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

Abstract

To provide a control device for a power converter capable of appropriately realizing a power conversion system in which a plurality of storage battery modules is electrically connected in parallel.SOLUTION: A control device 16 is applied to a power conversion system 10 in which a plurality of storage battery modules 30, 60 and 90 including storage batteries 31, 61 and 91 and power converters 40, 70 and 100 is electrically connected in parallel. The control device 16 comprises: a voltage acquisition section 16a which acquires a terminal voltage of at least one of the power converters 40, 70 and 100; and a control section 16c which performs switching control of the power converters 40, 70 and 100 in such a manner that a magnitude of the acquired terminal voltage is prevented from exceeding an upper limit voltage.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a control device for a power converter, a power conversion system, a program, and a control method for a power converter.

Background Art

[0002] Conventionally, a power conversion system having a power converter and a plurality of storage batteries is known. The power converter performs power conversion between the storage batteries. As an example of such a technology, the technology disclosed in Patent Document 1 can be cited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A plurality of storage unit modules each having a storage unit and a power converter may be electrically connected in parallel. In this case, it is desirable to appropriately realize a power conversion system in which each storage unit module is electrically connected in parallel.

[0005] The present disclosure has been made to solve the above problems, and its main object is to provide a control device for a power converter, a power conversion system, a program, and a control method for a power converter that can appropriately realize a power conversion system in which a plurality of storage unit modules are electrically connected in parallel.

Means for Solving the Problems

[0006] The present disclosure is A system including a plurality of power storage unit modules each having a power storage unit and a power converter electrically connected to the power storage unit, which is applied to a power conversion system in which the power storage unit modules are electrically connected in parallel. In a control device for a power converter, a voltage acquisition unit that acquires at least one terminal voltage of each of the power converters; a control unit that performs switching control of each of the power converters so as to suppress the magnitude of the acquired terminal voltage from exceeding an upper limit voltage; and is provided with.

[0007] In a configuration where a plurality of power storage unit modules are electrically connected in parallel, each power storage unit module shares the required power for the power conversion system. In this case, if the sharing of the required power is not appropriate, there is a concern that an overvoltage may be applied to at least one of the power converters. In this case, there is a concern that a power conversion system in which each power storage unit module is electrically connected in parallel cannot be appropriately realized.

[0008] Therefore, in the present disclosure, switching control of each power converter is performed so as to suppress the magnitude of at least one terminal voltage of each power converter from exceeding an upper limit voltage. In this case, it is possible to perform power adjustment in each power storage unit module to suppress the application of an overvoltage to each power converter. As a result, it is possible to suppress the application of an overvoltage to the power converter while corresponding to the requirements for the power conversion system. As a result, a power conversion system in which each power storage unit module is electrically connected in parallel can be appropriately realized.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] A plurality of embodiments will be described with reference to the drawings. In a plurality of embodiments, parts that are functionally and / or structurally corresponding and / or associated may be assigned the same reference numerals, or reference numerals that differ in the hundreds place or more. For corresponding parts and / or associated parts, the description of other embodiments can be referred to.

[0011] <First Embodiment> Hereinafter, a first embodiment in which the control device according to the present disclosure is embodied will be described with reference to the drawings. In this embodiment, the control device constitutes a power conversion system mounted on an electric vehicle such as an electric vehicle or a hybrid vehicle.

[0012] 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 battery modules (corresponding to "energy storage unit modules"). In this embodiment, it includes a first battery module 30, a second battery module 60, and a third battery module 90, which are three modules. Each of the battery modules 30, 60, 90 includes batteries 31, 61, 91 (corresponding to "energy storage units"). Each of the batteries 31, 61, 91 is a battery pack configured as a series connection of battery cells as single cells, for example. As the battery cells, secondary batteries such as lithium-ion batteries can be used, for example.

[0013] A load 21 is electrically connected to the high-potential side terminal 11 and the 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 battery modules 30, 60, 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 battery modules 30, 60, 90 via a low-potential side path 14 such as a bus bar. Thereby, the battery modules 30, 60, 90 are electrically connected in parallel to the load 21.

[0014] Specifically, the load 21 includes a three-phase inverter 22 and a rotating electric machine 23 having as many phases of armature windings as 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 a vehicle-mounted main machine, and the rotor of the rotating electric machine 23 is capable of power transmission to the drive wheels of the vehicle. The rotating electric machine 23 is, for example, a permanent magnet synchronous machine.

[0015] 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. Thereby, energization between the power conversion system 10 and the load 21 is enabled. The inverter 22 converts the DC power supplied from the power conversion system 10 into AC power and supplies power to each phase winding of the rotating electrical machine 23. In this case, the rotating electrical machine 23 serves as a driving power source for the vehicle. Further, the rotating electrical machine 23 performs regenerative power generation by the rotational force applied to the rotor. The inverter 22 converts the generated AC power into DC power and outputs the power to the power conversion system 10.

[0016] Each of the battery modules 30, 60, and 90 includes a power converter 40, 70, or 100. In each of the battery modules 30, 60, and 90, the power converters 40, 70, and 100 are electrically connected to the batteries 31, 61, and 91 and the load 21. Hereinafter, the battery 31 and the power converter 40 of the first battery module 30 may be referred to as the "first battery 31" and the "first power converter 40", the battery 61 and the power converter 70 of the second battery module 60 may be referred to as the "second battery 61" and the "second power converter 70", and the battery 91 and the power converter 100 of the third battery module 90 may be referred to as the "third battery 91" and the "third power converter 100".

[0017] Next, the connection relationships among the batteries 31, 61, and 91, the power converters 40, 70, and 100, and the load 21 in each of the battery modules 30, 60, and 90 will be specifically described. First, the first battery module 30 will be described as an example.

[0018] The first power converter 40 includes a primary positive terminal 41 and a primary negative terminal 42 that constitute a primary-side terminal pair, and a secondary positive terminal 43 and a secondary negative terminal 44 that constitute a secondary-side terminal pair. The primary positive terminal 41 of the first power converter 40 is electrically connected to the positive electrode side of the first battery 31. The primary negative terminal 42 of the first power converter 40 and the negative electrode side of the first battery 31 are electrically connected to the inverter 22 via the low-potential side path 14. That is, the primary-side terminal pair of the first power converter 40 is electrically connected in parallel to the first battery 31. In this case, the voltage of the first battery 31 is applied to the primary-side terminal pair of the first power converter 40.

[0019] The secondary negative terminal 44 of the first power converter 40 is electrically connected to the positive electrode side of the first battery 31. The secondary positive terminal 43 of the first power converter 40 is electrically connected to the inverter 22 via the high-potential side path 13. That is, the secondary-side terminal pair of the first power converter 40 is electrically connected in series to the first battery 31 on the positive electrode side of the first battery 31.

[0020] The second power converter 70 includes a primary positive terminal 71 and a primary negative terminal 72 that constitute a primary-side terminal pair, and a secondary positive terminal 73 and a secondary negative terminal 74 that constitute a secondary-side terminal pair. The third power converter 100 includes a primary positive terminal 101 and a primary negative terminal 102 that constitute a primary-side terminal pair, and a secondary positive terminal 103 and a secondary negative terminal 104 that constitute a secondary-side terminal pair. In the second and third battery modules 60 and 90, the connection relationships between the respective terminals 71 to 74 and 101 to 104 of the corresponding power converters 70 and 100, the corresponding batteries 61 and 91, and the load 21 are the same as those in the case of the first battery module 30, although detailed description is omitted. That is, each of the battery modules 30, 60, and 90 is electrically connected in parallel to the load 21.

[0021] In each of the battery modules 30, 60, and 90, the secondary terminal voltages Vo1, Vo2, and Vo3 applied to the secondary terminal pairs of the power converters 40, 70, and 100 are the differential voltages between the voltages across the respective paths 13 and 14 (specifically, the supply voltage to the inverter 22) and the voltages Vbat1, Vbat2, and Vbat3 of the corresponding batteries 31, 61, and 91. The secondary terminal voltages Vo1, Vo2, and Vo3 of each of the battery modules 30, 60, and 90 are lower than the rated voltage (e.g., 400V) of the corresponding battery 31, 61, and 91. Therefore, the secondary rated voltage on the secondary side of each of the power converters 40, 70, and 100 is set lower than the rated voltage of the corresponding battery 31, 61, and 91, and is, for example, 16V. Therefore, the size of each of the power converters 40, 70, and 100 can be reduced.

[0022] FIG. 2 shows an example of the 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 capacitor 51, a secondary capacitor 52, and a transformer 53. In the present embodiment, voltage-controlled semiconductor switching elements are used as the first to eighth switches S1 to S8, and more specifically, N-channel MOSFETs are used. In this case, the high-potential side terminals of the respective switches S1 to S8 are drains, and the low-potential side terminals are sources. Also, each of the switches S1 to S8 has a body diode.

[0023] The drain of the first switch S1 and the drain of the third switch S3 are electrically connected to the primary positive terminal 41 and the first end of the primary capacitor 51. The drain of the second switch S2 is connected to the source of the first switch S1, and the drain of the fourth switch S4 is connected to the source of the third switch S3. The source of the second switch S2 and the source of the fourth switch S4 are electrically connected to the primary negative terminal 42 and the second end of the primary capacitor 51.

[0024] The drain of the fifth switch S5 and the drain of the seventh switch S7 are electrically connected to the secondary positive terminal 43 and the first end of the secondary capacitor 52. The drain of the sixth switch S6 is connected to the source of the fifth switch S5, and the drain of the eighth switch S8 is connected to the source of the seventh switch S7. The secondary negative terminal 44 and the second end of the secondary capacitor 52 are electrically connected to the sources of the sixth switch S6 and the eighth switch S8.

