Power conversion device

Abstract

To provide a power conversion device whose constitution can be simplified.SOLUTION: A power conversion device comprises: a rotary electric machine 30 which has a stator coil 31; an inverter 20 which has upper and lower arm switches SWH, SWL and connects the stator coil 31 with first to sixth power storage part 11-16; a high potential side path LP which is connected to a high potential side terminal of the upper arm switch SWH; a low potential side path LN which is connected to a low potential side terminal of the lower arm switch SWL; and a neutral point path LM which is connected to a neutral point of the stator coil 31. The power conversion device further includes first to fifth neutral point switches SM1-SM5 which are individually provided correspondingly to battery connection points PB1-PB5 between positive terminals and negative terminals of the adjacent power storage parts of the power storage parts 11-16 and connect the battery connection points PB1-PB5 with the neutral point path LM.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power conversion device.

Background Art

[0002] Conventionally, as described in Patent Document 1, a charge equalization system including a series connection of a plurality of unit storage batteries, an isolated DCDC converter, and an auxiliary battery is known. The DCDC converter is provided individually for each unit storage battery, the output side is connected to the unit storage battery, and the input side is connected to the auxiliary battery. When the DCDC converter is driven, power is supplied from the auxiliary battery to the unit storage battery. Thereby, the remaining capacity of each unit storage battery can be equalized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the system described in Patent Document 1, a DCDC converter is required for each unit storage battery. Therefore, there is a concern that the system becomes complicated.

[0005] A main object of the present invention is to provide a power conversion device capable of simplifying the configuration.

Means for Solving the Problems

[0006] The present invention is a power conversion device applied to three or more storage units connected in series, a rotating electrical machine having a stator winding, an inverter having upper and lower arm switches and connecting the stator winding and the storage unit, The high-potential path connected to the high-potential side terminal of the upper arm switch, The low-potential path connected to the low-potential side terminal of the lower arm switch, The neutral point path connected to the neutral point of the stator winding, A neutral point switch that is individually provided corresponding to the battery connection points of the positive and negative terminals of adjacent power storage units among the respective power storage units, and that connects the battery connection point and the neutral point path, is provided.

[0007] In the present invention, for the power supply from the source power storage unit to the destination power storage unit among the respective power storage units, a neutral point switch individually provided corresponding to each battery connection point and a neutral point path are provided, and the stator winding and the inverter are diverted. Thereby, simplification of the configuration for supplying power from the source power storage unit to the destination power storage unit can be achieved.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] <First Embodiment> Hereinafter, a first embodiment in which the power conversion device according to the present invention is embodied will be described with reference to the drawings. The power conversion device of this embodiment is mounted on vehicles such as hybrid vehicles, electric vehicles, and fuel cell vehicles. Vehicles include, for example, passenger cars, buses, construction work vehicles, and agricultural machinery vehicles.

[0010] As shown in FIG. 1, the power conversion device includes a battery pack, an inverter 20, and a rotating electric machine 30. The battery pack includes a series connection body of power storage units. In this embodiment, the power storage unit is a battery cell that is a single battery. In this embodiment, the terminal voltage (for example, the rated voltage) of each power storage unit is set to the same voltage. As the battery cell, for example, a secondary battery such as a lithium ion battery can be used. FIG. 1 shows an example in which the battery pack includes six power storage units. In this embodiment, the power storage units included in the battery pack are referred to as the first to sixth power storage units 11 to 16. Among the power storage units 11 to 16, the highest potential power storage unit with the highest potential is the first power storage unit 11, and the lowest potential power storage unit with the lowest potential is the sixth power storage unit 16.

[0011] The negative electrode terminal of the first power storage unit 11 is connected to the positive electrode terminal of the second power storage unit 12 via the first connection point PB1. The negative electrode terminal of the second power storage unit 12 is connected to the positive electrode terminal of the third power storage unit 13 via the second connection point PB2. The negative electrode terminal of the third power storage unit 13 is connected to the positive electrode terminal of the fourth power storage unit 14 via the third connection point PB3. The negative electrode terminal of the fourth power storage unit 14 is connected to the positive electrode terminal of the fifth power storage unit 15 via the fourth connection point PB4. The negative electrode terminal of the fifth power storage unit 15 is connected to the positive electrode terminal of the sixth power storage unit 16 via the fifth connection point PB5. Note that each of the connection points PB1 to PB5 corresponds to a "battery connection point".

[0012] All or part of each of the power storage units 11 to 16 constituting the battery pack is replaceable. For example, when the remaining capacity of some of the power storage units 11 to 16 decreases, some of the power storage units are replaced with fully charged power storage units. Also, for example, when some of the power storage units have deteriorated over time, some of the power storage units are replaced with power storage units that have not deteriorated over time (for example, new power storage units).

[0013] The rotating electrical machine 30 is a three-phase synchronous machine and includes a three-phase stator winding 31 connected in star. The stator windings 31 of each phase are arranged with a 120° electrical angle shift from each other. The rotating electrical machine 30 is, for example, a permanent magnet synchronous machine. In the present embodiment, the rotating electrical machine 30 is an in-vehicle main machine and serves as a driving power source for the vehicle.

[0014] The inverter 20 includes three sets of series-connected bodies of an upper arm switch SWH and a lower arm switch SWL. In the present embodiment, as each of the switches SWH and SWL, a voltage-controlled semiconductor switching element is used, specifically an IGBT. Therefore, the high-potential side terminal of each of the switches SWH and SWL is a collector, and the low-potential side terminal is an emitter. Upper and lower arm diodes DH and DL as freewheel diodes are connected in anti-parallel to the upper and lower arm switches SWH and SWL.

[0015] In each phase, the first end of the stator winding 31 is connected to the emitter of the upper arm switch SWH and the collector of the lower arm switch SWL. The second ends of the stator windings 31 of each phase are connected to each other at the neutral point O. In this embodiment, the number of turns of the stator winding 31 of each phase is set to be the same. As a result, the stator windings 31 of each phase winding are set to have the same inductance, for example.

[0016] The power conversion device 10 includes a high potential side path LP, a low potential side path LN, and a capacitor 21. The collector of the upper arm switch SWH of each phase is connected to the positive terminal of the first power storage unit 11 by the high potential side path LP. The emitter of the lower arm switch SWL of each phase is connected to the negative terminal of the sixth power storage unit 16 by the low potential side path LN. The capacitor 21 connects the collector of the upper arm switch SWH of each phase and the emitter of the lower arm switch SWL of each phase. Note that the capacitor 21 may be built into the inverter 20 or may be provided outside the inverter 20.

[0017] The power conversion device 10 includes a monitoring unit 40 and a control device 50. The monitoring unit 40 monitors the terminal voltage [V], remaining capacity [Ah], SOC, SOH, temperature, etc. of each power storage unit 11 to 16 constituting the battery pack. The monitoring information of the monitoring unit 40 is input to the control device 50.

[0018] The power conversion device 10 includes a neutral point path LM. The neutral point path LM is connected to the neutral point O.

[0019] The power conversion device 10 includes a positive electrode switch SP and a negative electrode switch SN. In this embodiment, the positive electrode switch SP and the negative electrode switch SN are relays.

[0020] The positive electrode switch SP connects the positive electrode terminal of the first power storage unit 11 and the high-potential side path LP. When the positive electrode switch SP is turned on, the positive electrode terminal of the first power storage unit 11 and the high-potential side path LP are electrically connected. On the other hand, when the positive electrode switch SP is turned off, the positive electrode terminal of the first power storage unit 11 and the high-potential side path LP are electrically disconnected. The negative electrode switch SN connects the negative electrode terminal of the sixth power storage unit 16 and the low-potential side path LN. When the negative electrode switch SN is turned on, the negative electrode terminal of the sixth power storage unit 16 and the low-potential side path LN are electrically connected. On the other hand, when the negative electrode switch SN is turned off, the negative electrode terminal of the sixth power storage unit 16 and the low-potential side path LN are electrically disconnected.

[0021] The power conversion device includes first to fifth neutral point switches SM1 to SM5. In the present embodiment, each of the neutral point switches SM1 to SM5 is a relay. The nth neutral point switch SMn (n = 1, 2, 3, 4, 5) connects the nth connection point PBn and the neutral point path LM. When the nth neutral point switch SMn is turned on, the nth connection point PBn and the neutral point path LM are electrically connected. On the other hand, when the nth neutral point switch SMn is turned off, the nth connection point PBn and the neutral point path LM are electrically disconnected.

[0022] The control device 50 is mainly composed of a microcomputer and functions as a control unit. The microcomputer includes a CPU. 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 a control program shown in FIG. 2 and the like. 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 updated via a communication network such as the Internet, for example.

[0023] The control device 50 performs switching control of the upper and lower arm switches SWH and SWL of each phase constituting the inverter 20 to feedback-control the control amount of the rotating electric machine 30 to a command value. The control amount is, for example, torque. In each phase, the upper arm switch SWH and the lower arm switch SWL are alternately turned on.

[0024] The control device 50 turns on or off the positive electrode switch SP, the negative electrode switch SN, and each neutral point switch SM1 to SM5, and is also communicable with the monitoring unit 40.

[0025] The control device 50 performs a power supply process for reducing the difference in the capacity parameters of each of the power storage units 11 to 16. In the present embodiment, the capacity parameter is the terminal voltage [V], SOC, or remaining capacity [Ah] of the power storage unit. The control device 50 functions as a selection unit that selects, from among the power storage units 11 to 16, one power storage unit or some of the power storage units connected in series as a supply source power storage unit, and selects, from among the power storage units 11 to 16, the power storage units other than the supply source power storage unit as supply destination power storage units. Based on the information acquired from the monitoring unit 40, the control device 50 selects, for example, the power storage unit with the largest capacity parameter among the power storage units 11 to 16 as the supply source power storage unit, and selects the remaining power storage units as the supply destination power storage units. By the power supply process, the difference in the capacity parameters of each of the power storage units 11 to 16 can be reduced, and thus the capacity parameters of each of the power storage units 11 to 16 can be equalized.

[0026] FIG. 2 shows a flowchart of the power supply process performed by the control device 50.

[0027] In step S10, it is determined whether the selected supply source power storage unit includes the first power storage unit 11 or the sixth power storage unit 16.

[0028] If an affirmative determination is made in step S10, the process proceeds to step S11 and the first control is performed. Hereinafter, the first control in the case where the first power storage unit 11 is included in the supply source power storage unit and the case where the sixth power storage unit 16 is included in the supply source power storage unit will be described.

[0029] First, with reference to FIGS. 3 and 4, the case where the first power storage unit 11 is included in the supply source power storage unit will be described. Specifically, the case where the first and second power storage units 11 and 12 are replaced with new power storage units, the first and second power storage units 11 and 12 are selected as the supply source power storage unit, and the third to sixth power storage units 13 to 16 are selected as the supply destination power storage units will be described. In FIGS. 3 and the like, for the sake of convenience, the three-phase configuration of the inverter 20 and the rotating electric machine 30 is shown in a simplified manner as a single-phase configuration.

