be a detected value of the corresponding battery monitoring device 32, 62, 92. Even in this case, it is possible to determine the amount of power stored in each storage battery 31, 61, 91. In step S11, the control unit may set a target voltage for each storage battery 31, 61, 91. In this embodiment, the voltage of each storage battery 31, 61, 91 corresponds to the "power storage parameter," and the target voltage corresponds to the "target parameter."

[0138] The control device 16 may control the currents Ibat1, Ibat2, Ibat3 flowing through the storage batteries 31, 61, 91, instead of controlling the secondary currents Io1, Io2, Io3 of the power converters 40, 70, 100 corresponding to the storage battery modules 30, 60, 90. In this case, current command values ​​for the currents Ibat1, Ibat2, Ibat3 flowing through the storage batteries 31, 61, 91 may be set in steps S12, S16, S19, S20 of FIG. 3 . Even in this case, current distribution control can be performed.

[0139] In step S33 of FIG. 11 , the adjuster 16b may reset the current command values ​​for the currents Ibat1, Ibat2, and Ibat3 flowing through the storage batteries 31, 61, and 91. Even in this case, the overvoltage suppression control can be executed. Furthermore, in steps S45 and S46 of FIG. 12 , the adjuster 16b may reset the current command values ​​for the currents Ibat1, Ibat2, and Ibat3 flowing through the storage batteries 31, 61, and 91. Even in this case, the overcurrent suppression control can be executed. In this embodiment, the currents Ibat1, Ibat2, and Ibat3 flowing through the storage batteries 31, 61, and 91 correspond to the "module current."

[0140] The upper limit current IT may be determined according to the rated current of each storage battery 31, 61, 91, and may be set to a value between 80% and 90% or between 90% and 100% of the rated current of each storage battery 31, 61, 91, for example.

[0141] Second Embodiment A second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the adjustment unit 16b adjusts the secondary currents Io1, Io2, and Io3 in order to reduce variations in the amounts of stored power in the storage batteries 31, 61, and 91.

[0142] More specifically, the control device 16 performs a change process. The change process is a switching process that adjusts the secondary currents Io1, Io2, and Io3 when the discharge state or the charge state of the storage batteries 31, 61, and 91 is switched to reduce the variation in the amount of charge in the storage batteries 31, 61, and 91.

[0143] An example of the change process is shown in Figures 13 and 14. Figure 13 compares the secondary currents Io1, Io2, and Io3 before and after the storage batteries 31, 61, and 91 switch from a discharging state to a charging state. Figure 14 compares the secondary currents Io1, Io2, and Io3 before and after the storage batteries 31, 61, and 91 switch from a charging state to a discharging state.

[0144] As described in the first embodiment, the control unit 16a increases the secondary currents Io1, Io2, and Io3 as the deviation value increases. Specifically, in the discharging state of each of the storage batteries 31, 61, and 91, a surplus value obtained by subtracting the target value from the acquired amount of stored energy is used as the deviation value. In FIG. 13 , the surplus values ​​Pa1, Pa2, and Pa3 of the storage batteries 31, 61, and 91 increase in the order of the second storage battery module 60, the first storage battery module 30, and the third storage battery module 90. Therefore, in the discharging state of each of the storage batteries 31, 61, and 91 in FIG. 13 , the magnitudes of the secondary currents Io1, Io2, and Io3 flowing in a direction to discharge each of the storage batteries 31, 61, and 91 increase in the order of the second storage battery module 60, the first storage battery module 30, and the third storage battery module 90.

[0145] In addition, in the charging state of each storage battery 31, 61, 91, a deficit value obtained by subtracting the acquired amount of stored power from the target value is used as the deviation value. In Fig. 14 , the deficit values ​​Pb1, Pb2, and Pb3 of each storage battery 31, 61, 91 increase in the order of the second storage battery module 60, the first storage battery module 30, and the third storage battery module 90. Therefore, in the charging state of each storage battery 31, 61, 91 in Fig. 14 , the magnitudes of the secondary currents Io1, Io2, and Io3 flowing in a direction to charge each storage battery 31, 61, 91 increase in the order of the second storage battery module 60, the first storage battery module 30, and the third storage battery module 90.

[0146] Here, in order to equalize the amount of stored electricity in each of the storage batteries 31, 61, 91, it is desirable to control the amount of stored electricity in each of the storage batteries 31, 61, 91 even in a situation where each of the storage batteries 31, 61, 91 temporarily switches to a charging state or a discharging state. On the other hand, in a situation where each of the storage batteries 31, 61, 91 temporarily switches to a charging state or a discharging state, it may not be possible to control each of the secondary currents Io1, Io2, Io3 to a value suitable for equalizing the amount of stored electricity in each of the storage batteries 31, 61, 91, because the target value for each of the storage batteries 31, 61, 91 is not updated or sufficient time cannot be secured for current distribution control.

[0147] Note that a situation in which the state of each storage battery 31, 61, 91 temporarily switches from a discharged state to a charged state is assumed to be, for example, a situation in which the vehicle enters a downhill slope. Furthermore, a situation in which the state of each storage battery 31, 61, 91 temporarily switches from a charged state to a discharged state is assumed to be, for example, a situation in which, when power is supplied to the power conversion system 10 from a power grid, the supplied power becomes temporarily unstable. When multiple power supply targets are connected to a power grid, if the supplied power becomes unstable, a request may arise for the power conversion system 10 to temporarily supply power to the power grid in order to stabilize the supplied power.