[0025] The transformer 53 includes a primary winding 53a and a secondary winding 53b, and the primary winding 53a and the secondary winding 53b are wound around a common core. Thus, the primary winding 53a and the secondary winding 53b are magnetically coupled by the common core. When the potential of the first end of the primary winding 53a with respect to the second end becomes higher, an induced voltage is generated such that the potential of the first end of the secondary winding 53b is higher than that of the second end. On the other hand, when the potential of the second end of the primary winding 53a with respect to the first end becomes higher, an induced voltage is generated such that the second end of the secondary winding 53b is higher than the first end.

[0026] The first end of the primary winding 53a is electrically connected to the connection point of the first switch S1 and the second switch S2, and the second end of the primary winding 53a is electrically connected to the connection point of the third switch S3 and the fourth switch S4. The first end of the secondary winding 53b is connected to the connection point of the seventh switch S7 and the eighth switch S8, and the second end of the secondary winding 53b is electrically connected to the connection point of the fifth switch S5 and the sixth switch S6.

[0027] The second power converter 70 and the third power converter 100 are isolated DCDC converters, and like the first power converter 40, they include the first to eighth switches, a primary capacitor, a secondary capacitor, and a transformer. In this embodiment, since the configurations of the first power converter 40, the second power converter 70, and the third power converter 100 are basically the same, detailed descriptions of the second power converter 70 and the third power converter 100 are omitted.

[0028] 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, etc. 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 in the same manner as the first battery monitoring device 32. The third battery monitoring device 92 monitors the state of the third storage battery 91 in the same manner as the first battery monitoring device 32. The detection values detected by each of the battery monitoring devices 32, 62, and 92 are input to the control device 16 included in the power conversion system 10.

[0029] The power conversion system 10 includes voltage sensors 45, 75, and 105 and current sensors 46, 76, and 106. The voltage sensors 45, 75, and 105 and the current sensors 46, 76, and 106 are provided corresponding to the respective battery modules 30, 60, and 90. Each of the voltage sensors 45, 75, and 105 detects the secondary-side terminal voltages Vo1, Vo2, and Vo3 of the corresponding power converters 40, 70, and 100. Each of the current sensors 46, 76, and 106 detects the secondary-side currents Io1, Io2, and Io3 flowing on the secondary side of the corresponding power converters 40, 70, and 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 the current flowing through the secondary-side positive terminal 43 and the first end of the secondary-side capacitor 52. The detection values of each of the sensors 45, 46, 75, 76, 105, and 106 are input to the control device 16.

[0030] The control device 16 is an ECU (Electronic Control Unit), and is mainly configured by a microcomputer including a CPU and various memories. The functions provided by the microcomputer can be provided by software recorded in a physical memory device and a computer that executes it, software only, hardware only, or a combination thereof. For example, when the microcomputer is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a number of logic circuits or an analog circuit. For example, the microcomputer executes a program stored in a non-transitory tangible storage medium as a storage unit provided therein. The program includes, for example, programs for the processes shown in FIGS. 3, 8, etc. When the program is executed, a method corresponding to the program is executed. The storage unit is, for example, a non-volatile memory. Note that the program stored in the storage unit can be downloaded and updated via a communication network such as the Internet, for example, OTA (Over The Air).

[0031] The control device 16 performs switching control of each of the power converters 40, 70, and 100. In the present embodiment, the control device 16 controls the module currents of the respective battery modules 30, 60, and 90 in order to flow a required current to the power conversion system 10 in the switching control. Specifically, the module current is the secondary-side current Io1, Io2, Io3 of each of the battery modules 30, 60, and 90. The control device 16 sets current command values of the secondary-side currents Io1, Io2, Io3 in each of the battery modules 30, 60, and 90 based on the required current for the power conversion system 10. The control device 16 performs switching control of each of the power converters 40, 70, and 100 based on the set current command values. Thereby, the share of the required current is distributed to each of the battery modules 30, 60, and 90.

[0032] For example, the control device 16 sets a current command value based on a required current according to the driving state of the rotating electrical machine 23. Specifically, a request may occur to pass a current from the power conversion system 10 to the rotating electrical machine 23 in order to drive the rotating electrical machine 23 in power running. In this case, the control device 16 sets a current command value for discharging at least one of the storage batteries 31, 61, and 91. Further, a request may occur to pass a current from the rotating electrical machine 23 to the power conversion system 10 in order to drive the rotating electrical machine 23 in regeneration. In this case, the control device 16 sets a current command value for charging at least one of the storage batteries 31, 61, and 91.

[0033] For example, the control device 16 sets a current command value based on a required current according to the state of each of the storage batteries 31, 61, and 91. Specifically, a request may occur to transfer power among the storage batteries 31, 61, and 91 in order to control the stored power amount (for example, SOC) of each of the storage batteries 31, 61, and 91. In this case, the control device 16 sets a current command value for discharging a part of each of the storage batteries 31, 61, and 91 and charging at least a part of the remaining ones.

[0034] Note that, for example, a request may also occur to transfer power between the rotating electrical machine 23 and each of the storage batteries 31, 61, and 91 in order to drive the rotating electrical machine 23 in power running or regeneration and control the stored power amount of each of the storage batteries 31, 61, and 91. Also in this case, the control device 16 sets a current command value for discharging a part of each of the storage batteries 31, 61, and 91 and charging at least a part of the remaining ones. The control of the stored power amount of each of the storage batteries 31, 61, and 91 is performed, for example, to equalize the stored power amounts of each of the storage batteries 31, 61, and 91 or to charge or discharge only a specific storage battery among each of the storage batteries 31, 61, and 91.

[0035] By the way, there is a concern that an overvoltage may be applied to at least one secondary side terminal pair of each of the power converters 40, 70, and 100 due to an inappropriate burden share of the required current in each of the battery modules 30, 60, and 90. In this case, there is a concern that the power conversion system 10 in which each of the battery modules 30, 60, and 90 is electrically connected in parallel cannot be appropriately realized.

[0036] Therefore, during the execution of the switching control, the control device 16 performs overvoltage suppression control. The overvoltage suppression control is control for suppressing the application of an overvoltage to the secondary-side terminal pairs of the power converters 40, 70, and 100.

[0037] Specifically, in the overvoltage suppression control, the control device 16 acquires the secondary-side terminal voltages Vo1, Vo2, and Vo3 of the battery modules 30, 60, and 90. Then, the control device 16 performs switching control of the power converters 40, 70, and 100 so as to suppress the magnitudes of the acquired secondary-side terminal voltages Vo1, Vo2, and Vo3 of the battery modules 30, 60, and 90 from exceeding the upper limit voltage VT. The upper limit voltage VT is determined according to the secondary-side rated voltage of each of the power converters 40, 70, and 100, and is set, for example, to a value of 80% - 90% or 90% - 100% with respect to the secondary-side rated voltage.

[0038] In this embodiment, in the overvoltage suppression control, it is possible to perform power adjustment for suppressing the application of an overvoltage to the secondary-side terminal pairs of the power converters 40, 70, and 100 in each of the battery modules 30, 60, and 90. Thereby, while corresponding to the requirements for the power conversion system 10, it is possible to suppress the application of an overvoltage to the power converters 40, 70, and 100. As a result, it is possible to appropriately realize the power conversion system 10 in which the battery modules 30, 60, and 90 are electrically connected in parallel.

[0039] In each of the battery modules 30, 60, and 90, the primary side terminal pairs of the power converters 40, 70, and 100 are electrically connected in parallel to the batteries 31, 61, and 91, and the secondary side terminal pairs are electrically connected in series to the batteries 31, 61, and 91. In this configuration, the rated voltage of each of the power converters 40, 70, and 100 is set lower than the voltage of each of the batteries 31, 61, and 91, or the secondary side terminal voltages Vo1, Vo2, and Vo3 of each of the power converters 40, 70, and 100 are affected by the voltage of the corresponding batteries 31, 61, and 91. In this case, the possibility of an overvoltage being applied to the secondary side terminal pairs of each of the power converters 40, 70, and 100 becomes relatively high. Therefore, there is a great merit in performing overvoltage suppression control during the execution of switching control.

[0040] Hereinafter, the overvoltage suppression control will be specifically described.

[0041] The control device 16 includes a voltage acquisition unit 16a, a voltage determination unit 16b, and a control unit 16c. The voltage acquisition unit 16a acquires the secondary side terminal voltages Vo1, Vo2, and Vo3 of each of the battery modules 30, 60, and 90. In the present embodiment, the voltage acquisition unit 16a uses, as the secondary side terminal voltages Vo1, Vo2, and Vo3 of each of the battery modules 30, 60, and 90, · the detected voltages of each of the voltage sensors 45, 75, and 105, and · the calculated values of the secondary side terminal voltages Vo1, Vo2, and Vo3 in each of the battery modules 30, 60, and 90, and To obtain. For calculating the secondary-side terminal voltages Vo1, Vo2, and Vo3 in each battery module 30, 60, and 90, it is possible to use the detection values of the corresponding battery monitoring devices 32, 62, and 92. Specifically, it is possible to use the voltages Vbat1, Vbat2, and Vbat3 of the batteries 31, 61, and 91 detected by each battery monitoring device 32, 62, and 92 for calculating the secondary-side terminal voltages Vo1, Vo2, and Vo3 in the corresponding battery modules 30, 60, and 90. Also, it is possible to use the battery parameters detected by each battery monitoring device 32, 62, and 92 for calculating the secondary-side terminal voltages Vo1, Vo2, and Vo3 in the corresponding battery modules 30, 60, and 90. The battery parameters are parameters that have a correlation with the voltages Vbat1, Vbat2, and Vbat3 of the batteries, such as the currents Ibat1, Ibat2, and Ibat3 flowing through each battery 31, 61, and 91, the internal resistance, and the SOC, etc.