[0030] When the first power storage unit 11 is included in the power supply source power storage unit, the first control is to perform switching control of the inverter 20 with the positive electrode switch SP, the neutral point switch connected to the battery connection point on the lowest potential side of the power supply source power storage unit, and the negative electrode switch SN turned on, so as to supply power from the power supply source power storage unit to the power supply destination power storage unit via the inverter 20 and the neutral point path LM. As shown in FIG. 3, the control device 50 turns on the positive electrode switch SP, the negative electrode switch SN, and the second neutral point switch SM2, and turns off the first, third to fifth neutral point switches SM1, SM3 to SM5. The second neutral point switch SM2 is a switch connected to the battery connection point on the lowest potential side of the power supply destination power storage unit, that is, the second connection point PB2. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, a current flows through a closed circuit including the first and second power storage units 11 and 12, the high potential side path LP, the upper arm switch SWH, the stator winding 31, and the neutral point path LM, and magnetic energy is accumulated in the stator winding 31. Thereafter, as shown in FIG. 4, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the series connection of the third to sixth power storage units 13 to 16. By alternately repeating the switching states shown in FIGS. 3 and 4, power is supplied from the first and second power storage units 11 and 12 to the third to sixth power storage units 13 to 16. As a result, the difference between the capacity parameters of the first and second power storage units 11 and 12 and the capacity parameters of the third to sixth power storage units 13 to 16 becomes smaller.

[0031] Subsequently, with reference to FIGS. 5 and 6, the case where the sixth power storage unit 16 is included in the power supply source power storage unit will be described. Specifically, the case where the fifth and sixth power storage units 15 and 16 are selected as the power supply source power storage unit and the first to fourth power storage units 11 to 14 are selected as the power supply destination power storage unit will be described.

[0032] When the sixth power storage unit 16 is included in the power supply source power storage unit, the first control is to perform switching control of the inverter 20 with the positive electrode switch SP, the neutral point switch connected to the battery connection point on the highest potential side of the power supply source power storage unit, and the negative electrode switch SN turned on, so as to supply power from the power supply source power storage unit to the power supply destination power storage unit via the inverter 20 and the neutral point path LM. As shown in FIG. 5, the control device 50 turns on the positive electrode switch SP, the negative electrode switch SN, and the fourth neutral point switch SM4, and turns off the first to third and fifth neutral point switches SM1 to SM3, SM5. The fourth neutral point switch SM4 is a switch connected to the battery connection point on the highest potential side of the power supply source power storage unit, that is, the fourth connection point PB4. Then, the control device 50 turns on the lower arm switch SWL and turns off the upper arm switch SWH. As a result, a current flows through a closed circuit including the fifth and sixth power storage units 15, 16, the neutral point path LM, the stator winding 31, the lower arm switch SWL, and the low potential side path LN, and magnetic energy is accumulated in the stator winding 31. Then, as shown in FIG. 6, the control device 50 turns off the lower arm switch SWL and turns on the upper arm switch SWH. As a result, a charging current based on the accumulated magnetic energy is supplied to the series connection of the first to fourth power storage units 11 to 14. By alternately repeating the switching states shown in FIGS. 5 and 6, power is supplied from the fifth and sixth power storage units 15, 16 to the first to fourth power storage units 11 to 14. Thereby, the difference between the capacity parameters of the fifth and sixth power storage units 15, 16 and the capacity parameters of the first to fourth power storage units 11 to 14 becomes smaller.

[0033] Returning to the description of FIG. 2 above, in step S10, if it is determined that the power supply source power storage unit is sandwiched between the power supply destination power storage units, the process proceeds to step S12 to perform the second control. Hereinafter, with reference to FIGS. 7 to 10, the second control when the power supply source power storage units are the second and third power storage units 12 and 13 and the power supply destination power storage units are the first, fourth to sixth power storage units 11, 14 to 16 will be described.

[0034] As shown in FIG. 7, the control device 50 turns on the positive electrode switch SP, the negative electrode switch SN, and the first neutral point switch SM1, and turns off the second to fifth neutral point switches SM2 to SM5. The first neutral point switch SM1 is a switch connected to the battery connection point on the highest potential side of the power supply storage unit, that is, the first connection point PB1. Then, the control device 50 turns on the lower arm switch SWL and turns off the upper arm switch SWH. Thereby, magnetic energy is accumulated in the stator winding 31 using the second to sixth storage units 12 to 16 as energy sources. Thereafter, as shown in FIG. 8, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the first storage unit 11. The first storage unit 11 is a storage unit on the higher potential side than the power supply storage units (the second and third storage units 12 and 13) among the first to sixth storage units 11 to 16. By alternately repeating the switching states shown in FIGS. 7 and 8, power is supplied from the second to sixth storage units 12 to 16 to the first storage unit 11.

[0035] Thereafter, as shown in FIG. 9, the control device 50 turns on the positive electrode switch SP, the negative electrode switch SN, and the third neutral point switch SM3. The third neutral point switch SM3 is a switch connected to the battery connection point on the lowest potential side of the power supply storage unit, that is, the third connection point PB3. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, magnetic energy is accumulated in the stator winding 31 using the first to third storage units 11 to 13 as energy sources. Thereafter, as shown in FIG. 10, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the series connection of the fourth to sixth storage units 14 to 16. The fourth to sixth storage units 14 to 16 are storage units on the lower potential side than the power supply storage units (the second and third storage units 12 and 13) among the first to sixth storage units 11 to 16. By alternately repeating the switching states shown in FIGS. 9 and 10, power is supplied from the first to third storage units 11 to 13 to the fourth to sixth storage units 14 to 16.

[0036] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the second and third power storage units 12 and 13 to the first, fourth to sixth power storage units 11, 14 to 16. In this case, power is discharged from the second and third power storage units 12 and 13 in the switching state shown in FIG. 7 and the switching state shown in FIG. 9. As a result, the remaining capacities of the second and third power storage units 12 and 13 decrease, the remaining capacities of the first, fourth to sixth power storage units 11, 14 to 16 increase, and the difference in the capacity parameters of each of the power storage units 11 to 16 can be reduced. The power supply process may be executed while appropriately selecting the power supply source and the power supply destination power storage units until the difference between the maximum value and the minimum value among the capacity parameters of each of the power storage units 11 to 16 becomes equal to or less than the threshold value.

[0037] Incidentally, the second control in step S12 may be the control shown in FIGS. 11 to 14. FIGS. 11 to 14 show the case where, similar to the cases of FIGS. 7 to 10, the power supply source power storage units are the second power storage unit 12 and the third power storage unit 13, and the power supply destination power storage units are the first, fourth to sixth power storage units 14 to 16.

[0038] As shown in FIG. 11, the control device 50 turns on the positive electrode switch SP, the negative electrode switch SN, and the third neutral point switch SM3, and turns off the first, second, fourth, and fifth neutral point switches SM1, SM2, SM4, and SM5. The third neutral point switch SM3 is a switch connected to the battery connection point on the lowest potential side of the power supply source power storage unit, that is, the third connection point PB3. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, magnetic energy is accumulated in the stator winding 31. Thereafter, as shown in FIG. 12, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the fourth to sixth power storage units 14 to 16. The fourth to sixth power storage units 14 to 16 are power storage units on the lower potential side than the power supply source power storage units (the second and third power storage units 12 and 13) among the first to sixth power storage units 11 to 16. By alternately repeating the switching states shown in FIGS. 11 and 12, power is supplied from the first to third power storage units 11 to 13 to the fourth to sixth power storage units 14 to 16.

[0039] Thereafter, as shown in FIG. 13, the control device 50 turns on the positive electrode switch SP, the negative electrode switch SN, and the first neutral point switch SM1. The first neutral point switch SM1 is a switch connected to the battery connection point on the highest potential side of the power supply storage unit, that is, the first connection point PB1. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. Thereby, magnetic energy is accumulated in the stator winding 31. Thereafter, as shown in FIG. 14, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the first power storage unit 11. The first power storage unit 11 is a power storage unit on the higher potential side than the power supply storage units (the second and third power storage units 12 and 13) among the first to sixth power storage units 11 to 16. By alternately repeating the switching states shown in FIGS. 13 and 14, power is supplied from the second to sixth power storage units 12 to 16 to the first power storage unit 11.

[0040] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the second and third power storage units 12 and 13 to the first, fourth to sixth power storage units 11, 14 to 16. In this case, power is discharged from the second and third power storage units 12 and 13 in the switching state shown in FIG. 11 and the switching state shown in FIG. 13. As a result, the remaining capacities of the second and third power storage units 12 and 13 decrease, the remaining capacities of the first, fourth to sixth power storage units 11, 14 to 16 increase, and the difference in the capacity parameters of each power storage unit 11 to 16 can be reduced.

[0041] <Second Embodiment> Hereinafter, the second embodiment will be described with reference to the drawings, centering on the differences from the first embodiment. In this embodiment, as shown in FIG. 15, the power conversion device includes first to fifth negative electrode switches SN1 to SN5. In this embodiment, each negative electrode switch SN1 to SN5 is a relay and is turned on or off by the control device 50. In FIG. 15, the same components as those shown in FIG. 1 above are given the same reference numerals for convenience.

[0042] The n-th negative electrode switch SNn (n = 1, 2, 3, 4, 5) connects the negative electrode terminal of the (n + 1)-th power storage unit and the low-potential side path LN. When the n-th negative electrode switch SNn is turned on, the negative electrode terminal of the (n + 1)-th power storage unit and the low-potential side path LN are electrically connected. On the other hand, when the n-th negative electrode switch SNn is turned off, the negative electrode terminal of the (n + 1)-th power storage unit and the low-potential side path LN are electrically disconnected.

[0043] The control device 50 performs the first control and the second control in the same manner as the flowchart shown in FIG. 2 above. The first control is the same control as the first control described in the first embodiment.

[0044] Hereinafter, with reference to FIGS. 16 to 19, the second control will be described when the power supply source power storage units are the second power storage unit 12 and the third power storage unit 13, and the power supply destination power storage units are the first, fourth to sixth power storage units 14 to 16.

[0045] As shown in FIG. 16, the control device 50 turns on the positive electrode switch SP, the first neutral point switch SM1, and the second negative electrode switch SN2, and turns off the second to fifth neutral point switches SM2 to SM5 and the first, third to fifth negative electrode switches SN1, SN3 to SN5. Then, the control device 50 turns on the lower arm switch SWL and turns off the upper arm switch SWH. Thereby, magnetic energy is accumulated in the stator winding 31 using the second and third power storage units 12 and 13 as energy supply sources. Thereafter, as shown in FIG. 17, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the first power storage unit 11. By alternately repeating the switching states shown in FIGS. 16 and 17, power is supplied from the second and third power storage units 12 and 13 to the first power storage unit 11. In this case, since no charging current flows through the fourth to sixth power storage units 14 to 16 on the lower potential side than the power supply source power storage units, the loss in the power conversion device can be reduced and the progress of deterioration of the power storage units can be suppressed.

[0046] Thereafter, as shown in FIG. 18, the control device 50 turns on the positive electrode switch SP, the fifth negative electrode switch SN1, and the third neutral point switch SM3. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 using the first to third power storage units 11 to 13 as energy supply sources. Thereafter, as shown in FIG. 19, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the series connection of the fourth to sixth power storage units 14 to 16. By alternately repeating the switching states shown in FIGS. 18 and 19, power is supplied from the first to third power storage units 11 to 13 to the fourth to sixth power storage units 14 to 16.

[0047] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the second and third power storage units 12 and 13 to the first, fourth to sixth power storage units 11, 14 to 16. As a result, the difference in the capacity parameters of the respective power storage units 11 to 16 can be reduced.

[0048] <Third Embodiment> Hereinafter, the third embodiment will be described with reference to the drawings, centering on the differences from the second embodiment. In the present embodiment, as shown in FIG. 20, the power conversion device includes first to fifth positive electrode switches SP1 to SP5 instead of the first to fifth negative electrode switches SN1 to SN5. In the present embodiment, each of the positive electrode switches SP1 to SP5 is a relay and is turned on or off by the control device 50. In FIG. 20, the same components as those shown in FIG. 15 are denoted by the same reference numerals for convenience.

