Control device for rotary electric machine system, program, and control method for rotary electric machine system

Abstract

A rotary electric machine system (100, 110) comprises: a discharge resistor (70) connected in parallel to either a first capacitor (15a) connected to a first inverter (20, 120) or a second capacitor (15b) connected to a second inverter (30, 130); and a connection switch (QH, QL, RH) for connecting or disconnecting the discharge resistor and the specific capacitor not connected in parallel to the discharge resistor among the first capacitor and the second capacitor. A control device (60) for a rotary electric machine system comprises: an abnormality determination unit (84) that determines whether an abnormality has occurred in the rotary electric machine system; and a switch operation unit (80, 83) that turns a power supply switch (MH, MHa, MHb) off and turns the connection switch on when it is determined that an abnormality has occurred in the rotary electric machine system.

Description

Control device for rotating electric machine system, program, and control method for rotating electric machine system CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-089909, filed on June 3, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a control device for a rotating electric machine system, a program, and a control method for a rotating electric machine system.

[0003] A conventional rotating electric machine system includes a rotating electric machine and an inverter for controlling the rotating electric machine. A smoothing capacitor is connected in parallel to the DC side of the inverter. The rotating electric machine system includes a resistor for discharging the smoothing capacitor when an abnormality occurs. An example of such a technology is disclosed in Patent Document 1.

[0004] Patent No. 4418318

[0005] A rotating electric machine system is known in which a rotating electric machine is controlled by a first inverter and a second inverter, a first capacitor is connected in parallel to the first inverter, and a second capacitor is connected in parallel to the second inverter.

[0006] In a rotating electrical machine system including a first inverter and a second inverter, when an abnormality occurs, it is required to discharge the first capacitor and the second capacitor, and in this case, there is a concern that the number of components in the rotating electrical machine system will increase due to the provision of a resistor for discharging the first capacitor and a resistor for discharging the second capacitor.

[0007] An object of the present disclosure is to provide a control device for a rotating electric machine system, a program, and a control method for a rotating electric machine system that can suppress an increase in the number of parts.

[0008] The present disclosure relates to a control device for a rotating electric machine system including: a first inverter of multiple phases connected in parallel to a first capacitor; a second inverter of multiple phases connected in parallel to a second capacitor; a rotating electric machine having windings connected to the first inverter and the second inverter for the same number of phases; a DC power supply connected in parallel to at least one of the first capacitor and the second capacitor; and a power switch that connects or disconnects one of the first capacitor and the second capacitor that is connected in parallel to the DC power supply, wherein the rotating electric machine system includes: a discharge resistor connected in parallel to only one of the first capacitor and the second capacitor; and a connection switch that connects or disconnects the discharge resistor to a specific capacitor of the first capacitor and the second capacitor that is not connected in parallel to the discharge resistor; an abnormality determination unit that determines whether an abnormality has occurred in the rotating electric machine system; and a switch operation unit that turns off the power switch and turns on the connection switch when the abnormality determination unit determines that an abnormality has occurred in the rotating electric machine system.

[0009] In the present disclosure, when it is determined that an abnormality has occurred in the rotating electric machine system, the power switch is turned off and the connection switch is turned on. In this case, by turning the power switch off, one of the first capacitor and the second capacitor, to which a discharge resistor is connected in parallel, is allowed to discharge. By turning the power switch off and the connection switch on, the specific capacitor is allowed to discharge. Therefore, in a rotating electric machine system in which a discharge resistor is connected in parallel to only one of the first capacitor and the second capacitor, the first capacitor and the second capacitor can be discharged when an abnormality occurs. As a result, an increase in the number of components in the rotating electric machine system can be suppressed compared to a comparative example in which a resistor is provided in each of the first capacitor and the second capacitor.

[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 rotating electric machine system according to a first embodiment, Fig. 2 is a functional block diagram of processing executed by a control device, Fig. 3 is a diagram illustrating a control mode of H drive control, Fig. 4 is a diagram illustrating a control mode of Y drive control, Fig. 5 is a flowchart illustrating a procedure of processing executed by the control device, Fig. 6 is a flowchart illustrating a procedure of processing executed by the control device, Fig. 7 is a diagram illustrating an example of operation when an abnormality occurs in the rotating electric machine system, Fig. 8 is a diagram illustrating an example of operation when an abnormality occurs in the rotating electric machine system according to a second embodiment, Fig. 9 is a diagram illustrating an example of operation when an abnormality occurs in the rotating electric machine system according to a modification of the second embodiment, Fig. 10 is an overall configuration diagram of a rotating electric machine system according to another embodiment, and Fig. 11 is an overall configuration diagram of a rotating electric machine system according to another embodiment.

[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 control device according to the present disclosure will now be described with reference to the drawings. In this embodiment, the control device is mounted on an electric vehicle, a hybrid vehicle, or other electrically powered vehicle, and constitutes an on-board rotating electric machine system.

[0013] As shown in FIG. 1 , the rotating electrical machine system 100 includes a battery 10 (corresponding to a "DC power supply"), a first inverter 20, a second inverter 30, and a rotating electrical machine 40. The battery 10 is, for example, a battery pack including a series connection of unit cells. The unit cell is a single battery cell or a series connection of multiple battery cells. The battery cell is, for example, a secondary battery such as a lithium-ion battery.

[0014] The first inverter 20 and the second inverter 30 are power conversion circuits that convert DC power supplied from the battery 10 into three-phase AC power and supply it to the rotating electric machine 40 .

[0015] The first inverter 20 includes a series connection of U-, V-, and W-phase first upper arm switches SUHa, SVHa, and SWHa and U-, V-, and W-phase first lower arm switches SULa, SVLa, and SWLa. The second inverter 30 includes a series connection of U-, V-, and W-phase second upper arm switches SUHb, SVHb, and SWHb and U-, V-, and W-phase second lower arm switches SULb, SVLb, and SWLb.

[0016] In this embodiment, voltage-controlled semiconductor switching elements, more specifically, N-channel MOSFETs, are used as the switches SUHa to SWLa and SUHb to SWLb. In this case, the high-potential terminal of each of the switches SUHa to SWLa and SUHb to SWLb is the drain, and the low-potential terminal is the source. The switches SUHa, SVHa, SWHa, SULa, SVLa, SWLa, SUHb, SVHb, SWHb, SULb, SVLb, and SWLb each have a body diode DUHa, DVHa, DWHa, DULa, DVLa, DWLa, DUHb, DVHb, DWHb, DULb, DVLb, and DWLb.