[0042] The voltage determination unit 16b determines whether there is a voltage-exceeding module based on the obtained secondary-side terminal voltages Vo1, Vo2, and Vo3 of each battery module 30, 60, and 90. The voltage-exceeding module is a battery module among each battery module 30, 60, and 90 whose secondary-side terminal voltage Vo1, Vo2, or Vo3 exceeds the upper limit voltage VT.

[0043] According to this embodiment, in overvoltage suppression control, the detection voltages of each voltage sensor 45, 75, and 105 are obtained. Thereby, the secondary-side terminal voltages Vo1, Vo2, and Vo3 of each battery module 30, 60, and 90 can be appropriately grasped. Therefore, a configuration suitable for determining whether there is a voltage-exceeding module can be realized.

[0044] Also, in overvoltage suppression control, the calculated values of each secondary-side terminal voltage Vo1, Vo2, and Vo3 are obtained. Thereby, the determination accuracy of whether there is a voltage-exceeding module can be improved.

[0045] When it is determined that there is a voltage - exceeding module, the control unit 16c performs a redistribution process. The redistribution process is a process of redistributing the share of the required current to each of the battery modules 30, 60, and 90. In the redistribution process, the control unit 16c changes the secondary - side current so as to reduce the magnitude of the secondary - side terminal voltage in the voltage - exceeding module. Then, the control unit 16c changes the secondary - side current in the battery modules other than the voltage - exceeding module among the battery modules 30, 60, and 90 according to the change amount of the secondary - side current in the voltage - exceeding module. For example, in the redistribution process, the control unit 16c changes the secondary - side current of each of the battery modules 30, 60, and 90 by resetting the current command value in the switching control.

[0046] By reducing the magnitude of the secondary - side terminal voltage in the voltage - exceeding module, it is possible to accurately suppress the application of an over - voltage to the power converter corresponding to the voltage - exceeding module. Also, by changing the secondary - side current in the battery modules other than the voltage - exceeding module among the battery modules 30, 60, and 90, it is possible to compensate for the change amount of the secondary - side current in the voltage - exceeding module. Therefore, while corresponding to the requirements for the power conversion system 10, it is possible to accurately suppress the application of an over - voltage to each of the power converters 40, 70, and 100.

[0047] FIG. 3 shows the processing procedure of the over - voltage suppression control executed by the control device 16. This control is repeatedly executed at a predetermined cycle during the execution of the switching control.

[0048] In step S10, the voltage acquisition unit 16a acquires the secondary - side terminal voltages Vo1, Vo2, and Vo3 of each of the battery modules 30, 60, and 90. In step S11, the voltage determination unit 16b determines whether there is a voltage - exceeding module based on the acquired secondary - side terminal voltages Vo1, Vo2, and Vo3. If a negative determination is made in step S11, the process proceeds to step S12. On the other hand, if an affirmative determination is made in step S11, the process proceeds to step S13.

[0049] In step S12, the control unit 16c continues the current switching control in each of the power converters 40, 70, and 100. In this case, in each of the battery modules 30, 60, and 90, the current secondary-side currents Io1, Io2, and Io3 are maintained. Thereby, a state in which no overvoltage occurs can be continued.

[0050] In step S13, the control unit 16c performs a redistribution process. Hereinafter, the content of the redistribution process will be specifically described for each state of each of the batteries 31, 61, and 91.

[0051] In FIGS. 4 to 7, the secondary-side terminal voltages Vo1, Vo2, Vo3 and the secondary-side currents Io1, Io2, Io3 of each of the battery modules 30, 60, and 90 are compared before and after the redistribution process. Before the execution of the redistribution process, the secondary-side terminal voltages Vo1 and Vo3 of the first and third battery modules 30 and 90 are equal to or lower than the upper limit voltage VT, and the secondary-side terminal voltage Vo2 of the second battery module 60 exceeds the upper limit voltage VT. That is, among the battery modules 30, 60, and 90, the second battery module 60 is the voltage-exceeding module.

[0052] Here, as a factor for the occurrence of the voltage-exceeding module, for example, it is conceivable that the characteristics such as the voltages of the batteries 31, 61, and 91 are different. Specifically, in a battery module in which the voltage of the battery 31, 61, or 91 is low among the battery modules 30, 60, and 90, the differential voltage between the voltage between the paths 13 and 14 and the voltage of the battery becomes high. In this case, in a battery module having a high differential voltage among the battery modules 30, 60, and 90, the secondary-side terminal voltage may exceed the upper limit voltage VT. The voltages of the batteries 31, 61, and 91 can be in different states due to being different in the initial state or the internal resistance changing due to the deterioration of the batteries 31, 61, and 91. For example, in a battery having a high internal resistance among the batteries 31, 61, and 91, even when a discharge current of the same magnitude flows as in a battery having a low internal resistance, the voltage of the battery during discharge becomes low.

[0053] FIG. 4 assumes a case where a request to drive the rotating electrical machine 23 in power running occurs. In this case, each of the battery modules 30, 60, and 90 outputs by sharing the current flowing from the power conversion system 10 to the inverter 22. Therefore, each of the batteries 31, 61, and 91 is discharging.

[0054] The control unit 16c performs switching control of the second power converter 70 so as to reduce the magnitude of the secondary-side current Io2 in the second battery module 60 by an adjustment amount ΔIo. As a result, the discharge current of the second battery 61 is reduced. In this case, the voltage drop amount of the internal resistance in the second battery 61 during discharge is reduced, and the voltage of the second battery 61 increases. Therefore, the differential voltage between the voltage between each of the paths 13 and 14 and the voltage of the second battery 61 is reduced. Therefore, after the execution of the redistribution process, the secondary-side terminal voltage Vo2 of the second battery module 60 is reduced by ΔVo2, and the secondary-side terminal voltage Vo2 becomes equal to or lower than the upper limit voltage VT.

[0055] Also, the control unit 16c performs switching control of the first power converter 40 so as to increase the magnitude of the secondary-side current Io1 in the first battery module 30 by an adjustment amount ΔIo. As a result, the magnitude of the current flowing from the power conversion system 10 to the inverter 22 can be maintained before and after the redistribution process. Therefore, in the switching control for discharging each of the batteries 31, 61, and 91, it is possible to suppress the occurrence of overvoltage while driving the rotating electrical machine 23 in power running in the same manner as before the execution of the redistribution process.

[0056] The control unit 16c may increase the magnitude of the secondary-side current Io3 in the third battery module 90 to compensate for the adjustment amount ΔIo (specifically, the reduction amount) of the secondary-side current Io2 in the second battery module 60. The control unit 16c may increase the magnitudes of the secondary-side currents Io1 and Io3 in both the first and third battery modules 30 and 90 to compensate for the adjustment amount ΔIo (specifically, the reduction amount) of the secondary-side current Io2 in the second battery module 60.

[0057] FIG. 5 assumes a case where a request to regeneratively drive the rotating electrical machine 23 has occurred. In this case, each of the battery modules 30, 60, 90 receives power by sharing the current flowing from the inverter 22 to the power conversion system 10. Therefore, each of the batteries 31, 61, 91 is being charged.

[0058] The control unit 16c performs switching control of the second power converter 70 so as to increase the magnitude of the secondary-side current Io2 in the second battery module 60 by an adjustment amount ΔIo. As a result, the charging current of the second battery 61 increases. In this case, the voltage drop amount of the internal resistance in the second battery 61 during charging becomes high, and the voltage of the second battery 61 during charging becomes high. Therefore, the differential voltage between the voltage between each path 13, 14 and the voltage of the second battery 61 is reduced. Therefore, after the execution of the redistribution process, the secondary-side terminal voltage Vo2 of the second battery module 60 is reduced, and the secondary-side terminal voltage Vo2 becomes equal to or lower than the upper limit voltage VT.

[0059] Further, the control unit 16c performs switching control of the first power converter 40 so as to reduce the magnitude of the secondary-side current Io1 in the first battery module 30 by the adjustment amount ΔIo. Thereby, the magnitude of the current flowing from the inverter 22 to the power conversion system 10 can be maintained before and after the redistribution process. Therefore, in the switching control for charging each of the batteries 31, 61, 91, it is possible to suppress the occurrence of overvoltage while performing the regenerative drive of the rotating electrical machine 23 in the same manner as before the execution of the redistribution process.

[0060] The control unit 16c may reduce the magnitudes of the secondary-side currents Io1, Io3 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-side current Io2 in the second battery module 60.

[0061] FIG. 6 assumes a case where a request is generated to drive the rotating electrical machine 23 in power running and increase the power storage amount of the third storage battery 91. In this case, the first and second storage battery modules 30 and 60 output by sharing the current supplied to the inverter 22 and the third storage battery module 90. Therefore, the first and second storage batteries 31 and 61 are being discharged, and the third storage battery 91 is being charged.

[0062] The control unit 16c performs switching control of the second power converter 70 so as to reduce the magnitude of the secondary current Io2 in the second storage battery module 60 by the adjustment amount ΔIo. Thereby, similar to the case described with reference to FIG. 4, the secondary terminal voltage Vo2 in the second storage battery module 60 becomes equal to or lower than the upper limit voltage VT.