[0049] The n-th positive electrode switch SPn (n = 1, 2, 3, 4, 5) connects the positive electrode terminal of the n-th power storage unit and the high-potential side path LP. When the n-th positive electrode switch SPn is turned on, the positive electrode terminal of the n-th power storage unit and the high-potential side path LP are electrically connected. On the other hand, when the n-th positive electrode switch SPn is turned off, the positive electrode terminal of the n-th power storage unit and the high-potential side path LP are electrically disconnected.

[0050] Similar to the flowchart shown in the previous Figure 2, the control device 50 performs first control and second control. The first control is the same as the first control described in the first embodiment.

[0051] Hereinafter, with reference to FIGS. 21 to 24, second control will be described when the power supply storage units are the third and fourth storage units 13 and 14, and the power destination storage units are the first, second, fifth, and sixth storage units 11, 12, 15, and 16.

[0052] As shown in FIG. 21, the control device 50 turns on the third positive electrode switch SP3, the negative electrode switch SN, and the fourth neutral point switch SM4, and turns off the first, second, fourth, and fifth positive electrode switches SP1, SP2, SP4, SP5 and the first to third and fifth neutral point switches SM1 to SM3, SM5. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 using the third and fourth storage units 13 and 14 as energy supply sources. Thereafter, as shown in FIG. 22, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the fifth and sixth storage units 15 and 16. By alternately repeating the switching states shown in FIGS. 21 and 22, power is supplied from the third and fourth storage units 13 and 14 to the fifth and sixth storage units 15 and 16. In this case, since no charging current flows through the first and second storage units 11 and 12 on the higher potential side than the power supply storage units, it is possible to reduce the loss in the power conversion device and suppress the progress of deterioration of the storage units.

[0053] After that, as shown in FIG. 23, the control device 50 turns on the first positive electrode switch SP1, the negative electrode switch SN, and the second neutral point switch SM2. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 using the third to sixth power storage units 13 to 16 as energy sources. After that, as shown in FIG. 24, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the series connection of the first and second power storage units 11 and 12. By alternately repeating the switching states shown in FIGS. 23 and 24, power is supplied from the third to sixth power storage units 13 to 16 to the first and second power storage units 11 and 12.

[0054] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the third and fourth power storage units 13 and 14 to the first, second, fifth, and sixth power storage units 11, 12, 15, and 16. As a result, the difference in the capacity parameters of each of the power storage units 11 to 16 can be reduced.

[0055] <Fourth Embodiment> Hereinafter, the fourth embodiment will be described with reference to the drawings, centering on the differences from the first embodiment. In the present embodiment, as shown in FIG. 25, the power conversion device includes first to fourth positive electrode switches SP1 to SP4, first to third negative electrode switches SN1 to SN3, and an inter-battery switch SD. In the present embodiment, each of the positive electrode switches SP1 to SP4, each of the negative electrode switches SN1 to SN3, and the inter-battery switch SD is a relay and is turned on or off by the control device 50. In FIG. 25, the same components as those shown in FIG. 1 above are given the same reference numerals for convenience.

[0056] In the present embodiment, among the power storage units 11 to 16 that constitute the assembled battery, the first to fourth power storage units 11 to 14 on the high potential side correspond to the high potential power storage units, and the remaining fifth and sixth power storage units 15 and 16 correspond to the low potential power storage units.

[0057] The first positive electrode switch SP1 connects the positive electrode terminal of the first power storage unit 11 and the high-potential side path LP. The n-th positive electrode switch SPn (n = 2, 3, 4) connects the (n - 1)-th connection point PBn - 1 and the high-potential side path LP. When the n-th positive electrode switch SPn is turned on, the positive electrode terminal of the n-th power storage unit and the high-potential side path LP are electrically connected. On the other hand, when the n-th positive electrode switch SPn is turned off, the positive electrode terminal of the n-th power storage unit and the high-potential side path LP are electrically disconnected.

[0058] The m-th negative electrode switch SNm (m = 1, 2) connects the (m + 3)-th connection point PBm + 3 and the low-potential side path LN. When the m-th negative electrode switch SNm is turned on, the positive electrode terminal of the (m + 4)-th power storage unit and the low-potential side path LN are electrically connected. On the other hand, when the m-th negative electrode switch SNm is turned off, the positive electrode terminal of the (m + 4)-th power storage unit and the low-potential side path LN are electrically disconnected. The third negative electrode switch SN3 connects the negative electrode terminal of the sixth power storage unit 16 and the low-potential side path LN.

[0059] The inter-battery switch SD connects the negative electrode terminal of the fourth power storage unit 14 and the fourth connection point PB4. When the inter-battery switch SD is turned on, the negative electrode terminal of the fourth power storage unit 14 and the fourth connection point PB4 are electrically connected. On the other hand, when the inter-battery switch SD is turned off, the negative electrode terminal of the fourth power storage unit 14 and the fourth connection point PB4 are electrically disconnected. Note that the inter-battery switch SD may be provided not between the negative electrode terminal of the fourth power storage unit 14 and the fourth connection point PB4, but between the positive electrode terminal of the fourth power storage unit 14 and the third connection point PB3. Also, in the present embodiment, the fourth power storage unit 14 corresponds to the "specific power storage unit".

[0060] The control device 50 selects, among the power storage units 11 to 16, one power storage unit or a part of the power storage units connected in series as the source power storage unit, and selects, among the power storage units 11 to 16, one power storage unit other than the source power storage unit or a part of the power storage units connected in series other than the source power storage unit as the destination power storage unit. Based on the information acquired from the monitoring unit 40, the control device 50 selects, for example, the power storage unit with the largest capacity parameter among the power storage units 11 to 16 as the source power storage unit, and selects the power storage unit with the smallest capacity parameter as the destination power storage unit. Further, the control device 50 selects, among the power storage units 11 to 16, one power storage unit other than the source power storage unit and the destination power storage unit or a part of the power storage units connected in series other than the source power storage unit and the destination power storage unit as the temporary destination power storage unit.

[0061] Fig. 26 shows the procedure of the power supply process performed by the control device 50.

[0062] In step S20, it is determined whether any of the conditions that the source power storage unit is in the high potential group and the destination power storage unit is in the low potential group, or the source power storage unit is in the low potential group and the destination power storage unit is in the high potential group is satisfied. The high potential group is a group of the first to fourth power storage units 11 to 14 that are at a higher potential than the inter-battery switch SD among the power storage units 11 to 16. The low potential side group is a group of the fifth and sixth power storage units 15 and 16 that are at a lower potential than the inter-battery switch SD among the power storage units 11 to 16. For example, when the source power storage unit is the second power storage unit 12 and the destination power storage unit is the fifth power storage unit 15, or when the source power storage unit is the fourth power storage unit 14 and the destination power storage unit is the fifth power storage unit 15, an affirmative determination is made in step S20.

[0063] If an affirmative determination is made in step S20, the process proceeds to step S21 to determine whether another power storage unit is interposed between the power source power storage unit and the power destination power storage unit. For example, when the power source power storage unit is the second power storage unit 12 and the power destination power storage unit is the fifth power storage unit 15, since the third and fourth power storage units 13 and 14 are interposed between the second power storage unit 12 and the fifth power storage unit 15, an affirmative determination is made in step S21. On the other hand, for example, when the power source power storage unit is the fourth power storage unit 14 and the power destination power storage unit is the fifth power storage unit 15, since no other power storage unit is interposed between the fourth power storage unit 14 and the fifth power storage unit 15, a negative determination is made in step S21.

[0064] If a negative determination is made in step S21, the process proceeds to step S22 to turn on the inter-battery switch SD. On the other hand, if an affirmative determination is made in step S21, the process proceeds to step S23 to turn off the inter-battery switch SD. Turning off the inter-battery switch SD is to prevent a short circuit between the positive and negative terminals of the power storage unit when performing the first control in step S24.

[0065] After completion of the process in step S22 or S23, the first control is performed in step S24. Hereinafter, with reference to FIGS. 27 and 28, a case where the power source power storage unit is the second power storage unit 12, the power destination power storage unit is the fifth power storage unit 15, and an affirmative determination is made in step S21 will be described.

[0066] As shown in FIG. 27, the control device 50 turns on the second positive electrode switch SP2, the second and fourth neutral point switches SM2 and SM4, and the second negative electrode switch SN2, and turns off the first, third, and fourth positive electrode switches SP1, SP3, and SP4, the first and third negative electrode switches SN1 and SN3, the first, third, and fifth neutral point switches SM1, SM3, and SM5, and the inter-battery switch SD. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, magnetic energy is stored in the stator winding 31 with the second power storage unit 12 as an energy supply source. Thereafter, as shown in FIG. 28, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the stored magnetic energy is supplied to the fifth power storage unit 15. By alternately turning on the upper and lower arm switches SWH and SWL, power is supplied from the second power storage unit 12 to the fifth power storage unit 15.

[0067] Returning to the description of FIG. 26 above, in step S20, if it is determined that both the power supply source power storage unit and the power supply destination power storage unit are included in one of the high potential side group and the low potential side group, the process proceeds to step S25 to turn off the inter-battery switch SD. Thereafter, second control is performed in step S26. The second control will be described below.

[0068] First, a case where the control device 50 determines that the power supply source power storage unit and the power supply destination power storage unit are included in the high potential group will be described with reference to FIGS. 29 to 32. In the example shown in FIGS. 29 to 32, the power supply source power storage unit is the second power storage unit 12, and the power supply destination power storage unit is the third power storage unit 13.

[0069] As shown in Fig. 29, the control device 50 turns on the second positive electrode switch SP2, the second and fourth neutral point switches SM2 and SM4, and the second negative electrode switch SN2, and turns off the first, third, and fourth positive electrode switches SP1, SP3, and SP4, the first, third, and fifth neutral point switches SM1, SM3, and SM5, the first and third negative electrode switches SN1 and SN3, and the inter-battery switch SD. In this case, the first, fourth, and sixth power storage units 11, 14, and 16 are disconnected from the system using the neutral point path LM. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 using the second power storage unit 12 as an energy supply source.

[0070] Thereafter, as shown in Fig. 30, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the fifth power storage unit 15 selected as the "temporary supply destination power storage unit" by the control device 50. By alternately repeating the switching states shown in Figs. 29 and 30, power is supplied from the second power storage unit 12 to the fifth power storage unit 15. In this case, since the inter-battery switch SD is turned off, even if the second and fourth neutral point switches SM2 and SM4 are turned on, it is possible to prevent the positive electrode terminal of the third power storage unit 13 and the negative electrode terminal of the fourth power storage unit 14 from being short-circuited.

[0071] Thereafter, as shown in FIG. 31, the control device 50 turns on the third positive electrode switch SP3, the third and fourth neutral point switches SM3 and SM4, and the second negative electrode switch SN2, and turns off the first, second, and fourth positive electrode switches SP1, SP2, and SP4, the first, second, and fifth neutral point switches SM1, SM2, and SM5, the first and third negative electrode switches SN1 and SN3, and the inter-battery switch SD. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 using the fifth power storage unit 15 as an energy supply source. Thereafter, as shown in FIG. 32, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the third power storage unit 13. By alternately repeating the switching states shown in FIGS. 31 and 32, power is supplied from the fifth power storage unit 15 to the third power storage unit 13.

