Power conversion device and program

Abstract

This power conversion device comprises: a high potential-side electric path (22H) electrically connectable to a positive electrode terminal of a first power storage unit (31); a low potential-side electric path (22L) electrically connectable to a negative electrode terminal of a second power storage unit (32); an inverter (20); and a motor (10). The power conversion device comprises: an inter-power-storage-unit switch (40) provided on an inter-power-storage-unit electric path (24) electrically connecting a negative electrode terminal of the first power storage unit and a positive electrode terminal of the second power storage unit; a bypass switch (50, 51) that carries out electrical connection of at least one of electrical connection between the negative electrode terminals of the first power storage unit and the second power storage unit, and electrical connection between the positive electrode terminals of the first power storage unit and the second power storage unit; and a control unit (100) that determines whether, prior to making an ON operation of one of the inter-power-storage-unit switch and the bypass switch, the other is stuck in the ON position.

Description

Cross - reference to related applications

[0001] This application is based on Japanese Application No. 2022 - 144021 filed on September 9, 2022, the contents of which are incorporated herein by reference.

Technical Field

[0002] The present disclosure relates to a power conversion device and a program.

Background Art

[0003] Conventionally, when charging an in - vehicle battery using an external charger, a control device for determining whether a switch in a power conversion device is stuck on is known. For example, the control device described in Patent Document 1 transmits an on - command to the switch to be determined and checks the voltage across the switch. At this time, if the voltage across the switch is the same, the control device determines that the switch is stuck on.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] By the way, when switches in a power conversion device are connected in parallel, if one switch is stuck on and the other switch is turned on, a short - circuit current will flow between the switches.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a power conversion device and a program capable of suppressing the flow of a short - circuit current between switches.

[0007] The present disclosure is a high - potential - side electrical path electrically connectable to the positive - terminal of the first power storage unit, and A low-potential-side electrical path electrically connectable to the negative terminal of the second power storage unit, an inverter having an upper-arm switch electrically connected to the high-potential-side electrical path and a lower-arm switch electrically connected to the low-potential-side electrical path, a motor electrically connected to the connection point of the upper-arm switch and the lower-arm switch, In a power conversion device including: an inter-storage-unit switch provided in an inter-storage-unit electrical path that electrically connects the negative terminal of the first power storage unit and the positive terminal of the second power storage unit; a bypass switch that makes at least one of the electrical connection between the negative terminals of the first power storage unit and the second power storage unit and the electrical connection between the positive terminals of the first power storage unit and the second power storage unit; a control unit that determines whether the other switch is stuck on before turning on either one of the inter-storage-unit switch and the bypass switch.

[0008] According to the above configuration, when it is determined that one switch is stuck on, the other switch is not turned on, so that a short-circuit current flowing between the switches is suppressed.

Brief Description of the Drawings

[0009] The above object, other objects, features, and advantages of the present disclosure will become clearer from the following detailed description with reference to the accompanying drawings. The drawings are

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Embodiments for Carrying out the Invention

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

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

[0012] The system includes a power conversion device. As shown in FIG. 1, the power conversion device includes a motor 10, an inverter 20, a high-potential side electric path 22H, and a low-potential side electric path 22L. The motor 10 is a three-phase synchronous machine and includes stator windings 11 of U, V, and W phases connected in a star configuration and a rotor (not shown). The stator windings 11 of each phase are arranged with a 120° electrical angle shift. The motor 10 is, for example, a permanent magnet synchronous machine. The rotor is capable of power transmission to the drive wheels of the vehicle. Therefore, the motor 10 is a torque generation source for driving the vehicle.

[0013] The inverter 20 includes three sets of series-connected bodies of upper arm switches SWH and lower arm switches SWL. An upper arm diode DH, which is a freewheel diode, is connected in antiparallel to the upper arm switch SWH, and a lower arm diode DL, which is a freewheel diode, is connected in antiparallel to the lower arm switch SWL. In this embodiment, each switch SWH, SWL is an IGBT.

[0014] The inverter 20 includes a smoothing capacitor 21. The first end side of a long high-potential-side electrical path 22H is connected to the high-potential-side terminal of the smoothing capacitor 21. The first end side of a long low-potential-side electrical path 22L is connected to the low-potential-side terminal of the smoothing capacitor 21. Note that the smoothing capacitor 21 may be provided outside the inverter 20. The voltage of the smoothing capacitor 21 is detected by the SC voltage sensor 19.

[0015] In each phase, the first end of the armature winding 11 is connected to the connection point between the emitter, which is the low-potential-side terminal of the upper-arm switch SWH, and the collector, which is the high-potential-side terminal of the lower-arm switch SWL, via a conductive member 23 such as a bus bar. The second ends of the armature windings 11 of each phase are connected at the neutral point. In this embodiment, the number of turns of the armature winding 11 of each phase is set to be the same. As a result, the armature winding 11 of each phase is set to have, for example, the same inductance.

[0016] The high-potential-side electrical path 22H is connected to the collector of the upper-arm switch SWH of each phase. The low-potential-side electrical path 22L is connected to the emitter of the lower-arm switch SWL of each phase.

[0017] The system includes a first storage battery 31 (corresponding to the "first power storage unit") and a second storage battery 32 (corresponding to the "second power storage unit"). Each of the storage batteries 31 and 32 serves as a power supply source for rotationally driving the rotor of the motor 10. Each of the storage batteries 31 and 32 is a battery pack configured as a series connection of battery cells that are single cells. The positive terminal of the first storage battery 31 is connected to the high-potential-side electrical path 22H, and the negative terminal of the second storage battery 32 is connected to the low-potential-side electrical path 22L. In this embodiment, the terminal voltage (for example, the rated voltage) of the first storage battery 31 is 400V, and the terminal voltage (for example, the rated voltage) of the second storage battery 32 is 200V. However, it is not limited thereto, and it is sufficient that the terminal voltage of the first storage battery 31 is equal to or higher than the terminal voltage of the second storage battery 32. The battery cell is, for example, a secondary battery such as a lithium-ion battery.

[0018] Each of the storage batteries 31 and 32 can be charged by an external charger described later provided outside the vehicle. The external charger is, for example, a stationary charger. A positive electrode side connection portion to which the positive electrode terminal of the external charger can be connected is provided at the second end side of the high potential side electrical path 22H opposite to the connection point side of the smoothing capacitor 21. A negative electrode side connection portion to which the negative electrode terminal of the external charger can be connected is provided at the second end side of the low potential side electrical path 22L opposite to the connection point side of the smoothing capacitor 21.

[0019] The power conversion device includes a main switch for electrically connecting or disconnecting between the first and second storage batteries 31 and 32 and the inverter 20. Specifically, a high potential side main switch SMRH and a low potential side main switch SMRL are provided as the main switches. Further, the power conversion device includes a charging switch for electrically connecting or disconnecting between the external charger and the first and second storage batteries 31 and 32. Specifically, a high potential side charging switch DCRH and a low potential side charging switch DCRL are provided as the charging switches. In the present embodiment, each of the switches SMRH, SMRL, DCRH, and DCRL is described as a mechanical relay, but is not limited thereto, and may be a semiconductor switching element. Each of the switches SMRH, SMRL, DCRH, and DCRL blocks the flow of bidirectional current in the off state and allows the flow of bidirectional current in the on state. The high potential side electrical path 22H is provided with a high potential side main switch SMRH and a high potential side charging switch DCRH in order from the inverter 20 side. The low potential side electrical path 22L is provided with a low potential side main switch SMRL and a low potential side charging switch DCRL in order from the inverter 20 side.

[0020] The power conversion device includes a battery interconnection switch 40, a negative electrode bypass switch 50, a motor-side switch 60, and a connection switch 80 as switches for switching the connection state of the first battery 31 and the second battery 32 to either a series connection state or a parallel connection state with respect to an external charger. In the present embodiment, the battery interconnection switch 40, the negative electrode bypass switch 50, the motor-side switch 60, and the connection switch 80 are described as mechanical relays, but are not limited thereto, and may be semiconductor switching elements. The battery interconnection switch 40, the negative electrode bypass switch 50, the motor-side switch 60, and the connection switch 80 block the flow of bidirectional current in the off state and allow the flow of bidirectional current in the on state.

[0021] The battery interconnection switch 40 is provided in an inter-battery electrical path 24 (corresponding to an "inter-storage unit electrical path") that connects the negative electrode terminal of the first battery 31 and the positive electrode terminal of the second battery 32. When the battery interconnection switch 40 is in the on state, the negative electrode terminal of the first battery 31 and the positive electrode terminal of the second battery 32 are electrically connected. On the other hand, when the battery interconnection switch 40 is in the off state, the negative electrode terminal of the first battery 31 and the positive electrode terminal of the second battery 32 are electrically disconnected.

[0022] The negative electrode bypass switch 50 connects the negative electrode terminal of the first battery 31 and the low-potential-side electrical path 22L. When the negative electrode bypass switch 50 is in the on state, the negative electrode terminal of the first battery 31 and the negative electrode terminal of the second battery 32 are electrically connected. On the other hand, when the negative electrode bypass switch 50 is in the off state, the negative electrode terminal of the first battery 31 and the negative electrode terminal of the second battery 32 are electrically disconnected.

[0023] The motor-side switch 60 and the connection switch 80 are provided in a motor-side electrical path 25 that connects the side of the second storage battery 32 closer to the battery-interconnection switch 40 in the battery-interconnection electrical path 24 and the neutral point of the armature winding 11. More specifically, the connection switch 80 is provided on the neutral-point side of the motor-side electrical path 25 with respect to the motor-side switch 60. When the motor-side switch 60 and the connection switch 80 are in the ON state, the neutral point of the armature winding 11 and the positive terminal of the second storage battery 32 are electrically connected. On the other hand, when the motor-side switch 60 and the connection switch 80 are in the OFF state, the neutral point of the armature winding 11 and the positive terminal of the second storage battery 32 are electrically disconnected. The motor-side electrical path 25 is a path that electrically connects the neutral point of the armature winding 11 and the portion of the battery-interconnection electrical path 24 on the side of the second storage battery 32 closer to the battery-interconnection switch 40.

[0024] The power conversion device includes a first voltage sensor 71 that detects the voltage between the terminals of the first storage battery 31 and a second voltage sensor 72 that detects the voltage between the terminals of the second storage battery 32. The power conversion device includes a first current sensor 73 that detects the current flowing through the first storage battery 31 and a second current sensor 74 that detects the current flowing through the second storage battery 32. The first current sensor 73 is provided in an electrical path that connects the positive terminal of the first storage battery 31 and the high-potential-side electrical path 22H. The second current sensor 74 is provided in an electrical path that connects the negative terminal of the second storage battery 32 and the low-potential-side electrical path 22L. Note that the power conversion device also includes, as other sensors, a rotation angle sensor that detects the rotation angle (electrical angle) of the rotor and a phase current sensor that detects the phase current flowing through each phase of the armature winding 11.

[0025] The detected values of the respective sensors are input to a control device 100 (corresponding to a "control unit") provided in the power conversion device. The control device 100 is mainly configured by a microcomputer 101, and the microcomputer 101 includes a CPU. The functions provided by the microcomputer 101 can be provided by software recorded in a physical memory device and a computer that executes the software, software only, hardware only, or a combination thereof. For example, when the microcomputer 101 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 101 executes a program stored in a non-transitory tangible storage medium as a storage unit provided therein. The program includes, for example, a program for the processing shown in FIG. 9 described later. 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, such as OTA (Over The Air).

[0026] Based on the detected values of the respective sensors, the control device 100 performs switching control of each of the switches SWH and SWL constituting the inverter 20 to feedback-control the control amount of the motor 10 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. By this feedback control, the rotational power of the rotor is transmitted to the drive wheels, and the vehicle travels.

[0027] The positive electrode side connection portion of the high potential side electric path 22H and the negative electrode side connection portion of the low potential side electric path 22L are interfaces for connecting to an external charger. In the present embodiment, the external charger is a low voltage charger 200 or a high voltage charger 210 (see FIGS. 2 to 4). The charging voltage of the low voltage charger 200 is lower than the voltage between the terminals of the series connection of the first and second storage batteries 31 and 32 (specifically, the rated voltage), and is, for example, 400V.

[0028] The charging voltage of the high-voltage charger 210 is higher than the rated voltage of the series-connected body of the first and second storage batteries 31 and 32, for example, 800V. For example, when an external charger is connected to each connection part by a user or an operator and the first and second storage batteries 31 and 32 are charged by the external charger, the high-potential side charging switch DCRH and the low-potential side charging switch DCRL are switched to the on state by the control device 100.

[0029] On the other hand, when charging by the external charger is not carried out or when the external charger is not connected, the high-potential side charging switch DCRH and the low-potential side charging switch DCRL are switched to the off state by the control device 100. When the positive electrode side connection part and the negative electrode side connection part are exposed to the outside from the housing of the power conversion device, there is a possibility that they may be touched by a user or an operator. By turning off the high-potential side charging switch DCRH and the low-potential side charging switch DCRL, the occurrence of electric shock is prevented.