[0063] Further, the control unit 16c performs switching control of the third power converter 100 so as to reduce the magnitude of the secondary current Io3 in the third storage battery module 90 by the adjustment amount ΔIo. Thereby, the magnitude of the current flowing from the power conversion system 10 to the inverter 22 can be maintained before and after the redistribution process. Therefore, in the switching control for discharging the first and second storage batteries 31 and 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 electrical machine 23 in the same manner as before the execution of the redistribution process.

[0064] The control unit 16c may increase the magnitude of the secondary current Io1 in the first storage battery module 30 to compensate for the adjustment amount ΔIo (reduction amount) of the secondary current Io2 in the second storage battery module 60. Further, the control unit 16c may 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 to compensate for the adjustment amount ΔIo of the secondary current Io2 in the second storage battery module 60.

[0065] FIG. 7 assumes a case where there is a request to drive the rotating electrical machine 23 in power running and increase the stored power amount of the second storage battery 61. In this case, the first and third storage battery modules 30 and 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 and 91 are being discharged, and the second storage battery 61 is being charged.

[0066] The control unit 16c performs switching control of the second power converter 70 so as to increase the magnitude of the secondary-side current Io2 in the second storage battery module 60 by an adjustment amount ΔIo. As a result, similar to the case described in FIG. 5, the secondary-side terminal voltage Vo2 in the second storage battery module 60 becomes equal to or lower than the upper limit voltage VT.

[0067] Further, the control unit 16c performs switching control of the third power converter 100 so as to increase the magnitude of the secondary-side current Io3 in the third storage battery module 90 by an adjustment amount ΔIo. Thereby, the magnitude of the current flowing from the power conversion system 10 to the inverter 22 can be maintained before and after the redistribution process. Therefore, in the switching control for discharging the first and third storage batteries 31 and 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 electrical machine 23 in the same manner as before the execution of the redistribution process.

[0068] The control unit 16c may increase the secondary-side currents Io1 and Io3 in at least one of the first and third storage battery modules 30 and 60 to compensate for the adjustment amount ΔIo (increase amount) of the secondary-side current Io2 in the second storage battery module 60.

[0069] In the redistribution process described with reference to FIGS. 4 to 7, in either one of the first and third battery modules 30 and 90, the secondary-side terminal voltage increases (see ΔVo1 and ΔVo3) as the secondary-side current changes. Therefore, the control unit 16c may select the battery module with the lower secondary-side terminal voltage Vo1 or Vo3 among the first and third battery modules 30 and 90, and change the magnitude of the secondary-side current in the selected battery module. Thereby, it is possible to appropriately select the battery module that increases the secondary-side terminal voltage, and execute the process of changing the secondary-side currents Io1, Io2, and Io3 of the respective battery modules 30, 60, and 90.

[0070] Here, during the execution of the switching control, there is a concern that an overcurrent may flow through at least one of the battery modules 30, 60, and 90. For example, when the overvoltage suppression control is executed, in order to compensate for the adjustment of the secondary-side current for the overvoltage module, the magnitude of the secondary-side current in the battery modules other than the overvoltage module among the battery modules 30, 60, and 90 may increase. In this case, there is a concern that an overcurrent may flow in the battery module in which the magnitude of the secondary-side current increases.

[0071] Therefore, in the present embodiment, the control device 16 performs overcurrent suppression control during the execution of the switching control. The overcurrent suppression control is control for suppressing an overcurrent from flowing through the secondary-side terminals of the power converters 40, 70, and 100.

[0072] Hereinafter, the overcurrent suppression control will be specifically described.

[0073] The control device 16 includes a current acquisition unit 16d, a current determination unit 16e, and a distribution determination unit 16f. In the present embodiment, the current acquisition unit 16d acquires the secondary-side currents Io1, Io2, and Io3 of the battery modules 30, 60, and 90. As the secondary-side currents Io1, Io2, and Io3 of the battery modules 30, 60, and 90, the detected currents of the current sensors 46, 76, and 106 can be used.

[0074] The current determination unit 16e determines whether there is a module with an excessive current based on the secondary-side currents Io1, Io2, and Io3 of the acquired battery modules 30, 60, and 90. The module with an excessive current is a battery module among the battery modules 30, 60, and 90 in which the magnitude of the acquired secondary-side currents Io1, Io2, and Io3 exceeds the upper-limit current IT. The upper-limit current IT is determined according to at least one of the secondary-side rated currents of the power converters 40, 70, and 100 and the rated currents of the batteries 31, 61, and 91. For example, it is determined to be a value of 80% - 90% or 90% - 100% with respect to the secondary-side rated current.

[0075] When it is determined that there is a module with an excessive current, the distribution determination unit 16f determines whether to execute the redistribution process based on the acquired secondary-side terminal voltages Vo1, Vo2, and Vo3. The determination process of the distribution determination unit 16f will be described later.

[0076] When it is determined that the redistribution process is to be executed, the control unit 16c performs the redistribution process. In this case, in the redistribution process, the control unit 16c performs switching control of the power converters 40, 70, and 100 so as to distribute the excess of the secondary-side current in the module with an excessive current over the upper-limit current IT to the battery modules other than the module with an excessive current among the battery modules 30, 60, and 90.

[0077] On the other hand, when it is determined that the redistribution process is not to be executed, the control unit 16c performs the reduction process. In this case, in the reduction process, the control unit 16c performs switching control of the power converters 40, 70, and 100 so as to reduce the total current of the secondary-side currents Io1, Io2, and Io3 in the battery modules 30, 60, and 90.

[0078] Fig. 8 shows the processing procedure of the overcurrent suppression control executed by the control device 16. This control is repeatedly executed at a predetermined cycle in parallel with the overvoltage suppression control during the execution of the switching control.

[0079] In step S20, the voltage acquisition unit 16a acquires the secondary terminal voltages Vo1, Vo2, and Vo3 of the respective battery modules 30, 60, and 90. Further, the current acquisition unit 16d acquires the secondary currents Io1, Io2, and Io3 of the respective battery modules 30, 60, and 90.

[0080] In step S21, the current determination unit 16e determines whether there is a module with an overcurrent based on the acquired secondary currents Io1, Io2, and Io3 of the respective battery modules 30, 60, and 90. If a negative determination is made in step S21, the process proceeds to step S22. In step S22, the control unit 16c continues the current switching control in each of the power converters 40, 70, and 100. In this case, the current secondary currents Io1, Io2, and Io3 in each of the battery modules 30, 60, and 90 are maintained. Thereby, a state in which no overcurrent is generated can be continued. Note that even if the process of maintaining the secondary currents Io1, Io2, and Io3 in step S22 is executed, if an affirmative determination is made in step S11 of FIG. 3 above, the redistribution process in the overvoltage suppression control is executed, and the secondary currents Io1, Io2, and Io3 can be changed.

[0081] If an affirmative determination is made in step S21, the process proceeds to step S23. In step S23, the distribution determination unit 16f determines whether the secondary terminal voltages Vo1, Vo2, and Vo3 may exceed the upper limit voltage VT with the execution of the redistribution process based on the acquired secondary terminal voltages Vo1, Vo2, and Vo3 of the respective battery modules 30, 60, and 90. Here, the secondary terminal voltages Vo1, Vo2, and Vo3 can be changed from the current values until they reach the upper limit voltage VT. Therefore, in the present embodiment, the distribution determination unit 16f calculates the remaining voltage until the acquired secondary terminal voltages Vo1, Vo2, and Vo3 of the respective battery modules 30, 60, and 90 reach the upper limit voltage VT. The distribution determination unit 16f determines whether the secondary terminal voltages Vo1, Vo2, and Vo3 may exceed the upper limit voltage VT with the execution of the redistribution process based on the calculated remaining voltages.

[0082] For example, when the distribution determination unit 16f determines that there is a remaining voltage (for example, the remaining voltage is higher than 0) in a battery module among the battery modules 30, 60, and 90 whose secondary terminal voltage is increased by executing the redistribution process, it makes a negative determination in step S23. On the other hand, when the distribution determination unit 16f determines that there is no remaining voltage (for example, the remaining voltage is 0) in a battery module among the battery modules 30, 60, and 90 whose secondary terminal voltage is increased by executing the redistribution process, it makes an affirmative determination in step S23.

[0083] When a negative determination is made in step S23, the process proceeds to step S24. In step S24, the distribution determination unit 16f determines whether the current secondary currents Io1, Io2, and Io3 can be adjusted by the redistribution process based on the obtained secondary currents Io1, Io2, and Io3 in the battery modules 30, 60, and 90. Here, the secondary currents Io1, Io2, and Io3 can be adjusted from their current values until the upper limit current IT is reached. Therefore, in the present embodiment, the distribution determination unit 16f calculates the adjustable current until the magnitudes of the obtained secondary currents Io1, Io2, and Io3 in the battery modules 30, 60, and 90 reach the upper limit current IT. The distribution determination unit 16f determines whether the current secondary currents Io1, Io2, and Io3 can be adjusted by the redistribution process based on the calculated adjustable currents.

[0084] For example, when the distribution determination unit 16f determines that there is an adjustable current (for example, the adjustable current is greater than 0) in a battery module among the battery modules 30, 60, and 90 whose secondary current magnitude is increased by executing the redistribution process, it makes an affirmative determination in step S24. On the other hand, when the distribution determination unit 16f determines that there is no adjustable current (for example, the adjustable current is 0) in a battery module among the battery modules 30, 60, and 90 whose secondary current magnitude is increased by executing the redistribution process, it makes a negative determination in step S24.