[0017] The drains of the first upper arm switches SUHa, SVHa, SWHa of each phase and the drains of the second upper arm switches SUHb, SVHb, SWHb of each phase are electrically connected by a positive bus 11 such as a bus bar. The sources of the first lower arm switches SULa, SVLa, SWLa of each phase and the drains of the second lower arm switches SULb, SVLb, SWLb of each phase are electrically connected by a negative bus 12 such as a bus bar.

[0018] The positive terminal of the battery 10 is electrically connected to the positive bus 11 on the side opposite to the connection point with the second upper arm switches SUHb, SVHb, SWHb of each phase, relative to the connection point with the first upper arm switches SUHa, SVHa, SWHa of each phase. The negative terminal of the battery 10 is electrically connected to the negative bus 12 on the side opposite to the connection point with the second lower arm switches SULb, SVLb, SWLb of each phase, relative to the connection point with the first lower arm switches SULa, SVLa, SWLa of each phase.

[0019] The rotating electric machine 40 is an in-vehicle main motor. A rotor 41 of the rotating electric machine 40 is capable of transmitting power to drive wheels 43 of the vehicle. In this embodiment, the rotating electric machine 40 is a permanent magnet field type synchronous machine. The rotor 41 includes permanent magnets 42 (e.g., neodymium magnets) as field poles.

[0020] The rotating electric machine 40 includes a stator 50. The stator 50 includes armature windings, namely, a U-phase winding 51U, a V-phase winding 51V, and a W-phase winding 51W. The phase windings 51U, 51V, and 51W are arranged with an electrical angle offset of 120°. The phase windings 51U, 51V, and 51W are open-connected, and both ends of each phase winding 51U, 51V, and 51W are electrically connected to the first inverter 20 or the second inverter 30.

[0021] Specifically, in each phase, first ends 51Ua, 51Va, 51Wa of the windings 51U, 51V, 51W are electrically connected to the sources of the first upper switches SUHa, SVHa, SWHa and the drains of the first lower switches SULa, SVLa, SWLa. In addition, second ends 51Ub, 51Vb, 51Wb of the windings 51U, 51V, 51W are electrically connected to the sources of the second upper switches SUHb, SVHb, SWHb and the drains of the second lower switches SULb, SVLb, SWLb.

[0022] The rotating electrical machine system 100 includes a changeover switch QH. The changeover switch QH is provided on the positive bus 11 (corresponding to the "target bus") between the first inverter 20 and the second inverter 30. Specifically, the changeover switch QH is provided on the positive bus 11 between a connection point with the first upper arm switches SUHa, SVHa, SWHa of each phase and a connection point with the second upper arm switches SUHb, SVHb, SWHb of each phase.

[0023] The changeover switch QH is configured to be able to switch between bidirectional current flow in the positive bus 11. In this embodiment, a normally-off semiconductor switching element, specifically an N-channel MOSFET, is used as the switch constituting the changeover switch QH.

[0024] Specifically, the changeover switch QH is composed of a pair of switches, a first changeover switch QHa and a second changeover switch QHb. The drains of the first changeover switch QHa and the second changeover switch QHb are electrically connected to each other. The source of the first changeover switch QHa is electrically connected to the drains of the first upper arm switches SUHa, SVHa, and SWHa of each phase. The source of the second changeover switch QHb is electrically connected to the drains of the second upper arm switches SUHb, SVHb, and SWHb of each phase. The first and second changeover switches QHa and QHb have body diodes DHa and DHb.

[0025] When the changeover switch QH (i.e., each of the changeover switches QHa and QHb) is turned on, bidirectional current flow is permitted in the positive bus 11. When the changeover switch QH is turned off, bidirectional current flow in the positive bus 11 is blocked. In this embodiment, the changeover switch QH is controlled by a control device 60 provided in the rotating electric machine system 100. As will be described later, the changeover switch QH is provided to switch the driving state of the rotating electric machine system 100.

[0026] The rotating electrical machine system 100 includes a first capacitor 15a and a second capacitor 15b. Each of the capacitors 15a and 15b is a smoothing capacitor. For example, each of the capacitors 15a and 15b may be an electric double layer capacitor or an electrolytic capacitor.

[0027] The first capacitor 15a is electrically connected in parallel with the battery 10 and the series-connected assembly of the first upper arm switches SUHa, SVHa, SWHa of each phase and the first lower arm switches SULa, SVLa, SWLa of each phase. More specifically, a first end of the first capacitor 15a is electrically connected between a connection point of the positive side bus 11 with the first upper arm switches SUHa, SVHa, SWHa of each phase and the positive terminal of the battery 10. A second end of the first capacitor 15a is electrically connected between a connection point of the negative side bus 12 with the first lower arm switches SULa, SVLa, SWLa of each phase and the negative terminal of the battery 10.

[0028] The second capacitor 15b is electrically connected in parallel to the series-connected assembly of the second upper arm switches SUHb, SVHb, and SWHb for each phase and the second lower arm switches SULb, SVLb, and SWLb for each phase. Specifically, a first end of the second capacitor 15b is electrically connected to the positive bus 11 on the side opposite the change-over switch QH with respect to a connection point with the second upper arm switches SUHb, SVHb, and SWHb for each phase. A second end of the second capacitor 15b is electrically connected to the negative bus 12 on the side opposite the connection point with the first lower arm switches SULa, SVLa, and SWLa with respect to a connection point with the second lower arm switches SULb, SVLb, and SWLb for each phase.

[0029] The rotating electrical machine system 100 includes a power switch MH. The power switch MH is a switch that electrically connects or disconnects the battery 10 and the first capacitor 15a. For example, the power switch MH is a normally-off switch, such as a relay or a semiconductor switching element. In this embodiment, the power switch MH is provided between a connection point of the positive bus 11 with the first end of the first capacitor 15a and the positive terminal of the battery 10. The power switch MH is controlled by the control device 60.

[0030] The rotating electrical machine system 100 includes a voltage sensor 61, a current sensor 62, a rotational angle sensor 63, a start switch 64, and an acceleration sensor 65. The voltage sensor 61 detects the voltage V1r of the first capacitor 15a. The current sensor 62 detects the phase currents Iur, Ivr, and Iwr flowing through the respective phase windings 51U, 51V, and 51W. In this embodiment, the current sensor 62 is provided on one of the ends of each phase winding 51U, 51V, and 51W that is closer to the first inverter 20. Note that the current sensor 62 may also be provided on one of the ends of each phase winding 51U, 51V, and 51W that is closer to the second inverter 30. The rotational angle sensor 63 is, for example, a resolver, and detects the electrical angle θr of the rotor 41. The detected values ​​of the sensors 61 to 63 are input to the control device 60.