[0148] The control unit 16a executes a change process when it determines that each of the storage batteries 31, 61, and 91 has switched from a discharging state to a charging state. In this case, the control unit 16a resets the current command values ​​I1*, I2*, and I3* so that the magnitude of the secondary current is larger in a storage battery module with a smaller surplus value than in a storage battery module with a larger surplus value. Therefore, in the charging state of each of the storage batteries 31, 61, and 91 in FIG. 13 , the magnitudes of the secondary currents Io1, Io2, and Io3 flowing in a direction to charge each of the storage batteries 31, 61, and 91 increase in the order of the third storage battery module 90, the first storage battery module 30, and the second storage battery module 60. As a result, when each of the storage batteries 31, 61, and 91 has switched from a discharging state to a charging state, the amounts of stored power of each of the storage batteries 31, 61, and 91 are made closer to each other.

[0149] The control unit 16a executes a change process when it determines that each of the storage batteries 31, 61, and 91 has switched from a charging state to a discharging state. In this case, the control unit 16a resets the current command values ​​I1*, I2*, and I3* so that the magnitude of the secondary current is larger in a storage battery module with a smaller deficit value than in a storage battery module with a larger deficit value. Therefore, in the discharging state of each of the storage batteries 31, 61, and 91 in FIG. 14 , the magnitudes of the secondary currents Io1, Io2, and Io3 flowing in a direction to discharge each of the storage batteries 31, 61, and 91 increase in the order of the third storage battery module 90, the first storage battery module 30, and the second storage battery module 60. This causes the amounts of stored electricity in each of the storage batteries 31, 61, and 91 to approach each other.

[0150] 15 shows the procedure for the switching control including the change process. This control is repeatedly executed by the control device 16 at intervals shorter than the execution interval of the current distribution control. The execution interval of the switching control is, for example, several msec to several tens of msec.

[0151] In step S50, the acquisition unit 16c acquires the amount of stored power of each of the storage batteries 31, 61, and 91 and the secondary currents Io1, Io2, and Io3 of each of the storage battery modules 30, 60, and 90.

[0152] In step S51, the control unit 16a determines whether the state of each storage battery 31, 61, 91 has changed. For example, the control unit 16a determines whether the direction of each secondary current Io1, Io2, Io3 acquired this time has changed from the direction of each secondary current Io1, Io2, Io3 acquired last time. If the determination in step S51 is negative, the control ends. On the other hand, if the determination in step S51 is positive, the control proceeds to step S52.

[0153] In step S52, the control unit 16a performs a change process. In this case, the control unit 16a calculates a surplus value or a deficit value based on the acquired amount of stored power of each storage battery 31, 61, 91 and the currently set target value, depending on whether each storage battery 31, 61, 91 has switched from a discharging state to a charging state or from a charging state to a discharging state. Based on the calculated surplus value or deficit value, the control unit 16a resets each of the current command values ​​I1*, I2*, and I3*, as described above with reference to FIGS. 13 and 14 .

[0154] According to this embodiment, when it is determined that the states of the storage batteries 31, 61, and 91 have changed, the current command values ​​I1*, I2*, and I3* are reset based on the surplus or deficit values ​​to equalize the amounts of charge stored in the storage batteries 31, 61, and 91. The surplus and deficit values ​​can be calculated using the currently set target values. This allows the current command values ​​I1*, I2*, and I3* to be reset without updating the target values, thereby reducing the amount of calculation required to reset the current command values ​​I1*, I2*, and I3*. Therefore, when the charge and discharge states of the storage batteries 31, 61, and 91 temporarily change, the current command values ​​I1*, I2*, and I3* can be quickly reset. As a result, a configuration suitable for reducing variations in the amounts of charge stored in the storage batteries 31, 61, and 91 can be realized.

[0155] The change process does not have a function to suppress the occurrence of overvoltage or overcurrent as described in the current distribution control. This appropriately reduces the amount of calculation required to reset the current command values ​​I1*, I2*, and I3*. Therefore, when the charge state and discharge state of each storage battery 31, 61, and 91 temporarily change, the process to set the current command values ​​I1*, I2*, and I3* can be performed appropriately.

[0156] The switching control is executed in parallel with the overvoltage suppression control and the overcurrent suppression control, so that even when the charge state and discharge state of each storage battery 31, 61, 91 are temporarily switched and a change process is performed, it is possible to suppress the occurrence of an overvoltage or an overcurrent.

[0157] Third Embodiment A third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the configuration of the storage battery modules is changed. Specifically, as shown in FIG. 16 , the power conversion system 10 includes a first storage battery module 130, a second storage battery module 160, and a third storage battery module 190. First, the configuration of the first storage battery module 130 will be described below.

[0158] The first storage battery module 130 includes a first power converter 140 and a first storage battery 131. A primary side positive terminal 141 of the first power converter 140 and the positive electrode side of the first storage battery 131 are electrically connected to the inverter 22 via the high potential side path 13. A primary side negative terminal 142 of the first power converter 140 is electrically connected to the negative electrode side of the first storage battery 131.

