Control device, program, and control method

Abstract

A control device (100) is applied to a power conversion device comprising an inverter (20) and a motor (10) having an armature winding (11) and a rotor (13). The power conversion device is provided with a high-potential-side path (22H), a low-potential-side path (22L), a connection path (73), a first switch (71), neutral-point capacitors (74, 75), and a second switch (72). The control device comprises: a determination unit (103) that determines whether or not the first switch is fixed to ON; and a switch control unit (104) that performs switching control of the upper and lower arm switches (SH, SL) of the inverter in a state in which an OFF command for the first and second switches is issued. When it is determined that the first switch is fixed to ON, the switch control unit switches the second switch to the ON state and performs the switching control.

Description

Control device, program, and control method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-064154, filed on April 11, 2024, the contents of which are incorporated herein by reference.

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

[0003] Conventionally, a power conversion device applied to a system including a power storage unit has been known. The power conversion device includes an inverter, a motor, a connection path connecting the power storage unit and a neutral point of the armature winding of the motor, and a switch provided on the connection path. A control device for the power conversion device includes a device that switches between electrical connection and disconnection between the power storage unit and the neutral point of the armature winding by turning the switch on and off. An example of such a power conversion device is described in Patent Document 1.

[0004] Patent No. 7370223

[0005] In the above power conversion device, there is a concern that the controllability of the motor may be reduced due to the voltage at the neutral point of the armature winding becoming unstable.

[0006] A primary object of the present disclosure is to provide a control device, a program, and a control method that can suppress a decrease in motor controllability.

[0007] The present disclosure relates to a control device applicable to a power conversion device including an inverter having upper and lower arm switches of a plurality of phases, and a motor having an armature winding electrically connected to low potential side terminals of the upper arm switches of each phase and high potential side terminals of the lower arm switches of each phase, and a rotor, wherein the power conversion device includes: a high potential side path electrically connecting a positive terminal of a first power storage unit and a high potential side terminal of the upper arm switch; a low potential side path electrically connecting a negative terminal of a second power storage unit and a low potential side terminal of the lower arm switch; a connection path electrically connecting the negative terminal of the first power storage unit and the positive terminal of the second power storage unit and a neutral point of the armature winding; a first switch provided in the connection path; a neutral point capacitor electrically connecting the low potential side path or the high potential side path to the connection path; and a second switch provided in the connection path on the first power storage unit side or the second power storage unit side of a connection point with the neutral point capacitor, The motor comprises a determination unit that determines whether the first switch is stuck on or not, and a switch control unit that performs switching control of the upper and lower arm switches while issuing an OFF command for the first switch and the second switch in order to rotate the rotor, wherein when it is determined that the first switch is stuck on, the switch control unit switches the second switch to the ON state and performs the switching control.

[0008] When the first switch and the second switch are turned on, the neutral point of the armature winding is connected to the first and second power storage units via the connection path. The power conversion device includes a neutral point capacitor that electrically connects the low-potential side path or the high-potential side path to the connection path. The second switch is provided on the connection path closer to the first or second power storage unit than the connection point with the neutral point capacitor. Therefore, if the first switch is stuck on when an OFF command for the first switch and the second switch is issued, the neutral point of the armature winding is electrically connected to the first end of the neutral point capacitor. In this case, the voltage at the neutral point of the armature winding and the voltage at the neutral point capacitor become equal, which may result in a decrease in motor controllability.

[0009] Therefore, when it is determined that the first switch is stuck on, the switch control unit of the present disclosure switches the second switch to the on state to perform switching control, thereby suppressing voltage fluctuations at the neutral point of the armature winding and thereby suppressing deterioration in motor controllability.

[0010] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an overall configuration diagram of a system according to a first embodiment, Fig. 2 is a diagram showing the control states of switches when the motor is driven, Fig. 3 is a functional block diagram showing processing by the motor ECU, Fig. 4 is a diagram showing an operating region of an operating point determined by a command torque and a rotational speed, Fig. 5 is a flowchart showing the procedure for drive control processing, Fig. 6 is a flowchart showing the procedure for stuck-on determination processing, Fig. 7 is a flowchart showing the procedure for drive control processing according to a second embodiment, Fig. 8 is a flowchart showing the procedure for stuck-on determination processing, Fig. 9 is a flowchart showing the procedure for stuck-on determination processing according to a third embodiment, Fig. 10 is an overall configuration diagram of a system according to a fourth embodiment, Fig. 11 is a flowchart showing the procedure for drive control processing, Fig. 12 is an overall configuration diagram of a system according to other embodiments, and Fig. 13 is an overall configuration diagram of a system according to other embodiments.

[0011] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0012] A first embodiment of a power conversion device according to the present disclosure will now be described with reference to the drawings. The power conversion device of this embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, and forms an in-vehicle system.

[0013] As shown in FIG. 1 , the power conversion device includes a motor 10, an inverter 20, a high-potential side path 22H, and a low-potential side path 22L. The motor 10 is a three-phase synchronous machine and includes star-connected armature windings 11 of U, V, and W phases, and a rotor 13. The armature windings 11 of each phase are arranged with an electrical angle of 120°. The motor 10 is, for example, a permanent magnet synchronous machine. The rotor 13 is capable of transmitting power to the drive wheels of the vehicle. Therefore, the motor 10 serves as a source of torque for propelling the vehicle.

[0014] The inverter 20 includes three phases of series-connected upper and lower arm switches. Specifically, the inverter 20 includes three-phase upper arm switches SH and three-phase lower arm switches SL. An upper arm diode DH, which is a freewheeling diode, is connected in antiparallel to the upper arm switch SH, and a lower arm diode DL, which is also a freewheeling diode, is connected in antiparallel to the lower arm switch SL. In this embodiment, each of the switches SH and SL is an IGBT.

[0015] The inverter 20 includes a smoothing capacitor 21. A long high-potential side path 22H is connected to a high-potential side terminal of the smoothing capacitor 21. A long low-potential side path 22L is connected to a low-potential side terminal of the smoothing capacitor 21. The high-potential side path 22H and the low-potential side path 22L are, for example, electrical paths such as bus bars. The smoothing capacitor 21 may be provided outside the inverter 20.

[0016] First ends of U-, V-, and W-phase armature windings 11U, 11V, and 11W are connected to a connection point between the emitter, which is the low-potential terminal of the upper arm switch SH, and the collector, which is the high-potential terminal of the lower arm switch SL, via conductive members 23 such as bus bars. Second ends of the U-, V-, and W-phase armature windings 11U, 11V, and 11W are connected to each other at a neutral point O. In this embodiment, the U-, V-, and W-phase armature windings 11U, 11V, and 11W are set to have the same number of turns. As a result, the U-, V-, and W-phase armature windings 11U, 11V, and 11W are set to have the same inductance, for example.

[0017] A high potential side path 22H is connected to the collector of the upper arm switch SH, and a low potential side path 22L is connected to the emitter of the lower arm switch SL.