[0030] A low-potential side electric path 22L is connected to a portion between the motor side switch 60 and the connection switch 80 in the motor side electric path 25 via a neutral point capacitor 90. An NC voltage sensor 75 for detecting the voltage of the neutral point capacitor 90 is provided in the neutral point capacitor 90. The reason for providing the neutral point capacitor 90 between the motor side electric path 25 and the low-potential side electric path 22L is as follows. In the charging process when the external charger is connected, a high-frequency current is generated due to switching. The neutral point capacitor 90 is provided to suppress the high-frequency current generated due to switching from flowing from the inverter 20 side to the first and second storage batteries 31 and 32 and the external charger.

[0031] A series-connected body of a precharge switch SP and a resistor 95 is connected in parallel to the low-potential side main switch SMRL. The precharge switch SP is used, for example, in the precharge process of charging the smoothing capacitor 21 and the neutral point capacitor 90 when the power conversion device is started.

[0032] Next, with reference to FIGS. 2 to 4, the on / off states of each switch when the system is connected to an external charger and charging is performed will be described. In the drawings after FIG. 2, the illustrations of the control device 100 and the SC voltage sensor 19 are omitted.

[0033] FIG. 2 shows the on / off states of each switch when the external charger connected to each connection part of each electric path 22H, 22L is a low-voltage charger 200. As shown in FIG. 2, when the low-voltage charger 200 is connected, the control device 100 causes the first battery 31 to be connected in parallel to the low-voltage charger 200, and the second battery 32 to be connected in parallel to the low-voltage charger 200 via the inverter 20 and the armature winding 11. The main switches SMRH, SMRL, the inter-battery switch 40, the negative electrode bypass switch 50, the motor-side switch 60, the connection switch 80, and the upper and lower arm switches SWH, SWL of the inverter 20 are operated.

[0034] Specifically, the control device 100 turns on the main switches SMRH and SMRL, the negative electrode bypass switch 50, the motor side switch 60, and the connection switch 80, and turns off the battery connection switch 40. Further, the control device 100 turns off all-phase lower arm switches SWL of the inverter 20, and repeatedly turns on and off at least one-phase upper arm switch SWH. As a result, as shown in FIG. 2, the first storage battery 31 is connected in parallel to the low-voltage charger 200, and the second storage battery 32 is connected in parallel to the low-voltage charger 200 via the inverter 20 and the armature winding 11. Therefore, a current flows through a closed circuit including the low-voltage charger 200, the high-potential side electrical path 22H, the first storage battery 31, the negative electrode bypass switch 50, and the low-potential side electrical path 22L, and the first storage battery 31 is charged. Further, a current flows through a closed circuit including the low-voltage charger 200, the high-potential side electrical path 22H, the upper arm switch SWH, the armature winding 11, the neutral point, the connection switch 80, the motor side switch 60, the second storage battery 32, and the low-potential side electrical path 22L, and the second storage battery 32 is stepped down and charged. When a plurality of phases of the upper arm switches SWH are turned on, the impedance of the charging path can be reduced. In the present embodiment, the mode of charging in the switch state shown in FIG. 2 is called the "parallel mode".

[0035] FIG. 3 shows the on / off states of the respective switches when the external charger connected to each connection portion of the electrical paths 22H and 22L is the high-voltage charger 210. As shown in FIG. 3, when the high-voltage charger 210 is connected, the control device 100 operates the main switches SMRH and SMRL, the battery connection switch 40, the negative electrode bypass switch 50, the motor side switch 60, the connection switch 80, and the upper and lower arm switches SWH and SWL of the inverter 20 so that the first storage battery 31 and the second storage battery 32 are connected in series to the high-voltage charger 210.

[0036] Specifically, the control device 100 turns on the main switches SMRH and SMRL and the battery interconnection switch 40, and turns off the negative electrode bypass switch 50, the motor side switch 60, the connection switch 80, and the upper and lower arm switches SWH and SWL of all phases of the inverter 20. As a result, as shown in FIG. 3, the first battery 31 and the second battery 32 are connected in series to the high-voltage charger 210. Therefore, a current flows through a closed circuit including the high-voltage charger 210, the high-potential side electrical path 22H, the first battery 31, the battery interconnection switch 40, the second battery 32, and the low-potential side electrical path 22L, and the first battery 31 and the second battery 32 are charged in a series-connected state. At this time, since the upper arm switch SWH, the connection switch 80, and the motor side switch 60 of the inverter 20 are turned off, it is possible to prevent the charging current of the high-voltage charger 210 from flowing through the inverter 20 and the armature winding 11. In the present embodiment, the mode in which charging is performed in the switch state shown in FIG. 3 is called the "series mode".

[0037] Similar to FIG. 3, FIG. 4 shows the on / off states of the respective switches when the external charger connected to each connection portion of the electrical paths 22H and 22L is the high-voltage charger 210. The state in which the first battery 31 and the second battery 32 are connected in series to the high-voltage charger 210 is the same as in FIG. 3, but in FIG. 4, the on / off states of the respective switches are different from those in FIG. 3.

[0038] In FIG. 4, the control device 100 turns on the main switches SMRH and SMRL, the battery interconnection switch 40, the motor side switch 60, and the connection switch 80, and turns off the negative electrode bypass switch 50. As a result, as shown in FIG. 4, the first battery 31 and the second battery 32 are connected in series to the high-voltage charger 210. Thereby, a current flows through a closed circuit including the high-voltage charger 210, the high-potential side electrical path 22H, the first battery 31, the battery interconnection switch 40, the second battery 32, and the low-potential side electrical path 22L, and the first battery 31 and the second battery 32 are charged in a state of being connected in series. Further, the control device 100 alternately turns on the upper and lower arm switches SWH and SWL of the inverter. Thereby, a current flows through a closed circuit including the high-voltage charger 210, the high-potential side electrical path 22H, the upper arm switch SWH, the armature winding 11, the neutral point, the connection switch 80, the motor side switch 60, the second battery 32, and the low-potential side electrical path 22L, and the second battery 32 is charged. In the present embodiment, the mode of charging in the switch state shown in FIG. 4 is referred to as the "series neutral point mode".

[0039] Next, with reference to FIGS. 5(a) to 5(b), a case where either one of the battery interconnection switch 40 and the negative electrode bypass switch 50 is stuck on will be described. "Stuck on" is one of the failure modes of the switch, and is a failure mode in which the contact of the switch is fixed in a connected state (on state). For example, in the case of a mechanical relay in which the switch has contacts, the contacts may be welded when an arc occurs due to the opening and closing of the contacts or when a current exceeding the rated value flows through the contacts. In this case, the switch is fixed in the on state regardless of the control of the control device 100.

[0040] In Fig. 5(a), the system is not connected to an external charger, and each switch is in the off state. However, the battery-to-battery switch 40 is stuck on and does not turn off even when receiving an off command from the control device 100. In this state, for example, when a low-voltage charger 200 is connected, the negative electrode bypass switch 50 is turned on as described in Fig. 2. At this time, since the battery-to-battery switch 40 is stuck on, a short-circuit current flows through the closed circuit including the battery-to-battery switch 40, the negative electrode bypass switch 50, and the second storage battery 32 as shown in Fig. 5(b).

[0041] In Figs. 5(a) to 5(b), an example where the battery-to-battery switch 40 is stuck on has been described. However, the same applies when the negative electrode bypass switch 50 is stuck on instead of the battery-to-battery switch 40. That is, when the negative electrode bypass switch 50 is stuck on and, for example, a high-voltage charger 210 is connected, the battery-to-battery switch 40 is turned on as described in Figs. 3 and 4. As a result, a short-circuit current flows through the closed circuit including the battery-to-battery switch 40, the negative electrode bypass switch 50, and the second storage battery 32. Therefore, in any of the parallel mode, series mode, and series neutral point mode, when charging is performed, since either the battery-to-battery switch 40 or the negative electrode bypass switch 50 is turned on, it is required to determine whether the battery-to-battery switch 40 and the negative electrode bypass switch 50 are stuck on before starting charging or after charging is completed.

[0042] Next, an example of the on-sticking determination method will be described with reference to FIGS. 6 to 8. Here, a method for determining on-sticking using the voltage of the smoothing capacitor 21 will be described. Hereinafter, the voltage of the smoothing capacitor 21 detected by the SC voltage sensor 19 will be referred to as voltage Vinv. The on / off states of the respective switches in FIGS. 6 to 8 indicate the on / off states at the time of starting the power conversion device, that is, before starting charging. As shown in FIG. 6, when the power conversion device is started, the high-potential side main switch SMRH and the low-potential side main switch SMRL are turned on. Note that the precharge switch SP may be turned on instead of the low-potential side main switch SMRL. That is, the "low-potential side switch provided between the lower arm switch and the negative terminal of the second power storage unit in the low-potential side electrical path" includes the low-potential side main switch SMRL and the precharge switch SP.

[0043] The inter-battery switch 40, the negative terminal bypass switch 50, the motor side switch 60, and the connection switch 80 are in the off state. Since the inter-battery switch 40 and the negative terminal bypass switch 50 are in the off state, no current flows through the smoothing capacitor 21, and thus the voltage Vinv of the smoothing capacitor 21 is 0V. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V when the main switches SMRH and SMRL are turned on at the time of starting the power conversion device, it determines that the inter-battery switch 40 and the negative terminal bypass switch 50 are not on-stuck.

[0044] Similar to FIG. 6, when the power conversion device is started, main switches SMRH and SMRL are turned on. The difference between FIG. 7 and FIG. 6 is that the inter-battery switch 40 is stuck on. In this case, the first storage battery 31 and the second storage battery 32 are in a series connection state. As a result, current flows through a closed circuit including the second storage battery 32, the inter-battery switch 40, the first storage battery 31, the high-potential-side electrical path 22H, the smoothing capacitor 21, and the low-potential-side electrical path 22L, and the voltage Vinv of the smoothing capacitor 21 becomes 600V, which is the sum of the voltage of the first storage battery 31 and the voltage of the second storage battery 32. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 when the main switches SMRH and SMRL are turned on at the start of the power conversion device is equal to the sum of the voltage of the first storage battery 31 and the voltage of the second storage battery 32, the control device 100 determines that the inter-battery switch 40 is stuck on.

[0045] Similar to FIG. 6, when the power conversion device is started, main switches SMRH and SMRL are turned on. The difference between FIG. 8 and FIG. 6 is that the negative electrode bypass switch 50 is stuck on. In this case, current flows through a closed circuit including the negative electrode bypass switch 50, the first storage battery 31, the high-potential-side electrical path 22H, the smoothing capacitor 21, and the low-potential-side electrical path 22L, and the voltage Vinv of the smoothing capacitor 21 becomes 400V, which is the same as that of the first storage battery 31. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 when the main switches SMRH and SMRL are turned on at the start of the power conversion device is equal to the voltage of the first storage battery 31, the control device 100 determines that the negative electrode bypass switch 50 is stuck on.

[0046] Next, an operation example of the control device 100 will be described with reference to the flowchart of FIG. 9. The initial state of each switch at the start point of the flowchart is a state in which an off command from the control device 100 is received. In step S101, the control device 100 selects a charging mode. This may be done, for example, by selecting a mode according to the type of the connected external charger.

[0047] In step S102, the control device 100 turns on the main switches SMRH and SMRL, and acquires the voltage Vinv of the smoothing capacitor 21 detected by the SC voltage sensor 19. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, when the process of step S103 is YES, the process proceeds to step S104. In step S104, the control device 100 determines that the battery interconnection switch 40 and the negative electrode bypass switch 50 are not stuck on. The process proceeds to step S105, and the control device 100 switches the on / off states of the respective switches based on the charging mode. Thereby, charging is started.

[0048] On the other hand, when the process of step S103 is NO, the process proceeds to step S106. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the total value (600V) of the voltage of the first storage battery 31 and the voltage of the second storage battery 32, that is, when the process of step S106 is YES, the process proceeds to step S107. In step S107, the control device 100 determines that the battery interconnection switch 40 is stuck on. The process proceeds to step S108, and the control device 100 stops charging.

[0049] When the process of step S106 is NO, the process proceeds to step S109. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage of the first storage battery 31 (400V), that is, when the process of step S109 is YES, the process proceeds to step S110. In step S110, the control device 100 determines that the negative electrode bypass switch 50 is stuck on. Thereafter, the process proceeds to step S108. When the process of step S109 is NO, since an unexpected phenomenon may have occurred, the process proceeds to step S108.

[0050] According to the first embodiment described in detail above, the following effects can be obtained.

[0051] Before turning on either one of the inter-battery switch 40 and the negative electrode bypass switch 50, the control device 100 determines whether the other switch is stuck on. When it is determined that one of the switches is stuck on, since the other switch will not be turned on, as described with reference to FIG. 5, a short-circuit current flowing through the closed circuit including the inter-battery switch 40, the negative electrode bypass switch 50, and the secondary battery 32 is suppressed.

[0052] When starting up the power conversion device, that is, before starting charging, the control device 100 turns on the main switches SMRH and SMRL, and determines whether the inter-battery switch 40 or the negative electrode bypass switch 50 is stuck on based on the voltage Vinv of the smoothing capacitor 21 at that time. According to this configuration, it is possible to determine whether the inter-battery switch 40 or the negative electrode bypass switch 50 is stuck on without actually turning on or off the inter-battery switch 40 or the negative electrode bypass switch 50.