[0072] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the second power storage unit 12 to the third power storage unit 13. In this case, since no charging current flows through the power storage units other than the power supply source power storage unit and the power supply destination power storage unit, it is possible to reduce the loss in the power conversion device and suppress the progress of deterioration of the power storage units.

[0073] Subsequently, a case where the control device 50 determines that the power supply source power storage unit and the power supply destination power storage unit are included in the low potential group will be described with reference to FIGS. 33 to 36. In the example shown in FIGS. 33 to 36, the power supply source power storage unit is the fifth power storage unit 15, the power supply destination power storage unit is the sixth power storage unit 16, and the temporary power supply destination power storage unit is the third power storage unit 13.

[0074] As shown in FIG. 33, the control device 50 turns on the fourth neutral point switch SM4, the second negative electrode switch SN2, the third positive electrode switch SP3, and the fourth neutral point switch SM4, and turns off the first, second, and fourth positive electrode switches SP1, SP2, SP4, the first, second, and fifth neutral point switches SM1, SM2, SM5, the first and third negative electrode switches SN1, SN3, and the battery - to - battery switch SD. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 with the fifth power storage unit 15 as an energy supply source.

[0075] Thereafter, as shown in FIG. 34, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the third power storage unit 13 selected as the "temporary supply destination power storage unit". By alternately repeating the switching states shown in FIGS. 33 and 34, power is supplied from the fifth power storage unit 15 to the third power storage unit 13. In this case, since the battery - to - battery switch SD is turned off, even if the third and fourth neutral point switches SM2 and SM4 are turned on, it is possible to prevent the positive and negative terminals of the fourth power storage unit 14 from being short - circuited.

[0076] Thereafter, as shown in FIG. 35, the control device 50 turns on the third positive electrode switch SP3, the third neutral point switch SM3, the fifth neutral point switch SM5, and the third negative electrode switch SN3, and turns off the first, second, and fourth positive electrode switches SP1, SP2, SP4, the first, second, and fourth neutral point switches SM1, SM2, SM4, the first and second negative electrode switches SN1, SN2, and the inter-battery switch SD. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 using the third power storage unit 13 as an energy supply source. Thereafter, as shown in FIG. 36, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the sixth power storage unit 16. By alternately repeating the switching states shown in FIGS. 35 and 36, power is supplied from the third power storage unit 13 to the sixth power storage unit 16.

[0077] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the fifth power storage unit 15 to the sixth power storage unit 16. In this case, since no charging current flows through the power storage units other than the power storage unit as the supply source and the power storage unit as the supply destination, it is possible to reduce the loss in the power conversion device and suppress the progress of deterioration of the power storage units.

[0078] <Fifth Embodiment> Hereinafter, the fifth embodiment will be described with reference to the drawings, centering on the differences from the first embodiment. In this embodiment, as shown in FIG. 37, the power conversion device includes first to fifth positive electrode switches SP1 to SP5 and first to fifth negative electrode switches SN1 to SN5. In this embodiment, each of the positive electrode switches SP1 to SP5 and each of the negative electrode switches SN1 to SN5 are relays and are turned on or off by the control device 50. In FIG. 37, the same components as those shown in FIG. 1 above are given the same reference numerals for convenience.

[0079] The n-th positive electrode switch SPn (n = 1, 2, 3, 4, 5) connects the positive electrode terminal of the n-th power storage unit to the high potential side path LP. When the n-th positive electrode switch SPn is turned on, the positive electrode terminal of the n-th power storage unit and the high potential side path LP are electrically connected. On the other hand, when the n-th positive electrode switch SPn is turned off, the positive electrode terminal of the n-th power storage unit and the high potential side path LP are electrically disconnected.

[0080] The n-th negative electrode switch SNn connects the negative electrode terminal of the (n + 1)-th power storage unit to the low potential side path LN. When the n-th negative electrode switch SNn is turned on, the negative electrode terminal of the (n + 1)-th power storage unit and the low potential side path LN are electrically connected. On the other hand, when the n-th negative electrode switch SNn is turned off, the negative electrode terminal of the (n + 1)-th power storage unit and the low potential side path LN are electrically disconnected.

[0081] The control device 50 selects, among the power storage units 11 to 16, one power storage unit or a part of the power storage units connected in series as the source power storage unit, and selects, among the power storage units 11 to 16, one power storage unit other than the source power storage unit or a part of the power storage units connected in series other than the source power storage unit as the destination power storage unit.

[0082] Fig. 38 shows the procedure of the power supply process performed by the control device 50.

[0083] In step S30, it is determined whether the source power storage unit and the destination power storage unit are adjacent. For example, when the source power storage unit is the second power storage unit 12 and the destination power storage unit is the third power storage unit 13, an affirmative determination is made in step S30. When the source power storage unit is the second power storage unit 12 and the destination power storage unit is the sixth power storage unit 16, a negative determination is made in step S30.

[0084] If an affirmative determination is made in step S30, the process proceeds to step S31 and the first control is performed. Hereinafter, the first control will be described.

[0085] First, with reference to FIG. 39, a case where the control device 50 determines that the power supply source power storage unit is on the higher potential side than the power supply destination power storage unit will be described. In the example shown in FIG. 39, the power supply source power storage unit is the second power storage unit 12, and the power supply destination power storage unit is the third power storage unit 13.

[0086] The control device 50 turns on the second positive electrode switch SP2, the second neutral point switch SM2, and the second negative electrode switch SN2, and turns off the first, third to fifth positive electrode switches SP1, SP3 to SP5, the first, third, fifth neutral point switches SM1, SM3, SM5, and the first, third to fifth negative electrode switches SN1, SN3 to SN5. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, with the second power storage unit 12 as an energy supply source, magnetic energy is accumulated in the stator winding 31. After that, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the third power storage unit 13. By alternately turning on the upper and lower arm switches SWH and SWL, power is supplied from the second power storage unit 12 to the third power storage unit 13. Thereby, the difference in the capacity parameters between the second and third power storage units 12 and 13 can be reduced.

[0087] Subsequently, with reference to FIG. 40, a case where the control device 50 determines that the power supply source power storage unit is on the lower potential side than the power supply destination power storage unit will be described. In the example shown in FIG. 40, the power supply source power storage unit is the fourth power storage unit 14, and the power supply destination power storage unit is the third power storage unit 13.

[0088] The control device 50 turns on the third negative electrode switch SN3, the third neutral point switch SM3, and the third positive electrode switch SP3, and turns off the first, second, fourth, and fifth positive electrode switches SP1, SP2, SP4, SP5, the first, second, fourth, and fifth neutral point switches SM1, SM2, SM4, SM5, and the first, second, fourth, and fifth negative electrode switches SN1, SN2, SN4, SN5. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. Thereby, magnetic energy is accumulated in the stator winding 31 using the fourth power storage unit 14 as an energy supply source. After that, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the third power storage unit 13. By alternately turning on the upper and lower arm switches SWH and SWL, power is supplied from the fourth power storage unit 14 to the third power storage unit 13. Thereby, the difference in the capacity parameters between the third and fourth power storage units 13 and 14 can be reduced.

[0089] Returning to the description of the previous FIG. 38, if a negative determination is made in step S30, the process proceeds to step S32 to perform the second control. The second control will be described below.

[0090] First, with reference to FIGS. 41 to 44, the case where the control device 50 determines that the power supply source power storage unit is on the higher potential side than the power supply destination power storage unit will be described. In the example shown in FIGS. 41 to 44, the power supply source power storage unit is the second power storage unit 12, and the power supply destination power storage unit is the sixth power storage unit 16.

[0091] As shown in FIG. 41, the control device 50 turns on the second positive electrode switch SP2, the second neutral point switch SM2, and the fourth negative electrode switch SN4, and turns off the first, third to fifth positive electrode switches SP1, SP3 to SP5, the first, third to fifth neutral point switches SM1, SM3 to SM5, and the first to third, fifth negative electrode switches SN1 to SN3, SN5. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, magnetic energy is stored in the stator winding 31 with the second power storage unit 12 as an energy supply source. After that, as shown in FIG. 42, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the stored magnetic energy is supplied to the intermediate power storage units that are the third to fifth power storage units 13 to 15. By alternately repeating the switching states shown in FIGS. 41 and 42, power is supplied from the second power storage unit 12 to the intermediate power storage units.

[0092] After that, as shown in FIG. 43, the control device 50 turns on the third positive electrode switch SP3, the fifth neutral point switch SM5, and the fifth negative electrode switch SN5, and turns off the first, second, fourth, fifth positive electrode switches SP1, SP2, SP4, SP5, the first to fourth neutral point switches SM1 to SM4, and the first to fourth negative electrode switches SN1 to SN4. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, magnetic energy is stored in the stator winding 31 with the intermediate power storage unit as an energy supply source. After that, as shown in FIG. 44, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, a charging current based on the stored magnetic energy is supplied to the sixth power storage unit 16. By alternately repeating the switching states shown in FIGS. 43 and 44, power is supplied from the intermediate power storage unit to the sixth power storage unit 16.

[0093] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the second power storage unit 12 to the sixth power storage unit 16. As a result, the difference in the capacity parameters of the second and sixth power storage units 12 and 16 can be reduced.

[0094] Incidentally, the above-mentioned second control is control for supplying power from the power source storage unit to the intermediate storage unit and then supplying power from the intermediate storage unit to the power destination storage unit. However, it is not limited to this, and it may be the second control for supplying power from the intermediate storage unit to the power destination storage unit and then supplying power from the power source storage unit to the intermediate storage unit. Specifically, after the switching states shown in FIGS. 43 and 44 are alternately repeated, the switching states shown in FIGS. 41 and 42 may be alternately repeated. Even in this case, the difference in the capacity parameters of the second and sixth storage units 12 and 16 can be reduced.

[0095] Subsequently, with reference to FIGS. 45 to 48, a case where the control device 50 determines that the power source storage unit is on the lower potential side than the power destination storage unit will be described. In the example shown in FIGS. 45 to 48, the power source storage unit is the sixth storage unit 16, and the power destination storage unit is the second storage unit 12.

[0096] As shown in FIG. 45, the control device 50 turns on the fifth negative electrode switch SN5, the fifth neutral point switch SM5, and the third positive electrode switch SP3, and turns off the first, second, fourth, and fifth positive electrode switches SP1, SP2, SP4, SP5, the first to fourth neutral point switches SM1 to SM4, and the first to fourth negative electrode switches SN1 to SN4. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 with the sixth storage unit 16 as an energy supply source. Thereafter, as shown in FIG. 46, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the intermediate storage units which are the third to fifth storage units 13 to 15. By alternately repeating the switching states shown in FIGS. 45 and 46, power is supplied from the sixth storage unit 16 to the intermediate storage unit.

[0097] After that, as shown in FIG. 47, the control device 50 turns on the fourth negative electrode switch SN4, the second neutral point switch SM2, and the second positive electrode switch SP2, and turns off the first, third to fifth positive electrode switches SP1, SP3 to SP5, the first, third to fifth neutral point switches SM1, SM3 to SM5, and the first to third, fifth negative electrode switches SN1 to SN3, SN5. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. As a result, magnetic energy is accumulated in the stator winding 31 with the intermediate power storage unit as an energy supply source. After that, as shown in FIG. 48, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. As a result, a charging current based on the accumulated magnetic energy is supplied to the second power storage unit 12. By alternately repeating the switching states shown in FIGS. 47 and 48, power is supplied from the intermediate power storage unit to the second power storage unit 12.