[0018] 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 storage battery 31, 32 serves as a power supply source for rotating the rotor 13 of the motor 10. The negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32 are connected to each other. Each storage battery 31, 32 is a battery pack including a series connection of multiple unit batteries. A unit battery is a single battery cell, which is a single cell, or a series connection of multiple battery cells. In this embodiment, the unit batteries constituting the first storage battery 31 and the second storage battery 32 have the same full charge capacity (specifically, for example, rated full charge capacity) [Ah]. The positive terminal of the first storage battery 31 is connected to the high-potential side path 22H via a first fuse 41, and the negative terminal of the second storage battery 32 is connected to the low-potential side path 22L via a second fuse 42. The terminal voltages (e.g., rated voltages) of the battery cells constituting the battery pack are set to be the same. The battery cells are, for example, secondary batteries such as lithium-ion batteries. In this embodiment, the terminal voltages (e.g., rated voltages) of the first storage battery 31 and the second storage battery 32 are equal to each other.

[0019] In this embodiment, the first storage battery 31 and the second storage battery 32 constitute a battery unit 30 .

[0020] The power conversion device includes main switches for electrically connecting or disconnecting the first and second storage batteries 31, 32 from the inverter 20. Specifically, the main switches include a high-side main switch SMRH, a low-side main switch SMRL, and a pre-charge main switch SMRP. In this embodiment, the main switches SMRH, SMRL, and SMRP are mechanical relays. When turned off, the main switches SMRH, SMRL, and SMRP block bidirectional current flow, and when turned on, allow bidirectional current flow. The high-side main switch SMRH is provided in the high-side path 22H, and the low-side main switch SMRL is provided in the low-side path 22L. A series connection of the pre-charge main switch SMRP and a pre-charge resistor 40 is connected in parallel to the low-side main switch SMRL. The main switches SMRH, SMRL, and SMRP are not limited to mechanical relays, and may be semiconductor switching elements, for example.

[0021] The power conversion device includes a first motor-side switch 71 (corresponding to the "first switch"), a second motor-side switch 72 (corresponding to the "second switch"), and a connection path 73 as components for switching the connection state of the first storage battery 31 and the second storage battery 32. In this embodiment, each of the motor-side switches 71, 72 is a mechanical relay. When turned off, each of the motor-side switches 71, 72 blocks bidirectional current flow, and when turned on, each of the motor-side switches 71, 72 allows bidirectional current flow. Each of the motor-side switches 71, 72 is not limited to a mechanical relay, and may be, for example, a semiconductor switching element.

[0022] The connection path 73 is an electrical path connecting the intermediate terminal B and the neutral point O. The intermediate terminal B is on a path connecting the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32. A first motor-side switch 71 and a second motor-side switch 72 are provided on the connection path 73 in this order from the neutral point O.

[0023] The power conversion device includes a neutral point capacitor 74 that is a capacitor that connects the connection path 73 and the low potential side path 22L. A first end of the neutral point capacitor 74 is connected to a portion of the connection path 73 between the first motor side switch 71 and the second motor side switch 72. A second end of the neutral point capacitor 74 is connected to a portion of the low potential side path 22L that is closer to the inverter 20 than the low potential side main switch SMRL and the pre-charge main switch SMRP.

[0024] When the first motor-side switch 71 is turned on, the neutral point O of the armature winding 11 is electrically connected to the first end of the neutral point capacitor 74. On the other hand, when the first motor-side switch 71 is turned off, the neutral point O is electrically disconnected from the first end of the neutral point capacitor 74. When the second motor-side switch 72 is turned on, the first end of the neutral point capacitor 74 is electrically connected to the positive terminal of the second storage battery 32. On the other hand, when the second motor-side switch 72 is turned off, the first end of the neutral point capacitor 74 is electrically disconnected from the positive terminal of the second storage battery 32.

[0025] The power conversion device includes current sensors that detect currents flowing through various parts of the power conversion device itself, including a first current sensor 81A, a second current sensor 81B, a phase current sensor 82, and a motor current sensor 83 (corresponding to "current sensors"). The first current sensor 81A detects currents flowing through the first storage battery 31, and the second current sensor 81B detects currents flowing through the second storage battery 32. The phase current sensor 82 detects currents flowing through the U-, V-, and W-phase armature windings 11U, 11V, and 11W. The motor current sensor 83 detects currents flowing through the connection path 73, and in this embodiment, detects currents (hereinafter referred to as motor current IN) flowing through a portion of the connection path 73 that is closer to the neutral point O than the connection point with the neutral point capacitor 74.

[0026] The power conversion device includes a capacitor voltage sensor 84 (corresponding to a "voltage sensor") that detects the voltage across the neutral point capacitor 74 (hereinafter referred to as the neutral point capacitor voltage VN), a first voltage sensor 85A that detects the voltage across the terminals of the first storage battery 31 (hereinafter referred to as the first storage battery voltage VH), and a second voltage sensor 85B that detects the voltage across the terminals of the second storage battery 32 (hereinafter referred to as the second storage battery voltage VL). The power conversion device also includes a power supply voltage sensor 86 that detects the voltage across the terminals of the smoothing capacitor 21 (hereinafter referred to as the smoothing capacitor voltage VB), and a rotation angle sensor 87 that detects the rotation angle (electrical angle) of the rotor 13.

[0027] The system includes a battery ECU 90 that controls the battery unit 30, a motor ECU 100 that controls the inverter 20, and an EVECU 110 that manages the system. The battery ECU 90 is an electronic control unit and includes a processor 91 and a storage unit 92 as hardware. The motor ECU 100 is an electronic control unit and includes a processor 101 and a storage unit 102 as hardware. The EVECU 110 is an electronic control unit and includes a processor 111 and a storage unit 112 as hardware. The EVECU 110 is a higher-level control unit than the battery ECU 90 and the motor ECU 100. The battery ECU 90 and the motor ECU 100 can exchange information via the EVECU 110.

[0028] The memory units 92, 102, 112 include hardware memory and storage. The memory is a storage device for storing data used in the processing of the battery ECU 90, the motor ECU 100, or the EVECU 110. The memory provides the processors 91, 101, 111 with a working area for temporary use when the processors 91, 101, 111 perform processing, for example. The memory includes, for example, a ROM or a RAM. The storage is a storage device for storing various programs and data to be read and executed by the processors 91, 101, 111, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or flash memory. The storage stores program information and the like for the processing shown in FIGS. 5 to 9 and 11, which will be described later.

[0029] For example, program information stored on a non-transient physical recording medium is installed in the storage units 92, 102, and 112. The recording medium is, for example, a USB memory, a CD-ROM, or a DVD. Also, for example, program information transmitted via a communication network, such as over the air (OTA), is installed in the storage units 92, 102, and 112.