[0031] The start switch 64 is, for example, an ignition switch or a push-button start switch, and is operated by the vehicle user. The acceleration sensor 65 detects the acceleration a of the vehicle. A signal notifying that the start switch 64 has been turned on or off and the detected value of the acceleration sensor 65 are input to the control device 60.

[0032] The control device 60 is an electronic control unit (ECU) that performs various controls of the rotating electrical machine system 100, and includes a processor 60a and a storage unit 60b as hardware. In the rotating electrical machine system 100, each on-board device can be controlled by an ECU corresponding to that device. However, for convenience, multiple ECUs are shown as a single control device 60 in FIG. 1 .

[0033] The memory unit 60b includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the control device 60. For example, the memory provides the processor 60a with a working area for temporary use when the processor 60a performs processing. 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 processor 60a, and is a non-transitory tangible storage medium. For example, the storage includes an HDD or a flash memory. The storage stores program information and the like for the processing shown in FIGS. 5 and 6, which will be described later.

[0034] For example, program information stored in a non-transient physical recording medium is installed in the storage unit 60b. 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 unit 60b.

[0035] As shown in FIG. 2 , the control device 60 includes an inverter control unit 80, a speed calculation unit 81, a selection unit 82, and a switch control unit 83. A signal indicating that the start switch 64 has been turned on or off is input to the switch control unit 83. When the signal indicating that the start switch 64 has been turned on is input, the switch control unit 83 turns on the power switch MH. This allows current to flow from the battery 10 to the rotating electric machine 40. When the signal indicating that the start switch 64 has been turned off is input, the switch control unit 83 turns off the power switch MH. This stops current flow from the battery 10 to the rotating electric machine 40.

[0036] In order to control the control variable of the rotary electric machine 40 to a command value, the inverter control unit 80 controls the on / off of each of the switches SUHa to SWLa of the first inverter 20 and each of the switches SUHb to SWLb of the second inverter 30 while the power switch MH is turned on. For example, the control variable is torque.

[0037] More specifically, the inverter control unit 80 receives as input the detected voltage V1r from the voltage sensor 61, the phase currents Iur, Ivr, and Iwr detected by the current sensor 62, and the electrical angle θr detected by the rotation angle sensor 63. The inverter control unit 80 generates operation signals for the switches SUHa to SWLa and SUHb to SWLb based on the detected voltage V1r, the phase currents Iur, Ivr, and Iwr, and the electrical angle θr, in order to control the torque of the rotating electric machine 40 to a torque command value Trq* received from a control device that is higher in level than the control device 60. The operation signals include on and off commands for the switches.

[0038] The speed calculation unit 81 calculates the rotation speed Nr of the rotor 41 based on the electrical angle θr detected by the rotation angle sensor 63 .

[0039] The selection unit 82 determines whether the rotating electric machine system 100 should perform Y drive control or H drive control. In the present embodiment, the selection unit 82 selects whether the rotating electric machine system 100 should perform Y drive control or H drive control based on the operating point of the rotating electric machine 40, which is determined by the calculated rotation speed Nr and torque command value Trq*, and on the control map information. The control map information is information that defines the Y drive control region and the H drive control region in association with the rotation speed Nr and the torque command value Trq*. The control map information is stored in the storage unit 60b.

[0040] When the H drive control is selected by the selection unit 82, the switch control unit 83 turns on the changeover switch QH as the H drive control, as shown in Fig. 3. When the H drive control is selected by the selection unit 82, the inverter control unit 80 performs switching control to PWM-drive the switches SUHa to SWLa of the first inverter 20 and to PWM-drive the switches SUHb to SWLb of the second inverter 30.

[0041] On the other hand, when Y-drive control is selected by the selector 82, the switch control unit 83 turns off the changeover switch QH as Y-drive control, as shown in Fig. 4. When Y-drive control is selected by the selector 82, the inverter control unit 80 performs switching control to PWM-drive each of the switches SUHa to SWLa of the first inverter 20. In addition, the inverter control unit 80 fixes the second upper-arm switches SUHb, SVHb, and SWHb of each phase to on, and fixes the second lower-arm switches SULb, SVLb, and SWLb of each phase to off. As a result, the phase windings 51U, 51V, and 51W are star-connected via the second inverter 30.

[0042] Based on the generated operation signal, the inverter control unit 80 controls the charge / discharge current of the gates of the switches SUHa to SWLa and SUHb to SWLb in each of the inverters 20 and 30. As a result, the switches SUHa to SWLa and SUHb to SWLb of each of the inverters 20 and 30 are controlled to an on or off state in accordance with the operation signal. In this embodiment, the inverter control unit 80, the speed calculation unit 81, and the selection unit 82 correspond to a "control unit."

[0043] 5 is a flowchart showing the control process of the rotary electric machine 40 executed by the control device 60. The process shown in FIG. 5 is repeatedly executed by the processor 60a of the control device 60, for example, at a predetermined control cycle.

[0044] In step S10 , the selection unit 82 acquires the torque command value Trq* and the rotation speed Nr calculated by the speed calculation unit 81 .

[0045] In step S11, the selection unit 82 selects either the Y drive control or the H drive control based on the torque command value Trq* and the rotation speed Nr.

[0046] If Y drive control is selected in step S11, the process proceeds to step S13, where the inverter control unit 80 and the switch control unit 83 execute the Y drive control shown in Fig. 4. On the other hand, if H drive control is selected in step S11, the process proceeds to step S14, where the inverter control unit 80 and the switch control unit 83 execute the H drive control shown in Fig. 3.

[0047] Incidentally, it is required to discharge the capacitors 15a and 15b when an abnormality occurs in the rotating electrical machine system 100. For example, the abnormality in the rotating electrical machine system 100 occurs when the vehicle crashes.

[0048] It is conceivable to provide resistors in the rotating electrical machine system 100 for discharging the first capacitor 15 a and the second capacitor 15 b when an abnormality occurs in the rotating electrical machine system 100. In this case, there is a concern that the number of components in the rotating electrical machine system 100 will increase due to the provision of a resistor for discharging the first capacitor 15 a and a resistor for discharging the second capacitor 15 b.