[0159] A secondary-side positive terminal 143 of the first power converter 140 is electrically connected to the negative electrode side of the first storage battery 131. A secondary-side negative terminal 144 of the first power converter 140 is electrically connected to the inverter 22 via the low-potential-side path 14. In other words, the secondary-side terminal pair of the first power converter 140 is electrically connected in series to the first storage battery 131 on the negative electrode side of the first storage battery 131.

[0160] The second storage battery module 160 includes a second power converter 170 and a second storage battery 161. The third storage battery module 190 includes a third power converter 1100 and a third storage battery 191. The configurations of the second and third storage battery modules 160 and 190 are similar to that of the first storage battery module 130, and therefore detailed description thereof will be omitted. Note that, for example, the power converters 140, 170, and 1100 are isolated DC-DC converters, as in the first embodiment. For example, the storage batteries 131, 161, and 191 are assembled batteries, as in the first embodiment.

[0161] The control device 16 performs current distribution control, overvoltage suppression control, and overcurrent suppression control, similar to the first embodiment. The control device 16 also performs switching control, similar to the second embodiment. This embodiment may be implemented by modifying each component, as described in the modified example of the first embodiment.

[0162] Other Embodiments The above-described embodiments may be modified as follows.

[0163] The configuration of the storage battery modules may be changed as shown in Fig. 17. Specifically, the power conversion system 10 includes a first storage battery module 230, a second storage battery module 260, and a third storage battery module 290. The configuration of the first storage battery module 230 will be described below first.

[0164] The first storage battery module 230 includes a first power converter 240 and a first storage battery 231. A primary-side positive terminal 241 of the first power converter 240 is electrically connected to the positive electrode side of the first storage battery 231, and a primary-side negative terminal 242 of the first power converter 240 is electrically connected to the negative electrode side of the first storage battery 231. A secondary-side positive terminal 243 of the first power converter 240 is electrically connected to the inverter 22 via the high-potential side path 13, and a secondary-side negative terminal 244 of the first power converter 240 is electrically connected to the inverter 22 via the low-potential side path 14.

[0165] The second storage battery module 260 includes a second power converter 270 and a second storage battery 261. The third storage battery module 290 includes a third power converter 2100 and a third storage battery 291. The configurations of the second and third storage battery modules 260 and 290 are similar to that of the first storage battery module 230, and therefore detailed description thereof will be omitted. Note that, for example, the power converters 240, 270, and 2100 are isolated DC-DC converters, as in the first embodiment. The storage batteries 231, 261, and 291 are, for example, assembled batteries, as in the first embodiment.

[0166] The control device 16 performs current distribution control in the same manner as in the first embodiment. Execution of current distribution control enables appropriate use of the storage batteries 31, 61, and 91. Furthermore, the control device 16 performs overvoltage suppression control, overcurrent suppression control, and switching control in the same manner as in the above embodiments.

[0167] The voltage applied to the secondary terminal pairs of each power converter 240, 270, 2100 is the voltage between each path 13 and 14. Therefore, unlike the first and third embodiments, the voltage of each storage battery 231, 261, 291 has little effect on the voltage applied to the secondary terminal pairs of each power converter 240, 270, 2100. Therefore, the possibility of an overvoltage being applied to the secondary terminal pairs of each power converter 240, 270, 2100 is lower than in the first and third embodiments. However, for example, when the load 21 suddenly changes from a driving state to an unloaded state and when the change process described in the second embodiment is executed, an overvoltage may be temporarily applied to at least one of the power converters 240, 270, 2100. In this case, overvoltage suppression control is executed to suppress the occurrence of an overvoltage. Furthermore, when an adjustment process is executed in the overvoltage suppression control and an overcurrent occurs, overcurrent suppression control is executed to suppress the occurrence of an overcurrent.

[0168] The control device is not limited to one that controls the power converters 40, 70, and 100 collectively, but may also control each power converter 40, 70, and 100 individually. Specifically, as shown in FIG. 18 , the power conversion system 10 may include first, second, and third control devices 17, 18, and 19. The first control device 17 is provided corresponding to the first storage battery module 30. The first control device 17 receives the detection values ​​of the first battery monitoring device 32 and the sensors 45 and 46. The second control device 18 is provided corresponding to the second storage battery module 60. The second control device 18 receives the detection values ​​of the second battery monitoring device 62 and the sensors 75 and 76. The third control device 19 is provided corresponding to the third storage battery module 90. The third control device 19 receives the detection values ​​of the third battery monitoring device 92 and the sensors 105 and 106.

[0169] Each of the control devices 17, 18, and 19 sets a current command value for the secondary current in the corresponding storage battery module, and performs switching control of the corresponding power converter based on the set current command value.

[0170] The control devices 17, 18, and 19 are capable of communicating with each other via wired or wireless communication means, and are able to mutually transmit and receive information such as input detection values ​​and current command values. Even in this case, the functions of the control unit 16 a, adjustment unit 16 b, acquisition unit 16 c, voltage determination unit 16 d, current determination unit 16 e, and distribution determination unit 16 f described in the first embodiment and the modified example of the first embodiment can be realized by each of the control devices 17, 18, and 19.

[0171] Note that each of the control devices 17, 18, and 19 is not limited to being provided outside the corresponding storage battery module 30, 60, and 90, but may be provided inside the corresponding storage battery module 30, 60, and 90. In the power conversion system 10 described with reference to Figures 16 and 17, the control device may individually control each power converter, as in the present embodiment.