[0053] When the inter-battery switch 40 or the negative electrode bypass switch 50 is stuck on, the voltage of the smoothing capacitor 21 changes. Therefore, by paying attention to the voltage of the smoothing capacitor 21, it is possible to determine which one of the inter-battery switch 40 and the negative electrode bypass switch 50 is stuck on.

[0054] <Modification of the First Embodiment> · The on-sticking determination described with reference to FIGS. 6 to 8 may be performed not at the start-up of the power conversion device but at the end of the power conversion device. At the end of the power conversion device, that is, after the charging is completed, each switch is controlled to be in the off state, so the on-sticking can be determined in the same way as at the start-up. However, at the end of the power conversion device, charges are accumulated in the smoothing capacitor 21 due to the charging. Therefore, in order to determine the on-sticking at the end of the power conversion device, it is necessary to discharge the smoothing capacitor 21 to make the voltage of the smoothing capacitor 21 0V. As a method of discharging the smoothing capacitor 21, for example, a method of flowing a d-axis current through the inverter 20 and the motor 10 to discharge it can be mentioned. Note that since the voltage of the smoothing capacitor 21 is 0V at the start-up of the power conversion device, such a discharging process is unnecessary.

[0055] <Second Embodiment> Hereinafter, the second embodiment will be described with reference to FIGS. 10 to 13. The second embodiment is different from the first embodiment in the switch to be controlled at the start-up of the power conversion device. For the configurations overlapping with the first embodiment, the reference numerals are cited and the description thereof is omitted. Hereinafter, the description will focus on the differences.

[0056] FIG. 10 shows the on / off states of the respective switches at the start-up of the power conversion device. As shown in FIG. 10, at the start-up of the power conversion device, the high-potential-side main switch SMRH, the motor-side switch 60, and the connection switch 80 are turned on. The battery-interconnection switch 40, the negative-pole bypass switch 50, and the low-potential-side main switch SMRL are in the off state. Since the battery-interconnection switch 40 and the negative-pole bypass switch 50 are in the off state, no current flows through the smoothing capacitor 21, and thus the voltage Vinv of the smoothing capacitor 21 is 0V. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V when the high-potential-side main switch SMRH, the motor-side switch 60, and the connection switch 80 are turned on at the start-up of the power conversion device, it determines that the battery-interconnection switch 40 and the negative-pole bypass switch 50 are not on-stuck.

[0057] Similar to FIG. 10, when the power conversion device is started, the high-potential side main switch SMRH, the motor side switch 60, and the connection switch 80 are turned on. The difference between FIG. 11 and FIG. 10 is that the inter-battery switch 40 is stuck on. In this case, current flows through a closed circuit including the inter-battery switch 40, the first storage battery 31, the high-potential side electrical path 22H, the smoothing capacitor 21, the inverter 20, the neutral point of the motor 10, the connection switch 80, and the motor side switch 60, and the voltage Vinv of the smoothing capacitor 21 becomes 400V, the same as that of the first storage battery 31. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 when the high-potential side main switch SMRH, the motor side switch 60, and the connection switch 80 are turned on during the startup of the power conversion device is equal to the voltage of the first storage battery 31, it determines that the inter-battery switch 40 is stuck on.

[0058] Similar to FIG. 10, when the power conversion device is started, the high-potential side main switch SMRH, the motor side switch 60, and the connection switch 80 are turned on. The difference between FIG. 12 and FIG. 10 is that the negative electrode bypass switch 50 is stuck on. In this case, the first storage battery 31 and the second storage battery 32 are connected in parallel. As a result, current flows through a closed circuit including the second storage battery 32, the negative electrode bypass switch 50, the first storage battery 31, the high-potential side electrical path 22H, the smoothing capacitor 21, the inverter 20, the neutral point of the motor 10, the connection switch 80, and the motor side switch 60, and the voltage Vinv of the smoothing capacitor 21 becomes equal to the voltage difference (200V) between the voltage of the first storage battery 31 and the voltage of the second storage battery 32. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 when the high-potential side main switch SMRH, the motor side switch 60, and the connection switch 80 are turned on during the startup of the power conversion device is equal to the voltage difference between the voltage of the first storage battery 31 and the voltage of the second storage battery 32, it determines that the negative electrode bypass switch 50 is stuck on.

[0059] Next, with reference to the flowchart of FIG. 13, an operation example of the control device 100 will be described. The initial state of each switch at the start of the flowchart is a state in which an OFF command from the control device 100 is received. In step S201, the control device 100 selects a charging mode.

[0060] In step S202, the control device 100 turns on the high-potential side main switch SMRH, the motor side switch 60, and the connection switch 80 to obtain the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, when the process of step S203 is YES, the process proceeds to step S204. In step S204, the control device 100 determines that the battery-to-battery switch 40 and the negative electrode bypass switch 50 are not stuck on. The process proceeds to step S205, and the control device 100 switches the ON / OFF state of each switch based on the charging mode. Thereby, charging is started.

[0061] On the other hand, when the process of step S203 is NO, the process proceeds to step S206. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage (400V) of the first storage battery 31, that is, when the process of step S206 is YES, the process proceeds to step S207. In step S207, the control device 100 determines that the battery-to-battery switch 40 is stuck on. The process proceeds to step S208, and the control device 100 stops charging.

[0062] If the process in step S206 is NO, the process proceeds to step S209. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage difference (200V) between the voltage of the first storage battery 31 and the voltage of the second storage battery 32, that is, when the process in step S209 is YES, the process proceeds to step S210. In step S210, the control device 100 determines that the negative electrode bypass switch 50 is stuck on. Thereafter, the process proceeds to step S208. If the process in step S209 is NO, since an unexpected phenomenon may have occurred, the process proceeds to step S208.

[0063] According to the second embodiment described in detail above, the following effects can be obtained.

[0064] When starting the power conversion device, that is, before starting charging, the control device 100 turns on the high-potential side main switch SMRH, the motor side switch 60, and the connection switch 80, and determines whether the battery-to-battery switch 40 or the negative electrode bypass switch 50 is stuck on based on the voltage Vinv of the smoothing capacitor 21 at that time. According to this configuration, it is possible to determine whether the battery-to-battery switch 40 or the bypass switch is stuck on without actually turning on or off the battery-to-battery switch 40 or the negative electrode bypass switch 50.

[0065] When the battery-to-battery switch 40 or the negative electrode bypass switch 50 is stuck on, the voltage of the smoothing capacitor 21 changes. Therefore, by paying attention to the voltage of the smoothing capacitor 21, it is possible to determine which of the battery-to-battery switch 40 and the negative electrode bypass switch 50 is stuck on.

[0066] <Modification example of the second embodiment> · The on-sticking determination described with reference to FIGS. 10 to 12 may be performed not at the start-up of the power conversion device but at the end of the power conversion device. At the end of the power conversion device, that is, after charging is completed, each switch is controlled to be in the off state, so the on-sticking can be determined in the same way as at the start-up. However, at the end of the power conversion device, charges are accumulated in the smoothing capacitor 21 due to charging. Therefore, in order to determine on-sticking at the end of the power conversion device, it is necessary to discharge the smoothing capacitor 21 to make the voltage of the smoothing capacitor 21 0V. The method of discharging the smoothing capacitor 21 is the same as that in the modification of the first embodiment.

[0067] <Third Embodiment> Hereinafter, the third embodiment will be described with reference to FIG. 14. For the configuration overlapping with the first embodiment, the reference signs are cited and the description thereof is omitted. Hereinafter, the description will focus on the differences. FIG. 14 is a configuration diagram of the power conversion device in the third embodiment. As shown in FIG. 14, the power conversion device includes at least one of a battery-interconnecting switch voltage sensor 76 that detects the voltage across the battery-interconnecting switch 40, a bypass switch voltage sensor 77 that detects the voltage across the negative-pole bypass switch 50, a terminal voltage sensor 78 that detects the terminal voltage which is the voltage between the positive terminal of the first storage battery 31 and the positive terminal of the second storage battery 32, and a PN junction voltage sensor 79 that detects the PN junction voltage which is the voltage between the high-potential-side electrical path 22H and the low-potential-side electrical path 22L.

[0068] The control device 100 determines the on-sticking of the battery-interconnecting switch 40 and the negative-pole bypass switch 50 based on any one of the voltages across detected by the battery-interconnecting switch voltage sensor 76, the voltages across detected by the bypass switch voltage sensor 77, the terminal voltage detected by the terminal voltage sensor 78, and the PN junction voltage detected by the PN junction voltage sensor 79.

[0069] First, a determination method using the voltage across the battery switch 40 will be described with reference to the flowchart of FIG. 15. In step S301, the control device 100 determines whether the voltage VB across the battery switch 40 detected by the battery switch voltage sensor 76 is 600V, which is the sum of the voltages of the first storage battery 31 and the second storage battery 32. In the present embodiment, when the battery switch 40 and the negative electrode bypass switch 50 are not stuck on and are in the off state, the voltage VB across the battery switch 40 is 600V, which is the sum of the voltages of the first storage battery 31 and the second storage battery 32. Therefore, if the process in step S301 is YES, the process proceeds to step S302, and the control device 100 determines that the battery switch 40 and the negative electrode bypass switch 50 are not stuck on.

[0070] On the other hand, if the process in step S301 is NO, the process proceeds to step S303. In step S303, the control device 100 determines whether the voltage VB across the battery switch 40 is 0V. In the present embodiment, when the battery switch 40 is stuck on, the voltage VB across the battery switch 40 is 0V. Therefore, if the process in step S303 is YES, the process proceeds to step S304, and the control device 100 determines that the battery switch 40 is stuck on.

[0071] If the process in step S303 is NO, the process proceeds to step S305. In step S305, the control device 100 determines whether the voltage VB across the battery switch 40 is equal to the voltage of the second storage battery 32 (200V). In the present embodiment, when the negative electrode bypass switch 50 is stuck on, the voltage VB across the battery switch 40 is equal to the voltage of the second storage battery 32. Therefore, if the process in step S305 is YES, the process proceeds to step S306, and the control device 100 determines that the negative electrode bypass switch 50 is stuck on.

[0072] After steps S304 and S306, the process proceeds to step S307, and the control device 100 stops charging. Note that even if the process of step S305 is NO, the process also proceeds to step S307.

[0073] Next, a determination method using the voltage across both ends of the negative electrode bypass switch 50 will be described with reference to the flowchart of FIG. 16. In step S401, the control device 100 determines whether the voltage VP across both ends of the negative electrode bypass switch 50 detected by the bypass switch voltage sensor 77 is equal to the voltage (400V) of the first storage battery 31. In the present embodiment, when the inter-battery switch 40 and the negative electrode bypass switch 50 are not stuck on and are in the off state, the voltage VP across both ends of the negative electrode bypass switch 50 is equal to the voltage of the first storage battery 31. Therefore, when the process of step S401 is YES, the process proceeds to step S402, and the control device 100 determines that the inter-battery switch 40 and the negative electrode bypass switch 50 are not stuck on.

[0074] On the other hand, when the process of step S401 is NO, the process proceeds to step S403. In step S403, the control device 100 determines whether the voltage VP across both ends of the negative electrode bypass switch 50 is equal to the voltage (200V) of the second storage battery 32. In the present embodiment, when the inter-battery switch 40 is stuck on, the voltage VP across both ends of the negative electrode bypass switch 50 is equal to the voltage of the second storage battery 32. Therefore, when the process of step S403 is YES, the process proceeds to step S404, and the control device 100 determines that the inter-battery switch 40 is stuck on.

[0075] If the process in step S403 is NO, the process proceeds to step S405. In step S405, the control device 100 determines whether the voltage VP across both ends of the negative electrode bypass switch 50 is 0V. In the present embodiment, when the negative electrode bypass switch 50 is stuck in the ON state, the voltage VP across both ends of the negative electrode bypass switch 50 becomes 0V. Therefore, if the process in step S405 is YES, the process proceeds to step S406, and the control device 100 determines that the negative electrode bypass switch 50 is stuck in the ON state.

[0076] After steps S404 and S406, the process proceeds to step S407, and the control device 100 stops charging. Note that even if the process in step S405 is NO, the process also proceeds to step S407.

[0077] Next, a determination method using the inter-terminal voltage will be described with reference to the flowchart of FIG. 17. In step S501, the control device 100 determines whether the inter-terminal voltage VT detected by the inter-terminal voltage sensor 78 is equal to the voltage of the secondary battery 32. In the present embodiment, when the inter-battery switch 40 and the negative electrode bypass switch 50 are not stuck in the ON state and are in the OFF state, the inter-terminal voltage VT becomes equal to the voltage of the secondary battery 32. Therefore, if the process in step S501 is YES, the process proceeds to step S502, and the control device 100 determines that the inter-battery switch 40 and the negative electrode bypass switch 50 are not stuck in the ON state.