[0049] Therefore, in this embodiment, the rotating electric machine system 100 has the following configuration to enable the first capacitor 15a and the second capacitor 15b to be discharged when an abnormality occurs while suppressing an increase in the number of parts.

[0050] 1, the rotating electrical machine system 100 includes a discharge resistor 70 as a passive element and a series switch Ka. The discharge resistor 70 has a resistance value determined based on the voltage (e.g., rated voltage) of the battery 10 and the capacitance of each of the capacitors 15 a and 15 b.

[0051] The discharge resistor 70 is electrically connected in parallel with only the first capacitor 15a of the first capacitor 15a and the second capacitor 15b. In Fig. 1, a first end of the discharge resistor 70 is electrically connected between the power switch MH and a connection point of the positive bus 11 with the first end of the first capacitor 15a. A second end of the discharge resistor 70 is electrically connected between the negative terminal of the battery 10 and a connection point of the negative bus 12 with the second end of the first capacitor 15a.

[0052] The series switch Ka is connected in series to the discharge resistor 70 on the low potential side relative to the discharge resistor 70. Specifically, the second end of the discharge resistor 70 is electrically connected to the high potential side terminal of the series switch Ka. The low potential side terminal of the series switch Ka is electrically connected to the negative bus 12. In this embodiment, the series switch Ka is a normally-off switch, and is a semiconductor switching element or a relay. The series switch Ka is controlled by the switch control unit 83. Note that the series switch Ka may be connected in series to the discharge resistor 70 on the high potential side relative to the discharge resistor 70.

[0053] 2, the control device 60 includes an abnormality determination unit 84. The abnormality determination unit 84 determines whether or not an abnormality has occurred in the rotating electrical machine system 100. In this embodiment, the abnormality determination unit 84 acquires the acceleration ar of the vehicle detected by the acceleration sensor 65. The abnormality determination unit 84 determines whether or not a vehicle collision has occurred based on the acquired acceleration ar.

[0054] For example, the abnormality determination unit 84 may determine whether an abnormality associated with a vehicle collision has occurred. Specifically, the abnormality determination unit 84 may acquire the detection value V1r of the voltage sensor 61 and the detection values ​​Iur, Ivr, and Iwr of the current sensor 62, and determine whether a failure has occurred in at least one of the inverters 20, 30 based on the acquired detection values. The abnormality determination unit 84 may also determine whether an abnormality has occurred in the control device 60. For example, an abnormality may occur in the control device 60, causing at least a part of the function of the inverter control unit 80 to be lost, or an abnormality may occur in the control device 60, causing a drop in the power supply voltage of the control device 60.

[0055] When the abnormality determination unit 84 determines that no abnormality has occurred in the rotating electrical machine system 100, the switch control unit 83 turns off the series switch Ka, thereby preventing current from flowing through the discharge resistor 70 while the rotating electrical machine 40 is running.

[0056] When the abnormality determination unit 84 determines that an abnormality has occurred in the rotating electrical machine system 100, the switch control unit 83 performs switch operations to discharge the capacitors 15a, 15b. Specifically, when it is determined that an abnormality has occurred in the rotating electrical machine system 100, the switch control unit 83 turns off the power switch MH and turns on the series switch Ka and the changeover switch QH. In this embodiment, the switch control unit 83 turns on at least the first changeover switch QHa of the first changeover switch QHa and the second changeover switch QHb.

[0057] 6 is a flowchart showing the control process of the rotary electric machine 40 executed by the control device 60. The process shown in FIG. 6 is repeatedly executed by the processor 60a of the control device 60, for example, at a predetermined control cycle.

[0058] In step S20, the abnormality determination unit 84 determines whether an abnormality has occurred in the rotating electrical machine system 100. In this embodiment, the abnormality determination unit 84 determines at least one of whether a vehicle collision has occurred and whether an abnormality has occurred due to the vehicle collision. If the determination in step S20 is negative, the control ends. On the other hand, if the determination in step S20 is positive, the process proceeds to step S21.

[0059] In step S21, the switch control unit 83 turns off the power switch MH and turns on the series switch Ka. As a result, after it is determined that an abnormality has occurred in the rotating electrical machine system 100, the power switch MH is turned off and the series switch Ka is turned on.

[0060] Furthermore, the switch control unit 83 turns on the changeover switch QH. In this case, for example, if an abnormality occurs in the rotating electrical machine system 100 while the Y drive control is selected, the changeover switch QH is switched from the off state to the on state after it is determined that an abnormality has occurred in the rotating electrical machine system 100. By turning on the changeover switch QH, current is allowed to flow from the second capacitor 15b to the discharge resistor 70 in the positive bus 11.

[0061] In this embodiment, the changeover switch QH is a switch that can switch between bidirectional current flow in the positive bus 11. Therefore, in order to allow current to flow from the second capacitor 15b to the discharge resistor 70 in the positive bus 11 when an abnormality occurs in the rotating electrical machine system 100, the changeover switch QH needs to be turned on. The changeover switch QH corresponds to a "connection switch," and the switch control unit 83 corresponds to a "switch operation unit."

[0062] In this embodiment, when it is determined that an abnormality has occurred in the rotating electrical machine system 100, the power switch MH is turned off and the changeover switch QH is turned on. In this case, the power switch MH being turned off allows the first capacitor 15a to be discharged. The power switch MH being turned off and the changeover switch QH being turned on allows the second capacitor 15b to be discharged.

[0063] More specifically, as indicated by the dashed line in Fig. 7, the first capacitor 15a is discharged by a current flowing through a closed circuit including the first capacitor 15a and the discharge resistor 70. Also, as indicated by the dashed line in Fig. 7, the second capacitor 15b is discharged by a current flowing through a closed circuit including the second capacitor 15b, the positive bus 11, the negative bus 12, the changeover switch QH, and the discharge resistor 70.

[0064] According to the present embodiment described above, in the rotating electrical machine system 100 in which the discharge resistor 70 is connected in parallel only to the first capacitor 15a of the capacitors 15a, 15b, each of the capacitors 15a, 15b can be discharged when an abnormality occurs. Therefore, compared to the comparative example in which each of the capacitors 15a, 15b is provided with a resistor, an increase in the number of components in the rotating electrical machine system 100 can be suppressed.

[0065] When it is determined that an abnormality has occurred in the rotating electric machine system 100, the changeover switch QH is turned on. That is, in this embodiment, the changeover switch QH, which is used to switch between Y drive control and H drive control of the rotating electric machine system 100, can be used to connect the second capacitor 15b and the discharge resistor 70 when an abnormality has occurred in the rotating electric machine system 100. Therefore, an increase in the number of parts in the rotating electric machine system 100 can be effectively suppressed.