[0085] When an affirmative determination is made in step S24, the distribution determination unit 16f determines to execute the redistribution process and proceeds to step S25. In step S25, the control unit 16c executes the redistribution process. When an affirmative determination is made in step S23 or a negative determination is made in step S24, the distribution determination unit 16f determines not to execute the redistribution process and proceeds to step S26. In step S26, the control unit 16c executes the reduction process. Note that the distribution determination unit 16f may determine to execute the redistribution process when a negative determination is made in step S23 without performing the process of step S24.

[0086] FIGS. 9, 10, and 11 show an example of overcurrent suppression control. In FIGS. 9 to 11, among the battery modules 30, 60, and 90, the first battery module 30 is the current excess module. In FIGS. 9 and 11, the batteries 31, 61, and 91 are discharging. In FIG. 10, the batteries 31, 61, and 91 are charging.

[0087] In FIG. 9, the distribution determination unit 16f determines that there are remaining voltages Va2 and Va3 of the second and third battery modules 60 and 90, and makes a negative determination in step S23 of the previous FIG. 8. Further, the distribution determination unit 16f determines that there are adjustable currents Ia2 and Ia3 of the second and third battery modules 60 and 90, and makes an affirmative determination in step S24 of the previous FIG. 8. Therefore, the control unit 16c executes the redistribution process.

[0088] In the redistribution process, the control unit 16c performs switching control of the first power converter 40 so as to reduce the magnitude of the secondary current Io1 in the first battery module 30 by an adjustment amount ΔIo. The control unit 16c adjusts the secondary current Io1 in the first battery module 30 within a range where the secondary terminal voltages Vo2 and Vo3 of the second and third battery modules 60 and 90, which supplement the adjustment amount ΔIo, do not exceed the upper limit voltage VT. Here, the control unit 16c makes the adjustment amount ΔIo of the secondary current Io1 larger than the excess amount with respect to the upper limit current IT of the secondary current Io1. Therefore, after the execution of the redistribution process, the magnitude of the secondary current Io1 in the first battery module 30 is made equal to or less than the upper limit current IT.

[0089] Further, in the redistribution process, the control unit 16c distributes the adjustment amount ΔIo of the secondary current Io1 in the first battery module 30 to the second battery module 60. In other words, the control unit 16c performs switching control of the second power converter 70 so as to increase the magnitude of the secondary current Io2 in the second battery module 60 by the adjustment amount ΔIo. Accordingly, the secondary terminal voltage Vo2 rises by ΔVo2. In FIG. 9, the increase amount ΔVo2 of the secondary terminal voltage Vo2 in the second battery module 60 is lower than the residual voltage Va2, and the adjustment amount ΔIo of the secondary current Io2 is smaller than the adjustable current Ia2. Therefore, in the second battery module 60 after the execution of the redistribution process, the secondary terminal voltage Vo2 is made equal to or lower than the upper limit voltage VT, and the magnitude of the secondary current Io2 is made equal to or lower than the upper limit current IT.

[0090] In FIG. 10, the distribution determination unit 16f determines that there is a residual voltage Vb1 in the first battery module 30, and makes a negative determination in step S23 of FIG. 8 above. Further, the distribution determination unit 16f determines that there are adjustable currents Ib2 and Ib3 in the second and third battery modules 60 and 90, and makes an affirmative determination in step S24 of FIG. 8 above. Therefore, the control unit 16c executes the redistribution process.

[0091] In the redistribution process, the control unit 16c performs switching control of the first power converter 40 so as to reduce the magnitude of the secondary-side current Io1 in the first battery module 30 by an adjustment amount ΔIo. In FIG. 10, the control unit 16c makes the adjustment amount ΔIo of the secondary-side current Io1 larger than the excess with respect to the upper limit current IT of the secondary-side current Io1. Therefore, after the execution of the redistribution process, the magnitude of the secondary-side current Io1 of the first battery module 30 is made equal to or less than the upper limit current IT. Further, the control unit 16c adjusts the secondary-side current Io1 in the first battery module 30 within a range where the secondary-side terminal voltage Vo1 of the first battery module 30 does not exceed the upper limit voltage VT. In FIG. 10, the increase amount ΔVo1 of the secondary-side terminal voltage Vo1 in the first battery module 30 is lower than the remaining voltage Vb1. Therefore, after the execution of the redistribution process, the secondary-side terminal voltage Vo1 of the first battery module 30 is made equal to or less than the upper limit voltage VT.

[0092] Also, in the redistribution process, the control unit 16c distributes the adjustment amount ΔIo of the secondary-side current Io1 in the first battery module 30 to the second battery module 60. In other words, the control unit 16c performs switching control of the second power converter 70 so as to increase the magnitude of the secondary-side current Io2 in the second battery module 60 by the adjustment amount ΔIo. In FIG. 10, in the second battery module 60, the adjustment amount ΔIo of the secondary-side current Io2 is smaller than the adjustable current Ib2. Therefore, after the execution of the redistribution process, the magnitude of the secondary-side current Io2 is made equal to or less than the upper limit current IT.

[0093] According to the present embodiment, the redistribution process is performed in the overvoltage suppression control, and the redistribution process is also performed in the overcurrent suppression control. Thereby, the occurrence of overvoltage and overcurrent in each of the battery modules 30, 60, 90 can be suppressed. As a result, the occurrence of inconveniences during the execution of the switching control can be accurately suppressed.

[0094] In FIG. 11, the distribution determination unit 16f determines that there is no remaining voltage Vc2 and Vc3 in the second and third battery modules 60 and 90, and makes an affirmative determination in step S23 of FIG. 8 above. Further, the distribution determination unit 16f determines that there is no adjustable current Ic2 and Iac in the second and third battery modules 60 and 90, and makes a negative determination in step S24 of FIG. 8 above. Therefore, the control unit 16c executes a reduction process.

[0095] In the reduction process, the control unit 16c performs switching control of the first power converter 40 so as to reduce the magnitude of the secondary current Io1 in the first battery module 30 by an excess amount ΔIo with respect to the upper limit current IT. Further, the control unit 16c continues the current switching control in the second and third power converters 70 and 100.

[0096] According to the present embodiment, the total current of the secondary currents Io1, Io2, and Io3 in each of the battery modules 30, 60, and 90 is reduced. Thereby, even when it is determined that the redistribution process cannot be executed, the magnitude of the secondary current in the current excess module can be made equal to or less than the upper limit current IT. Therefore, it is possible to realize a configuration suitable for suppressing the occurrence of a situation in which an overcurrent flows through each of the battery modules 30, 60, and 90.

[0097] <Modification Example of the First Embodiment> · In the overvoltage suppression control, the control device 16 may suppress the application of an overvoltage to at least one of the secondary terminal pairs of the power converters 40, 70, and 100. In this case, the voltage acquisition unit 16a may acquire at least one of the secondary terminal voltages Vo1, Vo2, and Vo3 of the battery modules 30, 60, and 90.

[0098] · In the overcurrent suppression control, the control device 16 may suppress the flow of an overcurrent through at least one of the secondary terminal pairs of the power converters 40, 70, and 100. In this case, the current acquisition unit 16d may acquire at least one of the secondary currents Io1, Io2, and Io3 of the battery modules 30, 60, and 90.

[0099] · Instead of performing overvoltage suppression control and overcurrent suppression control, the control device 16 may perform only overvoltage suppression control among overvoltage suppression control and overcurrent suppression control.

[0100] · In the switching control, instead of controlling the secondary-side currents Io1, Io2, and Io3 of the battery modules 30, 60, and 90, the control device 16 may control the secondary-side current of any one or two of the battery modules 30, 60, and 90 and control the secondary-side terminal voltages Vo1, Vo2, and Vo3 of the remaining battery modules. For example, in the switching control, the control device 16 may control the secondary-side terminal voltage Vo1 of the first battery module 30 and control the secondary-side currents Io2 and Io3 of the second and third battery modules 60 and 90. In this case, the control device 16 may perform switching control of the first power converter 40 so that the secondary-side terminal voltage Vo1 in the first battery module 30 becomes the required voltage of the rotating electrical machine 23.

[0101] An overcurrent in each of the battery modules 30, 60, and 90 may also occur due to a sudden change in the demand for the power conversion system 10 of the rotating electrical machine 23. Specifically, when the required power of the rotating electrical machine 23 suddenly changes in the direction of increasing, in the battery module in which voltage control is being performed among the battery modules 30, 60, and 90, the increase in the required power is borne, and the secondary-side current may increase. In this case, there is a concern that an overcurrent may flow in the battery module in which voltage control is being performed among the battery modules 30, 60, and 90.

[0102] Even when the battery module among the battery modules 30, 60, and 90 where voltage control is being performed becomes a current - exceeding module, by executing the redistribution process in step S25 of FIG. 8 above, the generation of overcurrent in the current - exceeding module can be suppressed. In this case, the control unit 16c increases the magnitude of the secondary - side current in the battery modules that are other than the current - exceeding module among the battery modules 30, 60, and 90 and where current control is being performed. Along with this, the burden on the required power in the current - exceeding module is reduced, and the magnitude of the secondary - side current Io1 in the current - exceeding module is reduced. Thereby, the generation of overcurrent can be suppressed in the battery modules among the battery modules 30, 60, and 90 where voltage control is being performed. Also, in addition to the above - described overcurrent suppression control, overvoltage suppression control may be performed. Thereby, the generation of overcurrent and overvoltage in each of the battery modules 30, 60, and 90 can be suppressed.