[0172] The configuration of the power conversion system 10 may be changed as shown in Fig. 19. The power conversion system 10 may include first, second, and third high-side switches 301a, 302a, and 303a, and first, second, and third low-side switches 301b, 302b, and 303b. Each of the switches 301a, 302a, 303a, 301b, 302b, and 303b is a relay or a semiconductor switching element.

[0173] The first high potential side switch 301a is provided in the high potential side path 13 closer to the first storage battery module 30 than the connection point with the second storage battery module 60. The first low potential side switch 301b is provided in the low potential side path 14 closer to the first storage battery module 30 than the connection point with the second storage battery module 60, and on the lower potential side than the connection point with the primary side negative terminal 42 of the first power converter 40.

[0174] The second high-potential-side switch 302a is provided in a path that electrically connects the secondary-side positive terminal 73 of the second power converter 70 and the high-potential-side path 13. The second low-potential-side switch 302b is provided in a path that electrically connects the negative terminal of the second storage battery 61 and the low-potential-side path 14, on the lower-potential side of the connection point with the primary-side negative terminal 72 of the second power converter 70.

[0175] The third high-potential-side switch 303a is provided in a path electrically connecting the secondary-side positive terminal 103 of the third power converter 100 and the high-potential-side path 13. The third low-potential-side switch 303b is provided in a path electrically connecting the negative terminal of the third storage battery 91 and the low-potential-side path 14, on the lower potential side of the connection point with the primary-side negative terminal 102 of the third power converter 100.

[0176] The power conversion system 10 may include a first connection path 304 and a second connection path 305. A first end of the first connection path 304 is electrically connected between a connection point of the low potential side path 14 with the primary side negative terminal 42 of the first power converter 40 and the first low potential side switch 301b. A second end of the first connection path 304 is electrically connected between the secondary side positive terminal 73 of the second power converter 70 and the second high potential side switch 302a in a path electrically connecting the high potential side path 13 with the secondary side positive terminal 73 of the second power converter 70. Note that the configuration is not limited to that shown in FIG. 19 , and the first end of the first connection path 304 may be electrically connected between a connection point of the low potential side path 14 with the primary side negative terminal 42 of the first power converter 40 and the negative terminal of the first storage battery 31. In other words, the first end of the first connection path 304 may be electrically connected to the low potential side path 14 between the negative terminal of the first storage battery 31 and the first low potential side switch 301b.

[0177] A first end of the second connection path 305 is electrically connected between the second low-potential-side switch 302b and a connection point between the primary-side negative terminal 72 of the second power converter 70 and the second low-potential-side switch 302b in a path electrically connecting the negative terminal of the second storage battery 61 and the low-potential-side path 14. A second end of the second connection path 305 is electrically connected between the secondary-side positive terminal 103 of the third power converter 100 and the high-potential-side path 13 and the third high-potential-side switch 303a in a path electrically connecting the secondary-side positive terminal 103 of the third power converter 100 and the high-potential-side path 13. Note that the configuration is not limited to that shown in FIG. 19 , and the first end of the second connection path 305 may be electrically connected between the negative terminal of the second storage battery 61 and a connection point between the primary-side negative terminal 72 of the second power converter 70 and the negative terminal of the second storage battery 61 in a path electrically connecting the negative terminal of the second storage battery 61 and the low-potential-side path 14. In other words, the first end of the second connection path 305 needs only to be electrically connected between the negative terminal of the second storage battery 61 and the second low-potential side switch 302b, among the paths that electrically connect the negative terminal of the second storage battery 61 and the low-potential side path 14.

[0178] The power conversion system 10 includes a first connection switch 306 and a second connection switch 307. Each of the connection switches 306, 307 is a relay or a semiconductor switching element. The first connection switch 306 is provided on the first connection path 304. The second connection switch 307 is provided on the second connection path 305.

[0179] The control device 16 may switch the electrical connection relationship between the load 21 and the storage battery modules 30, 60, and 90 by controlling the switches 301a, 302a, 303a, 301b, 302b, 303b, 306, and 307. For example, the control device 16 may turn on the switches 301a, 302a, 303a, 301b, 302b, and 303b and turn off the connection switches 306 and 307. In this case, the storage battery modules 30, 60, and 90 are electrically connected in parallel to the load 21. Alternatively, for example, the control device 16 may turn on the switches 301a, 303b, 306, and 307 and turn off the switches 301b, 302a, 302b, and 303a. In this case, the storage battery modules 30, 60, and 90 are electrically connected in series to the load 21.

[0180] In this embodiment, when the storage battery modules 30, 60, 90 are electrically connected in parallel to the load 21, the control device 16 can perform at least one of current distribution control, overvoltage suppression control, overcurrent suppression control, and switchover control, as in the above-described embodiments. Note that, in the power conversion system 10 described with reference to Figures 16 and 17, it is also possible to configure the electrical connection relationship between the load 21 and each storage battery module to be switchable, as described in this embodiment.

[0181] The control device 16 may perform at least one of current distribution control, overvoltage suppression control, and overcurrent suppression control when the load 21 is not electrically connected to the power conversion system 10. For example, when there is no request to power or regenerate the rotating electric machine 23 and there is a request to control the amount of electricity stored in each of the storage batteries 31, 61, and 91, there may be a request to exchange power only between the storage batteries 31, 61, and 91. In this case, the control device 16 may perform at least one of current distribution control, overvoltage suppression control, and overcurrent suppression control.