[0066] When it is determined that no abnormality has occurred in the rotating electric machine system 100, the series switch Ka is turned off. In this case, current is prevented from flowing through the discharge resistor 70 while the rotating electric machine 40 is running. This makes it possible to prevent an increase in power loss in the rotating electric machine system 100 compared to a configuration without the series switch Ka. Furthermore, when it is determined that an abnormality has occurred in the rotating electric machine system 100, the series switch Ka is turned on. This makes it possible to allow current to flow through the discharge resistor 70 when an abnormality has occurred in the rotating electric machine system 100, thereby discharging the capacitors 15a, 15b. Therefore, it is possible to discharge the capacitors 15a, 15b when an abnormality has occurred while preventing an increase in power loss in the rotating electric machine system 100.

[0067] <Modification of First Embodiment> If it is determined that an abnormality has occurred in the rotating electrical machine system 100 during a period in which the H drive control is selected, the switch control unit 83 may execute the following processing.

[0068] 6, the switch control unit 83 maintains the ON operation of the changeover switch QH both before and after it is determined that an abnormality has occurred in the rotating electrical machine system 100. As a result, the ON state of the changeover switch QH is maintained both before and after it is determined that an abnormality has occurred in the rotating electrical machine system 100. This allows the discharge of the second capacitor 15b to start promptly.

[0069] The discharge resistor and the series switch may be electrically connected in parallel only to the second capacitor 15b of the capacitors 15a and 15b. In this case, in step S21 of Fig. 6, the switch control unit 83 performs a process of turning on at least the second switch QHb of the first switch QHa and the second switch QHb. This enables the first capacitor 15a and the second capacitor 15b to discharge.

[0070] Second Embodiment A second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, processing executed by the inverter control unit 80 is added as processing to be performed when it is determined that an abnormality has occurred in the rotating electrical machine system 100. Here, the processing performed by the inverter control unit 80 will be described assuming a situation in which it is determined that an abnormality has occurred in the rotating electrical machine system 100 during a period in which H drive control is selected.

[0071] 6, the switch control unit 83 performs the same processing as in the first embodiment. Furthermore, the inverter control unit 80 generates an ON command for the second upper arm switches SUHb, SVHb, and SWHb of each phase of the second inverter 30 in order to discharge the second capacitor 15b. As a result, after it is determined that an abnormality has occurred in the rotating electrical machine system 100, the second upper arm switches SUHb, SVHb, and SWHb of each phase are turned ON. The inverter control unit 80 and the switch control unit 83 correspond to a "switch operation unit."

[0072] In this embodiment, as shown in FIG. 8 , in addition to the discharge path of the second capacitor 15b via the selector switch QH described in FIG. 7 , a current flows through a path including the inverters 20 and 30 and the respective phase windings 51U, 51V, and 51W. Specifically, a current flows through a closed circuit including the second capacitor 15b, the respective phase second upper-arm switches SUHb, SVHb, and SWHb, the respective phase windings 51U, 51V, and 51W, the respective phase first upper-arm diodes DUHa, DVHa, and DWHa, and the discharge resistor 70. This discharges the second capacitor 15b. Therefore, a large number of discharge paths can be secured for discharging the second capacitor 15b when an abnormality occurs in the rotating electrical machine system 100. As a result, a configuration suitable for discharging the second capacitor 15b can be realized. For example, even if a failure occurs in one of the changeover switch QH and the second upper arm switches SUHb, SVHb, and SWHb of each phase, the second capacitor 15b can be discharged by keeping a switch other than the failed switch in the on state. Furthermore, compared to the configuration in which the second capacitor 15b is discharged only through the discharge path described in Fig. 7, for example, it is possible to shorten the discharge time from when it is determined that an abnormality has occurred in the rotating electrical machine system 100 until the discharge of the second capacitor 15b is completed, and to suppress heat generation in the switches QH, SUHa, SVHa, SWHa, SUHb, SVHb, and SWHb.

[0073] <Modification of Second Embodiment> If it is determined that an abnormality has occurred in the rotating electrical machine system 100 during a period in which the Y drive control is selected, the inverter control unit 80 executes the following process.

[0074] 6 , the switch control unit 83 performs the same process as in the first embodiment. Furthermore, the inverter control unit 80 maintains the output of the ON command to the second upper arm switches SUHb, SVHb, and SWHb of each phase across the period before and after it is determined that an abnormality has occurred in the rotating electrical machine system 100. This maintains the ON state of the second upper arm switches SUHb, SVHb, and SWHb of each phase across the period before and after it is determined that an abnormality has occurred in the rotating electrical machine system 100. As a result, the discharge of the second capacitor 15b can be started promptly.

[0075] 9, during the period from when the power switch MH is turned off and the series switch Ka is turned on until the changeover switch QH is turned on, a current can flow through a path including the inverters 20, 30 and the phase windings 51U, 51V, 51W. Therefore, when it is determined that an abnormality has occurred in the rotating electrical machine system 100, discharging of the second capacitor 15b can be started promptly.

[0076] 6, the switch control unit 83 may not perform the process of turning on the selector switch QH, and the inverter control unit 80 may perform the process of generating an ON command for the second upper arm switches SUHb, SVHb, SWHb of each phase. Even in this case, when it is determined that an abnormality has occurred in the rotating electrical machine system 100, it is possible to discharge the second capacitor 15b.

[0077] The discharge resistor and the series switch may be connected in parallel only to the second capacitor 15b of the capacitors 15a and 15b. In this case, in step S21 of FIG. 6, the switch control unit 83 may perform the same process as in the first embodiment. Also, the inverter control unit 80 may perform the process of generating an ON command for the first upper arm switches SUHa, SVHa, and SWHa of each phase.

[0078] Other Embodiments The above-described embodiments may be modified as follows.

[0079] The sources of the first and second changeover switches QHa and QHb constituting the changeover switch QH may be electrically connected to each other. In this case, the drain of the first changeover switch QHa may be electrically connected to the drains of the first upper arm switches SUHa, SVHa, and SWHa of each phase. The drain of the second changeover switch QHb may be electrically connected to the drains of the second upper arm switches SUHb, SVHb, and SWHb of each phase.

[0080] The changeover switch may be provided on the negative bus bar 12 (corresponding to the “target bus bar”) instead of the positive bus bar 11 .