[0098] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the sixth power storage unit 16 to the second power storage unit 12. As a result, the difference in the capacity parameters of the second and sixth power storage units 12 and 16 can be reduced.

[0099] Incidentally, the second control described above is control for supplying power from the power supply source power storage unit to the intermediate power storage unit and then supplying power from the intermediate power storage unit to the power supply destination power storage unit. However, it is not limited to this, and it may be the second control for supplying power from the power supply source power storage unit to the intermediate power storage unit after supplying power from the intermediate power storage unit to the power supply destination power storage unit. Specifically, after the switching states shown in FIGS. 47 and 48 are alternately repeated, the switching states shown in FIGS. 45 and 46 may be alternately repeated. Even in this case, the difference in the capacity parameters of the second and sixth power storage units 12 and 16 can be reduced.

[0100] <Sixth Embodiment> Hereinafter, the sixth embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, as shown in FIG. 49, the power conversion device includes first to fifth positive electrode switches SP1 to SP5, first to fifth negative electrode switches SN1 to SN5, and first to fourth inter-battery switches SD1 to SD4. In this embodiment, each of the positive electrode switches SP1 to SP5, each of the negative electrode switches SN1 to SN5, and each of the inter-battery switches SD1 to SD4 is a relay and is turned on or off by the control device 50. In FIG. 49, the same components as those shown in the previous FIG. 1 are given the same reference numerals for convenience.

[0101] The first positive electrode switch SP1 connects the positive electrode terminal of the first power storage unit and the high-potential side path LP. The nth positive electrode switch SPn (n = 2, 3, 4, 5) connects the (n - 1)th connection point PBn-1 and the high-potential side path LP. When the nth positive electrode switch SPn is turned on, the (n - 1)th connection point PBn-1 and the high-potential side path LP are electrically connected. On the other hand, when the nth positive electrode switch SPn is turned off, the (n - 1)th connection point PBn-1 and the high-potential side path LP are electrically disconnected.

[0102] The fifth negative electrode switch SN5 connects the negative electrode terminal of the sixth power storage unit and the low-potential side path LN. The mth negative electrode switch SNm (m = 1, 2, 3, 4) connects the (m + 1)th connection point PBm+1 and the low-potential side path LN. When the mth negative electrode switch SNm is turned on, the (m + 1)th connection point PBm+1 and the low-potential side path LN are electrically connected. On the other hand, when the mth negative electrode switch SNm is turned off, the (m + 1)th connection point PBm+1 and the low-potential side path LN are electrically disconnected.

[0103] The m-th inter-battery switch SDm connects the negative terminal of the (m + 1)-th power storage unit to the (m + 1)-th connection point PBm+1. When the m-th inter-battery switch SDm is turned on, the negative terminal of the (m + 1)-th power storage unit and the (m + 1)-th connection point PBm+1 are electrically connected. On the other hand, when the m-th inter-battery switch SDm is turned off, the negative terminal of the (m + 1)-th power storage unit and the (m + 1)-th connection point PBm+1 are electrically disconnected. Note that the m-th inter-battery switch SDm may be provided between the positive terminal of the (m + 1)-th power storage unit and the m-th connection point PBm instead of between the negative terminal of the (m + 1)-th power storage unit and the (m + 1)-th connection point PBm+1.

[0104] The control device 50 selects, among the power storage units 11 to 16, one power storage unit or a part of the power storage units connected in series as the source power storage unit, and selects, among the power storage units 11 to 16, one power storage unit other than the source power storage unit or a part of the power storage units connected in series other than the source power storage unit as the destination power storage unit.

[0105] Fig. 50 shows the procedure of the power supply process performed by the control device 50.

[0106] In step S40, the same process as step S30 in Fig. 38 is performed.

[0107] If an affirmative determination is made in step S40, the process proceeds to step S41, and the inter-battery switch between the source power storage unit and the destination power storage unit is turned on. For example, when the source power storage unit is the second power storage unit 12 and the destination power storage unit is the third power storage unit 13, the first inter-battery switch SD1 is turned on. Also, for example, when the source power storage units are the second and third power storage units 12 and 13 and the destination power storage units are the fourth and fifth power storage units 14 and 15, the first to third inter-battery switches SD1 to SD3 are turned on.

[0108] In step S42, the same first control as step S31 in Fig. 38 described above is performed. An example of the driving mode of the switch when it is determined that the source power storage unit is adjacent to the high potential side of the destination power storage unit is shown in Fig. 39, and an example of the driving mode of the switch when it is determined that the source power storage unit is adjacent to the low potential side of the destination power storage unit is shown in Fig. 40.

[0109] On the other hand, if a negative determination is made in step S40, the process proceeds to step S43 to perform second control. The second control will be described below.

[0110] First, with reference to FIGS. 51 and 52, a case where the control device 50 determines that the power supply source storage unit is on the higher potential side than the power supply destination storage unit will be described. In the examples shown in FIGS. 51 and 52, the power supply source storage unit is the second storage unit 12, and the power supply destination storage unit is the fifth storage unit 15. In FIGS. 51 and 52, the third and fourth storage units 13 and 14 correspond to the "intermediate storage units".

[0111] As shown in FIG. 51, the control device 50 turns on the second positive electrode switch SP2, the second and fourth neutral point switches SM2 and SM4, the fourth negative electrode switch SN4, and the first and fourth inter-battery switches SD1 and SD4, and turns off the first, third to fifth positive electrode switches SP1, SP3 to SP5, the first, third, and fifth neutral point switches SM1, SM3, and SM5, the first, second, third, and fifth negative electrode switches SN1, SN2, SN3, and SN5, and the second and third inter-battery switches SD2 and SD3. The first and fourth inter-battery switches SD1 and SD4 are inter-battery switches between the second to fourth connection points PB2 to PB4 existing between the second power storage unit 12, which is the power supply source power storage unit, and the fifth power storage unit 15, which is the power supply destination power storage unit. Then, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, magnetic energy is accumulated in the stator winding 31 with the second power storage unit 12 as the energy supply source. Thereafter, as shown in FIG. 52, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the fifth power storage unit 15. By alternately repeating the switching states shown in FIGS. 51 and 52, power is supplied from the second power storage unit 12 to the fifth power storage unit 15. Thereby, the difference in the capacity parameters between the second and fifth power storage units 12 and 15 can be reduced. In this case, since the second and third inter-battery switches SD2 and SD3 are turned off, even if the second and fourth neutral point switches SM2 and SM4 are turned on, it is possible to prevent the positive electrode terminal of the third power storage unit 13 and the negative electrode terminal of the fourth power storage unit 14 from being short-circuited. Note that only one of the second and third inter-battery switches SD2 and SD3 may be turned off. Further, when the power supply source power storage unit is the first and second power storage units 11 and 12 instead of the second power storage unit 12, and the power supply destination power storage unit is the fifth and sixth power storage units 15 and 16 instead of the fifth power storage unit 15, the inter-battery switch turned off in the second control is at least one of the second and third inter-battery switches SD2 and SD3. The second and third inter-battery switches SD2 and SD3 are inter-battery switches between the second to fourth connection points PB2 to PB4 existing between the second power storage unit 12, which is the lowest potential side power storage unit of the power supply source power storage unit, and the fifth power storage unit 15, which is the highest potential side power storage unit of the power supply destination power storage unit.

[0112] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the second power storage unit 12 to the fifth power storage unit 15. In this case, since no charging current flows through the power storage units other than the power supply source power storage unit and the power supply destination power storage unit, it is possible to reduce the loss in the power conversion device and suppress the progress of deterioration of the power storage units.

[0113] Subsequently, with reference to FIGS. 53 and 54, a case where the control device 50 determines that the power supply source power storage unit is on the lower potential side than the power supply destination power storage unit will be described. In the example shown in FIGS. 53 and 54, the power supply source power storage units are the fifth and sixth power storage units 15 and 16, and the power supply destination power storage unit is the first power storage unit 11. In FIGS. 53 and 54, the second to fourth power storage units 12 to 14 correspond to the "intermediate power storage units".

[0114] As shown in FIG. 53, the control device 50 turns on the fifth negative electrode switch SN5, the first neutral point switch SM1, the fourth neutral point switch SM4, and the first positive electrode switch SP1, and turns off the second to fifth positive electrode switches SP2 to SP5, the second, third, and fifth neutral point switches SM2, SM3, SM5, the first to fourth negative electrode switches SN1 to SN4, and the first to third inter-battery switches SD1 to SD3. The first to third inter-battery switches SD1 to SD3 are inter-battery switches between the first to fourth connection points PB1 to PB4 existing between the fifth power storage unit 15, which is the highest potential side power storage unit of the power supply source power storage unit, and the first power storage unit 11, which is the power supply destination power storage unit. Then, the control device 50 turns off the upper arm switch SWH and turns on the lower arm switch SWL. Thereby, magnetic energy is accumulated in the stator winding 31 with the fifth and sixth power storage units 15 and 16 as energy supply sources. Thereafter, as shown in FIG. 54, the control device 50 turns on the upper arm switch SWH and turns off the lower arm switch SWL. Thereby, a charging current based on the accumulated magnetic energy is supplied to the first power storage unit 11. By alternately repeating the switching states shown in FIGS. 53 and 54, power is supplied from the fifth and sixth power storage units 15 and 16 to the first power storage unit 11. Thereby, the difference in the capacity parameters between the second and fifth power storage units 12 and 15 can be reduced. In this case, since the first to third inter-battery switches SD1 to SD3 are turned off, even if the first and fourth neutral point switches SM1 and SM4 are turned on, it is possible to prevent the positive electrode terminal of the second power storage unit 12 and the negative electrode terminal of the fourth power storage unit 14 from being short-circuited. Note that, among the first to third inter-battery switches SD1 to SD3, only one or two of the inter-battery switches may be turned off. Also, when the power supply destination power storage unit is the first and second power storage units 11 and 12 instead of the first power storage unit 11, the inter-battery switch turned off in the second control is at least one of the second and third inter-battery switches SD2 and SD3. The second and third inter-battery switches SD2 and SD3 are inter-battery switches between the second to fourth connection points PB2 to PB4 existing between the fifth power storage unit 15, which is the highest potential side power storage unit of the power supply source power storage unit, and the second power storage unit 12, which is the lowest potential side power storage unit of the power supply destination power storage unit.

[0115] By performing the switching control of the upper and lower arm switches SWH and SWL of the inverter 20 described above, power is supplied from the fifth and sixth power storage units 15 and 16 to the first power storage unit 11. In this case, since no charging current flows through the power storage units other than the power supply source power storage unit and the power supply destination power storage unit, it is possible to reduce the loss in the power conversion device and suppress the progress of deterioration of the power storage unit.

[0116] <Seventh Embodiment> Hereinafter, the seventh embodiment will be described with reference to the drawings, centering on the differences from the first embodiment. The control device 50 of this embodiment performs the switching control of the inverter 20 so that the number of phases of the stator winding 31 through which current flows is the number of phases at which the power conversion efficiency is maximized when power is supplied from the power supply source power storage unit to the power supply destination power storage unit.