[0182] In the second embodiment, when the target values ​​of the storage batteries 31, 61, and 91 are set to values ​​that are not the same or equivalent, switching control including a change process may be performed. For example, in a situation where one or two of the storage batteries 31, 61, and 91 are degraded and need to be replaced at a factory or the like, using up the stored power of the degraded battery may be prioritized over the normal battery. In this case, the target value of the degraded battery may be set to a value lower than the target value of the normal battery.

[0183] In the case where the target values ​​of the storage batteries 31, 61, and 91 are set differently, the change process is performed when the charging or discharging state of the storage batteries 31, 61, and 91 temporarily switches, thereby preventing imbalances in the amounts of stored electricity among the storage batteries 31, 61, and 91. For example, when the storage batteries 31, 61, and 91 temporarily switch from a discharging state to a charging state, it is possible to prevent a situation in which a degraded storage battery is charged with a larger charging current than a normal storage battery. Furthermore, for example, when the storage batteries 31, 61, and 91 temporarily switch from a charging state to a discharging state, it is possible to prevent a situation in which a degraded storage battery is discharged with a smaller discharging current than a normal storage battery.

[0184] The load electrically connected to the power conversion system 10 is not limited to the inverter 22 and the rotating electric machine 23, but may be a DC-DC converter, an external charger, an electric heater, or the like.

[0185] The power converter is not limited to the one described in FIG. 2, and it is also possible to use a non-insulated DC-DC converter such as a center-tap type isolated DC-DC converter, a resonant DC-DC converter, or a buck converter.

[0186] 20 and 21 show a center-tapped isolated DC-DC converter as an example of the first power converter 40. In Figs. 20 and 21, the configuration of the primary side of the power converter 40 is the same as that shown in Fig. 2, and therefore a detailed description thereof will be omitted.

[0187] 20 , the first power converter 40 includes two secondary-side switches Q1a and Q2a and a reactor 54. In this embodiment, each of the secondary-side switches Q1a and Q2a is a voltage-controlled semiconductor switching element, more specifically, an N-channel MOSFET. Each of the secondary-side switches Q1a and Q2a has a body diode.

[0188] A first end of the secondary winding 53b is electrically connected to the source of the secondary switch Q1a. A second end of the secondary winding 53b is electrically connected to the source of the secondary switch Q2a. The drains of the secondary switches Q1a and Q2a are electrically connected to a first end of a reactor 54. A second end of the reactor 54 is electrically connected to the secondary positive terminal 43 and the first end of the secondary capacitor 52. A center tap provided on the secondary winding 53b is electrically connected to the secondary negative terminal 44 and the second end of the secondary capacitor 52.

[0189] 21 , the first power converter 40 includes two secondary-side switches Q1b, Q2b and a reactor 54. In this embodiment, each of the secondary-side switches Q1b, Q2b is a voltage-controlled semiconductor switching element, more specifically, an N-channel MOSFET. Each of the secondary-side switches Q1b, Q2b has a body diode.

[0190] A first end of the secondary winding 53b is electrically connected to the drain of the secondary switch Q1b. A second end of the secondary winding 53b is electrically connected to the drain of the secondary switch Q2b. The sources of the secondary switches Q1b and Q2b are electrically connected to the secondary negative terminal 44 and the second end of the secondary capacitor 52. A center tap provided in the secondary winding 53b is electrically connected to the first end of the reactor 54.

[0191] It should be noted that the center-tapped isolated DC-DC converters described in FIGS. 20 and 21 may also be employed in the first power converter 140, the second power converters 70 and 170, and the third power converters 100 and 1100 described in the above embodiments.

[0192] When the center-tapped isolated DC-DC converter described in FIGS. 20 and 21 is used as the power converter for each storage battery module, the operation of the power converter in the specific storage battery module may be stopped. For example, the operation of the power converter in the specific storage battery module may be stopped when the first to fourth switches are fixed off and the secondary switches Q1a and Q2a (or Q1b and Q2b) are fixed off. In this case, the body diodes of the secondary switches Q1a and Q2a (or Q1b and Q2b) become conductive, causing the storage battery of the specific storage battery module to enter a discharged state. Furthermore, the operation of the power converter in the specific storage battery module may be stopped when the first to fourth switches are fixed off and the secondary switches Q1a and Q2a (or Q1b and Q2b) are fixed on. In this case, when each of the secondary-side switches Q1a, Q2a (or Q1b, Q2b) is turned on, the storage battery of the specific storage battery module can be put into a charging state or a discharging state.

[0193] The power conversion system 10 may be a combination of at least two of the storage battery module described in the first embodiment, the storage battery module described in the third embodiment, and the storage battery module described in FIG. 17 .

[0194] The number of storage battery modules included in the power conversion system may be two, four, or more. In this case, each storage battery module may be configured similarly to the storage battery module described in the first embodiment, the storage battery module described in the third embodiment, or the storage battery module described in FIG. 17 .

[0195] The power storage unit included in each power storage module is not limited to a storage battery, but may be, for example, a large-capacity electric double layer capacitor, or both a storage battery and an electric double layer capacitor. The power storage unit may also be a fuel cell.