[0081] Specifically, as shown in FIG. 10, the changeover switch QL may be provided between the connection point of the negative side bus 12 with the first upper arm switches SUHa, SVHa, SWHa of each phase and the connection point of the second upper arm switches SUHb, SVHb, SWHb of each phase.

[0082] The changeover switch QL is configured to be able to switch between conducting and blocking bidirectional current flowing through the negative bus 12. In this embodiment, the changeover switch QL is configured by a pair of switches, a first changeover switch QLa and a second changeover switch QLb. The drains of the first changeover switch QLa and the second changeover switch QLb are electrically connected to each other. The source of the first changeover switch QLa is electrically connected to the sources of the first lower arm switches SULa, SVLa, and SWLa of each phase. The source of the second changeover switch QLb is electrically connected to the sources of the second lower arm switches SULb, SVLb, and SWLb of each phase. The first and second changeover switches QLa and QLb have body diodes DLa and DLb.

[0083] When the changeover switch QL (i.e., each of the changeover switches QLa and QLb) is turned on, bidirectional current flow is permitted in the negative bus bar 12. When the changeover switch QL is turned off, bidirectional current flow in the negative bus bar 12 is blocked.

[0084] When the selection unit 82 selects H drive control, the switch control unit 83 turns on the changeover switch QL provided on the negative bus 12. On the other hand, when the selection unit 82 selects Y drive control, the switch control unit 83 turns off the changeover switch QL. When the selection unit 82 selects Y drive control, the inverter control unit 80 performs switching control to PWM drive the switches SUHa to SWLa of the first inverter 20. In addition, the inverter control unit 80 fixes the second lower arm switches SULb, SVLb, and SWLb of each phase to on and fixes the second upper arm switches SUHb, SVHb, and SWHb of each phase to off.

[0085] 6, the changeover switch QL is set as the operation target, and the same processing as that described in the first and second embodiments can be performed. In this embodiment, the switch control unit 83 turns on at least the second changeover switch QLb of the first changeover switch QLa and the second changeover switch QLb. The changeover switch QL corresponds to the "connection switch."

[0086] In step S21, for example, the switch control unit 83 turns off the power switch MH and turns on the series switch Ka and the selector switch QL. In this case, a current flows through a closed circuit including the second capacitor 15b, the positive bus 11, the negative bus 12, the selector switch QL, and the discharge resistor 70, thereby discharging the second capacitor 15b. Note that if it is determined that an abnormality has occurred in the rotating electrical machine system 100 during the period in which the H drive control is selected, the switch control unit 83 may maintain the ON operation of the selector switch QL throughout the period before and after it is determined that an abnormality has occurred in the rotating electrical machine system 100.

[0087] In step S21, for example, the inverter control unit 80 generates an ON command for the second lower arm switches SULb, SVLb, and SWLb of each phase of the second inverter 30 in order to discharge the charge accumulated in the second capacitor 15b. Even in this case, a large number of discharge paths can be secured for discharging the second capacitor 15b when an abnormality occurs in the rotating electric machine system 100. Note that, when it is determined that an abnormality has occurred in the rotating electric machine system 100 during the period in which the Y-drive control is selected, the inverter control unit 80 may maintain output of the ON command for the second lower arm switches SULb, SVLb, and SWLb of each phase throughout the period before and after it is determined that an abnormality has occurred in the rotating electric machine system 100.

[0088] The changeover switches may be provided on both the positive bus bar 11 and the negative bus bar 12. In this case, the changeover switch provided on one of the bus bars does not have to consist of a pair of switches. For example, the changeover switches QHa and QHb may be provided on the positive bus bar 11, and only the first changeover switch QLa of the changeover switches QLa and QLb may be provided on the negative bus bar 12.

[0089] When the H drive control is selected by the selection unit 82 , the switch control unit 83 turns on the changeover switch QH provided on the positive bus 11 and the changeover switch QL provided on the negative bus 12 .

[0090] When the selection unit 82 selects Y-drive control, the switch control unit 83 can execute Y-drive control, for example, as follows. The switch control unit 83 turns off the changeover switch QH provided on the positive bus 11 and the changeover switch QL provided on the negative bus 12. The inverter control unit 80 performs switching control to PWM-drive the switches SUHa to SWLa of the first inverter 20. In addition, the inverter control unit 80 fixes one of the second lower arm switches SULb, SVLb, SWLb for each phase and the second upper arm switches SUHb, SVHb, SWHb for each phase to on, and fixes the other to off.

[0091] In this embodiment as well, in step S21 of FIG. 6, the process for discharging the second capacitor 15b can be performed.

[0092] In the configuration shown in Fig. 10 , the discharge resistor and the series switch may be connected in parallel only to the second capacitor 15b instead of the first capacitor 15a of the capacitors 15a and 15b. In this case, the switch control unit 83 may perform the same process as in the first embodiment in step S21 of Fig. 6 . Furthermore, the inverter control unit 80 may generate an ON command for the first lower arm switches SULa, SVLa, and SWLa of the first inverter 20.

[0093] The changeover switch may be configured such that the source of the first changeover switch and the source of the second changeover switch are connected to each other, instead of the drain of the first changeover switch and the drain of the second changeover switch being connected to each other. The changeover switch may also be a mechanical relay. Even in the above configuration, the changeover switch can switch the flow of current in both directions in the target bus.

[0094] The power switch may be provided on the negative bus bar 12 instead of the positive bus bar 11. Also, the power switch may be provided on both the positive bus bar 11 and the negative bus bar 12.

[0095] The rotating electrical machine system 100 does not necessarily have to include the series switch Ka.

[0096] The rotating electric machine system is not limited to one that drives the rotating electric machine by switching between Y drive control and H drive control.

[0097] 11 , the rotating electric machine system 110 may be a system for driving a rotating electric machine 140. The rotating electric machine 140 is a three-phase double-winding rotating electric machine, and may be, for example, a motor constituting an electric power steering device. Note that the rotating electric machine 140 may also be an in-vehicle main motor.

[0098] The rotating electric machine system 110 includes a first battery 10a, a second battery 10b, a first inverter 120, a second inverter 130, a first capacitor 15a, a second capacitor 15b, a first power switch MHa, and a second power switch MHb. The first inverter 120 is a power conversion circuit that converts DC power supplied from the first battery 10a into three-phase AC power and supplies it to the rotating electric machine 140. The second inverter 130 is a power conversion circuit that converts DC power supplied from the second battery 10b into three-phase AC power and supplies it to the rotating electric machine 140. In other words, the rotating electric machine system 110 is a dual-power supply system in which a battery is connected to each of the inverters 120, 130.