[0030] The battery ECU 90 receives the detected values ​​of the first current sensor 81A, the second current sensor 81B, the first voltage sensor 85A, and the second voltage sensor 85B. The motor ECU 100 receives the detected values ​​of the phase current sensor 82, the motor current sensor 83, the capacitor voltage sensor 84, the power supply voltage sensor 86, and the rotation angle sensor 87.

[0031] The main switches SMRH, SMRL, and SMRP and the motor-side switches 71 and 72 may be controlled by any one of the battery ECU 90, the motor ECU 100, and the EVECU 110, or may be controlled by an ECU other than the ECUs 90, 100, and 110. In the present embodiment, the main switches SMRH, SMRL, and SMRP and the motor-side switches 71 and 72 are hereinafter assumed to be controlled by the motor ECU 100.

[0032] Next, the drive control will be described. The drive control rotates the rotor 13 of the motor 10.

[0033] 2 shows the control state of each switch when drive control is executed. When the motor ECU 100 determines that there is a drive request, it inputs an OFF command to the first motor-side switch 71 and the second motor-side switch 72, and inputs an ON command to the high-potential side main switch SMRH and the low-potential side main switch SMRL. In this embodiment, the drive request is a request to rotate the rotor 13 to run the vehicle.

[0034] In drive control, the motor ECU 100 performs switching control of the upper and lower arm switches SH and SL that constitute the inverter 20 to feedback control the control variable of the motor 10 to a command value based on the detection values ​​of each sensor. The control variable is, for example, torque. In each phase, the upper arm switch and the lower arm switch are alternately turned on. This feedback control transmits the rotational power of the rotor 13 to the drive wheels, causing the vehicle to run.

[0035] When executing drive control, the motor ECU 100 controls the switching of the upper and lower arm switches SH and SL while issuing an OFF command to the first motor-side switch 71 and the second motor-side switch 72. However, for some reason, the first motor-side switch 71 may be stuck on. In this case, the neutral point O is connected to the first end of the neutral point capacitor 74, and the voltage between the low-potential path 22L and the neutral point O (hereinafter referred to as the neutral point voltage VM) fluctuates according to the neutral point capacitor voltage VN. This may result in a decrease in controllability of the motor 10. Therefore, if the motor ECU 100 determines that the first motor-side switch 71 is stuck on, it executes the limiting control described below.

[0036] FIG. 3 shows a block diagram including the limit control executed by the motor ECU 100. As shown in FIG.

[0037] The motor ECU 100 includes a determination unit 103 , a switch control unit 104 , and a command unit 105 .

[0038] The determination unit 103 determines whether the first motor-side switch 71 is stuck on. If the determination unit 103 determines that the neutral point capacitor voltage VN is not 0 and is equal to the neutral point voltage VM, the determination unit 103 determines that the first motor-side switch 71 is stuck on. The determination unit 103 inputs the determination result to the command unit 105 and the switch control unit 104.

[0039] The command unit 105 receives the determination result by the determination unit 103 that the first motor-side switch 71 is stuck on or normal. If the command unit 105 receives the determination result that the first motor-side switch 71 is normal, the command unit 105 selects the normal control map and inputs the selection result to the switch control unit 104. On the other hand, if the command unit 105 receives the determination result that the first motor-side switch 71 is stuck on, the command unit 105 selects the limit control map and inputs the selection result to the switch control unit 104.

[0040] FIG. 4 shows examples of the limit control map and the normal control map. The normal control map is a control map that defines a region of operating points (Trq*, Nr) that can be output by the motor 10 in relation to the rotational speed Nr and the command torque Trq* during drive control when the first motor-side switch 71 is normal (hereinafter referred to as normal control). In FIG. 4, the region of the normal control map is the area surrounded by the vertical and horizontal axes of the graph and the second maximum speed Nmax2 indicated by the dashed line. In the normal control map, the maximum value of the rotational speed Nr is the second maximum speed Nmax2. In the region where the rotational speed Nr is equal to or less than the normal speed Nusu, the second maximum speed Nmax2 increases as the command torque Trq* decreases.

[0041] The limit control map is a control map that defines a region of operating points that can be output by the motor 10 in relation to the rotational speed Nr and the command torque Trq* under limit control. In Fig. 4, the region of the limit control map is the area surrounded by the vertical and horizontal axes of the graph and the first maximum speed Nmax1 indicated by a solid line. In the limit control map, the maximum value of the rotational speed Nr is the first maximum speed Nmax1. In the region where the rotational speed Nr is equal to or less than the speed limit Nlim, the first maximum speed Nmax1 increases as the command torque Trq* decreases.

[0042] Here, the second maximum speed Nmax2 is a value greater than the first maximum speed Nmax1. The limit control map and the normal control map are stored in the storage unit 102, for example.

[0043] Returning to the explanation of Fig. 3, the switch control unit 104 receives the determination result from the determination unit 103 and the selection result from the command unit 105. A case will be described in which the switch control unit 104 receives the determination result that the first motor-side switch 71 is normal and the selection result that the normal control map has been selected. In this case, the switch control unit 104 inputs an OFF command to the first and second motor-side switches 71 and 72. The switch control unit 104 also inputs switching signals to the upper and lower arm switches SU and SL to control the switching of the upper and lower arm switches SU and SL based on the normal control map.

[0044] A case will be described in which the switch control unit 104 receives a determination result that the first motor-side switch 71 is stuck on and a selection result that the limit control map has been selected. In this case, the switch control unit 104 inputs an ON command to the second motor-side switch 72. The switch control unit 104 also inputs switching signals to the upper and lower arm switches SU and SL to control the switching of the upper and lower arm switches SU and SL based on the limit control map.

[0045] 5, the procedure of drive control performed by the motor ECU 100 will be described. In this embodiment, the initial state of the power conversion device is a state in which the upper and lower arm switches SU and SL are in the OFF state, and the rotor 13 is not rotated.

[0046] In step S10, it is determined whether or not there is a request to drive the motor 10. If it is determined that there is a request to drive the motor 10, the process proceeds to step S11. In this embodiment, the drive request is a request to rotate the rotor 13 to run the vehicle. In step S11, an OFF command is input to the first and second motor-side switches 71 and 72 to execute drive control.

[0047] In step S12, the determination unit 103 executes a stuck-on determination to determine whether the first motor-side switch 71 is stuck-on.

[0048] In this embodiment, the stuck-on determination is performed after a drive request is made and before switching control of the upper and lower arm switches SH, SL is started to rotate the rotor 13. This allows the stuck-on determination to be performed during a period in which fluctuations in the neutral point voltage VM are suppressed. This improves the accuracy of the stuck-on determination compared to when the stuck-on determination is performed during a period in which the rotor 13 is being rotated.

[0049] FIG. 6 shows the processing procedure of step S12.