[0078] On the other hand, if the process in step S501 is NO, the process proceeds to step S503. In step S503, the control device 100 determines whether the inter-terminal voltage VT is equal to the voltage of the primary battery 31. In the present embodiment, when the inter-battery switch 40 is stuck in the ON state, the inter-terminal voltage VT becomes equal to the voltage of the primary battery 31. Therefore, if the process in step S503 is YES, the process proceeds to step S504, and the control device 100 determines that the inter-battery switch 40 is stuck in the ON state.

[0079] If the process in step S503 is NO, the process proceeds to step S505. In step S505, the control device 100 determines whether the inter-terminal voltage VT is equal to the voltage difference between the voltage of the first battery 31 and the voltage of the second battery 32. In the present embodiment, when the negative electrode bypass switch 50 is stuck on, the inter-terminal voltage VT becomes equal to the voltage difference between the voltage of the first battery 31 and the voltage of the second battery 32. Therefore, if the process in step S505 is YES, the process proceeds to step S506, and the control device 100 determines that the negative electrode bypass switch 50 is stuck on.

[0080] After steps S504 and S506, the process proceeds to step S507, and the control device 100 stops charging. Note that even if the process in step S505 is NO, the process also proceeds to step S507.

[0081] Next, a determination method using the PN junction voltage will be described with reference to the flowchart of FIG. 18. In step S601, the control device 100 determines whether the PN junction voltage VPN detected by the PN junction voltage sensor 79 is 0V. In the present embodiment, when the inter-battery switch 40 and the negative electrode bypass switch 50 are not stuck on and are in the off state, the PN junction voltage VPN becomes 0V. Therefore, if the process in step S601 is YES, the process proceeds to step S602, and the control device 100 determines that the inter-battery switch 40 and the negative electrode bypass switch 50 are not stuck on.

[0082] On the other hand, if the process in step S601 is NO, the process proceeds to step S603. In step S603, the control device 100 determines whether the PN junction voltage VPN is 600V, which is the sum of the voltage of the first battery 31 and the voltage of the second battery 32. In the present embodiment, when the inter-battery switch 40 is stuck on, the PN junction voltage VPN becomes 600V, which is the sum of the voltage of the first battery 31 and the voltage of the second battery 32. Therefore, if the process in step S603 is YES, the process proceeds to step S604, and the control device 100 determines that the inter-battery switch 40 is stuck on.

[0083] If the process in step S603 is NO, the process proceeds to step S605. In step S605, the control device 100 determines whether the voltage VPN between P and N is equal to the voltage of the first battery 31 (400V). In the present embodiment, when the bypass switch 50 between the negative electrodes is stuck on, the voltage VPN between P and N becomes equal to the voltage of the first battery 31. Therefore, if the process in step S605 is YES, the process proceeds to step S606, and the control device 100 determines that the bypass switch 50 between the negative electrodes is stuck on.

[0084] After steps S604 and S606, the process proceeds to step S607, and the control device 100 stops charging. Note that even if the process in step S605 is NO, the process also proceeds to step S607.

[0085] According to the third embodiment described in detail above, the following effects can be obtained.

[0086] When starting the power conversion device, that is, before starting charging, the control device 100 determines whether the battery - to - battery switch 40 or the bypass switch 50 between the negative electrodes is stuck on using any of the voltages detected by the voltage sensors 76 to 79. According to this configuration, it is possible to determine whether the battery - to - battery switch 40 or the bypass switch 50 between the negative electrodes is stuck on without actually turning on or off the battery - to - battery switch 40 or the bypass switch 50 between the negative electrodes.

[0087] When the battery - to - battery switch 40 or the bypass switch 50 between the negative electrodes is stuck on, the voltages detected by the voltage sensors 76 to 79 change. Therefore, by paying attention to any of the voltages detected by the voltage sensors 76 to 79, it is possible to determine which of the battery - to - battery switch 40 and the bypass switch 50 between the negative electrodes is stuck on.

[0088] <Modification Example of the Third Embodiment> ·The on-sticking determination described with reference to FIGS. 15 to 18 may be performed not at the start-up of the power conversion device but at the end of the power conversion device. At the end of the power conversion device, that is, after the charging is completed, each switch is controlled to be in the off state, so the on-sticking can be determined in the same way as at the start-up.

[0089] <Fourth Embodiment> Hereinafter, the fourth embodiment will be described. In the previous embodiment, it was explained that the on-sticking of the inter-battery switch 40 and the negative electrode bypass switch 50 is determined, and charging is started when it is determined that the inter-battery switch 40 and the negative electrode bypass switch 50 are not on-stuck. After it is determined that the inter-battery switch 40 and the negative electrode bypass switch 50 are not on-stuck, it may be determined whether any other switches are faulty before starting the charging. Hereinafter, an example of the determination method will be described for each of the series mode, the parallel mode, and the series neutral point mode.

[0090] FIG. 19 is a flowchart in the series mode. This flowchart is the flow after it is determined that the inter-battery switch 40 and the negative electrode bypass switch 50 are not on-stuck.

[0091] In step S701, the control device 100 turns on the inter-battery switch 40. In the subsequent step S702, the control device 100 turns on the pre-charge switch SP and acquires the voltage Vinv of the smoothing capacitor 21. If the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, if the process in step S703 is YES, the process proceeds to step S704.

[0092] In step S704, the control device 100 turns on the high-potential side main switch SMRH and acquires the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 600V, which is the sum of the voltages of the first battery 31 and the second battery 32, that is, when the process of step S706 is YES, the process proceeds to step S708. In step S708, the control device 100 turns on the low-potential side main switch SMRL. In the subsequent step S709, the control device 100 turns off the precharge switch SP. In the subsequent step S710, the control device 100 starts charging.

[0093] If the process of step S703 is NO, the process proceeds to step S705, and the control device 100 determines that the high-potential side main switch SMRH is stuck on. The process proceeds to step S711, and the control device 100 aborts charging.

[0094] If the process of step S706 is NO, the process proceeds to step S707, and the control device 100 determines that the high-potential side main switch SMRH is stuck off. "Stuck off" is a failure mode in which the contacts of the switch are fixed in a non-connected state. The process proceeds to step S711, and the control device 100 aborts charging. The fact that the process of step S706 is NO means that although the control device 100 output an on command to the high-potential side main switch SMRH in step S704, the high-potential side main switch SMRH did not turn on due to being stuck off.

[0095] Figure 20 is a flowchart in the parallel mode. This flowchart is the flow after it is determined that the inter-battery switch 40 and the negative electrode bypass switch 50 are not stuck on.

[0096] In step S801, the control device 100 turns on the negative electrode bypass switch 50. In the subsequent step S802, the control device 100 turns on the precharge switch SP and acquires the voltage Vinv of the smoothing capacitor 21 and the voltage Vcb of the neutral point capacitor 90 detected by the NC voltage sensor 75. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, when the process of step S803 is YES, the process proceeds to step S804.

[0097] When the control device 100 determines that the voltage Vcb of the neutral point capacitor 90 is equal to 0V, that is, when the process of step S804 is YES, the process proceeds to step S807. In step S807, the control device 100 turns on the high-potential side main switch SMRH and acquires the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage of the first battery 31 (400V), that is, when the process of step S808 is YES, the process proceeds to step S809. In step S809, the control device 100 turns on the motor side switch 60 and acquires the voltage Vcb of the neutral point capacitor 90.

[0098] When the control device 100 determines that the voltage Vcb of the neutral point capacitor 90 is equal to the voltage of the second battery 32 (200V), that is, when the process of step S811 is YES, the process proceeds to step S812. In step S812, the control device 100 turns on the low-potential side main switch SMRL. In the subsequent step S814, the control device 100 turns off the precharge switch SP.

[0099] In the subsequent step S815, the control device 100 determines whether the voltage Vinv of the smoothing capacitor 21 is greater than the voltage Vcb of the neutral point capacitor 90. The reason for making such a determination in step S815 is that when the voltage Vcb of the neutral point capacitor 90 is greater than the voltage Vinv of the smoothing capacitor 21, there is a possibility that current may flow from the neutral point capacitor 90 to the battery side via the upper arm diode DH. If the process of step S815 is YES, the process proceeds to step S816. If the process of step S815 is NO, the process proceeds to step S818 to determine whether the phenomenon that the voltage Vcb of the neutral point capacitor 90 is greater than the voltage Vinv of the smoothing capacitor 21 occurs more than a predetermined number of times. If it is determined that the phenomenon that the voltage Vcb of the neutral point capacitor 90 is greater than the voltage Vinv of the smoothing capacitor 21 occurs more than a predetermined number of times, that is, if the process of step S818 is YES, the process proceeds to step S819 and the control device 100 stops charging.

[0100] In step S816, the control device 100 turns on the connection switch 80. In the subsequent step S817, the control device 100 starts charging.

[0101] If the process of step S803 is NO, the process proceeds to step S805 and the control device 100 determines that the high-potential side main switch SMRH is stuck on. If the process of step S804 is NO, the process proceeds to step S806 and the control device 100 determines that the motor side switch 60 is stuck on. If the process of step S808 is NO, the process proceeds to step S810 and the control device 100 determines that the high-potential side main switch SMRH is stuck off. If the process of step S811 is NO, the process proceeds to step S813 and the control device 100 determines that the motor side switch 60 is stuck off. After steps S805, S806, S810, and S813, the process proceeds to step S819 and the control device 100 stops charging.

[0102] The fact that the process in step S808 is NO means that although the control device 100 output an on command to the high-potential side main switch SMRH in step S807, the high-potential side main switch SMRH did not turn on due to sticking off. Also, the fact that the process in step S811 is NO means that although the control device 100 output an on command to the motor side switch 60 in step S809, the motor side switch 60 did not turn on due to sticking off.

[0103] In addition, in the flow of FIG. 20, the motor side switch 60 may be turned on before the high-potential side main switch SMRH. The flow in this case will be described with reference to FIG. 21. However, the processes in steps S901, S902, S903, S904, S905, S906, S914, S916, S917, S918, S919, S920, and S921 in FIG. 21 are the same as the processes in steps S801, S802, S803, S804, S805, S806, S812, S814, S815, S816, S817, S818, and S819 in FIG. 20, so the description thereof will be omitted.

[0104] In step S907, the control device 100 turns on the motor side switch 60 and acquires the voltages Vinv of the neutral point capacitor 90 and the smoothing capacitor 21. When the control device 100 determines that the voltage Vcb of the neutral point capacitor 90 is equal to the voltage (200V) of the second storage battery 32, that is, when the process in step S908 is YES, the process proceeds to step S909.

[0105] When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, when the process in step S909 is YES, the process proceeds to step S911. In step S911, the control device 100 turns on the high-potential side main switch SMRH and acquires the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage (400V) of the first storage battery 31, that is, when the process in step S913 is YES, the process proceeds to step S914.

[0106] If the process of step S908 is NO, the process proceeds to step S910, and the control device 100 determines that the motor-side switch 60 is stuck off. If the process of step S909 is NO, the process proceeds to step S912, and the control device 100 determines that the connection switch 80 is stuck on. If the process of step S913 is NO, the process proceeds to step S915, and the control device 100 determines that the high-potential-side main switch SMRH is stuck off.

[0107] The fact that the process of step S908 is NO means that although the control device 100 output an on command to the motor-side switch 60 in step S907, the motor-side switch 60 did not turn on due to being stuck off. Also, the fact that the process of step S913 is NO means that although the control device 100 output an on command to the high-potential-side main switch SMRH in step S911, the high-potential-side main switch SMRH did not turn on due to being stuck off.

[0108] FIG. 22 is a flowchart in the series neutral point mode. This flowchart is the flow after it is determined that the battery-interconnection switch 40 and the negative-pole-interconnection bypass switch 50 are not stuck on.

[0109] In step S1001, the control device 100 turns on the battery-interconnection switch 40. In the subsequent step S1002, the control device 100 turns on the precharge switch SP and acquires the voltage of the smoothing capacitor 21 and the voltage Vcb of the neutral point capacitor 90. If the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, if the process of step S1003 is YES, the process proceeds to step S1004.

[0110] When the control device 100 determines that the voltage Vcb of the neutral point capacitor 90 is equal to 0V, that is, when the process in step S1004 is YES, the process proceeds to step S1007. In step S1007, the control device 100 turns on the high-potential side main switch SMRH and acquires the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 600V, which is the sum of the voltages of the first battery 31 and the second battery 32, that is, when the process in step S1008 is YES, the process proceeds to step S1009. In step S1009, the control device 100 turns on the motor side switch 60 and acquires the voltage Vcb of the neutral point capacitor 90.

[0111] When the control device 100 determines that the voltage Vcb of the neutral point capacitor 90 is equal to the voltage of the second battery 32 (200V), that is, when the process in step S1011 is YES, the process proceeds to step S1012. In step S1012, the control device 100 turns on the low-potential side main switch SMRL. In the subsequent step S1014, the control device 100 turns off the precharge switch SP.

[0112] In the subsequent step S1015, the control device 100 determines whether the voltage Vinv of the smoothing capacitor 21 is greater than the voltage Vcb of the neutral point capacitor 90. If the process in step S1015 is YES, the process proceeds to step S1016. If the process in step S1015 is NO, the process proceeds to step S1018 to determine whether the phenomenon that the voltage Vcb of the neutral point capacitor 90 is greater than the voltage Vinv of the smoothing capacitor 21 occurs more than a predetermined number of times. If it is determined that the phenomenon that the voltage Vcb of the neutral point capacitor 90 is greater than the voltage Vinv of the smoothing capacitor 21 occurs more than a predetermined number of times, that is, when the process in step S1018 is YES, the process proceeds to step S1019 and the control device 100 stops charging.