[0103] In this embodiment, instead of performing both overvoltage suppression control and overcurrent suppression control, the control device 16 may perform only overcurrent suppression control among overvoltage suppression control and overcurrent suppression control.

[0104] · Instead of controlling the secondary - side currents Io1, Io2, Io3 of the battery modules 30, 60, 90 in steps S12, S13 of FIG. 3 above and steps S22, S25, S26 of FIG. 8 above, the control unit 16c may control the currents Ibat1, Ibat2, Ibat3 flowing through the batteries 31, 61, 91. Even in this case, overvoltage suppression control and overcurrent suppression control can be executed. In this embodiment, the currents Ibat1, Ibat2, Ibat3 flowing through the batteries 31, 61, 91 correspond to the "module current".

[0105] · Instead of obtaining the secondary-side currents Io1, Io2, and Io3 of each battery module 30, 60, and 90, the current acquisition unit 16d may obtain the currents Ibat1, Ibat2, and Ibat3 flowing through each battery 31, 61, and 91. As the currents Ibat1, Ibat2, and Ibat3 flowing through each battery 31, 61, and 91, it is possible to use the detected currents of each battery monitoring device 32, 62, and 92.

[0106] · Based on the obtained currents Ibat1, Ibat2, and Ibat3 flowing through each battery 31, 61, and 91, the current determination unit 16e may determine whether there is a current excess module. In this case, the upper limit current IT may be determined according to the rated current of each battery 31, 61, and 91. For example, it may be determined as a value of 80% - 90% or 90% - 100% with respect to the rated current of each battery 31, 61, and 91.

[0107] · The voltage acquisition unit 16a may acquire at least one or two of the detected voltages of each voltage sensor 45, 75, and 105, the secondary-side terminal voltages Vo1, Vo2, and Vo3 calculated based on the detected voltages of each battery monitoring device 32, 62, and 92, and the secondary-side terminal voltages Vo1, Vo2, and Vo3 calculated based on the battery parameters of each battery monitoring device 32, 62, and 92. Note that when the secondary-side terminal voltages Vo1, Vo2, and Vo3 calculated based on the detected values of each battery monitoring device 32, 62, and 92 are acquired, the voltage sensors 45, 75, and 105 may not be provided in each power converter 40, 70, and 100.

[0108] · In overvoltage suppression control, the control unit 16c may change the secondary-side current in the battery modules other than the voltage excess module among each battery module 30, 60, and 90 by an amount larger or smaller than the adjustment amount ΔIo. In this case, although the current flowing between the power conversion system 10 and the inverter 22 changes before and after the execution of the redistribution process, it is possible to suppress the application of an overvoltage to the secondary-side terminals of each power converter 40, 70, and 100.

[0109] <Second Embodiment> Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the configuration of the battery module is changed. Specifically, as shown in FIG. 12, the power conversion system 10 includes a first battery module 130, a second battery module 160, and a third battery module 190. First, the configuration of the first battery module 130 will be described below.

[0110] The first battery module 130 includes a first power converter 140 and a first battery 131. The primary positive terminal 141 of the first power converter 140 and the positive side of the first battery 131 are electrically connected to the inverter 22 via the high-potential side path 13. The primary negative terminal 142 of the first power converter 140 is electrically connected to the negative side of the first battery 131.

[0111] The secondary positive terminal 143 of the first power converter 140 is electrically connected to the negative side of the first battery 131. The secondary negative terminal 144 of the first power converter 140 is electrically connected to the inverter 22 via the low-potential side path 14. That is, the secondary terminal pair of the first power converter 140 is electrically connected in series to the first battery 131 on the negative side of the first battery 131.

[0112] The second battery module 160 includes a second power converter 170 and a second battery 161. The third battery module 190 includes a third power converter 1100 and a third battery 191. Since the configurations of the second and third battery modules 160 and 190 are the same as that of the first battery module 130, detailed descriptions thereof are omitted. Each of the power converters 140, 170, and 1100 is, for example, an isolated DCDC converter as in the first embodiment. Each of the batteries 131, 161, and 191 is, for example, a battery pack as in the first embodiment.

[0113] Similar to the first embodiment, the control device 16 performs switching control of each of the power converters 140, 170, and 1100. Also, similar to the first embodiment, the control device 16 performs overvoltage suppression control and overcurrent suppression control during the execution of the switching control.

[0114] As described as a modification of the first embodiment, each configuration may be changed and implemented in this embodiment.

[0115] <Other Embodiments> Note that each of the above embodiments may be implemented with the following changes.

[0116] · As shown in FIG. 13, the configuration of the battery module may be changed. Specifically, the power conversion system 10 includes a first battery module 230, a second battery module 260, and a third battery module 290. First, the configuration of the first battery module 230 will be described below.

[0117] The first battery module 230 includes a first power converter 240 and a first battery 231. The primary positive terminal 241 of the first power converter 240 is electrically connected to the positive side of the first battery 231, and the primary negative terminal 242 of the first power converter 240 is electrically connected to the negative side of the first battery 231. The secondary positive terminal 243 of the first power converter 240 is electrically connected to the inverter 22 via the high-potential side path 13, and the secondary negative terminal 244 of the first power converter 240 is electrically connected to the inverter 22 via the low-potential side path 14.

[0118] The second battery module 260 includes a second power converter 270 and a second battery 261. The third battery module 290 includes a third power converter 2100 and a third battery 291. Since the configurations of the second and third battery modules 260 and 290 are the same as that of the first battery module 230, detailed descriptions thereof are omitted. Each of the power converters 240, 270, and 2100 is, for example, an isolated DCDC converter as in the first embodiment. Each of the batteries 231, 261, and 291 is, for example, a battery pack as in the first embodiment.

[0119] The control device 16 performs switching control of each of the power converters 240, 270, and 2100 in the same manner as in the first embodiment. Further, the control device 16 performs overvoltage suppression control and overcurrent suppression control during the execution of the switching control in the same manner as in the first embodiment.

[0120] The voltage applied to the secondary side terminal pair of each of the power converters 240, 270, and 2100 is the voltage between each of the paths 13 and 14. Therefore, unlike the cases of the first embodiment and the second embodiment, each of the power converters 240, 270, and 2100 is less affected by the voltage of each of the batteries 231, 261, and 291 with respect to the voltage applied to the secondary side terminal pair. Therefore, the possibility that an overvoltage is applied to the secondary side terminal pair of each of the power converters 240, 270, and 2100 is lower than that in the cases of the first embodiment and the second embodiment. However, for example, when the load 21 suddenly changes from the driving state to the no-load state, a current may temporarily flow between the battery modules 230, 260, and 290. In this case, in the battery module into which the current flows from another battery module among the battery modules 230, 260, and 290, an overvoltage may be temporarily applied to the power converter or an overcurrent may flow. Therefore, by executing at least one of the overvoltage suppression control and the overcurrent suppression control by the control device 16, the power conversion system 10 in which the battery modules 230, 260, and 290 are electrically connected in parallel can be appropriately realized.

[0121] ·The control device is not limited to controlling the power converters 40, 70, and 100 in an integrated manner, and may individually control the power converters 40, 70, and 100. Specifically, as shown in FIG. 14, 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 battery module 30. The detection values of the first battery monitoring device 32 and the detection values of the sensors 45 and 46 are input to the first control device 17. The second control device 18 is provided corresponding to the second battery module 60. The detection values of the second battery monitoring device 62 and the detection values of the sensors 75 and 76 are input to the second control device 18. The third control device 19 is provided corresponding to the third battery module 90. The detection values of the third battery monitoring device 92 and the detection values of the sensors 105 and 106 are input to the third control device 19.

[0122] Each of the control devices 17, 18, and 19 sets a current command value for the secondary-side current in the corresponding battery module. Each of the control devices 17, 18, and 19 performs switching control of the corresponding power converter based on the set current command value.

[0123] Each of the control devices 17, 18, and 19 is communicable by wired or wireless communication means, and information such as the input detection values and current command values can be transmitted and received to and from each other. Even in this case, the functions of the voltage acquisition unit 16a, voltage determination unit 16b, control unit 16c, current acquisition unit 16d, current determination unit 16e, and distribution determination unit 16f described in the first embodiment and the modification of the first embodiment can be realized by the control devices 17, 18, and 19.

[0124] Note that each of the control devices 17, 18, and 19 is not limited to being provided outside the corresponding battery modules 30, 60, and 90, and may be provided inside the corresponding battery modules 30, 60, and 90. Also, in the power conversion system 10 described in the second embodiment or FIG. 13, similar to this embodiment, the control device may individually control each power converter.

[0125] · As shown in FIG. 15, the configuration of the power conversion system 10 may be changed. The power conversion system 10 may include first, second, and third high-potential side switches 301a, 302a, 303a and first, second, and third low-potential side switches 301b, 302b, 303b. Each of the switches 301a, 302a, 303a, 301b, 302b, 303b is a relay or a semiconductor switching element.

[0126] The first high-potential side switch 301a is provided on the first battery module 30 side of the high-potential side path 13, closer to the first battery module 30 than the connection point with the second battery module 60. The first low-potential side switch 301b is on the first battery module 30 side of the low-potential side path 14, closer to the first battery module 30 than the connection point with the second battery module 60, and is provided at a lower potential than the connection point with the primary side negative terminal 42 of the first power converter 40.

[0127] The second high-potential side switch 302a is provided in the 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 at a lower potential than the connection point with the primary side negative terminal 72 of the second power converter 70 in the path that electrically connects the negative terminal of the second battery 61 and the low-potential side path 14.