[0050] In step S17, determination unit 103 acquires neutral point capacitor voltage VN, which is the value detected by capacitor voltage sensor 84. In step S18, neutral point voltage VM is calculated. Here, neutral point voltage VM may be calculated based on, for example, smoothing capacitor voltage VB, which is the value detected by power supply voltage sensor 86, and second storage battery voltage VL, which is the value detected by second voltage sensor 85B. Specifically, motor ECU 100 calculates neutral point voltage VM (= VB - VL) by subtracting second storage battery voltage VL from smoothing capacitor voltage VB. Note that the power conversion device may also be equipped with a neutral point voltage sensor that directly detects the voltage at neutral point O. In this case, in step S18, the value detected by the neutral point voltage sensor may be used as neutral point voltage VM.

[0051] In step S19, the determining unit 103 determines whether the neutral point capacitor voltage VN is 0 or not.

[0052] If it is determined in step S19 that the neutral point capacitor voltage VN is 0, it is determined in step S22 that the first motor side switch 71 is normal. If it is determined that the neutral point capacitor voltage VN is not 0, the process proceeds to step S20.

[0053] In step S20, the determination unit 103 determines whether the neutral point capacitor voltage VN and the neutral point voltage VM are equivalent. In this embodiment, the neutral point capacitor voltage VN being equivalent to the neutral point voltage VM includes a case where the neutral point capacitor voltage VN is equal to the neutral point voltage VM and a case where the deviation between the neutral point capacitor voltage VN and the neutral point voltage VM is equal to or less than a first predetermined voltage value. For example, the first predetermined voltage value is equal to or less than 1 / 200, 1 / 300, or 1 / 400 of the sum of the rated voltage of the first storage battery 31 and the rated voltage of the second storage battery 32.

[0054] If it is determined in step S20 that the neutral point capacitor voltage VN and the neutral point voltage VM are not equal, it is determined in step S22 that the first motor side switch 71 is normal.

[0055] If it is determined in step S20 that the neutral point capacitor voltage VN is equal to the neutral point voltage VM, it is determined in step S21 that the first motor side switch 71 is stuck on.

[0056] If the motor ECU 100 determines in step S10 that a drive request has been made, it discharges the neutral point capacitor 74, for example, by controlling the switching of a discharge circuit or the inverter 20, before executing drive control. The motor ECU 100 also inputs an OFF command to the first and second motor-side switches 71 and 72. Therefore, if the first and second motor-side switches 71 and 72 are OFF during the period after a drive request has been made and before drive control is executed, the neutral point capacitor voltage VN is 0. As a result, if a drive request has been made and it is determined that the neutral point capacitor voltage VN is not 0, it can be determined in step S19 that the first motor-side switch 71 or the second motor-side switch 72 is ON.

[0057] When the second motor-side switch 72 is in the OFF state and the first motor-side switch 71 is stuck ON, the first end of the neutral point capacitor 74 is connected to the neutral point O, and the neutral point capacitor voltage VN is equal to the neutral point voltage VM. Therefore, if it is determined that the neutral point capacitor voltage VN is equal to the neutral point voltage VM, it can be determined that the first motor-side switch 71 is stuck ON. On the other hand, if the neutral point capacitor voltage VN is 0, or if the neutral point capacitor voltage VN is not 0 and is not equal to the neutral point voltage VM, it can be determined that the first motor-side switch 71 is normal.

[0058] Returning to the explanation of FIG. 5, in step S13, the switch control unit 104 determines whether or not it has been determined by the stuck-on determination that the first motor-side switch 71 is stuck-on.

[0059] If it is determined in step S13 that the first motor switch 71 is not stuck on, the process proceeds to step S16. In step S16, the command unit 105 selects a normal control map. Then, the switch control unit 104 executes normal control for controlling the switching of the upper and lower arm switches SU and SL based on the normal control map.

[0060] If it is determined in step S13 that the first motor side switch 71 is stuck on, the process proceeds to step S14, where an on command is input to the second motor side switch 72, switching the second motor side switch 72 to the on state.

[0061] In step S15, the command unit 105 selects a limit control map. Then, the switch control unit 104 executes limit control for controlling the switching of the upper and lower arm switches SU and SL based on the limit control map.

[0062] Drive control is performed with the neutral point O and the intermediate terminal B connected via the connection path 73 under limit control. Therefore, the neutral point voltage VM is set to half the power supply voltage Vbat, which is the voltage between the high-potential path 22H and the low-potential path 22L. Limit control suppresses fluctuations in the neutral point voltage VM, thereby preventing a decrease in controllability of the motor 10. Furthermore, if the first motor switch 71 is stuck on during drive control, current may flow through a closed circuit including the neutral point capacitor 74, the neutral point O, the armature winding 11, and the lower-arm switch SL, potentially reducing controllability of the motor 10. In response to this, limit control connects the neutral point O and the intermediate terminal B via the connection path 73 by turning on the first and second motor switches 71 and 72. This prevents current from flowing through unintended current paths, thereby preventing a decrease in controllability of the motor 10.

[0063] When the second motor-side switch 72 is in the OFF state and the first motor-side switch 71 is not fixed ON but is in the OFF state, the neutral point O and the intermediate terminal B are not connected via the connection path 73. When normal control, which is the drive control executed in this case, is executed, the maximum value of the terminal voltage of the U-, V-, and W-phase armature windings 11U, 11V, and 11W is two-thirds of the power supply voltage Vbat. On the other hand, during limit control, the first motor-side switch 71 is fixed ON and the second switch is switched to the ON state, so that the neutral point O and the intermediate terminal B are electrically connected. In this case, the maximum value of the terminal voltage of the U-, V-, and W-phase armature windings 11U, 11V, and 11W is one-half of the power supply voltage Vbat.

[0064] Therefore, when limit control is executed, the range of operating points at which the motor 10 can output is smaller than the range of operating points at which the motor 10 can output under normal control. In this embodiment, when limit control is executed after determining that the first motor-side switch 71 is stuck on, the command unit 105 selects a limit control map in which the maximum value of the rotational speed Nr is smaller than that of the normal control map. Furthermore, the switch control unit 104 controls the switching of the upper and lower arm switches SH and SL based on the limit control map so that the rotational speed Nr of the motor 10 is equal to or less than the first maximum speed Nmax1, which is smaller than the second maximum speed Nmax2. This allows the motor 10 to be driven within the range of operating points at which the motor 10 can output when limit control is executed, for example.

[0065] 6 may be replaced with a process of determining whether the absolute value of the neutral point capacitor voltage VN is equal to or less than a second predetermined voltage value. For example, the second predetermined voltage value is equal to or less than 1 / 200, 1 / 300, or 1 / 400 of the sum of the rated voltage of the first storage battery 31 and the rated voltage of the second storage battery 32.

[0066] In step S20, the voltage of the neutral point capacitor 74 compared with the neutral point voltage VM is not limited to the value detected by the capacitor voltage sensor 84. For example, the power conversion device may include a capacitor current sensor that detects the current flowing through the neutral point capacitor 74, and the motor ECU 100 may calculate the voltage of the neutral point capacitor 74 based on the value detected by the capacitor current sensor.