[0196] The power conversion system is not limited to being installed in a vehicle, but may also be installed in a moving object such as an aircraft or a ship. If the moving object is an aircraft, the rotating electric machine serves as the power source for the aircraft's flight, and if the moving object is a ship, the rotating electric machine serves as the power source for the ship's navigation. Furthermore, the power conversion system is not limited to being installed in a moving object, but can also be used as a stationary power source.

[0197] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0198] Characteristic configurations extracted from the above-described embodiments are described below. [Configuration 1] A system including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, wherein a power converter control device (16-19) applied to a power conversion system (10) in which the power storage modules are electrically connected in parallel comprises: a control unit (16a) that performs switching processing of each of the power converters so that the amount of power stored in each of the power storage units approaches a target value; and an adjustment unit (16b) that performs adjustment processing. A control device for a power converter, wherein the adjustment process is a switching process that adjusts a module current flowing through at least one of the storage modules so as to prevent the magnitude of a terminal voltage in at least one of the power converters from exceeding an upper limit voltage. [Configuration 2] The control device for a power converter according to Configuration 1, wherein in each of the power storage modules (30, 60, 90, 130, 160, 190), one of the pair of primary-side terminals of the power converter (40, 70, 100, 140, 170, 1100) is electrically connected to a positive electrode side of the power storage unit, and the other is electrically connected to a negative electrode side of the power storage unit; in each of the power storage modules, one of the pair of secondary-side terminals of the power converter is electrically connected to the positive electrode side or the negative electrode side of the power storage unit, and the other is electrically connected to a load (21); in each of the power storage modules, one of the positive electrode side and the negative electrode side of the power storage unit that is not connected to the pair of secondary-side terminals of the power converter is electrically connected to the load; and the adjustment unit performs the adjustment process to prevent a magnitude of a secondary-side terminal voltage applied to the pair of secondary-side terminals of at least one of the power converters from exceeding the upper limit voltage. [Configuration 3] The control device for a power converter according to configuration 1 or 2, wherein the adjustment unit performs the adjustment process with priority over bringing the amount of stored power in each of the power storage units closer to the target value.[Configuration 4] The control device for a power converter according to any one of Configurations 1 to 3, further comprising: an acquisition unit (16c) that acquires a power storage parameter that is a stored amount or a voltage of each of the power storage units; wherein the target value is a target parameter that is a target value of the power storage parameter; and wherein the control unit performs the switching process of making the magnitude of the module current of a power storage module among the power storage modules, which has a large deviation value between the acquired power storage parameter and the target parameter, larger than the magnitude of the module current of a power storage module which has a small deviation value. [Configuration 5] The control device for a power converter according to Configuration 4, wherein the control unit performs the switching process, when it is determined that each of the power storage units has switched from a discharging state to a charging state, to make the magnitude of the module current in a power storage module having a small deviation value, obtained by subtracting the currently set target parameter from the acquired power storage parameter, larger than the magnitude of the module current in a power storage module having a large deviation value; and when it is determined that each of the power storage units has switched from a charging state to a discharging state, to make the magnitude of the module current in a power storage module having a small deviation value, obtained by subtracting the acquired amount of power stored in the power storage unit from the currently set target value, larger than the magnitude of the module current in a power storage module having a large deviation value. [Configuration 6] The control device for a power converter according to any one of Configurations 2 to 5, further comprising: a voltage determination unit (16d) that determines whether any of the power storage modules includes an over-voltage module whose secondary-side terminal voltage exceeds the upper limit voltage, and when it is determined that any of the power storage modules includes an over-voltage module, the adjustment unit performs the following adjustment process: a switching process that adjusts the module current of the over-voltage module so as to reduce the secondary-side terminal voltage of the over-voltage module; and a switching process that adjusts the module current of the power storage modules other than the over-voltage module, among the power storage modules, in accordance with an adjustment amount of the module current of the over-voltage module.[Configuration 7] The control device for a power converter according to Configuration 6, wherein, when it is determined that there is an over-voltage module, the adjustment unit performs, in the adjustment process, the switching process of reducing the magnitude of the module current in the over-voltage module whose power storage unit is discharging, and the switching process of increasing the magnitude of the module current in an power storage module other than the over-voltage module among the power storage modules that is discharging the power storage unit or reducing the magnitude of the module current in an power storage module whose power storage unit is charging. [Configuration 8] The control device for a power converter according to Configuration 6 or 7, wherein, when it is determined that there is an over-voltage module, the adjustment unit performs, in the adjustment process, the switching process of increasing the magnitude of the module current in an over-voltage module whose power storage unit is charging, and the switching process of reducing the magnitude of the module current in an power storage module other than the over-voltage module among the power storage modules that is charging the power storage unit or increasing the magnitude of the module current in an power storage module whose power storage unit is discharging [Configuration 9] The control device for a power converter according to any one of Configurations 6 to 8, further comprising: a current determination unit (16e) that determines whether or not there is an excess current module among the power storage modules, the magnitude of the module current of which exceeds an upper limit current, and the adjustment unit performs a distribution process when it is determined that there is an excess current module, the distribution process being the switching process of distributing the excess amount of the module current in the excess current module over the upper limit current to the power storage modules other than the excess current module among the power storage modules. [Configuration 10] The control device for a power converter according to Configuration 9, further comprising: a distribution determination unit (16f) that determines whether or not to execute the distribution process when it is determined that there is a current excess module, and the adjustment unit performs the distribution process when it is determined that the distribution process should be executed, and performs the switching process of reducing the total current of the module currents in the power storage modules when it is determined that the distribution process should not be executed.[Configuration 11] The control device for a power converter according to any one of Configurations 2 to 10, wherein the control unit sets a current command value of a module current flowing in each of the power storage modules, as a command value to be used in the switching process, so that the amount of power stored in each of the power storage modules approaches the target value; the adjustment unit performs a first adjustment process and a second adjustment process as the adjustment process; the first adjustment process is the switching process of calculating, in each of the power storage modules, the secondary-side terminal voltage in a case where the switching process is performed based on the set current command value, and adjusting the set current command value so as to prevent the magnitude of the calculated secondary-side terminal voltage from exceeding the upper limit voltage; and the second adjustment process is the switching process of acquiring, in each of the power storage modules, the current secondary-side terminal voltage during execution of the switching process, and adjusting the current command value used in the current switching process so as to prevent the magnitude of the acquired secondary-side terminal voltage from exceeding the upper limit voltage; and the adjustment unit performs the second adjustment process at an execution interval shorter than an execution interval of the first adjustment process.[Configuration 12] A system including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, wherein a control device (16-19) for a power converter applied to a power conversion system (10) in which the power storage modules are electrically connected in parallel includes: a control unit (16a) that performs switching processing of each of the power converters so that the amount of charge stored in each of the power storage units approaches a target value; and a current determination unit (16e) that determines whether or not there is a current exceeding module among the power storage modules, the magnitude of a module current flowing through the power storage module exceeding an upper limit current. and an adjustment unit (16b) that performs the switching process to distribute, when it is determined that there is an excess current module, the excess module current of the excess current module over the upper limit current to the power storage modules other than the excess current module among the power storage modules. [Configuration 13] A power conversion system comprising: a plurality of the power converters; and the control unit according to any one of Configurations 1 to 12.[Configuration 14] A system including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, wherein a program applied to a power conversion system (10) in which the power storage modules are electrically connected in parallel includes: a control process for performing a switching process of each power converter so that the amount of stored power in each power storage unit approaches a target value; and a current determination process for determining whether or not there is a current exceeding module among the power storage modules, the magnitude of a module current flowing through the power storage module exceeding an upper limit current. an adjustment process that performs the switching process to distribute, when it is determined that there is a current exceeding module, the excess of the module current in the current exceeding module relative to the upper limit current to the power storage modules other than the current exceeding module among the power storage modules.[Configuration 15] A control method for a power converter applied to a power conversion system (10) including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, in which the power storage modules are electrically connected in parallel, the method comprising: a control step of performing switching processing of each power converter so that the amount of charge stored in each power storage unit approaches a target value; and a current determination step of determining whether or not there is a current exceeding module among the power storage modules, the magnitude of which module current flowing through the power storage module exceeding an upper limit current. and an adjustment step of performing the switching process to distribute, when it is determined that there is an excess current module, the excess module current of the excess current module over the upper limit current to the power storage modules other than the excess current module among the power storage modules.