[0128] The third high-potential side switch 303a is provided in the path that electrically connects 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 at a lower potential than the connection point with the primary side negative terminal 102 of the third power converter 100 in the path that electrically connects the negative terminal of the third battery 91 and the low-potential side path 14.

[0129] The power conversion system 10 may include a first connection path 304 and a second connection path 305. The first end of the first connection path 304 is electrically connected between the 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. The 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 the path that electrically connects the secondary side positive terminal 73 and the high potential side path 13. Note that, not limited to the configuration shown in FIG. 15, the first end of the first connection path 304 may be electrically connected between the 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. That is, the first end of the first connection path 304 only needs to be electrically connected between the negative terminal of the first storage battery 31 and the first low potential side switch 301b in the low potential side path 14.

[0130] The first end of the second connection path 305 is electrically connected between the connection point of the low potential side path 14 with the primary side negative terminal 72 of the second power converter 70 and the second low potential side switch 302b in the path that electrically connects the negative terminal of the second storage battery 61 and the low potential side path 14. The 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 third high potential side switch 303a in the path that electrically connects the secondary side positive terminal 103 and the high potential side path 13. Note that, not limited to the configuration shown in FIG. 15, the first end of the second connection path 305 may be electrically connected between the connection point of the low potential side path 14 with the primary side negative terminal 72 of the second power converter 70 and the negative terminal of the second storage battery 61 in the path that electrically connects the negative terminal of the second storage battery 61 and the low potential side path 14. That is, the first end of the second connection path 305 only needs to be electrically connected between the negative terminal of the second storage battery 61 and the second low potential side switch 302b in the path that electrically connects the negative terminal of the second storage battery 61 and the low potential side path 14.

[0131] The power conversion system 10 includes a first connection switch 306 and a second connection switch 307. Each connection switch 306, 307 is a relay or a semiconductor switching element. The first connection switch 306 is provided in the first connection path 304. The second connection switch 307 is provided in the second connection path 305.

[0132] The control device 16 may switch the electrical connection relationships of the load 21 and each of the battery modules 30, 60, 90 by controlling each of the switches 301a, 302a, 303a, 301b, 302b, 303b, 306, 307. For example, the control device 16 may turn on each of the switches 301a, 302a, 303a, 301b, 302b, 303b and turn off each of the connection switches 306, 307. In this case, each of the battery modules 30, 60, 90 is electrically connected in parallel to the load 21. Also, for example, the control device 16 may turn on each of the switches 301a, 303b, 306, 307 and turn off each of the switches 301b, 302a, 302b, 303a. In this case, each of the battery modules 30, 60, 90 is electrically connected in series to the load 21.

[0133] In the present embodiment, when the control device 16 electrically connects each of the battery modules 30, 60, 90 in parallel to the load 21, it is possible to perform at least one of overvoltage suppression control and overcurrent suppression control in the same manner as in each of the above embodiments. In the power conversion system 10 described in the second embodiment or FIG. 13, it is also possible to configure the electrical connection relationships of the load 21 and each of the battery modules to be switchable as described in the present embodiment.

[0134] · When the load 21 is not electrically connected to the power conversion system 10, the control device 16 may perform at least one of overvoltage suppression control and overcurrent suppression control. For example, when there is no request to drive the rotating electrical machine 23 in power running or regeneration, and there is a request to control the power storage levels of the respective storage batteries 31, 61, 91, a request to transfer power may occur only between the respective storage batteries 31, 61, 91. In this case, the control device 16 may perform at least one of overvoltage suppression control and overcurrent suppression control during the execution of the switching control.

[0135] · When the control device 16 stops the operation of the power converter in a specific storage battery module which is any one of the respective storage battery modules 30, 60, 90, the control device 16 may perform only overcurrent suppression control of overvoltage suppression control and overcurrent suppression control on the specific storage battery module. In this case, in step S10, the voltage acquisition unit 16a may not acquire the secondary-side terminal voltage of the specific storage battery module. Further, for example, in step S11, the voltage determination unit 16b may not determine whether the specific storage battery module is a voltage-exceeding module.

[0136] · The load electrically connected to the power conversion system 10 is not limited to the inverter 22 and the rotating electrical machine 23, and may be a DCDC converter, an external charger, an electric heater, or the like.

[0137] · The switch constituting the power converter is not limited to an N-channel MOSFET, and an IGBT may be used. In this case, in each switch, the high-potential side terminal is the collector, and the low-potential side terminal is the emitter. A freewheel diode is connected in anti-parallel to each switch.

[0138] · The power converter is not limited to that described with reference to FIG. 2, and a non-insulated DCDC converter such as a center-tapped insulated DCDC converter, a resonant DCDC converter, and a buck converter can be adopted.

[0139] · In the power conversion system 10, at least two of the battery modules described in the first embodiment, the battery module described in the second embodiment, and the battery module described in FIG. 13 may be combined.

[0140] · The number of battery modules included in the power conversion system may be two or four or more. In this case, each battery module can be configured in the same way as the battery module described in the first embodiment, or in the same way as the battery module described in the second embodiment, or in the same way as the battery module described in FIG. 13.

[0141] · The power storage unit included in each power storage unit module is not limited to a battery, and may be, for example, a large-capacity electric double layer capacitor, or one including both a battery and an electric double layer capacitor. Further, the power storage unit may be a fuel cell.

[0142] · The mounting destination of the power conversion system is not limited to a vehicle, and may be a moving body such as an aircraft or a ship, for example. When the moving body is an aircraft, the rotating electric machine becomes the flight power source of the aircraft, and when the moving body is a ship, the rotating electric machine becomes the navigation power source of the ship. Further, the power conversion system is not limited to being mounted on a moving body, and can also be used as a stationary power source.

[0143] ·The control unit and its method described in the present disclosure may be implemented by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and its method described in the present disclosure may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Or, the control unit and its method described in the present disclosure may be implemented by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured by one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executable by a computer.

[0144] ·Hereinafter, characteristic configurations extracted from each of the above-described embodiments will be described. [Configuration 1] A power conversion system (10) including a plurality of power storage unit modules (30, 60, 90, 130, 160, 190, 230, 260, 290) 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 in a control device (16 - 19) of the power converter applied to the power conversion system in which the power storage unit modules are electrically connected in parallel, a voltage acquisition unit (16a) that acquires at least one terminal voltage of each of the power converters; a control unit (16c) that performs switching control of each of the power converters so as to suppress the magnitude of the acquired terminal voltage from exceeding an upper limit voltage; A control device for a power converter, comprising. [Configuration 2] In each of the power storage unit modules (31, 61, 91, 131, 161, 191), one of the primary side terminal pairs 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 unit modules, one of the secondary side terminal pairs 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 the load (21). In each of the power storage unit modules, of the positive electrode side and the negative electrode side of the power storage unit, the side not connected to the secondary side terminal pair of the power converter is electrically connected to the load. The voltage acquisition unit acquires the secondary side terminal voltage applied to at least one of the secondary side terminal pairs of each of the power converters. The control unit performs the switching control so as to suppress the magnitude of the acquired secondary side terminal voltage from exceeding the upper limit voltage. The control device for a power converter according to Configuration 1. [Configuration 3] A voltage determination unit (16b) is provided that determines whether or not there is a voltage exceeding module among the power storage unit modules in which the magnitude of the acquired secondary side terminal voltage exceeds the upper limit voltage. When it is determined that there is a voltage exceeding module, the control unit, in the switching control, changes the module current flowing through the voltage exceeding module so that the magnitude of the secondary side terminal voltage in the voltage exceeding module is reduced. The control device for a power converter according to Configuration 2, which changes the module current flowing through the power storage unit modules other than the voltage exceeding module among each of the power storage unit modules in accordance with the change amount of the module current in the voltage exceeding module. [Configuration 4] When it is determined that there is a voltage exceeding module, the control unit, in the switching control for discharging the power storage unit of the voltage exceeding module, reduces the magnitude of the module current in the voltage exceeding module. A control device for a power converter according to Configuration 3, which increases the magnitude of the module current in a power storage unit module that is a power storage unit module other than the voltage-exceeding module among the respective power storage unit modules and is discharging, or reduces the magnitude of the module current in a power storage unit module that is a power storage unit module other than the voltage-exceeding module among the respective power storage unit modules and is charging. [Configuration 5] When it is determined that there is a voltage-exceeding module, in the switching control for charging the power storage unit of the voltage-exceeding module, the magnitude of the module current of the voltage-exceeding module is increased, A control device for a power converter according to Configuration 3 or 4, which reduces the magnitude of the module current in a power storage unit module that is a power storage unit module other than the voltage-exceeding module among the respective power storage unit modules and is charging, or increases the magnitude of the module current in a power storage unit module that is a power storage unit module other than the voltage-exceeding module among the respective power storage unit modules and is discharging. [Configuration 6] a current acquisition unit (16d) that acquires the module current of at least one of the respective power storage unit modules; a current determination unit (16e) that determines whether there is a current-exceeding module in which the magnitude of the acquired module current exceeds the upper limit current among the respective power storage unit modules, and When it is determined that there is a current-exceeding module, in the switching control, a distribution process is performed in which the excess of the module current in the current-exceeding module with respect to the upper limit current is distributed to power storage unit modules other than the current-exceeding module among the respective power storage unit modules. A control device for a power converter according to any one of Configurations 3 to 5. [Configuration 7] including a distribution determination unit (16f) that determines whether to execute the distribution process when it is determined that there is a current-exceeding module, In the switching control, the control unit when it is determined that the distribution process is to be executed, executes the distribution process, When it is determined not to execute the distribution process, a control device for a power converter according to Configuration 6 that reduces the total current of the module currents in each power storage unit module. [Configuration 8] In the switching control, when it is determined that there is no voltage-exceeding module and no current-exceeding module, the control device for a power converter according to Configuration 6 or 7 that maintains the magnitude of the module current in each power storage unit module. [Configuration 9] The voltage acquisition unit acquires, as the secondary-side terminal voltage, the detected voltage of a voltage sensor (45, 75, 105) provided at a secondary-side terminal pair of at least one of the power converters, in the control device for a power converter according to any one of Configurations 2 to 8. [Configuration 10] The voltage acquisition unit acquires the secondary-side terminal voltage calculated based on the voltage of at least one of the power storage units, in the control device for a power converter according to any one of Configurations 2 to 9. [Configuration 11] The voltage acquisition unit acquires the secondary-side terminal voltage calculated based on a power storage unit parameter indicating the state of at least one of the power storage units, in the control device for a power converter according to any one of Configurations 2 to 10. [Configuration 12] A system including a plurality of power storage unit modules (30, 60, 90, 130, 160, 190, 230, 260, 290) having power 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 power storage units, in a control device (16 to 19) for a power converter applied to a power conversion system (10) in which the power storage unit modules are electrically connected in parallel, A current acquisition unit (16d) that acquires at least one module current of each of the power storage unit modules, A current determination unit (16e) that determines whether there is a current-exceeding module in which the magnitude of the acquired module current exceeds an upper limit current among the power storage unit modules. When it is determined that there is the overcurrent module, control unit (16c) performs switching control of each power converter so as to distribute the excess of the module current in the overcurrent module with respect to the upper limit current to power storage unit modules other than the overcurrent module among the respective power storage unit modules. A control device for a power converter, comprising: [Configuration 13] A plurality of the power storage unit modules, The control device according to any one of Configurations 1 to 12, A power conversion system, comprising: [Configuration 14] In a program applied to a power conversion system (10) including a plurality of power storage unit 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, and the power storage unit modules are electrically connected in parallel, Causing a computer (16 to 19) to perform a current acquisition process of acquiring at least one module current among the respective power storage unit modules; perform a current determination process of determining whether there is an overcurrent module in which the magnitude of the acquired module current exceeds an upper limit current among the respective power storage unit modules; when it is determined that there is the overcurrent module, perform a control process of performing switching control of each power converter so as to distribute the excess of the module current in the overcurrent module with respect to the upper limit current to power storage unit modules other than the overcurrent module among the respective power storage unit modules. A program for causing the above to be executed. [Configuration 15] A power conversion system (10) including a plurality of power storage unit modules (30, 60, 90, 130, 160, 190, 230, 260, 290) 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 each of the power storage unit modules is electrically connected in parallel. In a control method of the power converter applied to this power conversion system, a current acquisition step of acquiring at least one module current among the respective power storage unit modules; a current determination step of determining whether there is a current exceeding module in which the magnitude of the acquired module current exceeds an upper limit current among the respective power storage unit modules; a control step of performing switching control of each of the power converters so that, when it is determined that there is a current exceeding module, an excess of the module current in the current exceeding module with respect to the upper limit current is distributed to power storage unit modules other than the current exceeding module among the respective power storage unit modules; A control method of a power converter, including the above steps.