[0067] Second Embodiment A second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, it is determined whether the second motor switch 72 is stuck on in addition to the first motor switch 71.

[0068] 7, the procedure of drive control performed by the motor ECU 100 will be described. In this embodiment, the initial state of the power conversion device is a state in which the upper and lower arm switches SU and SL are in the OFF state, and the rotor 13 is not rotated.

[0069] After steps S10 and S11 are executed, in step S12, the determination unit 103 executes a stuck-on determination to determine whether the first and second motor-side switches 71 and 72 are stuck-on.

[0070] FIG. 8 shows the processing procedure of step S12.

[0071] After execution of step S17, in step S40, determination unit 103 acquires second storage battery voltage VL, which is the detection value of second voltage sensor 85B.

[0072] In step S19, the determining unit 103 determines whether the neutral point capacitor voltage VN is 0 or not.

[0073] If it is determined in step S19 that the neutral point capacitor voltage VN is 0, it is determined in step S22 that the first motor side switch 71 is normal. On the other hand, if it is determined that the neutral point capacitor voltage VN is not 0, the process proceeds to step S41.

[0074] In step S41, the determination unit 103 determines whether the neutral point capacitor voltage VN is equivalent to the second storage battery voltage VL. In this embodiment, the neutral point capacitor voltage VN being equivalent to the second storage battery voltage VL includes a case where the neutral point capacitor voltage VN is equal to the second storage battery voltage VL and a case where the deviation between the neutral point capacitor voltage VN and the second storage battery voltage VL is equal to or less than a predetermined voltage value. For example, the predetermined voltage value is equal to or less than 1 / 200, 1 / 300, or 1 / 400 of the sum of the rated voltage of the first storage battery 31 and the rated voltage of the second storage battery 32.

[0075] If it is determined in step S41 that the neutral point capacitor voltage VN is not equal to the second storage battery voltage VL, it is determined in step S21 that the first motor side switch 71 is stuck on.

[0076] If it is determined in step S41 that the neutral point capacitor voltage VN is equal to the second storage battery voltage VL, it is determined in step S42 that the second motor side switch 72 is stuck on.

[0077] Returning to the explanation of FIG. 7, if it is determined in step S13 that the first motor side switch 71 is stuck on, step S14 is executed, and then step S15 is executed.

[0078] If it is determined in step S13 that the first motor side switch 71 is normal, the process proceeds to step S30.

[0079] In step S30, it is determined whether the second motor side switch 72 is determined to be stuck on by the stuck-on determination in the switch control unit 104. If it is determined that the second motor side switch 72 is normal, the process proceeds to step S16.

[0080] If it is determined in step S30 that the second motor side switch 72 is stuck on, a process may be performed to notify the driver of an abnormality that the second motor side switch 72 is stuck on.

[0081] When the first motor-side switch 71 is in the OFF state and the second motor-side switch 72 is stuck ON, the first end of the neutral point capacitor 74 is connected to the intermediate terminal B, and therefore the neutral point capacitor voltage VN and the second storage battery voltage VL become equal. Therefore, when it is determined that the neutral point capacitor voltage VN is equal to the second storage battery voltage VL, it can be determined that the first motor-side switch 71 is in the OFF state and the second motor-side switch 72 is stuck ON.

[0082] 8, the rated voltage of the second storage battery 32 may be used as the threshold value to be compared with the neutral point capacitor voltage VN instead of the second storage battery voltage VL. Furthermore, the inter-terminal voltage of the second storage battery 32 used as the threshold value is not limited to the detected value of the second voltage sensor 85B, and may be calculated based on the detected value of the second current sensor 81B.

[0083] Third Embodiment A third embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, whether or not the first motor-side switch 71 is stuck on is determined based on the current flowing through the connection path 73.

[0084] In this embodiment as well, the drive control shown in FIG. 5 is executed, and in step S12, the stuck-on determination shown in FIG. 9 is executed.

[0085] In step S50 of FIG. 9, the determining unit 103 acquires the motor current IN, which is the detection value of the motor current sensor 83, as the current flowing through the connection path 73.

[0086] In step S51, the determining unit 103 determines whether the motor current IN is 0 or not.

[0087] If it is determined that the motor current IN is 0, then in step S22, it is determined that the first motor-side switch 71 is normal.

[0088] On the other hand, if it is determined that the motor current IN is not 0, it is determined in step S21 that the first motor-side switch 71 is stuck on.

[0089] When a drive request is made, an OFF command is issued to the first motor-side switch 71. Therefore, during drive control, when the first motor-side switch 71 is in the OFF state, the current flowing in the portion of the connection path 73 closer to the neutral point O than the connection point with the neutral point capacitor 74 is zero. When a drive request is made and it is determined that the current flowing in the portion of the connection path 73 closer to the neutral point O than the connection point with the neutral point capacitor 74 is not zero, it can be determined that the first motor-side switch 71 is stuck ON.

[0090] Fourth Embodiment A fourth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in Fig. 10 , the power conversion device includes two sets of motors and inverters.

[0091] In this embodiment, the motor 10, inverter 20, armature winding 11, and rotor 13 in the first embodiment are respectively referred to as a first motor 10, a first inverter 20, a first armature winding 11, and a first rotor 13. Furthermore, the upper and lower arm switches SH and SL and the upper and lower arm diodes DH and DL in the first embodiment are respectively referred to as first upper and lower arm switches SAH and SAL and first upper and lower arm diodes DAH and DAL.

[0092] In addition, the smoothing capacitor 21, conductive member 23, phase current sensor 82, and power supply voltage sensor 86 in the first embodiment will be referred to as the first smoothing capacitor 21, the first conductive member 23, the first phase current sensor 82, and the first power supply voltage sensor 86, respectively.

[0093] The power conversion device includes a second motor 210 and a second inverter 220. The second motor 210 is a three-phase synchronous machine and includes star-connected U-, V-, and W-phase second armature windings 211 and a second rotor 213. The second armature windings 211 for each phase are arranged with an electrical angle offset of 120°. The second motor 210 is, for example, a permanent magnet synchronous machine. The second rotor 213 is capable of transmitting power to second drive wheels 302 of the vehicle. Therefore, the second motor 210 serves as a source of torque for propelling the vehicle. In this embodiment, the first rotor 213 is also capable of transmitting power to first drive wheels 301 of the vehicle. One of the first drive wheels 301 and the second drive wheels 302 is the front wheel of the vehicle, and the other is the rear wheel of the vehicle.

[0094] The second inverter 220 includes three phases of series-connected upper and lower arm switches. Specifically, the second inverter 220 includes a second upper arm switch SBH and a second lower arm switch SBL. A second upper arm diode DBH, which is a freewheeling diode, is connected in antiparallel to the second upper arm switch SBH, and a second lower arm diode DBL, which is also a freewheeling diode, is connected in antiparallel to the second lower arm switch SBL. In this embodiment, each of the switches SBH and SBL is an IGBT.