[0113] In step S1016, the control device 100 turns on the connection switch 80. In the subsequent step S1017, the control device 100 starts charging.

[0114] If the process of step S1003 is NO, the process proceeds to step S1005, and the control device 100 determines that the high-potential side main switch SMRH is stuck on. If the process of step S1004 is NO, the process proceeds to step S1006, and the control device 100 determines that the motor side switch 60 is stuck on. If the process of step S1008 is NO, the process proceeds to step S1010, and the control device 100 determines that the high-potential side main switch SMRH is stuck off. If the process of step S1011 is NO, the process proceeds to step S1013, and the control device 100 determines that the motor side switch 60 is stuck off. After steps S1005, S1006, S1010, and S1013, the process proceeds to step S1019, and the control device 100 stops charging.

[0115] The fact that the process of step S1008 is NO means that although the control device 100 output an on command to the high-potential side main switch SMRH in step S1007, the high-potential side main switch SMRH did not turn on due to being stuck off. Also, the fact that the process of step S1011 is NO means that although the control device 100 output an on command to the motor side switch 60 in step S1009, the motor side switch 60 did not turn on due to being stuck off.

[0116] In the flow of FIG. 22, the motor-side switch 60 may be turned on before the high-potential-side main switch SMRH. The flow in this case will be described with reference to FIG. 23. However, the processes in steps S1101, S1102, S1103, S1104, S1105, S1106, S1114, S1116, S1117, S1118, S1119, S1120, and S1121 in FIG. 23 are the same as the processes in steps S1001, S1002, S1003, S1004, S1005, S1006, S1012, S1014, S1015, S1016, S1017, S1018, and S1019 in FIG. 22, so the description thereof will be omitted.

[0117] In step S1107, the control device 100 turns on the motor-side switch 60 and acquires the voltages Vinv of the neutral-point capacitor 90 and the smoothing capacitor 21. When the control device 100 determines that the voltage Vcb of the neutral-point capacitor 90 is equal to the voltage (200V) of the second storage battery 32, that is, when the process in step S1108 is YES, the process proceeds to step S1109.

[0118] When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, when the process in step S1109 is YES, the process proceeds to step S1111. In step S1111, the control device 100 turns on the high-potential-side main switch SMRH and acquires the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 600V, which is the sum of the voltages of the first storage battery 31 and the second storage battery 32, that is, when the process in step S1113 is YES, the process proceeds to step S1114.

[0119] If the process in step S1108 is NO, the process proceeds to step S1110, and the control device 100 determines that the motor side switch 60 is stuck off. If the process in step S1109 is NO, the process proceeds to step S1112, and the control device 100 determines that the connection switch 80 is stuck on. If the process in step S1113 is NO, the process proceeds to step S1115, and the control device 100 determines that the high-potential side main switch SMRH is stuck off.

[0120] The fact that the process in step S1108 is NO means that although the control device 100 output an on command to the motor side switch 60 in step S1107, the motor side switch 60 did not turn on due to being stuck off. Also, the fact that the process in step S1113 is NO means that although the control device 100 output an on command to the high-potential side main switch SMRH in step S1111, the high-potential side main switch SMRH did not turn on due to being stuck off.

[0121] The control device 100 terminates the power conversion device after charging is completed. At this time, the power conversion device may be terminated along the flow shown in FIG. 24. The flow shown in FIG. 24 starts after charging is completed. In step S1201, the control device 100 turns off each switch except the connection switch 80. In the subsequent step S1202, the control device 100 discharges the neutral point capacitor 90. As a method of discharging the neutral point capacitor 90, it may be boosted by the inverter 30 and the charge of the neutral point capacitor 90 may be transferred to the smoothing capacitor 21. After discharging the neutral point capacitor 90 until the voltage of the neutral point capacitor 90 becomes 0V, the process proceeds to step S1203, and the control device 100 turns off the connection switch 80.

[0122] In step S1204, the control device 100 causes the charge of the smoothing capacitor 21 to be transferred to the neutral point capacitor 90 via the inverter 20 and the motor 10. At this time, if the connection switch 80 is not stuck on, the charge of the smoothing capacitor 21 will not be transferred to the neutral point capacitor 90, and the voltage Vcb of the neutral point capacitor 90 is 0V. When the control device 100 determines that the voltage Vcb of the neutral point capacitor 90 is equal to 0V, that is, when the process of step S1205 is YES, the process proceeds to step S1206. In step S1206, the control device 100 discharges the smoothing capacitor 21 until the voltage of the smoothing capacitor 21 becomes 0V and terminates the power conversion device.

[0123] If the process of step S1205 is NO, the process proceeds to step S1207, and the control device 100 determines that the connection switch 80 is stuck on. The process proceeds to step S1208, and the control device 100 notifies the driver that an abnormality has occurred.

[0124] The fact that the process of step S1205 is NO means that although the control device 100 outputs an off command to the connection switch 80 in step S1203, the connection switch 80 does not turn off due to being stuck on.

[0125] <Fifth Embodiment> Hereinafter, the fifth embodiment will be described centering on the differences from the first embodiment with reference to the drawings. In this embodiment, as shown in FIG. 25, the power conversion device includes a positive electrode bypass switch 51 that connects the positive electrode terminal of the second battery 32 and the high-potential side electrical path 22H, while not including the negative electrode bypass switch 50 shown in FIG. 1 above. Further, the power conversion device includes a neutral point capacitor 91 and an NC voltage sensor 75A that detects the voltage of the neutral point capacitor 91 between the motor side electrical path 25 and the high-potential side electrical path 22H, while not including the neutral point capacitor 90 and the NC voltage sensor 75 shown in FIG. 1 above. Further, the motor side electrical path 25 connects the neutral point of the armature winding 11 and the portion of the inter-battery electrical path 24 on the side of the first battery 31 closer to the inter-battery switch 40. A motor side switch 61 is provided in the motor side electrical path 25. Further, the voltage of the first battery 31 is 200V, and the voltage of the second battery 32 is 400V.

[0126] An example of a method for determining the on-sticking of the inter-battery switch 40 and the positive electrode bypass switch 51 in the circuit configuration shown in FIG. 25 will be described with reference to the flowchart of FIG. 26. The initial state of each switch at the start point of the flowchart is a state in which it has received an off command from the control device 100. In step S1301, the control device 100 selects a charging mode.

[0127] In step S1302, the control device 100 turns on the main switches SMRH and SMRL to obtain the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, when the process of step S1303 is YES, the process proceeds to step S1304. In step S1304, the control device 100 determines that the inter-battery switch 40 and the positive electrode bypass switch 51 are not on-stuck. The process proceeds to step S1305, and the control device 100 switches the on / off state of each switch based on the charging mode. Thereby, charging is started.

[0128] On the other hand, when the process in step S1303 is NO, the process proceeds to step S1306. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the sum of the voltages of the first battery 31 and the second battery 32 (600V), that is, when the process in step S1306 is YES, the process proceeds to step S1307. In step S1307, the control device 100 determines that the inter-battery switch 40 is stuck on. The process proceeds to step S1308, and the control device 100 stops charging.

[0129] When the process in step S1306 is NO, the process proceeds to step S1309. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage of the second battery 32 (400V), that is, when the process in step S1309 is YES, the process proceeds to step S1310. In step S1310, the control device 100 determines that the positive-pole bypass switch 51 is stuck on. Then, the process proceeds to step S1308. When the process in step S1309 is NO, since an unexpected phenomenon may have occurred, the process proceeds to step S1308.

[0130] According to the fifth embodiment described in detail above, the following effects can be obtained.

[0131] When starting up the power conversion device, that is, before starting charging, the control device 100 turns on the main switches SMRH and SMRL, and determines whether the inter-battery switch 40 or the positive-pole bypass switch 51 is stuck on based on the voltage Vinv of the smoothing capacitor 21 at that time. According to this configuration, it is possible to determine whether the inter-battery switch 40 or the positive-pole bypass switch 51 is stuck on without actually turning on or off the inter-battery switch 40 or the positive-pole bypass switch 51.

[0132] <Modification Example 1 of the Fifth Embodiment> ·Regarding the ON-sticking of the battery-to-battery switch 40 and the positive-pole bypass switch 51, the determination may be made according to the flowchart shown in FIG. 27. Hereinafter, the flowchart will be described. The initial state of each switch at the start point of the flowchart is a state in which an OFF command from the control device 100 is received.

[0133] In step S1401, the control device 100 selects a charging mode. In step S1402, the control device 100 turns on the low-potential side main switch SMRL, the motor side switch 61, and the connection switch 80 to obtain the voltage Vinv of the smoothing capacitor 21. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to 0V, that is, when the process of step S1403 is YES, the process proceeds to step S1404. In step S1404, the control device 100 determines that the battery-to-battery switch 40 and the positive-pole bypass switch 51 are not ON-stuck. The process proceeds to step S1405, and the control device 100 switches the ON / OFF state of each switch based on the charging mode. Thereby, charging is started.

[0134] On the other hand, when the process of step S1403 is NO, the process proceeds to step S1406. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage of the secondary battery 32, that is, when the process of step S1406 is YES, the process proceeds to step S1407. In step S1407, the control device 100 determines that the battery-to-battery switch 40 is ON-stuck. The process proceeds to step S1408, and the control device 100 stops charging.

[0135] If the process in step S1406 is NO, the process proceeds to step S1409. When the control device 100 determines that the voltage Vinv of the smoothing capacitor 21 is equal to the voltage difference between the voltage of the second storage battery 32 and the voltage of the first storage battery 31, that is, if the process in step S1409 is YES, the process proceeds to step S1410. In step S1410, the control device 100 determines that the positive electrode bypass switch 51 is stuck on. Thereafter, the process proceeds to step S1408. If the process in step S1409 is NO, since an unexpected phenomenon may have occurred, the process proceeds to step S1408.

[0136] When the inter-battery switch 40 or the positive electrode bypass switch 51 is stuck on, the voltage of the smoothing capacitor 21 changes. Therefore, by paying attention to the voltage of the smoothing capacitor 21, it is possible to determine which of the inter-battery switch 40 and the positive electrode bypass switch 51 is stuck on.

[0137] · The stuck-on determination described with reference to FIGS. 26 to 27 may be performed not at the start of the power conversion device but at the end of the power conversion device. At the end of the power conversion device, that is, after charging is completed, since each switch is controlled to be in the OFF state, the stuck-on state can be determined in the same manner as at the start-up. However, at the end of the power conversion device, charges are accumulated in the smoothing capacitor 21 due to charging. Therefore, in order to determine the stuck-on state at the end of the power conversion device, it is necessary to discharge the smoothing capacitor 21 to set the voltage of the smoothing capacitor 21 to 0V. The method of discharging the smoothing capacitor 21 is the same as the modification example of the first embodiment.

[0138] <Sixth Embodiment> Next, the sixth embodiment will be described with reference to the drawings, focusing on the differences from the fifth embodiment. As shown in FIG. 28, the power conversion device includes at least one of a battery - to - battery switch voltage sensor 86 that detects the voltage across the battery - to - battery switch 40, a bypass switch voltage sensor 87 that detects the voltage across the positive - terminal bypass switch 51, a terminal - to - terminal voltage sensor 88 that detects the voltage between the negative - terminal of the first storage battery 31 and the negative - terminal of the second storage battery 32, and a PN - junction voltage sensor 89 that detects the voltage between the high - potential - side electrical path 22H and the low - potential - side electrical path 22L.

[0139] The control device 100 determines the stuck - on state of the battery - to - battery switch 40 or the positive - terminal bypass switch 51 based on any one of the voltages across the battery - to - battery switch 40 detected by the battery - to - battery switch voltage sensor 86, the voltage across the bypass switch detected by the bypass switch voltage sensor 87, the terminal - to - terminal voltage detected by the terminal - to - terminal voltage sensor 88, and the PN - junction voltage detected by the PN - junction voltage sensor 89.

[0140] First, a determination method using the voltage across the battery - to - battery switch 40 will be described with reference to the flowchart of FIG. 29. In step S1501, the control device 100 determines whether the voltage VB2 across the battery - to - battery switch 40 detected by the battery - to - battery switch voltage sensor 86 is 600V, which is the sum of the voltage of the first storage battery 31 and the voltage of the second storage battery 32. In this embodiment, when the battery - to - battery switch 40 and the positive - terminal bypass switch 51 are not stuck - on and are in the off state, the voltage VB2 across the battery - to - battery switch 40 is 600V, which is the sum of the voltage of the first storage battery 31 and the voltage of the second storage battery 32. Therefore, if the process in step S1501 is YES, the process proceeds to step S1502, and the control device 100 determines that the battery - to - battery switch 40 and the positive - terminal bypass switch 51 are not stuck - on.