[0099] Two winding groups, a first winding group 151 and a second winding group 152, are wound around a stator that constitutes the rotating electric machine 140. The rotor of the rotating electric machine 140 is shared by the first and second winding groups 151 and 152. The first winding group 151 includes U-, V-, and W-phase first windings 151U, 151V, and 151W. The second winding group 152 includes U-, V-, and W-phase second windings 152U, 152V, and 152W.

[0100] As in the first embodiment, the first inverter 120 includes a series connection of U-, V-, and W-phase first upper arm switches SUHa, SVHa, and SWHa and U-, V-, and W-phase first lower arm switches SULa, SVLa, and SWLa. The drains of the first upper arm switches SUHa, SVHa, and SWHa of each phase are electrically connected to the positive terminal of the first battery 10a via a first positive bus 111a. The sources of the first lower arm switches SULa, SVLa, and SWLa of each phase are electrically connected to the negative terminal of the first battery 10a via a first negative bus 112a.

[0101] As in the first embodiment, the second inverter 130 includes a series connection of U-, V-, and W-phase second upper arm switches SUHb, SVHb, and SWHb and U-, V-, and W-phase second lower arm switches SULb, SVLb, and SWLb. The drains of the second upper arm switches SUHb, SVHb, and SWHb for each phase are electrically connected to the positive terminal of the second battery 10b via a second positive bus 111b. The sources of the second lower arm switches SULb, SVLb, and SWLb for each phase are electrically connected to the negative terminal of the second battery 10b via a second negative bus 112b.

[0102] First, the electrical connection relationship between the first battery 10a, the first capacitor 15a, the first inverter 120, the first winding group 151, and the first power switch MHa will be described below.

[0103] In each phase, first ends of the first windings 151U, 151V, 151W are electrically connected to the sources of the first upper arm switches SUHa, SVHa, SWHa and the drains of the first lower arm switches SULa, SVLa, SWLa. Second ends of the first windings 151U, 151V, 151W are connected to each other at the neutral point.

[0104] As in the first embodiment, the first capacitor 15a is electrically connected in parallel with the first battery 10a and the series connection of the first upper arm switches SUHa, SVHa, SWHa of each phase and the first lower arm switches SULa, SVLa, SWLa of each phase.

[0105] The first power switch MHa electrically connects or disconnects the first battery 10a and the first capacitor 15a. In this embodiment, the first power switch MHa is provided between the connection point of the first positive bus 111a with the first end of the first capacitor 15a and the positive terminal of the first battery 10a.

[0106] The electrical connection relationship between the second battery 10b, the second capacitor 15b, the second inverter 130, the second winding group 152, and the second power switch MHb is similar to the electrical connection relationship between the first battery 10a, the first capacitor 15a, the first inverter 120, the first winding group 151, and the first power switch MHa described above, and therefore detailed explanation will be omitted.

[0107] In this embodiment, similarly to the first embodiment, the discharge resistor 70 is electrically connected in parallel only to the first capacitor 15a of the first capacitor 15a and the second capacitor 15b. The series switch Ka is connected in series to the discharge resistor 70 on the low potential side of the discharge resistor 70.

[0108] The rotating electrical machine system 110 includes a connection path 113 and a connection switch RH. The connection path 113 connects the second capacitor 15b and the discharge resistor 70. Specifically, a first end of the connection path 113 is electrically connected to a portion of the first positive bus 111a, which is a connection point between the first power switch MHa and the first upper arm switches SUHa, SVHa, and SWHa of each phase. A second end of the connection path 113 is electrically connected to a portion of the second positive bus 111b, which is a connection point between the second power switch MHb and the second upper arm switches SUHb, SVHb, and SWHb of each phase. The low-potential side of the discharge resistor 70 and the second ends of the capacitors 15a and 15b are electrically connected to a common ground GND.

[0109] The connection switch RH is provided in the connection path 113. The connection switch RH is configured to be able to switch between conducting and blocking bidirectional current flowing through the connection path 113. The connection switch RH is, for example, a voltage-controlled semiconductor switching element or a mechanical relay. The connection switch RH is controlled by the control device 60.

[0110] When a signal indicating that the start switch 64 is turned on is input, the switch control unit 83 turns on the power switches MHa and MHb and turns off the connection switch RH. With the power switches MHa and MHb turned on and the connection switch RH turned off, the inverter control unit 80 performs switching control of the switches SUHa to SWLa and SUHb to SWLb to control the control variable of the rotating electrical machine 140 to a command value. For example, the control variable is torque.

[0111] 6, the switch control unit 83 turns off the power switches MHa and MHb and turns on the series switch Ka and the connection switch RH. As a result, after it is determined that an abnormality has occurred in the rotating electrical machine system 100, the power switches MHa and MHb are turned off and the series switch Ka and the connection switch RH are turned on.

[0112] In this embodiment, when it is determined that an abnormality has occurred in the rotating electrical machine system 100, the power supply switches MHa and MHb are turned off and the connection switch RH is turned on. In this case, the power supply switches MHa and MHb are turned off and the connection switch RH is turned on, so that the second capacitor 15b and the discharge resistor 70 are electrically connected via the connection switch RH. In this case, the second capacitor 15b is enabled to discharge.

[0113] In the above-described embodiment, too, each of the capacitors 15a and 15b can be discharged while suppressing an increase in the number of components in the rotating electric machine system 100, compared to the comparative example in which a resistor is provided in each of the capacitors 15a and 15b.

[0114] In the rotating electric machine system 110 shown in FIG. 11, the discharge resistor and the series switch may be electrically connected in parallel only to the second capacitor 15b, instead of the first capacitor 15a, of the first capacitor 15a and the second capacitor 15b.

[0115] The control amount of the rotating electrical machine is not limited to torque, and may be, for example, rotation speed.

[0116] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0117] The rotating electrical machine and the inverter are not limited to three-phase ones, but may be two-phase or four or more-phase ones.

[0118] The semiconductor switches constituting the first inverter and the second inverter are not limited to N-channel MOSFETs, but may be, for example, IGBTs. In this case, the high-potential terminal of the switch is the collector, and the low-potential terminal is the emitter. Each switch also has a freewheel diode.