[0095] The second inverter 220 includes a second smoothing capacitor 221. The second smoothing capacitor 221 may be provided outside the second inverter 220.

[0096] First ends of U-, V-, and W-phase second armature windings 211U, 211V, and 211W are connected to a connection point between the emitter serving as the low-potential terminal of the second upper arm switch SBH and the collector serving as the high-potential terminal of the second lower arm switch SBL via second conductive members 223 such as bus bars. Second ends of the U-, V-, and W-phase second armature windings 211U, 211V, and 211W are connected to each other. In this embodiment, the U-, V-, and W-phase second armature windings 211U, 211V, and 211W are set to have the same number of turns. As a result, the U-, V-, and W-phase second armature windings 211U, 211V, and 211W are set to have the same inductance, for example.

[0097] A high potential side path 22H is connected to the collector of the second upper arm switch SBH, and a low potential side path 22L is connected to the emitter of the second lower arm switch SBL.

[0098] The power conversion device includes a second phase current sensor 282. The second phase current sensor 282 detects the current flowing through the second armature winding 211. The power conversion device also includes a second power supply voltage sensor 286 that detects the voltage across the second smoothing capacitor 221, and a second rotation angle sensor 287 (not shown) that detects the rotation angle (electrical angle) of the second rotor 213.

[0099] The motor ECU 100 receives the detection values ​​of a second phase current sensor 282 , a second power supply voltage sensor 286 , and a second rotation angle sensor 287 .

[0100] When limit control is performed, the motor ECU 100 performs switching control of the upper and lower arm switches SBH and SBL constituting the second inverter 220 to rotate the second rotor 213. Specifically, the motor ECU 100 performs switching control of the second upper and lower arm switches SBH and SBL constituting the second inverter 220 to feedback control the control variable of the second motor 210 to a command value based on the detection values ​​of each sensor. The control variable is, for example, torque. In each phase, the upper arm switch and the lower arm switch are alternately turned on. Through this feedback control, the rotational power of the second rotor 213 of the second motor 210 is transmitted to the second drive wheels 302, causing the vehicle to travel.

[0101] In limit control, the range of operating points at which the first motor 10 can output is smaller than the range of operating points at which the first motor 10 can output in normal control. Therefore, in this embodiment, the motor ECU 100 controls the switching of the second upper and lower arm switches SBH, SBL so that the torque of the second motor 210 compensates for the torque of the first motor 10, which has been reduced by limit control.

[0102] The procedure of drive control performed by the motor ECU 100 will be described with reference to FIG.

[0103] If it is determined in step S10 that a drive request has been made, the process proceeds to step S50. In step S50, the command unit 105 acquires a higher-level command torque Trqt*. The higher-level command torque Trqt* is, for example, a command torque input from the EVECU 110 to the motor ECU 100. After steps S11 and S12 are executed, if it is determined in step S13 that the first motor-side switch 71 is normal, normal control is executed in step S16. In normal control, the motor ECU 100 controls the switching of the first upper and lower arm switches SAH and SAL to control the torque of the first motor 10 to the higher-level command torque Trqt*.

[0104] On the other hand, if it is determined in step S13 that the first motor switch 71 is stuck on, step S14 is executed, and then the process proceeds to step S15, where limit control is executed.

[0105] The limit control of this embodiment will be described. The command unit 105 calculates a first command torque Trq1* and a second command torque Trq2*. The first command torque Trq1* is the command torque for the first motor 10, and the second command torque Trq2* is the command torque for the second motor 210.

[0106] The command unit 105 calculates the first command torque Trq1* and the second command torque Trq2*, for example, as follows: The command unit 105 calculates the operating point of the first motor 10 from the rotation speed of the first rotor 13 and the higher-level command torque Trqt*. Here, the rotation speed of the first rotor 13 is calculated based on the rotation angle of the first rotor 13 detected by the rotation angle sensor 87, for example.

[0107] The command unit 105 determines whether the operating point of the first motor 10 is within the range of the limit control map. If the command unit 105 determines that the operating point of the first motor 10 is outside the range of the limit control map, it reduces the first command torque Trq1* so that the operating point of the first motor 10 is within the range of the limit control map. The command unit 105 calculates the second command torque Trq2* by subtracting the first command torque Trq1* from the higher-level command torque Trqt*. In this way, the higher-level command torque Trqt* is distributed to the first command torque Trq1* and the second command torque Trq2*.

[0108] In limit control, the switch control unit 104 controls the switching of the first upper and lower arm switches SAH and SAL to control the torque of the first motor 10 to the first command torque Trq1*, and controls the switching of the second upper and lower arm switches SBH and SBL to control the torque of the second motor 210 to the second command torque Trq2*.

[0109] In this embodiment, the higher-level command torque Trqt* is distributed to the first command torque Trq1* and the second command torque Trq2*. This allows the second motor 210 to compensate for the torque of the first motor 10, which is reduced by turning on the first and second motor switches 71 and 72 during limit control. As a result, the total torque of the first and second motors 10 and 210 can be controlled to the higher-level command torque Trqt*.

[0110] <Modification of Fourth Embodiment> In limit control, the switch control unit 104 does not have to rotationally drive the first rotor 13. In this case, for example, the command unit 105 sets the first command torque Trq1* to 0 and sets the second command torque Trq2* to the higher-order command torque Trqt*.

[0111] Other Embodiments The above-described embodiments may be modified as follows.

[0112] 12 , the power conversion device may include an inter-battery switch 50 and a bypass switch 60 as a configuration for switching the connection state between the first storage battery 31 and the second storage battery 32. In this case, the terminal voltage (e.g., rated voltage) of the first storage battery 31 is higher than the terminal voltage (e.g., rated voltage) of the second storage battery 32. This configuration can be realized, for example, by making the number of unit batteries constituting the first storage battery 31 greater than the number of unit batteries constituting the second storage battery 32.

[0113] The inter-battery switch 50 and the bypass switch 60 are mechanical relays. When turned off, the inter-battery switch 50 and the bypass switch 60 block bidirectional current flow, and when turned on, allow bidirectional current flow. Note that the inter-battery switch 50 and the bypass switch 60 are not limited to mechanical relays and may be, for example, semiconductor switching elements.

[0114] The inter-battery switch 50 connects the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32. When the inter-battery switch 50 is turned on, the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32 are electrically connected. When the inter-battery switch 50 is turned off, the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32 are electrically disconnected.

[0115] The bypass switch 60 connects the negative terminal of the first storage battery 31 and the low potential side path 22L. When the bypass switch 60 is turned on, the negative terminal of the first storage battery 31 and the negative terminal of the second storage battery 32 are electrically connected. When the bypass switch 60 is turned off, the negative terminal of the first storage battery 31 and the negative terminal of the second storage battery 32 are electrically disconnected.