[0141] On the other hand, if the process in step S1501 is NO, the process proceeds to step S1503. In step S1503, the control device 100 determines whether the voltage VB2 across the battery switch 40 is 0V. In this embodiment, when the battery switch 40 is stuck on, the voltage VB2 across the battery switch 40 becomes 0V. Therefore, if the process in step S1503 is YES, the process proceeds to step S1504, and the control device 100 determines that the battery switch 40 is stuck on.

[0142] If the process in step S1503 is NO, the process proceeds to step S1505. In step S1505, the control device 100 determines whether the voltage VB2 across the battery switch 40 is equal to the voltage of the first storage battery 31 (200V). In this embodiment, when the positive electrode bypass switch 51 is stuck on, the voltage VB2 across the battery switch 40 becomes equal to the voltage of the first storage battery 31. Therefore, if the process in step S1505 is YES, the process proceeds to step S1506, and the control device 100 determines that the positive electrode bypass switch 51 is stuck on.

[0143] After steps S1504 and S1506, the process proceeds to step S1507, and the control device 100 stops charging. Note that even if the process in step S1505 is NO, the process also proceeds to step S1507.

[0144] Next, a determination method using the voltage across the positive electrode bypass switch 51 will be described with reference to the flowchart of FIG. 30. In step S1601, the control device 100 determines whether the voltage VP2 across the positive electrode bypass switch 51 detected by the bypass switch voltage sensor 87 is equal to the voltage of the second battery 32 (400V). In the present embodiment, when the inter-battery switch 40 and the positive electrode bypass switch 51 are not stuck on and are in the off state, the voltage VP2 across the positive electrode bypass switch 51 is equal to the voltage of the second battery 32. Therefore, if the process in step S1601 is YES, the process proceeds to step S1602, and the control device 100 determines that the inter-battery switch 40 and the positive electrode bypass switch 51 are not stuck on.

[0145] On the other hand, if the process in step S1601 is NO, the process proceeds to step S1603. In step S1603, the control device 100 determines whether the voltage VP2 across the positive electrode bypass switch 51 is equal to the voltage of the first battery 31 (200V). In the present embodiment, when the inter-battery switch 40 is stuck on, the voltage VP2 across the positive electrode bypass switch 51 is equal to the voltage of the first battery 31. Therefore, if the process in step S1603 is YES, the process proceeds to step S1604, and the control device 100 determines that the inter-battery switch 40 is stuck on.

[0146] If the process in step S1603 is NO, the process proceeds to step S1605. In step S1605, the control device 100 determines whether the voltage VP2 across the positive electrode bypass switch 51 is 0V. In the present embodiment, when the positive electrode bypass switch 51 is stuck on, the voltage VP2 across the positive electrode bypass switch 51 becomes 0V. Therefore, if the process in step S1605 is YES, the process proceeds to step S1606, and the control device 100 determines that the positive electrode bypass switch 51 is stuck on.

[0147] After steps S1604 and S1606, the process proceeds to step S1607, and the control device 100 stops charging. Note that even if the process of step S1605 is NO, the process also proceeds to step S1607.

[0148] Next, a determination method using the inter-terminal voltage will be described with reference to the flowchart of FIG. 31. In step S1701, the control device 100 determines whether the inter-terminal voltage VT2 detected by the inter-terminal voltage sensor 88 is equal to the voltage of the first battery 31. In the present embodiment, when the inter-battery switch 40 and the positive-pole bypass switch 51 are not stuck on and are in the off state, the inter-terminal voltage VT2 is equal to the voltage of the first battery 31. Therefore, if the process of step S1701 is YES, the process proceeds to step S1702, and the control device 100 determines that the inter-battery switch 40 and the positive-pole bypass switch 51 are not stuck on.

[0149] On the other hand, if the process of step S1701 is NO, the process proceeds to step S1703. In step S1703, the control device 100 determines whether the inter-terminal voltage VT2 is equal to the voltage of the second battery 32. In the present embodiment, when the inter-battery switch 40 is stuck on, the inter-terminal voltage VT2 is equal to the voltage of the second battery 32. Therefore, if the process of step S1703 is YES, the process proceeds to step S1704, and the control device 100 determines that the inter-battery switch 40 is stuck on.

[0150] If the process of step S1703 is NO, the process proceeds to step S1705. In step S1705, the control device 100 determines whether the inter-terminal voltage VT2 is equal to the voltage difference between the voltage of the second battery 32 and the voltage of the first battery 31. In the present embodiment, when the positive-pole bypass switch 51 is stuck on, the inter-terminal voltage VT2 is equal to the voltage difference between the voltage of the first battery 31 and the voltage of the second battery 32. Therefore, if the process of step S1705 is YES, the process proceeds to step S1706, and the control device 100 determines that the positive-pole bypass switch 51 is stuck on.

[0151] After steps S1704 and S1706, the process proceeds to step S1707, and the control device 100 stops charging. Note that even if the process of step S1705 is NO, the process also proceeds to step S1707.

[0152] Next, a determination method using the PN junction voltage will be described with reference to the flowchart of FIG. 32. In step S1801, the control device 100 determines whether the PN junction voltage VPN2 detected by the PN junction voltage sensor 89 is 0V. In the present embodiment, when the battery-to-battery switch 40 and the positive terminal bypass switch 51 are not stuck on and are in the OFF state, the PN junction voltage VPN2 becomes 0V. Therefore, if the process of step S1801 is YES, the process proceeds to step S1802, and the control device 100 determines that the battery-to-battery switch 40 and the positive terminal bypass switch 51 are not stuck on.

[0153] On the other hand, if the process of step S1801 is NO, the process proceeds to step S1803. In step S1803, the control device 100 determines whether the PN junction voltage VPN2 is 600V, which is the sum of the voltage of the first storage battery 31 and the voltage of the second storage battery 32. In the present embodiment, when the battery-to-battery switch 40 is stuck on, the PN junction voltage VPN2 becomes 600V, which is the sum of the voltage of the first storage battery 31 and the voltage of the second storage battery 32. Therefore, if the process of step S1803 is YES, the process proceeds to step S1804, and the control device 100 determines that the battery-to-battery switch 40 is stuck on.

[0154] If the process in step S1803 is NO, the process proceeds to step S1805. In step S1805, the control device 100 determines whether the voltage VPN2 between P and N is equal to the voltage (400V) of the second battery 32. In the present embodiment, when the positive electrode bypass switch 51 is stuck on, the voltage VPN2 between P and N becomes equal to the voltage of the second battery 32. Therefore, if the process in step S1805 is YES, the process proceeds to step S1806, and the control device 100 determines that the positive electrode bypass switch 51 is stuck on.

[0155] After steps S1804 and S1806, the process proceeds to step S1807, and the control device 100 stops charging. Note that even if the process in step S1805 is NO, the process proceeds to step S1807.

[0156] According to the sixth embodiment described in detail above, the following effects can be obtained.

[0157] When starting the power conversion device, that is, before starting charging, the control device 100 determines whether the battery - to - battery switch 40 or the positive - electrode bypass switch 51 is stuck on using any of the voltages detected by the voltage sensors 86 to 89. According to this configuration, it is possible to determine whether the battery - to - battery switch 40 or the positive - electrode bypass switch 51 is stuck on without actually turning on or off the battery - to - battery switch 40 or the positive - electrode bypass switch 51.

[0158] When the battery - to - battery switch 40 or the positive - electrode bypass switch 51 is stuck on, the voltages detected by the voltage sensors 86 to 89 change. Therefore, by paying attention to any of the voltages detected by the voltage sensors 86 to 89, it is possible to determine which of the battery - to - battery switch 40 and the positive - electrode bypass switch 51 is stuck on.

[0159] <Modification Example of the Sixth Embodiment> ·The on-sticking determination described with reference to FIGS. 29 to 32 may be performed not at the start-up of the power conversion device but at the end of the power conversion device. At the end of the power conversion device, that is, after the charging is completed, since each switch is controlled to be in the off state, the on-sticking can be determined in the same manner as at the start-up.

[0160] <Seventh Embodiment> Hereinafter, the seventh embodiment will be described with reference to the drawings, centering on the differences from the first embodiment. In this embodiment, as shown in FIG. 33, the power conversion device further includes a positive bypass switch 51 that connects the positive terminal of the second storage battery 32 and the high-potential-side electrical path 22H.

[0161] The control device 100 can, for example, individually charge the second storage battery 32 by the low-voltage charger 200 with the positive bypass switch 51 turned on and the negative bypass switch 50, the battery-to-battery switch 40, the motor-side switch 60, the connection switch 80, the high-potential-side main switch SMRH, and the low-potential-side main switch SMRL turned off.

[0162] <Eighth Embodiment> Hereinafter, the eighth embodiment will be described with reference to the drawings, centering on the differences from the fifth embodiment. In this embodiment, as shown in FIG. 34, the power conversion device further includes a negative bypass switch 50 that connects the negative terminal of the first storage battery 31 and the low-potential-side electrical path 22L.

[0163] The control device 100 can, for example, individually charge the first storage battery 31 by the low-voltage charger 200 with the negative bypass switch 50 turned on and the positive bypass switch 51, the battery-to-battery switch 40, the motor-side switch 60, the connection switch 80, the high-potential-side main switch SMRH, and the low-potential-side main switch SMRL turned off.

[0164] <Ninth Embodiment> Hereinafter, the ninth embodiment will be described with reference to the drawings, focusing on the differences from the above embodiments. In this embodiment, as shown in FIG. 35, as the motor-side switch, in addition to the switch connecting the neutral point of the armature winding 11 and the negative terminal of the first storage battery 31, a switch connecting the neutral point of the armature winding 11 and the positive terminal of the second storage battery 32 is provided.

[0165] The first end of the common path 26 is connected to the neutral point of the armature winding 11. The first end of the first electrical path 27 is connected to the second end of the common path 26, and the second end of the first electrical path 27 is connected to the side of the second storage battery 32 rather than the battery-interconnect switch 40 in the battery-interconnect electrical path 24. Also, the first end of the second electrical path 28 is connected to the second end of the common path 26, and the second end of the second electrical path 28 is connected to the side of the first storage battery 31 rather than the battery-interconnect switch 40 in the battery-interconnect electrical path 24. A first motor-side switch 60 is provided in the first electrical path 27. A second motor-side switch 61 is provided in the second electrical path 28. Note that the common path 26 may not be provided, and the first ends of the first electrical path 27 and the second electrical path 28 may each be connected to the neutral point of the armature winding 11.

[0166] According to the present embodiment described above, the processes of FIG. 9 and FIG. 13 in the circuit configuration shown in FIG. 1 can be performed.

[0167] <Tenth Embodiment> Hereinafter, the tenth embodiment will be described with reference to the drawings, focusing on the differences from the above embodiments. In this embodiment, as shown in FIG. 36, as the motor-side switch, in addition to the switch connecting the neutral point of the armature winding 11 and the negative terminal of the first storage battery 31, a switch connecting the neutral point of the armature winding 11 and the positive terminal of the second storage battery 32 is provided.

[0168] The first end of a common path 26 is connected to the neutral point of the armature winding 11. The first end of a first electric path 27 is connected to the second end of the common path 26, and the second end of the first electric path 27 is connected to the side of the second storage battery 32 rather than the battery - to - battery switch 40 in the battery - to - battery electric path 24. Also, the first end of a second electric path 28 is connected to the second end of the common path 26, and the second end of the second electric path 28 is connected to the side of the first storage battery 31 rather than the battery - to - battery switch 40 in the battery - to - battery electric path 24. A first motor - side switch 60 is provided in the first electric path 27. A second motor - side switch 61 is provided in the second electric path 28. Note that the common path 26 may not be provided, and the first ends of the first electric path 27 and the second electric path 28 may each be connected to the neutral point of the armature winding 11.

[0169] According to the present embodiment described above, the processes of FIG. 26 and FIG. 27 in the circuit configuration shown in FIG. 25 can be performed.

[0170] <Other Embodiments> Note that each of the above - described embodiments may be implemented with the following modifications.

[0171] · The motor is not limited to being star - connected, and may be delta - connected. Also, the motor and the inverter are not limited to three - phase ones, and may be two - phase ones, or four - phase or more ones. Further, the motor is not limited to a permanent - magnet type synchronous machine having a permanent magnet as a field pole on the rotor, and may be a wound - field type synchronous machine having a field winding as a field pole on the rotor. In this case, the rotor may be provided with both a field winding and a permanent magnet. Also, the motor is not limited to a synchronous machine, and may be an induction machine.

[0172] · The switch of the inverter 20 is not limited to an IGBT with a free - wheel diode connected in anti - parallel, and may be, for example, an N - channel MOSFET having a body diode. In this case, the high - potential - side terminal of the N - channel MOSFET becomes the drain, and the low - potential - side terminal becomes the source.

[0173] ·As the power storage unit to be charged by the external charger, it is not limited to a storage battery. For example, it may be a large-capacity electric double layer capacitor, or one that includes both a storage battery and an electric double layer capacitor.

[0174] ·The mounting location of the power conversion device is not limited to a moving body and may be a stationary device.

[0175] ·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. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0176] Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to such embodiments or structures. The present disclosure includes various modifications and modifications within the equivalent scope. In addition, various combinations and forms, and further, other combinations and forms including only one element, more, or less thereof, are within the scope and spirit of the present disclosure.