[0199] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A system including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, wherein a power converter control device (16-19) applied to a power conversion system (10) in which the power storage modules are electrically connected in parallel comprises: a control unit (16a) that performs switching processing of each of the power converters so that the amount of stored power in each of the power storage units approaches a target value; and an adjustment unit (16b) that performs adjustment processing; A control device for a power converter, wherein the adjustment process is a switching process that adjusts a module current flowing through at least one of the storage modules so as to prevent the magnitude of a terminal voltage in at least one of the power converters from exceeding an upper limit voltage.

2. The power converter control device according to claim 1, wherein in each of the power storage modules (30, 60, 90, 130, 160, 190), one of the pair of primary terminals of the power converter (40, 70, 100, 140, 170, 1100) is electrically connected to the positive electrode side of the power storage unit, and the other is electrically connected to the negative electrode side of the power storage unit; in each of the power storage modules, one of the pair of secondary terminals of the power converter is electrically connected to the positive electrode side or the negative electrode side of the power storage unit, and the other is electrically connected to a load (21); in each of the power storage modules, the one of the positive electrode side and the negative electrode side of the power storage unit that is not connected to the pair of secondary terminals of the power converter is electrically connected to the load; and the adjustment unit performs the adjustment process so as to prevent the magnitude of the secondary terminal voltage applied to the pair of secondary terminals of at least one of the power converters from exceeding the upper limit voltage.

3. The control device for a power converter according to claim 1, wherein the adjustment unit performs the adjustment process with priority over bringing the amount of stored power in each of the power storage units closer to the target value.

4. The control device for a power converter according to claim 1, further comprising an acquisition unit (16c) that acquires a storage parameter that is a storage amount or voltage of each of the storage units, wherein the target value is a target parameter that is a target value of the storage parameter, and wherein the control unit performs the switching process to make the magnitude of the module current of a storage unit module among the storage unit modules that has a large deviation value between the acquired storage parameter and the target parameter larger than the magnitude of the module current of a storage unit module that has a small deviation value.