[0116] The connection path 73 is an electrical path that connects the low potential side intermediate terminal BL and the neutral point O. The low potential side intermediate terminal BL is on the path that connects the inter-battery switch 50 and the positive terminal of the second storage battery 32.

[0117] In the power conversion device shown in Fig. 12, when drive control is performed, the inter-battery switch 50 is turned on and the bypass switch 60 is turned off. The power conversion device shown in Fig. 12 can also perform the drive control and limit control shown in the first to third embodiments.

[0118] As shown in FIG. 13, the power conversion device may have a configuration in which the connection path 73 electrically connects the neutral point O of the armature winding 11 and the high potential side intermediate terminal BH.

[0119] The high-potential-side intermediate terminal BH is on a path connecting the inter-battery switch 50 and the negative terminal of the first storage battery 31. The bypass switch 61 connects the positive terminal of the second storage battery 32 and the high-potential-side path 22H. A first end of the neutral point capacitor 75 is connected to a portion of the connection path 73 between the first motor-side switch 71 and the second motor-side switch 72. A second end of the neutral point capacitor 75 is connected to a portion of the high-potential-side path 22H that is closer to the inverter 20 than the high-potential-side main switch SMRH.

[0120] In the power conversion device shown in FIG. 13 , the terminal voltage (for example, rated voltage) of the first storage battery 31 is lower than the terminal voltage (for example, rated voltage) of the second storage battery 32 .

[0121] In the power conversion device shown in FIG. 13 , when drive control is performed, the inter-battery switch 50 is turned on and the bypass switch 61 is turned off. The power conversion device shown in FIG. 13 can also perform the drive control and limiting control described in the first to third embodiments. Note that, in the power conversion device shown in FIG. 13 , when step S18 of FIG. 6 is performed, the voltage between the high-potential side path 22H and the neutral point O is calculated as the neutral point voltage VM. The motor ECU 100 calculates the neutral point voltage VM, for example, by subtracting the first storage battery voltage VH, which is the detection value of the first voltage sensor 85A, from the smoothing capacitor voltage VB, which is the detection value of the power supply voltage sensor 86. In the power conversion device shown in FIG. 13 , when step S41 of FIG. 8 is performed, the inter-terminal voltage of the first storage battery 31 is used as the threshold value to be compared with the neutral point capacitor voltage VN. For example, the detection value of the first voltage sensor 85A can be used as the inter-terminal voltage of the first storage battery 31.

[0122] In the fourth embodiment, the control shown in Figures 7 and 8 of the second embodiment may be executed. Also, in the fourth embodiment, the control shown in Figure 9 of the third embodiment may be executed.

[0123] The motor ECU 100 may determine whether the first and second motor-side switches 71 and 72 are stuck on while the rotor 13 is being rotated.

[0124] The switches of the inverter 20 are not limited to IGBTs and may be, for example, N-channel MOSFETs having body diodes. In this case, the high-potential terminal of the N-channel MOSFET serves as the drain, and the low-potential terminal serves as the source.

[0125] The high-potential side main switch SMRH does not have to be provided.

[0126] Instead of the low-potential side main switch SMRL, a series connection of the pre-charge main switch SMRP and the pre-charge resistor 40 may be connected in parallel to the high-potential side main switch SMRH. In this case, the low-potential side main switch SMRL does not have to be provided.

[0127] The fuses 41 and 42 do not have to be provided.

[0128] The motor is not limited to a star-connected motor, but may be a delta-connected motor. The motor and inverter are not limited to a three-phase motor, but may be a two-phase motor, or a four-phase or more phase motor. The motor is not limited to a permanent magnet synchronous machine having a permanent magnet as a field pole on the rotor, but may be a wound field 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. The motor is not limited to a synchronous machine, but may be an induction machine.

[0129] The control device that performs the drive control is not limited to the motor ECU 100. For example, each control may be performed by a plurality of control devices, such as the battery ECU 90, the EVECU 110, and the motor ECU 100, working together.

[0130] The power storage unit is not limited to a storage battery, and may be, for example, a large-capacity electric double layer capacitor, or may be a unit including both a storage battery and an electric double layer capacitor.

[0131] The mobile body on which the power conversion device is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship.Furthermore, the power conversion device is not limited to a mobile body, but may be a stationary device.

[0132] The control device and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and method described herein may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the control device and method described herein may be implemented by one or more special-purpose computers configured with a combination of a processor and memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0133] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A control device (100) applicable to a power conversion device including: an inverter (20) having upper and lower arm switches (SH, SL) of a plurality of phases; an armature winding (11) electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase; and a motor (10) having a rotor (13), wherein the power conversion device includes: a high potential side path (22H) electrically connecting a positive terminal of a first power storage unit (31) and a high potential side terminal of the upper arm switch; a low potential side path (22L) electrically connecting a negative terminal of a second power storage unit (32) and a low potential side terminal of the lower arm switch; a connection path (73) electrically connecting a negative terminal of the first power storage unit and a positive terminal of the second power storage unit to a neutral point (O) of the armature winding; and a first switch (71) provided on the connection path. a neutral point capacitor (74, 75) electrically connecting the low potential side path or the high potential side path to the connection path; and a second switch (72) provided in the connection path closer to the first storage unit or the second storage unit than a connection point with the neutral point capacitor; a determination unit (103) determining whether the first switch is stuck on or not; and a switch control unit (104) performing switching control of the upper and lower arm switches while issuing an OFF command for the first switch and the second switch to rotate the rotor, wherein the switch control unit switches the second switch to an ON state to perform the switching control when it is determined that the first switch is stuck on. [Configuration 2] The control device according to Configuration 1, wherein the power conversion device includes a voltage sensor (84) that detects a voltage of the neutral point capacitor, and the determination unit determines that the first switch is stuck on when it determines that the voltage (VN) of the neutral point capacitor detected by the voltage sensor is equivalent to a voltage of the neutral point of the armature winding.[Configuration 3] The control device according to Configuration 1, wherein the power conversion device includes a voltage sensor (84) that detects a voltage of the neutral point capacitor, and the determination unit determines that the second switch is stuck on when it is determined that the voltage of the neutral point capacitor detected by the voltage sensor is equivalent to the inter-terminal voltage (VL, VH) of either the first or second power storage unit. [Configuration 4] The control device according to Configuration 1, wherein the power conversion device includes a current sensor (83) that detects a current flowing in the connection path, and the determination unit determines that the first switch is stuck on when it is determined that a current is flowing in the connection path based on the current (IN) detected by the current sensor. [Configuration 5] The control device according to any one of Configurations 1 to 4, wherein the determination unit determines whether the first switch is stuck on after an OFF command is issued for the first switch and the second switch and before the switching control is performed. [Configuration 6] The control device according to any one of configurations 1 to 5, wherein the determination unit determines whether or not the second switch is stuck on after an OFF command is issued for the first switch and the second switch and before the switching control is performed. [Configuration 7] The control device according to any one of configurations 1 to 6, wherein, when it is determined that the first switch is stuck on, the switch control unit performs the switching control under a condition that the maximum rotation speed of the rotor is reduced below the maximum rotation speed before it is determined that the first switch is stuck on.[Configuration 8] The inverter is a first inverter having first upper and lower arm switches (SAH to SAL) as the upper and lower arm switches, and the motor is a first motor having a first armature winding as the armature winding, and the power conversion device is provided with: a second inverter (220) having second upper and lower arm switches (SBH, SBL) of a plurality of phases; and a second motor (210) having second armature windings (211U to 211W) electrically connected to low potential side terminals of the second upper arm switches of each phase and high potential side terminals of the second lower arm switches of each phase, wherein high potential side terminals of the second upper arm switches are electrically connected to the high potential side path, and low potential side terminals of the second lower arm switches are electrically connected to the low potential side path, The control device according to any one of configurations 1 to 7, wherein, when it is determined that the first switch is stuck on, the switch control unit performs switching control of the first and second inverters so as to control the total torque of the first and second motors to a command torque (Trqt*).