Claims

1. A high-potential-side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31), A low-potential-side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential-side electrical path and a lower arm switch (SWL) electrically connected to the low-potential-side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a power conversion device comprising: An inter-storage-unit switch (40) provided in an inter-storage-unit electrical path (24) that electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit, A bypass switch (50, 51) that makes at least one of the electrical connections between the negative electrode terminals of the first power storage unit and the second power storage unit and the electrical connections between the positive electrode terminals of the first power storage unit and the second power storage unit, A smoothing capacitor (21) that electrically connects the high-potential-side electrical path and the low-potential-side electrical path and smoothes the input voltage of the inverter, A voltage sensor (19) that detects the voltage of the smoothing capacitor, A high-potential-side switch (SMRH) provided between the connection point with the upper arm switch and the connection point with the positive electrode terminal of the first power storage unit in the high-potential-side electrical path, A low-potential-side switch (SMRL) provided between the connection point with the lower arm switch and the connection point with the negative electrode terminal of the second power storage unit in the low-potential-side electrical path, A control unit (100) that determines whether one of the inter-storage-unit switch and the bypass switch is stuck on before turning on the other switch, and The control unit determines whether one of the inter-storage-unit switch and the bypass switch is stuck on based on the voltage of the smoothing capacitor detected by the voltage sensor when the high-potential-side switch and the low-potential-side switch are turned on. A power conversion device.

2. The bypass switch is a negative electrode-to-negative electrode bypass switch (50) that electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit, The control unit is When it is determined that the voltage of the smoothing capacitor is equal to 0 V, it is determined that the inter-storage-section switch and the bypass switch between the negative electrodes are not stuck on, When it is determined that the voltage of the smoothing capacitor is equal to the sum of the voltage of the first storage section and the voltage of the second storage section, it is determined that the inter-storage-section switch is stuck on, The power conversion device according to claim 1, wherein when it is determined that the voltage of the smoothing capacitor is equal to the voltage of the first storage section, it is determined that the bypass switch between the negative electrodes is stuck on.

3. A high-potential-side electrical path (22H) electrically connectable to the positive electrode terminal of the first storage section (31), A low-potential-side electrical path (22L) electrically connectable to the negative electrode terminal of the second storage section (32), An inverter (20) having an upper-arm switch (SWH) electrically connected to the high-potential-side electrical path and a lower-arm switch (SWL) electrically connected to the low-potential-side electrical path, A motor (10) electrically connected to the connection point of the upper-arm switch and the lower-arm switch, In a power conversion device comprising: The motor has an armature winding (11), The connection point of the upper-arm switch and the lower-arm switch is electrically connected to the first end side of the armature winding, An inter-storage-section switch (40) provided in an inter-storage-section electrical path (24) that electrically connects the negative electrode terminal of the first storage section and the positive electrode terminal of the second storage section, A bypass switch (50, 51) that makes at least one of the electrical connection between the negative electrode terminals of the first storage section and the second storage section and the electrical connection between the positive electrode terminals of the first storage section and the second storage section, A smoothing capacitor (21) that electrically connects the high-potential-side electrical path and the low-potential-side electrical path and smoothes the input voltage of the inverter, A voltage sensor (19) that detects the voltage of the smoothing capacitor, A high-potential-side switch (SMRH) provided between the connection point with the upper-arm switch and the connection point with the positive electrode terminal of the first storage section in the high-potential-side electrical path, A motor-side electrical path (25) that electrically connects the second end side of the armature winding and the inter-storage-section electrical path, A motor-side switch (60) provided in the motor-side electrical path, A connection switch (80) provided on the connection point side of the motor-side switch in the motor-side electrical path, A control unit (100) that determines whether one of the switches between the power storage units and the bypass switch is stuck on before turning on either one of the switches; The control unit is a power conversion device that determines whether one of the switches between the power storage units and the bypass switch is stuck on based on the voltage of the smoothing capacitor detected by the voltage sensor when the high-potential side switch, the motor side switch, and the connection switch are turned on.

4. The bypass switch is a negative electrode bypass switch (50) that electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit. The motor-side electrical path is a path that electrically connects the second end side of the armature winding and a portion of the electrical path between the power storage units on the side of the second power storage unit with respect to the switch between the power storage units. The control unit When it is determined that the voltage of the smoothing capacitor is equal to 0 V, it is determined that the switch between the power storage units and the negative electrode bypass switch are not stuck on. When it is determined that the voltage of the smoothing capacitor is equal to the voltage of the first power storage unit, it is determined that the switch between the power storage units is stuck on. The power conversion device according to claim 3, wherein when it is determined that the voltage of the smoothing capacitor is equal to the voltage difference between the voltage of the first power storage unit and the voltage of the second power storage unit, it is determined that the negative electrode bypass switch is stuck on.

5. A high-potential side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31); A low-potential side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32); An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path; A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch; In a power conversion device including A switch between power storage units (40) provided in an electrical path between power storage units (24) that electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit; A negative electrode bypass switch (50) that electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit; A control unit (100) for determining whether or not one of the switches between the power storage units and the bypass switch between the negative electrodes is stuck on before turning on one of the switches; The control unit is When it is determined that the voltage across the switch between the power storage units is equal to the sum of the voltage of the first power storage unit and the voltage of the second power storage unit, it is determined that the switch between the power storage units and the bypass switch between the negative electrodes are not stuck on. When it is determined that the voltage across the switch between the power storage units is equal to 0V, it is determined that the switch between the power storage units is stuck on. A power conversion device that determines that the bypass switch between the negative electrodes is stuck on when it is determined that the voltage across the switch between the power storage units is equal to the voltage of the second power storage unit.

6. A high-potential side electrical path (22H) electrically connectable to the positive terminal of the first power storage unit (31); A low-potential side electrical path (22L) electrically connectable to the negative terminal of the second power storage unit (32); An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path; A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch; In a power conversion device comprising: A switch between power storage units (40) provided in an electrical path between power storage units (24) that electrically connects the negative terminal of the first power storage unit and the positive terminal of the second power storage unit; A bypass switch between negative electrodes (50) that electrically connects the negative terminal of the first power storage unit and the negative terminal of the second power storage unit; A control unit (100) for determining whether or not one of the switches between the power storage units and the bypass switch between the negative electrodes is stuck on before turning on one of the switches; The control unit is When it is determined that the voltage across the bypass switch between the negative electrodes is equal to the voltage of the first power storage unit, it is determined that the switch between the power storage units and the bypass switch between the negative electrodes are not stuck on. When it is determined that the voltage across the bypass switch between the negative electrodes is equal to the voltage of the second power storage unit, it is determined that the switch between the power storage units is stuck on. A power conversion device that determines that the bypass switch between the negative electrodes is stuck on when it is determined that the voltage across the bypass switch between the negative electrodes is equal to 0V.

7. A high-potential-side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31), A low-potential-side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential-side electrical path and a lower arm switch (SWL) electrically connected to the low-potential-side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a power conversion device comprising: An inter-storage-unit switch (40) provided in an inter-storage-unit electrical path (24) that electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit, A negative electrode bypass switch (50) that electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit, A control unit (100) that determines whether one of the inter-storage-unit switch and the negative electrode bypass switch is stuck on before turning on the other switch, The control unit is configured to: When it is determined that the voltage between the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit is equal to the voltage of the second power storage unit, determine that the inter-storage-unit switch and the negative electrode bypass switch are not stuck on. When it is determined that the voltage between the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit is equal to the voltage of the first power storage unit, determine that the inter-storage-unit switch is stuck on. When it is determined that the voltage between the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit is equal to the voltage difference between the voltage of the first power storage unit and the voltage of the second power storage unit, determine that the negative electrode bypass switch is stuck on. A power conversion device.

8. The bypass switch is a positive electrode bypass switch (51) that electrically connects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit, The control unit is configured to: When it is determined that the voltage of the smoothing capacitor is equal to 0V, determine that the inter-storage-unit switch and the positive electrode bypass switch are not stuck on. When it is determined that the voltage of the smoothing capacitor is equal to the sum of the voltage of the first power storage unit and the voltage of the second power storage unit, determine that the inter-storage-unit switch is stuck on. The power conversion device according to claim 1, wherein when it is determined that the voltage of the smoothing capacitor is equal to the voltage of the second power storage unit, it is determined that the positive electrode bypass switch is stuck on.

9. A high-potential-side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31), A low-potential-side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential-side electrical path and a lower arm switch (SWL) electrically connected to the low-potential-side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a power conversion device comprising: The motor has an armature winding (11), One end side of the armature winding is electrically connected to the connection point of the upper arm switch and the lower arm switch, An inter-storage-unit switch (40) provided in an inter-storage-unit electrical path (24) that electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit, Among the electrical connections between the negative electrode terminals of the first power storage unit and the second power storage unit and the electrical connections between the positive electrode terminals of the first power storage unit and the second power storage unit, a bypass switch (50, 51) that makes at least one of the electrical connections, A smoothing capacitor (21) that electrically connects the high-potential-side electrical path and the low-potential-side electrical path and smoothes the input voltage of the inverter, A voltage sensor (19) that detects the voltage of the smoothing capacitor, A low-potential-side switch (SMRL) provided between the connection point with the lower arm switch and the connection point with the negative electrode terminal of the second power storage unit in the low-potential-side electrical path, A motor-side electrical path (25) that electrically connects the second end side of the armature winding and the inter-storage-unit electrical path, A motor-side switch (61) provided in the motor-side electrical path, A connection switch (80) provided on the connection point side of the motor-side electrical path with respect to the motor-side switch, A control unit (100) that determines whether or not one of the inter-storage-unit switch and the bypass switch is stuck on before the other switch is turned on, The control unit is a power conversion device that determines whether any one of the inter-storage unit switch and the bypass switch is stuck on based on the voltage of the smoothing capacitor detected by the voltage sensor when the low-potential side switch, the motor side switch, and the connection switch are turned on.

10. The bypass switch is a positive electrode bypass switch (51) that electrically connects the positive electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit. The motor side electrical path is a path that electrically connects the second end side of the armature winding and a portion of the inter-storage unit electrical path on the side of the first storage unit closer to the inter-storage unit switch than the inter-storage unit switch. The control unit When it is determined that the voltage of the smoothing capacitor is equal to 0 V, it is determined that the inter-storage unit switch and the positive electrode bypass switch are not stuck on. When it is determined that the voltage of the smoothing capacitor is equal to the voltage of the second storage unit, it is determined that the inter-storage unit switch is stuck on. The power conversion device according to claim 9, wherein when it is determined that the voltage of the smoothing capacitor is equal to the voltage difference between the voltage of the second storage unit and the voltage of the first storage unit, it is determined that the positive electrode bypass switch is stuck on.

11. A high-potential side electrical path (22H) electrically connectable to the positive electrode terminal of the first storage unit (31), A low-potential side electrical path (22L) electrically connectable to the negative electrode terminal of the second storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a power conversion device including An inter-storage unit switch (40) provided in an inter-storage unit electrical path (24) that electrically connects the negative electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit, A positive electrode bypass switch (51) that electrically connects the positive electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit, A control unit (100) that determines whether the other switch is stuck on before turning on any one of the inter-storage unit switch and the positive electrode bypass switch, and The control unit When it is determined that the voltage across both ends of the inter-storage-section switch is equal to the sum of the voltage of the first storage section and the voltage of the second storage section, it is determined that the inter-storage-section switch and the bypass switch between the positive electrodes are not stuck on, When it is determined that the voltage across both ends of the inter-storage-section switch is equal to 0 V, it is determined that the inter-storage-section switch is stuck on, A power conversion device that determines that the bypass switch between the positive electrodes is stuck on when it is determined that the voltage across both ends of the inter-storage-section switch is equal to the voltage of the first storage section.

12. A high-potential-side electrical path (22H) that can be electrically connected to the positive electrode terminal of the first storage section (31), A low-potential-side electrical path (22L) that can be electrically connected to the negative electrode terminal of the second storage section (32), An inverter (20) having an upper-arm switch (SWH) electrically connected to the high-potential-side electrical path and a lower-arm switch (SWL) electrically connected to the low-potential-side electrical path, A motor (10) electrically connected to the connection point of the upper-arm switch and the lower-arm switch, In a power conversion device including: An inter-storage-section switch (40) provided in an inter-storage-section electrical path (24) that electrically connects the negative electrode terminal of the first storage section and the positive electrode terminal of the second storage section, A bypass switch (51) between the positive electrodes that electrically connects the positive electrode terminal of the first storage section and the positive electrode terminal of the second storage section, A control unit (100) that determines whether either one of the inter-storage-section switch and the bypass switch between the positive electrodes is stuck on before turning on either one of the switches, The control unit, When it is determined that the voltage across both ends of the bypass switch between the positive electrodes is equal to the voltage of the second storage section, it is determined that the inter-storage-section switch and the bypass switch between the positive electrodes are not stuck on, When it is determined that the voltage across both ends of the bypass switch between the positive electrodes is equal to the voltage of the first storage section, it is determined that the inter-storage-section switch is stuck on, A power conversion device that determines that the bypass switch between the positive electrodes is stuck on when it is determined that the voltage across both ends of the bypass switch between the positive electrodes is equal to 0 V.