5. The control device for a power converter according to claim 4, wherein the control unit performs the switching process, when it is determined that each of the power storage units has switched from a discharging state to a charging state, to make the magnitude of the module current in a power storage module having a small deviation value, obtained by subtracting the currently set target parameter from the acquired power storage parameter, larger than the magnitude of the module current in a power storage module having a large deviation value, when it is determined that each of the power storage units has switched from a charging state to a discharging state, to make the magnitude of the module current in a power storage module having a small deviation value, obtained by subtracting the acquired amount of power stored in the power storage unit from the currently set target value, larger than the magnitude of the module current in a power storage module having a large deviation value.

6. The control device for a power converter according to claim 2, further comprising a voltage determination unit (16d) that determines whether or not any of the power storage modules is an over-voltage module whose secondary terminal voltage exceeds the upper limit voltage, and when it is determined that any of the power storage modules is present, the adjustment unit performs the following adjustment process: a switching process that adjusts the module current of the over-voltage module so as to reduce the secondary terminal voltage of the over-voltage module; and a switching process that adjusts the module current of the power storage modules other than the over-voltage module among the power storage modules, in accordance with the adjustment amount of the module current of the over-voltage module.

7. The control device for a power converter according to claim 6, wherein, when it is determined that there is an over-voltage module, in the adjustment process, the adjustment unit performs the switching process of reducing the magnitude of the module current in the over-voltage module whose power storage unit is discharging, and the switching process of increasing the magnitude of the module current in a power storage module other than the over-voltage module among the power storage modules whose power storage unit is discharging, or reducing the magnitude of the module current in a power storage module whose power storage unit is charging.

8. The control device for a power converter according to claim 6, wherein, when it is determined that there is an over-voltage module, in the adjustment process, the adjustment unit performs the switching process of increasing the magnitude of the module current of the over-voltage module whose power storage unit is being charged, and the switching process of reducing the magnitude of the module current of a power storage module other than the over-voltage module among the power storage modules whose power storage unit is being charged, or increasing the magnitude of the module current of a power storage module whose power storage unit is being discharged.

9. The control device for a power converter according to claim 6, further comprising a current determination unit (16e) that determines whether or not any of the power storage modules is an excess-current module whose module current exceeds an upper limit current, and the adjustment unit performs a distribution process when it is determined that any of the power storage modules is an excess-current module, and the distribution process is a switching process that distributes the excess of the module current in the excess-current module over the upper limit current to any of the power storage modules other than the excess-current module.

10. A control device for a power converter as described in claim 9, further comprising a distribution determination unit (16f) that determines whether or not to execute the distribution process when it is determined that there is a current-excess module, wherein the adjustment unit executes the distribution process when it is determined that the distribution process should be executed, and performs the switching process to reduce the total current of the module currents in each of the storage modules when it is determined that the distribution process should not be executed.

11. The control device for a power converter according to claim 2, wherein the control unit sets a current command value of a module current flowing in each of the power storage modules, which is a command value to be used in the switching process, so that the amount of stored power in each of the power storage modules approaches the target value; the adjustment unit performs a first adjustment process and a second adjustment process as the adjustment process; the first adjustment process is a switching process in which, in each of the power storage modules, the secondary-side terminal voltage is calculated in a case where the switching process is performed based on the set current command value, and the set current command value is adjusted so as to prevent the magnitude of the calculated secondary-side terminal voltage from exceeding the upper limit voltage; and the second adjustment process is a switching process in which, in each of the power storage modules, the current secondary-side terminal voltage during execution of the switching process is acquired, and the current command value used in the current switching process is adjusted so as to prevent the magnitude of the acquired secondary-side terminal voltage from exceeding the upper limit voltage; and the adjustment unit performs the second adjustment process at an execution interval shorter than that of the first adjustment process.

12. A system including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, wherein a control device (16-19) for a power converter applied to a power conversion system (10) in which the power storage modules are electrically connected in parallel includes: a control unit (16a) that performs switching processing for each of the power converters so that the amount of charge stored in each of the power storage units approaches a target value; and a current determination unit (16e) that determines whether or not there is a current exceeding module among the power storage modules, the magnitude of the module current flowing through the power storage module exceeding an upper limit current. an adjustment unit (16b) that performs the switching process to distribute, when it is determined that there is an excess current module, the excess module current of the excess current module relative to the upper limit current to the power storage modules other than the excess current module among the power storage modules.

13. A power conversion system comprising: a plurality of the power converters; and the control device according to any one of claims 1 to 12.

14. A program applied to a power conversion system (10) including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, wherein the power storage modules are electrically connected in parallel, the program causing a computer (16-19) to execute processes including: a control process that performs switching processing on each power converter so that the amount of power stored in each power storage unit approaches a target value; and an adjustment process that performs switching processing to adjust a module current flowing in at least one of the power storage modules so as to prevent the magnitude of the terminal voltage in at least one of the power converters from exceeding an upper limit voltage.

15. A control method for a power converter applied to a power conversion system (10) including a plurality of power storage modules (30, 60, 90, 130, 160, 190, 230, 260, 290) each having a power storage unit (31, 61, 91, 131, 161, 191, 231, 261, 291) and a power converter (40, 70, 100, 140, 170, 1100, 240, 270, 2100) electrically connected to the power storage unit, wherein the power storage modules are electrically connected in parallel, the control method comprising: a control step of performing switching processing of each power converter so that the amount of power stored in each power storage unit approaches a target value; and an adjustment step of performing the switching processing to adjust a module current flowing in at least one of the power storage modules so as to prevent the magnitude of a terminal voltage in at least one of the power converters from exceeding an upper limit voltage.

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