[0117] FIG. 55 shows the relationship between the power transmitted and received for each number of phases of the stator winding 31 and the power conversion efficiency when current flows from the power supply source power storage unit to the power supply destination power storage unit via the inverter 20 and the neutral point path LM. The solid line indicates the case where the number of phases of the stator winding 31 through which current flows is one phase, the broken line indicates the case where the number of phases of the stator winding 31 through which current flows is two phases, and the alternate long and short dash line indicates the case where the number of phases of the stator winding 31 through which current flows is three phases. As the number of phases of the stator winding 31 through which current flows increases, the power transmitted and received at which the power conversion efficiency is maximized also increases. In other words, the maximum efficiency power Wmax1 when the number of phases of the stator winding 31 through which current flows is one phase is smaller than the maximum efficiency power Wmax2 when the number of phases of the stator winding 31 through which current flows is two phases. Also, the maximum efficiency power Wmax2 when the number of phases of the stator winding 31 through which current flows is two phases is smaller than the maximum efficiency power Wmax3 when the number of phases of the stator winding 31 through which current flows is three phases.

[0118] FIG. 56 shows the procedure of the phase number selection process executed by the control device 50.

[0119] In step S50, the power transfer Wreq from the power supply storage unit to the power destination storage unit is calculated. Specifically, first, the difference in remaining capacity between the power supply storage unit and the power destination storage unit is calculated. Then, the calculated difference in remaining capacity is divided by the target time to calculate the power transfer Wreq. In this case, the larger the difference in remaining capacity or the shorter the target time, the larger the calculated power transfer Wreq.

[0120] In step S51, the number of phases is selected based on the calculated power transfer Wreq. Specifically, when the power transfer Wreq is within the range of the first region DP1 shown in FIG. 44, one phase is selected. The first region DP1 is a region of power transfer where the power conversion efficiency in the case of one phase is higher than the power conversion efficiency in the case of other numbers of phases.

[0121] When the power transfer Wreq is within the range of the second region DP2, two phases are selected. The second region DP2 is a region of power transfer where the power conversion efficiency in the case of two phases is higher than the power conversion efficiency in the case of other numbers of phases.

[0122] When the power transfer Wreq is within the range of the third region DP3, three phases are selected. The third region DP3 is a region of power transfer where the power conversion efficiency in the case of three phases is higher than the power conversion efficiency in the case of other numbers of phases.

[0123] Thereafter, in the power supply process, the control device 50 performs switching control to pass current through the stator windings 31 of the selected number of phases. For example, when two or three phases are selected, the upper and lower arm switches SWH and SWL for two or three phases are synchronized to turn on and off. Thereby, the power conversion efficiency in the case where the power supply process is executed can be increased.

[0124] <Other Embodiments> Note that each of the above embodiments may be implemented with the following modifications.

[0125] · As shown in FIGS. 57 and 58, the power storage unit may be a battery connected in parallel. FIG. 57 shows a modified example of the configuration of FIG. 1, and FIG. 58 shows a modified example of the configuration of FIG. 49. Note that the number of parallel connections is not limited to two and may be three or more. FIG. 58 also shows a configuration in which a first inter-battery switch SD1 is provided between the negative electrode terminal of the first power storage unit 11 and the first connection point PB1.

[0126] · The number of power storage units is not limited to six and may be four, for example, as shown in FIGS. 58, 60, and 61, or may be five, as shown in FIG. 59. Note that FIG. 59 shows a modified example of the configuration of FIG. 25, FIG. 60 shows a modified example of the configuration of FIG. 15, and FIG. 61 shows a modified example of the configuration of FIG. 20.

[0127] · As shown in FIGS. 59 to 61, the power storage unit is not limited to one battery and may be a series connection of a plurality of batteries. In this case, the number of series connections is not limited to two and may be three or more. Also, the number of batteries constituting each power storage unit may be different.

[0128] · The power storage unit is not limited to a battery and may be, for example, a capacitor (for example, an electric double layer capacitor).

[0129] · As the upper and lower arm switches constituting the inverter, it is not limited to IGBTs and may be, for example, an N-channel MOSFET with a built-in body diode. In this case, the high potential side terminal becomes the drain and the low potential side terminal becomes the source.

[0130] · The positive electrode switch, negative electrode switch, neutral point switch, and inter-battery switch are not limited to relays and may be, for example, a pair of N-channel MOSFETs with their sources connected or IGBTs.

[0131] · The rotating electrical machine and the inverter may be other than three-phase, such as five-phase or seven-phase.

[0132] · The mobile body on which the power conversion device is mounted is not limited to a vehicle, and may be, for example, an aircraft or a ship. Further, the power conversion device is not limited to a device mounted on a mobile body, and may be a stationary device.

[0133] · The control unit and its method described in the present disclosure may be realized 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 realized 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 realized 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. Further, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

Description of Reference Numerals

[0134] 11 to 16... First to sixth power storage units, 20... Inverter, 30... Rotating electric machine, 50... Control device, LP... High potential side path, LN... Low potential side path, LM... Neutral point path, SP... Positive electrode switch, SN... Negative electrode switch, SM1 to SM5... First to fifth neutral point switches.

Claims

1. In a power conversion device applied to three or more power storage units (11 to 16) connected in series, a rotating electrical machine (30) having a stator winding (31); an inverter (20) having upper and lower arm switches (SWH, SWL) and connecting the stator winding and the power storage unit; a high potential side path (LP) connected to the high potential side terminal of the upper arm switch; a low potential side path (LN) connected to the low potential side terminal of the lower arm switch; a neutral point path (LM) connected to the neutral point of the stator winding; neutral point switches (SM1 to SM5) individually provided corresponding to battery connection points (PB1 to PB5) between the positive and negative terminals of adjacent power storage units among the respective power storage units, and connecting the battery connection points and the neutral point path; A power conversion device comprising:

2. a positive electrode switch (SP) connecting the positive electrode terminal of the highest potential power storage unit (11), which is the power storage unit with the highest potential among the respective power storage units, and the high potential side path; a negative electrode switch (SN) connecting the negative electrode terminal of the lowest potential power storage unit (16), which is the power storage unit with the lowest potential among the respective power storage units, and the low potential side path; a selection unit that selects one power storage unit or a part of the power storage units connected in series as a supply source power storage unit among the respective power storage units, and selects the remaining power storage units as supply destination power storage units; a control unit that performs drive control of at least one of the positive electrode switch and the negative electrode switch and switching control of the inverter so as to supply power from the supply source power storage unit to the supply destination power storage unit via the inverter and the neutral point path; The power conversion device according to claim 1, comprising:

3. When the highest potential power storage unit is the supply source power storage unit, the control unit performs switching control of the inverter with the positive electrode switch, the neutral point switch connected to the lowest potential side battery connection point of the supply source power storage unit, and the negative electrode switch turned on, thereby supplying power from the supply source power storage unit to the supply destination power storage unit via the inverter and the neutral point path. The power conversion device according to claim 2.

4. When the minimum potential power storage unit is the power supply source power storage unit, the control unit performs switching control of the inverter with the positive electrode switch, the neutral point switch connected to the battery connection point on the highest potential side of the power supply source power storage unit, and the negative electrode switch turned on, so as to supply power from the power supply source power storage unit to the power supply destination power storage unit via the inverter and the neutral point path. The power conversion device according to claim 2.

5. The control unit is When the power supply source power storage unit is sandwiched between the power supply destination power storage units, the control unit performs switching control of the inverter with the positive electrode switch, the negative electrode switch, and the neutral point switch connected to the battery connection point on the highest potential side of the power supply source power storage unit turned on, so as to supply power from the power storage unit on the lower potential side than the power supply source power storage unit among the respective power storage units and the power supply source power storage unit to the power storage unit on the higher potential side than the power supply source power storage unit among the respective power storage units via the inverter and the neutral point path. After that, the control unit performs switching control of the inverter with the positive electrode switch, the negative electrode switch, and the neutral point switch connected to the battery connection point on the lowest potential side of the power supply source power storage unit turned on, so as to supply power from the power storage unit on the higher potential side than the power supply source power storage unit among the respective power storage units and the power supply source power storage unit to the power storage unit on the lower potential side than the power supply source power storage unit among the respective power storage units via the inverter and the neutral point path. The power conversion device according to claim 2.

6. The control unit is When the power supply source power storage unit is sandwiched between the power supply destination power storage units, the control unit performs switching control of the inverter with the positive electrode switch, the negative electrode switch, and the neutral point switch connected to the battery connection point on the lowest potential side of the power supply source power storage unit turned on, so as to supply power from the power storage unit on the higher potential side than the power supply source power storage unit among the respective power storage units and the power supply source power storage unit to the power storage unit on the lower potential side than the power supply source power storage unit among the respective power storage units via the inverter and the neutral point path. After that, by performing switching control of the inverter with the positive electrode switch, the negative electrode switch, and the neutral point switch connected to the battery connection point on the highest potential side of the power supply source power storage unit turned on, power is supplied from the power storage unit on the lower potential side than the power supply source power storage unit and the power supply source power storage unit among the respective power storage units, via the neutral point path and the inverter, to the power storage unit on the higher potential side than the power supply source power storage unit among the respective power storage units. The power conversion device according to claim 2.

7. A positive electrode switch (SP) that connects the positive electrode terminal of the highest potential power storage unit (11), which is the power storage unit with the highest potential among the respective power storage units, and the high potential side path; Negative electrode switches (SN1 to SN5) that are individually provided corresponding to the negative electrode terminals of the power storage units (12 to 16) other than the highest potential power storage unit among the respective power storage units and that connect the negative electrode terminals and the low potential side path; The power conversion device according to claim 1, comprising:

8. A selection unit that selects, as a power supply source power storage unit, one power storage unit or a part of the power storage units connected in series, and selects the remaining power storage units as power supply destination power storage units; A control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter so as to supply power from the power supply source power storage unit to the power supply destination power storage unit via the inverter and the neutral point path; Comprising: The control unit: When the power supply source power storage unit is sandwiched between the power supply destination power storage units, by performing switching control of the inverter with the positive electrode switch, the neutral point switch connected to the battery connection point on the highest potential side of the power supply source power storage unit, and the negative electrode switch connected to the negative electrode terminal on the lowest potential side of the power supply source power storage unit turned on, power is supplied from the power supply source power storage unit, via the inverter and the neutral point path, to the power storage unit on the higher potential side than the power supply source power storage unit among the respective power storage units. Thereafter, by performing switching control of the inverter with the positive electrode switch, the negative electrode switch connected to the negative electrode terminal on the lowest potential side of the power receiving storage unit, and the neutral point switch connected to the battery connection point on the lowest potential side of the power supply storage unit turned on, power is supplied from the storage unit on the higher potential side than the power supply storage unit among the respective storage units and the power supply storage unit to the storage unit on the lower potential side than the power supply storage unit among the respective storage units via the inverter and the neutral point path. The power conversion device according to claim 7.

9. A negative electrode switch (SN) that connects the negative electrode terminal of the lowest potential storage unit (16), which is the storage unit with the lowest potential among the respective storage units, and the low potential side path; Positive electrode switches (SP1 to SP5) that are individually provided corresponding to the positive electrode terminals of the storage units (11 to 15) other than the lowest potential storage unit among the respective storage units and connect the positive electrode terminals and the high potential side path; The power conversion device according to claim 1, comprising:

10. A selection unit that selects one storage unit or a part of the storage units connected in series as the power supply storage unit and selects the remaining storage units as the power receiving storage units; A control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter so as to supply power from the power supply storage unit to the power receiving storage unit via the inverter and the neutral point path; comprising The control unit When the power supply storage unit is sandwiched between the power receiving storage units, by performing switching control of the inverter with the positive electrode switch connected to the positive electrode terminal on the highest potential side of the power supply storage unit, the negative electrode switch, and the neutral point switch connected to the battery connection point on the lowest potential side of the power supply storage unit turned on, power is supplied from the power supply storage unit to the storage unit on the lower potential side than the power supply storage unit among the respective storage units via the inverter and the neutral point path. After that, with the positive electrode switch connected to the positive electrode terminal on the highest potential side of the power supply destination power storage unit, the negative electrode switch, and the neutral point switch connected to the battery connection point on the highest potential side of the power supply source power storage unit turned on, by performing switching control of the inverter, power is supplied from the power storage unit on the lower potential side than the power supply source power storage unit and the power supply source power storage unit among the respective power storage units to the power storage unit on the higher potential side than the power supply source power storage unit among the respective power storage units via the inverter and the neutral point path. The power conversion device according to claim 9.