13. A high-potential-side electrical path (22H) that can be electrically connected to the positive electrode terminal of the first storage section (31), A low-potential-side electrical path (22L) that can be electrically connected to the negative electrode terminal of the second storage section (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high potential side electrical path and a lower arm switch (SWL) electrically connected to the low potential side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a power conversion device comprising: An inter-storage unit switch (40) provided in an inter-storage unit electrical path (24) that electrically connects the negative terminal of the first storage unit and the positive terminal of the second storage unit; A positive terminal bypass switch (51) that electrically connects the positive terminal of the first storage unit and the positive terminal of the second storage unit; A control unit (100) that determines whether one of the inter-storage unit switch and the positive terminal bypass switch is stuck on before turning on the other switch; The control unit, When it is determined that the voltage between the negative terminal of the first storage unit and the negative terminal of the second storage unit is equal to the voltage of the first storage unit, it is determined that the inter-storage unit switch and the positive terminal bypass switch are not stuck on, When it is determined that the voltage between the negative terminal of the first storage unit and the negative terminal of the second storage unit is equal to the voltage of the second storage unit, it is determined that the inter-storage unit switch is stuck on, A power conversion device that determines that the positive terminal bypass switch is stuck on when it is determined that the voltage between the negative terminal of the first storage unit and the negative terminal of the second storage unit is equal to the voltage difference between the second storage unit and the first storage unit.

14. A high potential side electrical path (22H) electrically connectable to the positive terminal of the first storage unit (31); A low potential side electrical path (22L) electrically connectable to the negative terminal of the second storage unit (32); An inverter (20) having an upper arm switch (SWH) electrically connected to the high potential side electrical path and a lower arm switch (SWL) electrically connected to the low potential side electrical path; A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch; In a program applied to a power conversion device including a computer (101), The power conversion device, An inter-storage unit switch (40) provided in an inter-storage unit electrical path (24) that electrically connects the negative terminal of the first storage unit and the positive terminal of the second storage unit; A bypass switch (50, 51) that makes at least one of the electrical connections between the negative terminals of the first power storage unit and the second power storage unit and the electrical connections between the positive terminals of the first power storage unit and the second power storage unit. A smoothing capacitor (21) that electrically connects the high-potential side electrical path and the low-potential side electrical path and smoothes the input voltage of the inverter. A voltage sensor (19) that detects the voltage of the smoothing capacitor. A high-potential side switch (SMRH) provided between the connection point with the upper arm switch and the connection point with the positive terminal of the first power storage unit in the high-potential side electrical path. A low-potential side switch (SMRL) provided between the connection point with the lower arm switch and the connection point with the negative terminal of the second power storage unit in the low-potential side electrical path. Comprising In the computer Execute a determination process to determine whether one of the switches between the power storage units and the bypass switch is stuck on before turning on one of the switches. In the determination process, based on the voltage of the smoothing capacitor detected by the voltage sensor when the high-potential side switch and the low-potential side switch are turned on, determine whether one of the switches between the power storage units and the bypass switch is stuck on. A program.

15. A high-potential side electrical path (22H) electrically connectable to the positive terminal of the first power storage unit (31). A low-potential side electrical path (22L) electrically connectable to the negative terminal of the second power storage unit (32). An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path. A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch. In a program applied to a power conversion device including a computer (101), The motor has an armature winding (11). The connection point of the upper arm switch and the lower arm switch is electrically connected to the first end side of the armature winding. The power conversion device An inter-power storage unit switch (40) provided in an inter-power storage unit electrical path (24) that electrically connects the negative terminal of the first power storage unit and the positive terminal of the second power storage unit. A bypass switch (50, 51) that makes at least one of the electrical connections between the negative terminals of the first power storage unit and the second power storage unit and the electrical connections between the positive terminals of the first power storage unit and the second power storage unit; A smoothing capacitor (21) that electrically connects the high-potential-side electrical path and the low-potential-side electrical path and smoothes the input voltage of the inverter; A voltage sensor (19) that detects the voltage of the smoothing capacitor; A high-potential-side switch (SMRH) provided between the connection point with the upper-arm switch and the connection point with the positive terminal of the first power storage unit in the high-potential-side electrical path; A motor-side electrical path (25) that electrically connects the second end side of the armature winding and the electrical path between the power storage units; A motor-side switch (60) provided in the motor-side electrical path; A connection switch (80) provided on the connection point side of the motor-side switch in the motor-side electrical path; Comprising; In the computer, Execute a determination process to determine whether one of the switches of the switch between the power storage units and the bypass switch is stuck on before turning on one of the switches; In the determination process, based on the voltage of the smoothing capacitor detected by the voltage sensor when the high-potential-side switch, the motor-side switch, and the connection switch are turned on, determine whether one of the switches of the switch between the power storage units and the bypass switch is stuck on. Program.

16. A high-potential-side electrical path (22H) electrically connectable to the positive terminal of the first power storage unit (31); A low-potential-side electrical path (22L) electrically connectable to the negative terminal of the second power storage unit (32); An inverter (20) having an upper-arm switch (SWH) electrically connected to the high-potential-side electrical path and a lower-arm switch (SWL) electrically connected to the low-potential-side electrical path; A motor (10) electrically connected to the connection point of the upper-arm switch and the lower-arm switch; In a program applied to a power conversion device including a computer (101), The power conversion device is A switch (40) between the power storage units provided in an electrical path (24) between the negative terminal of the first power storage unit and the positive terminal of the second power storage unit; A negative electrode bypass switch (50) that electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit; Comprising: To the computer, Before turning on either one of the switches between the power storage units and the negative electrode bypass switch, execute a determination process to determine whether the other switch is stuck on. In the determination process, When it is determined that the voltage across the switch between the power storage units is equal to the sum of the voltage of the first power storage unit and the voltage of the second power storage unit, it is determined that the switch between the power storage units and the negative electrode bypass switch are not stuck on. When it is determined that the voltage across the switch between the power storage units is equal to 0V, it is determined that the switch between the power storage units is stuck on. When it is determined that the voltage across the switch between the power storage units is equal to the voltage of the second power storage unit, it is determined that the negative electrode bypass switch is stuck on. A program.

17. A high-potential side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31); A low-potential side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32); An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path; A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch; In a program applied to a power conversion device including a computer (101), The power conversion device is A switch (40) between power storage units provided in an electrical path (24) between power storage units that electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit; A negative electrode bypass switch (50) that electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit; Comprising: To the computer, Before turning on either one of the switches between the power storage units and the negative electrode bypass switch, execute a determination process to determine whether the other switch is stuck on. In the determination process, When it is determined that the voltage across the negative electrode bypass switch is equal to the voltage of the first power storage unit, it is determined that the switch between the power storage units and the negative electrode bypass switch are not stuck on. When it is determined that the voltage across both ends of the bypass switch between the negative electrodes is equal to the voltage of the second power storage unit, it is determined that the switch between the power storage units is stuck on. A program that determines that the bypass switch between the negative electrodes is stuck on when it is determined that the voltage across both ends of the bypass switch between the negative electrodes is equal to 0V.

18. A high-potential-side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31), A low-potential-side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential-side electrical path and a lower arm switch (SWL) electrically connected to the low-potential-side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a program applied to a power conversion device including a computer (101), The power conversion device, A switch (40) between power storage units provided in an electrical path (24) between power storage units that electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit, A bypass switch (50) between negative electrodes that electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit, Comprising, To the computer, Before turning on either one of the switch between power storage units and the bypass switch between negative electrodes, execute a determination process to determine whether the other switch is stuck on, In the determination process, When it is determined that the voltage between the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit is equal to the voltage of the second power storage unit, it is determined that the switch between power storage units and the bypass switch between negative electrodes are not stuck on. When it is determined that the voltage between the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit is equal to the voltage of the first power storage unit, it is determined that the switch between power storage units is stuck on. A program that determines that the bypass switch between negative electrodes is stuck on when it is determined that the voltage between the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit is equal to the voltage difference between the first power storage unit and the second power storage unit.

19. A high-potential-side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31), A low-potential-side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high potential side electrical path and a lower arm switch (SWL) electrically connected to the low potential side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a program applied to a power conversion device including a computer (101), The motor has an armature winding (11), The connection point of the upper arm switch and the lower arm switch is electrically connected to the first end side of the armature winding, The power conversion device, An inter-storage unit switch (40) provided in an inter-storage unit electrical path (24) that electrically connects the negative terminal of the first storage unit and the positive terminal of the second storage unit, A bypass switch (50, 51) that makes at least one of the electrical connections between the negative terminals of the first storage unit and the second storage unit and the electrical connections between the positive terminals of the first storage unit and the second storage unit, A smoothing capacitor (21) that electrically connects the high potential side electrical path and the low potential side electrical path and smoothes the input voltage of the inverter, A voltage sensor (19) that detects the voltage of the smoothing capacitor, A low potential side switch (SMRL) provided between the connection point with the lower arm switch and the connection point with the negative terminal of the second storage unit in the low potential side electrical path, A motor side electrical path (25) that electrically connects the second end side of the armature winding and the inter-storage unit electrical path, A motor side switch (61) provided in the motor side electrical path, A connection switch (80) provided on the connection point side of the motor side electrical path with respect to the motor side switch, Comprising, In the computer, Execute a determination process to determine whether the other switch is stuck on before turning on either one of the inter-storage unit switch and the bypass switch, In the determination process, based on the voltage of the smoothing capacitor detected by the voltage sensor when the low potential side switch, the motor side switch, and the connection switch are turned on, determine whether either one of the inter-storage unit switch and the bypass switch is stuck on. Program.

20. A high-potential side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31), A low-potential side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a program applied to a power conversion device including a computer (101), The power conversion device, An inter-storage unit switch (40) provided in an inter-storage unit electrical path (24) that electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit, A positive electrode bypass switch (51) that electrically connects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit, Comprising, To the computer, Execute a determination process to determine whether one of the inter-storage unit switch and the positive electrode bypass switch is stuck on before turning on the other switch, In the determination process, When it is determined that the voltage across the inter-storage unit switch is equal to the sum of the voltage of the first power storage unit and the voltage of the second power storage unit, it is determined that the inter-storage unit switch and the positive electrode bypass switch are not stuck on, When it is determined that the voltage across the inter-storage unit switch is equal to 0V, it is determined that the inter-storage unit switch is stuck on, When it is determined that the voltage across the inter-storage unit switch is equal to the voltage of the first power storage unit, it is determined that the positive electrode bypass switch is stuck on. Program.

21. A high-potential side electrical path (22H) electrically connectable to the positive electrode terminal of the first power storage unit (31), A low-potential side electrical path (22L) electrically connectable to the negative electrode terminal of the second power storage unit (32), An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path, A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch, In a program applied to a power conversion device including a computer (101), The power conversion device, An inter-battery switch (40) provided in an inter-battery electrical path (24) that electrically connects the negative terminal of the first battery unit and the positive terminal of the second battery unit; A positive electrode bypass switch (51) that electrically connects the positive terminal of the first battery unit and the positive terminal of the second battery unit; Comprising; To the computer, Before turning on either one of the inter-battery switch and the positive electrode bypass switch, execute a determination process to determine whether the other switch is stuck on, In the determination process, When it is determined that the voltage across both ends of the positive electrode bypass switch is equal to the voltage of the second battery unit, it is determined that the inter-battery switch and the positive electrode bypass switch are not stuck on, When it is determined that the voltage across both ends of the positive electrode bypass switch is equal to the voltage of the first battery unit, it is determined that the inter-battery switch is stuck on, When it is determined that the voltage across both ends of the positive electrode bypass switch is equal to 0V, it is determined that the positive electrode bypass switch is stuck on, a program.

22. A high-potential side electrical path (22H) electrically connectable to the positive terminal of the first battery unit (31); A low-potential side electrical path (22L) electrically connectable to the negative terminal of the second battery unit (32); An inverter (20) having an upper arm switch (SWH) electrically connected to the high-potential side electrical path and a lower arm switch (SWL) electrically connected to the low-potential side electrical path; A motor (10) electrically connected to the connection point of the upper arm switch and the lower arm switch; In a program applied to a power conversion device including a computer (101), The power conversion device, An inter-battery switch (40) provided in an inter-battery electrical path (24) that electrically connects the negative terminal of the first battery unit and the positive terminal of the second battery unit; A positive electrode bypass switch (51) that electrically connects the positive terminal of the first battery unit and the positive terminal of the second battery unit; Comprising; To the computer, Before turning on either one of the inter-battery switch and the positive electrode bypass switch, execute a determination process to determine whether the other switch is stuck on, In the determination process, When it is determined that the voltage between the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit is equal to the voltage of the first power storage unit, it is determined that the switch between the power storage units and the bypass switch between the positive electrodes are not stuck on, When it is determined that the voltage between the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit is equal to the voltage of the second power storage unit, it is determined that the switch between the power storage units is stuck on, A program for determining that the bypass switch between the positive electrodes is stuck on when it is determined that the voltage between the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit is equal to the voltage difference between the voltage of the second power storage unit and the voltage of the first power storage unit.

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