[0134] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A control device (100) applicable to a power conversion device including an inverter (20) having upper and lower arm switches (SH, SL) of a plurality of phases, an armature winding (11) electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase, and a motor (10) having a rotor (13), wherein the power conversion device includes: a high potential side path (22H) electrically connecting a positive terminal of a first storage unit (31) and a high potential side terminal of the upper arm switch, a low potential side path (22L) electrically connecting a negative terminal of a second storage unit (32) and a low potential side terminal of the lower arm switch, a connection path (73) electrically connecting a negative terminal of the first storage unit and a positive terminal of the second storage unit with a neutral point (O) of the armature winding, and a first switch (71) provided on the connection path, a neutral point capacitor (74, 75) electrically connecting the low potential side path or the high potential side path to the connection path; and a second switch (72) provided in the connection path closer to the first storage unit or the second storage unit than a connection point with the neutral point capacitor; a determination unit (103) determining whether the first switch is stuck on or not; and a switch control unit (104) performing switching control of the upper and lower arm switches while issuing an OFF command for the first switch and the second switch to rotate the rotor, wherein the switch control unit switches the second switch to an ON state to perform the switching control when it is determined that the first switch is stuck on.

2. The control device according to claim 1, wherein the power conversion device includes a voltage sensor (84) that detects the voltage of the neutral point capacitor, and the determination unit determines that the first switch is stuck on when it determines that the voltage (VN) of the neutral point capacitor detected by the voltage sensor is equivalent to the voltage of the neutral point of the armature winding.

3. The control device according to claim 1, wherein the power conversion device includes a voltage sensor (84) that detects the voltage of the neutral point capacitor, and the determination unit determines that the second switch is stuck on when it determines that the voltage of the neutral point capacitor detected by the voltage sensor is equivalent to the inter-terminal voltage (VL, VH) of either the first or second storage unit.

4. The control device according to claim 1, wherein the power conversion device is provided with a current sensor (83) that detects a current flowing in the connection path, and the determination unit determines that the first switch is stuck on when it determines that a current is flowing in the connection path based on the current (IN) detected by the current sensor.

5. A control device according to any one of claims 1 to 4, wherein the determination unit determines whether the first switch is stuck on after an OFF command is issued for the first switch and the second switch and before the switching control is performed.

6. The control device according to claim 3, wherein the determination unit determines whether the second switch is stuck on after an OFF command is issued for the first switch and the second switch and before the switching control is performed.

7. A control device according to any one of claims 1 to 4, wherein the switch control unit performs the switching control under the condition that, when it is determined that the first switch is stuck on, the maximum rotation speed of the rotor is reduced below the maximum rotation speed before it was determined that the first switch was stuck on.

8. The inverter is a first inverter having first upper and lower arm switches (SAH-SAL) as the upper and lower arm switches, and the motor is a first motor having a first armature winding as the armature winding, and the power conversion device is provided with: a second inverter (220) having second upper and lower arm switches (SBH, SBL) of multiple phases; and a second motor (210) having second armature windings (211U-211W) electrically connected to low potential side terminals of the second upper arm switches of each phase and high potential side terminals of the second lower arm switches of each phase, and the high potential side terminals of the second upper arm switches are electrically connected to the high potential side path, and the low potential side terminals of the second lower arm switches are electrically connected to the low potential side path, 5. The control device according to claim 1, wherein, when it is determined that the first switch is stuck on, the switch control unit performs switching control of the first and second inverters so as to control the total torque of the first and second motors to a command torque (Trqt*).

9. A program applicable to a power conversion device including an inverter (20) having upper and lower arm switches (SH, SL) of a plurality of phases, an armature winding (11) electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase, and a motor (10) having a rotor (13), wherein the power conversion device includes: a high potential side path (22H) electrically connecting a positive terminal of a first storage unit (31) and a high potential side terminal of the upper arm switch; a low potential side path (22L) electrically connecting a negative terminal of a second storage unit (32) and a low potential side terminal of the lower arm switch; a connection path (73) electrically connecting a negative terminal of the first storage unit and a positive terminal of the second storage unit with a neutral point (O) of the armature winding; and a first switch (71) provided on the connection path. a neutral point capacitor (74, 75) electrically connecting the low potential side path or the high potential side path to the connection path; and a second switch (72) provided in the connection path closer to the first storage unit or the second storage unit than a connection point with the neutral point capacitor, wherein the program causes a processor (101) to execute: a determination process for determining whether the first switch is stuck on; and a control process for performing switching control of the upper and lower arm switches while issuing an OFF command for the first switch and the second switch in order to rotationally drive the rotor, and when it is determined in the control process that the first switch is stuck on, the program switches the second switch to an ON state to perform the switching control.

10. A control method applicable to a power conversion device including an inverter (20) having upper and lower arm switches (SH, SL) of a plurality of phases, an armature winding (11) electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase, and a motor (10) having a rotor (13), wherein the power conversion device includes: a high potential side path (22H) electrically connecting a positive terminal of a first storage unit (31) and a high potential side terminal of the upper arm switch; a low potential side path (22L) electrically connecting a negative terminal of a second storage unit (32) and a low potential side terminal of the lower arm switch; a connection path (73) electrically connecting a negative terminal of the first storage unit and a positive terminal of the second storage unit with a neutral point (O) of the armature winding; and a first switch (71) provided on the connection path. a neutral point capacitor (74, 75) electrically connecting the low potential side path or the high potential side path to the connection path; and a second switch (72) provided in the connection path closer to the first storage unit or the second storage unit than a connection point with the neutral point capacitor, the control method comprising: a determination step of determining whether the first switch is stuck on; and a control step of performing switching control of the upper and lower arm switches while issuing an OFF command for the first switch and the second switch to rotate the rotor, wherein if it is determined in the control step that the first switch is stuck on, the second switch is switched on to perform the switching control.