11. A selection unit that selects, as a power supply source power storage unit, one power storage unit or a part of the power storage units connected in series among the respective power storage units, and selects the remaining power storage units as power supply destination power storage units; When the highest potential power storage unit (11), which is the power storage unit on the highest potential side among the respective power storage units, is the power supply source power storage unit, the positive electrode switch (SP, SP1) connected to the positive electrode terminal of the highest potential power storage unit, the negative electrode switch (SN5, SN) connected to the negative electrode terminal of the power storage unit (16) on the lowest potential side among the respective power storage units, and the inverter is switched on with the neutral point switch connected to the battery connection point on the lowest potential side of the power supply source power storage unit. By performing control, a control unit that supplies power from the power supply source power storage unit to the power supply destination power storage unit via the inverter and the neutral point path; The power conversion device according to claim 7 or 9, comprising:

12. A selection unit that selects, as a power supply source power storage unit, one power storage unit or a part of the power storage units connected in series among the respective power storage units, and selects the remaining power storage units as power supply destination power storage units; When the lowest potential power storage unit (16), which is the power storage unit on the lowest potential side among the respective power storage units, is the power supply source power storage unit, the positive electrode switch (SP, SP1) connected to the positive electrode terminal of the power storage unit (11) on the highest potential side among the respective power storage units, the negative electrode switch (SN5, SN) connected to the negative electrode terminal of the lowest potential power storage unit, and the inverter is switched on with the neutral point switch connected to the battery connection point on the lowest potential side of the power supply destination power storage unit. By performing control, a control unit that supplies power from the power supply source power storage unit to the power supply destination power storage unit via the inverter and the neutral point path; The power conversion device according to claim 7 or 9, comprising:

13. Among the respective power storage units, there are a plurality of high-potential power storage units (11 to 14) which are the power storage units on the high-potential side, and there are a plurality of low-potential power storage units (15, 16) which are the remaining power storage units. Positive electrode switches (SP1 to SP4) that are individually provided corresponding to the positive electrode terminals of the highest-potential power storage unit (11) which is the power storage unit with the highest potential among the respective power storage units, and the battery connection points (PB1 to PB3) on the positive electrode terminal sides of the power storage units (12 to 14) other than the highest-potential power storage unit among the respective high-potential power storage units, and that connect the positive electrode terminals and the high-potential side path. Negative electrode switches (SN1 to SN3) that are individually provided corresponding to the negative electrode terminal of the lowest-potential power storage unit (16) which is the power storage unit with the lowest potential among the respective power storage units, the battery connection point (PB5) on the negative electrode terminal side of the power storage unit (15) other than the lowest-potential power storage unit among the respective low-potential power storage units, and the battery connection point (PB4) on the negative electrode terminal side of the specific power storage unit (14) which is the power storage unit with the lowest potential among the respective high-potential power storage units, and that connect the negative electrode terminals and the low-potential side path. An inter-battery switch (SD) that connects between the battery connection point on the negative electrode terminal side of the specific power storage unit and the negative electrode terminal of the specific power storage unit, or between the battery connection point (PB3) on the positive electrode terminal side of the specific power storage unit and the positive electrode terminal of the specific power storage unit. The power conversion device according to claim 1, comprising the above.

14. A selection unit that selects, as a supply-source power storage unit, one power storage unit or a part of the power storage units connected in series among the respective power storage units, and that selects, as a supply-destination power storage unit, one power storage unit other than the supply-source power storage unit or a part of the power storage units connected in series other than the supply-source power storage unit among the respective power storage units. When the power supply source storage unit is included in the group of the high potential storage units, and the power supply destination storage unit is included in the group of the low potential storage units, and there are other storage units intervening between the power supply source storage unit and the power supply destination storage unit, or when the power supply source storage unit is included in the group of the low potential storage units, and the power supply destination storage unit is included in the group of the high potential storage units, and there are other storage units intervening between the power supply source storage unit and the power supply destination storage unit, turn off the inter-battery switch, and perform switching control of the inverter with the positive electrode switch corresponding to the most high potential side positive electrode terminal of the power supply source storage unit, the neutral point switch connected to the battery connection point on the most low potential side of the power supply source storage unit, the neutral point switch connected to the battery connection point on the most high potential side of the power supply destination storage unit, and the negative electrode switch corresponding to the most low potential side negative electrode terminal of the power supply destination storage unit turned on, thereby a control unit for supplying power from the power supply source storage unit to the power supply destination storage unit via the inverter and the neutral point path, The power conversion device according to claim 13, comprising the above.

15. A selection unit that selects, as the power supply source storage unit, one storage unit or a part of the storage units connected in series among the respective storage units, selects, as the power supply destination storage unit, one storage unit other than the power supply source storage unit or a part of the storage units connected in series other than the power supply source storage unit among the respective storage units, and selects, as the temporary power supply destination storage unit, one storage unit other than the power supply source storage unit and the power supply destination storage unit or a part of the storage units connected in series other than the power supply source storage unit and the power supply destination storage unit among the respective storage units, A control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter to supply power from the power supply source storage unit to the power supply destination storage unit via the inverter and the neutral point path, Comprising the above, The control unit is, When both the power supply storage unit and the power supply destination storage unit are included in the group of the high-potential storage units, and both the power supply storage unit and the power supply destination storage unit are not included in the group of the low-potential storage units, the inter-battery switch is turned off, and the positive electrode switch corresponding to the most high-potential side positive electrode terminal of the power supply storage unit, the neutral point switch connected to the battery connection point on the most low-potential side of the power supply storage unit, the neutral point switch connected to the battery connection point on the most high-potential side of the temporary power supply destination storage unit, and the negative electrode switch corresponding to the most low-potential side negative electrode terminal of the temporary power supply destination storage unit are turned on, and the switching control of the inverter is performed, so as to supply power from the power supply storage unit to the temporary power supply destination storage unit through the inverter and the neutral point path. Thereafter, the inter-battery switch is turned off, and the neutral point switch connected to the battery connection point on the most high-potential side of the temporary power supply destination storage unit, the negative electrode switch corresponding to the most low-potential side negative electrode terminal of the temporary power supply destination storage unit, the positive electrode switch corresponding to the most high-potential side positive electrode terminal of the power supply destination storage unit, and the neutral point switch connected to the battery connection point on the most low-potential side of the power supply destination storage unit are turned on, and the switching control of the inverter is performed, so as to supply power from the temporary power supply destination storage unit to the power supply destination storage unit through the inverter and the neutral point path. The power conversion device according to claim 13.

16. A selection unit that selects, as a power supply storage unit, one storage unit or a part of the storage units connected in series among the respective storage units, selects, as a power supply destination storage unit, one storage unit other than the power supply storage unit or a part of the storage units connected in series other than the power supply storage unit among the respective storage units, and selects, as a temporary power supply destination storage unit, one storage unit other than the power supply storage unit and the power supply destination storage unit or a part of the storage units connected in series other than the power supply storage unit and the power supply destination storage unit among the respective storage units; A control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter so as to supply power from the power supply storage unit to the power supply destination storage unit through the inverter and the neutral point path; Comprising: The control unit is When both the power supply storage unit and the power destination storage unit are included in the group of the low potential storage units and neither the power supply storage unit nor the power destination storage unit is included in the group of the high potential storage units, the inter-battery switch is turned off, and the neutral point switch connected to the battery connection point on the highest potential side of the power supply storage unit, the negative electrode switch corresponding to the negative electrode terminal on the lowest potential side of the power supply storage unit, the positive electrode switch corresponding to the positive electrode terminal on the highest potential side of the temporary power destination storage unit, and the neutral point switch connected to the battery connection point on the lowest potential side of the temporary power destination storage unit are turned on, and switching control of the inverter is performed, whereby power is supplied from the power supply storage unit to the temporary power destination storage unit via the inverter and the neutral point path. Thereafter, the inter-battery switch is turned off, and the positive electrode switch corresponding to the positive electrode terminal on the highest potential side of the temporary power destination storage unit, the neutral point switch connected to the battery connection point on the lowest potential side of the temporary power destination storage unit, the neutral point switch connected to the battery connection point on the highest potential side of the power destination storage unit, and the negative electrode switch corresponding to the negative electrode terminal on the lowest potential side of the power destination storage unit are turned on, and switching control of the inverter is performed, whereby power is supplied from the temporary power destination storage unit to the power destination storage unit via the inverter and the neutral point path. The power conversion device according to claim 13.

17. There are four or more storage units. Positive electrode switches (SP1 to SP5) that are individually provided corresponding to the positive electrode terminals of the storage units (11 to 15) other than the storage unit (16) with the lowest potential among the respective storage units and that connect the positive electrode terminals to the high potential side path. Negative electrode switches (SN1 to SN5) that are individually provided corresponding to the negative electrode terminals of the storage units (12 to 16) other than the storage unit (11) with the highest potential among the respective storage units and that connect the negative electrode terminals to the low potential side path. The power conversion device according to claim 1, comprising:

18. A selection unit that selects, as a power supply storage unit, one storage unit or a part of the storage units connected in series among the respective storage units, and selects, as a power destination storage unit, one storage unit other than the power supply storage unit or a part of the storage units connected in series other than the power supply storage unit among the respective storage units. When the power supply source storage unit and the power supply destination storage unit are adjacent to each other and the power supply source storage unit is on the higher potential side than the power supply destination storage unit, a control unit that supplies power from the power supply source storage unit to the power supply destination storage unit via the inverter and the neutral point path by performing switching control of the inverter with the positive electrode switch connected to the most high-potential-side positive electrode terminal of the power supply source storage unit, the neutral point switch connected to the battery connection point on the lowest potential side of the power supply source storage unit, and the negative electrode switch connected to the negative electrode terminal on the lowest potential side of the power supply destination storage unit turned on, The power conversion device according to claim 17, comprising the above.

19. A selection unit that selects, as a power supply source storage unit, one storage unit or a part of the storage units connected in series among the respective storage units, and selects, as a power supply destination storage unit, one storage unit other than the power supply source storage unit or a part of the storage units connected in series other than the power supply source storage unit among the respective storage units, When the power supply source storage unit and the power supply destination storage unit are adjacent to each other and the power supply source storage unit is on the lower potential side than the power supply destination storage unit, a control unit that supplies power from the power supply source storage unit to the power supply destination storage unit via the inverter and the neutral point path by performing switching control of the inverter with the negative electrode switch connected to the most low-potential-side negative electrode terminal of the power supply source storage unit, the neutral point switch connected to the battery connection point on the highest potential side of the power supply source storage unit, and the positive electrode switch connected to the positive electrode terminal on the highest potential side of the power supply destination storage unit turned on, The power conversion device according to claim 17, comprising the above.