Explanation of Signs

[0145] 10... Power conversion system, 16... Control device, 16a... Voltage acquisition unit, 16c... Control unit, 30, 60, 90... First, second, third battery modules, 31, 61, 91... First, second, third batteries, 40, 70, 100... First, second, third power converters.

Claims

1. In a power conversion system (10) including a plurality of power storage unit modules (30, 60, 90, 130, 160, 190, 230, 260, 290) 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 a control device (16 - 19) of the power converter applied to the power conversion system in which each of the power storage unit modules is electrically connected in parallel, a voltage acquisition unit (16a) that acquires at least one terminal voltage of each of the power converters; a control unit (16c) that performs switching control of each of the power converters so as to suppress the magnitude of the acquired terminal voltage from exceeding an upper limit voltage; A control device for a power converter, comprising:

2. In each of the power storage unit modules (31, 61, 91, 131, 161, 191), one of the primary side terminal pairs 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 unit modules, one of the secondary side terminal pairs 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 unit modules, the side that is not connected to the secondary side terminal pair of the power converter among the positive electrode side and the negative electrode side of the power storage unit is electrically connected to the load. The voltage acquisition unit acquires a secondary side terminal voltage applied to at least one of the secondary side terminal pairs of each of the power converters. The control unit performs the switching control so as to suppress the magnitude of the acquired secondary side terminal voltage from exceeding the upper limit voltage. The control device for a power converter according to claim 1.

3. A voltage determination unit (16b) is provided to determine whether there is a voltage - exceeding module in which the magnitude of the acquired secondary side terminal voltage exceeds the upper limit voltage among each of the power storage unit modules. When it is determined that there is a voltage - exceeding module, the control unit, in the switching control, changes the module current flowing through the voltage - exceeding module so that the magnitude of the secondary side terminal voltage in the voltage - exceeding module is reduced. The control device for a power converter according to claim 2, wherein a module current flowing through a power storage unit module other than the voltage-exceeding module among the power storage unit modules is changed according to a change amount of the module current in the voltage-exceeding module.

4. When it is determined that there is a voltage-exceeding module, in the switching control for discharging the power storage unit of the voltage-exceeding module, the control unit reduces the magnitude of the module current in the voltage-exceeding module, and increases the magnitude of the module current in a power storage unit module that is a power storage unit module other than the voltage-exceeding module among the power storage unit modules and is in the process of discharging the power storage unit, or reduces the magnitude of the module current in a power storage unit module that is in the process of charging the power storage unit. The control device for a power converter according to claim 3.

5. When it is determined that there is a voltage-exceeding module, in the switching control for charging the power storage unit of the voltage-exceeding module, the control unit increases the magnitude of the module current of the voltage-exceeding module, and reduces the magnitude of the module current in a power storage unit module that is a power storage unit module other than the voltage-exceeding module among the power storage unit modules and is in the process of charging the power storage unit, or increases the magnitude of the module current in a power storage unit module that is in the process of discharging the power storage unit. The control device for a power converter according to claim 3.

6. a current acquisition unit (16d) that acquires at least one of the module currents among the power storage unit modules; a current determination unit (16e) that determines whether there is a current-exceeding module in which the magnitude of the acquired module current exceeds an upper limit current among the power storage unit modules; and When it is determined that there is a current-exceeding module, in the switching control, the control unit performs a distribution process of distributing an excess of the module current in the current-exceeding module with respect to the upper limit current to power storage unit modules other than the current-exceeding module among the power storage unit modules. The control device for a power converter according to claim 3.

7. comprising a distribution determination unit (16f) that determines whether to execute the distribution process when it is determined that there is a current-exceeding module, In the switching control, the control unit When it is determined that the distribution process is to be executed, execute the distribution process, The control device for a power converter according to claim 6, wherein when it is determined that the distribution process is not to be executed, the total current of the module currents in each of the power storage unit modules is reduced.

8. The control unit according to claim 6, wherein in the switching control, when it is determined that there is no voltage-exceeding module and no current-exceeding module, the magnitude of the module current in each of the power storage unit modules is maintained.

9. The control device for a power converter according to claim 2, wherein the voltage acquisition unit acquires the detected voltage of a voltage sensor (45, 75, 105) provided at at least one secondary terminal pair of each of the power converters as the secondary terminal voltage.

10. The control device for a power converter according to claim 2, wherein the voltage acquisition unit acquires the secondary terminal voltage calculated based on the voltage of at least one of each of the power storage units.

11. The control device for a power converter according to claim 2, wherein the voltage acquisition unit acquires the secondary terminal voltage calculated based on a power storage unit parameter indicating the state of at least one of each of the power storage units.

12. In a control device (16-19) for a power converter applied to a power conversion system (10) including a plurality of power storage unit modules (30, 60, 90, 130, 160, 190, 230, 260, 290) 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, and each of the power storage unit modules being electrically connected in parallel, a current acquisition unit (16d) that acquires at least one module current of each of the power storage unit modules; a current determination unit (16e) that determines whether there is a current-exceeding module among the power storage unit modules in which the magnitude of the acquired module current exceeds the upper limit current; a control unit (16c) that performs switching control of each of the power converters so that when it is determined that there is a current-exceeding module, the excess of the module current in the current-exceeding module over the upper limit current is distributed to the power storage unit modules other than the current-exceeding module among each of the power storage unit modules. A control device for a power converter, comprising

13. A plurality of said power storage unit modules, The control device according to any one of claims 1 to 12, A power conversion system, comprising

14. In a program applied to a power conversion system (10) comprising a plurality of power storage unit 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, A computer (16 - 19) is caused to Execute a voltage acquisition process for acquiring at least one terminal voltage of each of said power converters, Execute a control process for performing switching control of each of said power converters so as to suppress the magnitude of the acquired terminal voltage from exceeding an upper limit voltage. A program.

15. In a control method for a power converter applied to a power conversion system (10) comprising a plurality of power storage unit 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, A voltage acquisition step of acquiring at least one terminal voltage of each of said power converters, A control step of performing switching control of each of said power converters so as to suppress the magnitude of the acquired terminal voltage from exceeding an upper limit voltage. A control method for a power converter, comprising

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