20. A selection unit that selects, as a power supply source storage unit, one storage unit or a part of the storage units connected in series among the respective storage units, and selects, as a power supply destination storage unit, one storage unit other than the power supply source storage unit or a part of the storage units connected in series other than the power supply source storage unit among the respective storage units, A control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter to supply power from the power supply source storage unit to the power supply destination storage unit via the inverter and the neutral point path, Comprising The control unit is When an intermediate power storage unit, which is another one of the power storage units, is interposed between the power supply source power storage unit and the power supply destination power storage unit, and the power supply source power storage unit is on the higher potential side than the power supply destination power storage unit, by performing switching control of the inverter with the positive electrode switch connected to the most high-potential-side positive electrode terminal of the power supply source power storage unit, the neutral point switch connected to the battery connection point on the most low-potential side of the power supply source power storage unit, and the negative electrode switch connected to the most low-potential-side negative electrode terminal of the intermediate power storage unit turned on, power is supplied from the power supply source power storage unit to the intermediate power storage unit via the inverter and the neutral point path. Thereafter, by performing switching control of the inverter with the positive electrode switch connected to the most high-potential-side positive electrode terminal of the intermediate power storage unit, the neutral point switch connected to the battery connection point on the most low-potential side of the intermediate power storage unit, and the negative electrode switch connected to the most low-potential-side negative electrode terminal of the power supply destination power storage unit turned on, power is supplied from the intermediate power storage unit to the power supply destination power storage unit via the inverter and the neutral point path. The power conversion device according to claim 17.

21. A selection unit that selects, as a power supply source power storage unit, one power storage unit or a part of the power storage units connected in series among the respective power storage units, and selects, as a power supply destination power storage unit, one power storage unit other than the power supply source power storage unit or a part of the power storage units connected in series other than the power supply source power storage unit among the respective power storage units; A control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter to supply power from the power supply source power storage unit to the power supply destination power storage unit via the inverter and the neutral point path; Comprising: The control unit: When an intermediate power storage unit, which is another one of the power storage units, is interposed between the power supply source power storage unit and the power supply destination power storage unit, and the power supply source power storage unit is on the lower potential side than the power supply destination power storage unit, by performing switching control of the inverter with the negative electrode switch connected to the most low-potential-side negative electrode terminal of the power supply source power storage unit, the neutral point switch connected to the battery connection point on the most high-potential side of the power supply source power storage unit, and the positive electrode switch connected to the most high-potential-side positive electrode terminal of the intermediate power storage unit turned on, power is supplied from the power supply source power storage unit to the intermediate power storage unit via the inverter and the neutral point path. After that, by performing switching control of the inverter with the negative electrode switch connected to the negative electrode terminal on the lowest potential side of the intermediate power storage unit, the neutral point switch connected to the battery connection point on the highest potential side of the intermediate power storage unit, and the positive electrode switch connected to the positive electrode terminal on the highest potential side of the destination power storage unit turned on, power is supplied from the intermediate power storage unit to the destination power storage unit via the inverter and the neutral point path. The power conversion device according to claim 17.

22. A selection unit that selects, as a source power storage unit, one power storage unit or a part of the power storage units connected in series among the respective power storage units, and selects, as a destination power storage unit, one power storage unit other than the source power storage unit or a part of the power storage units connected in series other than the source power storage unit among the respective power storage units; A control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter in order to supply power from the source power storage unit to the destination power storage unit via the inverter and the neutral point path; Comprising: The control unit: When an intermediate power storage unit, which is another one of the power storage units, is interposed between the source power storage unit and the destination power storage unit, and the source power storage unit is on the higher potential side than the destination power storage unit, the positive electrode switch connected to the positive electrode terminal on the highest potential side of the intermediate power storage unit, the neutral point switch connected to the battery connection point on the lowest potential side of the intermediate power storage unit, and the negative electrode switch connected to the negative electrode terminal on the lowest potential side of the destination power storage unit are turned on, and by performing switching control of the inverter, power is supplied from the intermediate power storage unit to the destination power storage unit via the inverter and the neutral point path. After that, by performing switching control of the inverter with the positive electrode switch connected to the positive electrode terminal on the highest potential side of the source power storage unit, the neutral point switch connected to the battery connection point on the lowest potential side of the source power storage unit, and the negative electrode switch connected to the negative electrode terminal on the lowest potential side of the intermediate power storage unit turned on, power is supplied from the source power storage unit to the intermediate power storage unit via the inverter and the neutral point path. The power conversion device according to claim 17.

23. Among the respective power storage units, one power storage unit or a part of the power storage units connected in series is selected as a source power storage unit, and among the respective power storage units, one power storage unit other than the source power storage unit or a part of the power storage units connected in series other than the source power storage unit is selected as a destination power storage unit; a selection unit a control unit that performs drive control of the positive electrode switch and the negative electrode switch and switching control of the inverter so as to supply power from the source power storage unit to the destination power storage unit via the inverter and the neutral point path; is provided with The control unit When an intermediate power storage unit, which is another one of the power storage units, is interposed between the source power storage unit and the destination power storage unit, and the source power storage unit is on the lower potential side than the destination power storage unit, the negative electrode switch connected to the most low-potential-side negative electrode terminal of the intermediate power storage unit, the neutral point switch connected to the battery connection point on the most high-potential side of the intermediate power storage unit, and the positive electrode switch connected to the most high-potential-side positive electrode terminal of the destination power storage unit are turned on, and switching control of the inverter is performed, whereby power is supplied from the intermediate power storage unit to the destination power storage unit via the inverter and the neutral point path. Thereafter, switching control of the inverter is performed with the negative electrode switch connected to the most low-potential-side negative electrode terminal of the source power storage unit, the neutral point switch connected to the battery connection point on the most high-potential side of the source power storage unit, and the positive electrode switch connected to the most high-potential-side positive electrode terminal of the intermediate power storage unit turned on, whereby power is supplied from the source power storage unit to the intermediate power storage unit via the inverter and the neutral point path. The power conversion device according to claim 17. **Claim 24** Four or more power storage units including a highest potential power storage unit (11) that is the power storage unit with the highest potential and a lowest potential power storage unit (16) that is the power storage unit with the lowest potential are provided among the respective power storage units. Positive electrode switches (SP1 to SP5) that are individually provided corresponding to the positive electrode terminals of the power storage units (12 to 15) other than the highest potential power storage unit and the lowest potential power storage unit among the respective power storage units and the battery connection points (PB1 to PB4) on the positive electrode terminal sides, and that connect the positive electrode terminal and the high potential side path The negative terminal of the lowest potential power storage unit and the battery connection points (PB2 to PB5) on the negative terminal side of the power storage units other than the highest potential power storage unit and the lowest potential power storage unit (12 to 15) among the respective power storage units are provided individually, and negative switches (SN1 to SN5) that connect the negative terminal and the low potential side path; Inter-battery switches (SD1 to SD4) provided between the respective battery connection points; The power conversion device according to claim 1, comprising the same.

25. A selection unit that selects one power storage unit or a part of the power storage units connected in series as a supply source power storage unit among the respective power storage units, and selects one power storage unit other than the supply source power storage unit or a part of the power storage units connected in series other than the supply source power storage unit as a supply destination power storage unit among the respective power storage units; When the supply source power storage unit and the supply destination power storage unit are adjacent to each other and the supply source power storage unit is on the higher potential side than the supply destination power storage unit, the positive switch corresponding to the most high potential side positive terminal of the supply source power storage unit, the neutral point switch connected to the battery connection point on the lowest potential side of the supply source power storage unit, the negative switch corresponding to the most low potential side negative terminal of the supply destination power storage unit, and the inverter is switched on by performing switching control of the inverter with the inter-battery switch between the supply source power storage unit and the supply destination power storage unit in an on state, so that power is supplied from the supply source power storage unit to the supply destination power storage unit via the inverter and the neutral point path. A control unit; The power conversion device according to claim 24, comprising the same.

26. A selection unit that selects one power storage unit or a part of the power storage units connected in series as a supply source power storage unit among the respective power storage units, and selects one power storage unit other than the supply source power storage unit or a part of the power storage units connected in series other than the supply source power storage unit as a supply destination power storage unit among the respective power storage units; When the power supply source storage unit and the power supply destination storage unit are adjacent to each other and the power supply source storage unit is on the lower potential side than the power supply destination storage unit, by performing switching control of the inverter in a state where the negative electrode switch corresponding to the most low-potential-side negative electrode terminal of the power supply source storage unit, the neutral point switch connected to the battery connection point on the most high-potential side of the power supply source storage unit, the positive electrode switch corresponding to the most high-potential-side positive electrode terminal of the power supply destination storage unit, and the inter-battery switch between the power supply source storage unit and the power supply destination storage unit are turned on, a control unit that supplies power from the power supply source storage unit to the power supply destination storage unit via the inverter and the neutral point path, The power conversion device according to claim 24, comprising the above.

27. A selection unit that selects, as a power supply source storage unit, one storage unit or a part of the storage units connected in series among the respective storage units, and selects, as a power supply destination storage unit, one storage unit other than the power supply source storage unit or a part of the storage units connected in series other than the power supply source storage unit among the respective storage units, When an intermediate storage unit, which is another one of the storage units, is interposed between the power supply source storage unit and the power supply destination storage unit and the power supply source storage unit is on the higher potential side than the power supply destination storage unit, after turning off at least one of the inter-battery switches between the battery connection points existing between the power supply source storage unit and the power supply destination storage unit, by performing switching control of the inverter in a state where the positive electrode switch corresponding to the most high-potential-side positive electrode terminal of the power supply source storage unit, the neutral point switch connected to the battery connection point on the most high-potential side of the intermediate storage unit, the neutral point switch connected to the battery connection point on the most low-potential side of the intermediate storage unit, and the negative electrode switch corresponding to the most low-potential-side negative electrode terminal of the power supply destination storage unit are turned on, a control unit that supplies power from the power supply source storage unit to the power supply destination storage unit via the inverter and the neutral point path, The power conversion device according to claim 24, comprising the above.

28. A selection unit that selects, as a power supply source storage unit, one storage unit or a part of the storage units connected in series among the respective storage units, and selects, as a power supply destination storage unit, one storage unit other than the power supply source storage unit or a part of the storage units connected in series other than the power supply source storage unit among the respective storage units, When an intermediate power storage unit, which is another one of the power storage units, is interposed between the power supply source power storage unit and the power supply destination power storage unit, and the power supply source power storage unit is on the lower potential side than the power supply destination power storage unit, at least one of the battery inter-switching switches between the battery connection points existing between the power supply source power storage unit and the power supply destination power storage unit is turned off, and the negative electrode switch corresponding to the most low-potential-side negative electrode terminal of the power supply source power storage unit, the neutral point switch connected to the battery connection point on the highest potential side of the intermediate power storage unit, the neutral point switch connected to the battery connection point on the lowest potential side of the intermediate power storage unit, and the positive electrode switch corresponding to the most high-potential-side positive electrode terminal of the power supply destination power storage unit are turned on, and the switching control of the inverter is performed, thereby providing a control unit that supplies power from the power supply source power storage unit to the power supply destination power storage unit via the inverter and the neutral point path. The power conversion device according to claim 24, comprising the above.

29. The control unit performs switching control of the inverter such that the number of phases of the stator winding through which current flows is the number of phases at which the power conversion efficiency is maximized when power is supplied from the power supply source power storage unit to the power supply destination power storage unit via the inverter and the neutral point path. The power conversion device according to any one of claims 2 to 6, 8, 10 to 12, 14 to 16, 18 to 23, 25 to 28.

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