[0119] The inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle, such as an aircraft or a ship. If the mobile body is an aircraft, the rotating electric machine serves as a power source for the aircraft's flight, and if the mobile body is a ship, the rotating electric machine serves as a power source for the ship's navigation. Furthermore, the inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle.

[0120] 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.

[0121] The technical concepts extracted from the above-described embodiments are described below. [Configuration 1] In a control device (60) for a rotating electric machine system (100, 110) including: a first inverter (20, 120) of multiple phases connected in parallel to a first capacitor (15a); a second inverter (30, 130) of multiple phases connected in parallel to a second capacitor (15b); a rotating electric machine (40, 140) having windings (51U, 51V, 51W, 151U, 151V, 151W, 152U, 152V, 152W) connected to the first inverter and the second inverter in the number equal to the number of phases; a DC power supply (10, 10a, 10b) connected in parallel to at least one of the first capacitor and the second capacitor; and a power supply switch (MH, MHa, MHb) for connecting or disconnecting one of the first capacitor and the second capacitor that is connected in parallel to the DC power supply, the rotating electric machine system comprising: a discharge resistor (70) connected in parallel to only one of the first capacitor and the second capacitor; and connection switches (QH, QL, RH) that connect or disconnect the discharge resistor to a specific capacitor of the first capacitor and the second capacitor to which the discharge resistor is not connected in parallel; an abnormality determination unit (84) that determines whether an abnormality has occurred in the rotating electric machine system; and a switch operation unit (80, 83) that turns off the power switch and turns on the connection switch when the abnormality determination unit determines that an abnormality has occurred in the rotating electric machine system.[Configuration 2] The first inverter (20) has first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) connected in series, the number of which corresponds to the number of phases; the second inverter (30) has second upper arm switches (SUHb, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) connected in series, the number of which corresponds to the number of phases; the DC power source (10) is connected in parallel only to the series connection of the first upper arm switches and the first lower arm switches out of the series connection of the first upper arm switches and the first lower arm switches and the series connection of the second upper arm switches and the second lower arm switches; and in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are connected to a first end of the winding; a positive bus (11) connecting the high potential terminal of the first upper arm switch and the high potential terminal of the second lower arm switch in each phase, and a negative bus (12) connecting the low potential terminal of the first lower arm switch and the low potential terminal of the second lower arm switch in each phase, and the connection switch is a switch (QH, QL) provided on a target bus that is at least one of the positive bus and the negative bus. [Configuration 3] The control device for a rotating electric machine system according to Configuration 2, wherein the connection switch allows bidirectional current flow in the target bus when turned on and prevents bidirectional current flow in the target bus when turned off.[Configuration 4] The control device for a rotating electric machine system according to Configuration 2 or 3, further comprising: a control unit (80-82) that controls a control amount of the rotating electric machine in an H drive state in which switching control of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch is performed with the connection switch operated on, wherein, when the abnormality determination unit determines that an abnormality has occurred in the rotating electric machine system during control of the rotating electric machine in the H drive state, the switch operation unit maintains the connection switch in an ON operation across the entire range before and after it is determined that the abnormality has occurred. [Configuration 5] The control device for a rotating electric machine system according to any one of Configurations 2 to 4, wherein, when the abnormality determination unit determines that an abnormality has occurred in the rotating electric machine system, the switch operation unit further turns on an upper arm switch or a lower arm switch of each phase included in one of the first inverter and the second inverter that is connected in parallel to the specific capacitor. the control device for a rotating electric machine system according to any one of configurations 2 to 5, wherein the discharge resistor is connected in parallel to only the first capacitor (15a) of the first and second capacitors, the specific capacitor is the second capacitor (15b), the target bus is the positive bus, diodes (DUHa, DVHa, DWHa) are connected in anti-parallel to the first upper arm switch, and a control unit (80-82) controls a control amount of the rotating electric machine in a Y-drive state in which, with the connection switch in an OFF state, the second upper arm switch of each phase is fixed to an ON operation, the second lower arm switch of each phase is fixed to an OFF operation, and switching control of the first upper arm switch and the first lower arm switch is performed, and when it is determined that an abnormality has occurred in the rotating electric machine system during control of the rotating electric machine in the Y-drive state, the switch operation unit maintains the second upper arm switch of each phase in an ON operation throughout the period before and after it is determined that the abnormality has occurred.[Configuration 7] The control device for a rotating electric machine system according to any one of Configurations 2 to 5, wherein the discharge resistor is connected in parallel to only the first capacitor (15a) of the first and second capacitors, the specific capacitor is the second capacitor (15b), the target bus is the negative bus, diodes (DULa, DVLa, DWLa) are connected in anti-parallel to the first lower arm switch, and a control unit (80-82) controls a control amount of a rotating electric machine in a Y-drive state in which, with the connection switch being turned off, the second lower arm switch of each phase is fixed to an on-operation, the second upper arm switch of each phase is fixed to an off-operation, and switching control of the first upper arm switch and the first lower arm switch is performed, and when it is determined that an abnormality has occurred in the rotating electric machine system during control of the rotating electric machine in the Y-drive state, the switch operation unit maintains the second lower arm switch of each phase in an on-operation across the period before and after it is determined that the abnormality has occurred. [Configuration 8] The control device for a rotating electric system according to any one of Configurations 1 to 7, wherein the rotating electric machine system is mounted on a vehicle, and the abnormality determination unit determines whether a collision has occurred in the vehicle as the determination whether an abnormality has occurred in the rotating electric system. [Configuration 9] The control device for a rotating electric system according to any one of Configurations 1 to 8, wherein the rotating electric machine system includes a series switch (Ka) connected in series to the discharge resistor on a high potential side or a low potential side of the discharge resistor, and the switch operation unit turns off the series switch when the abnormality determination unit determines that no abnormality has occurred in the rotating electric system, and turns on the series switch when the abnormality determination unit determines that an abnormality has occurred in the rotating electric system.

[0122] 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 (60) for a rotating electric machine system (100, 110) including: a first inverter (20, 120) of multiple phases connected in parallel to a first capacitor (15a); a second inverter (30, 130) of multiple phases connected in parallel to a second capacitor (15b); a rotating electric machine (40, 140) having windings (51U, 51V, 51W, 151U, 151V, 151W, 152U, 152V, 152W) connected to the first inverter and the second inverter in the number equal to the number of phases; a DC power supply (10, 10a, 10b) connected in parallel to at least one of the first capacitor and the second capacitor; and a power switch (MH, MHa, MHb) for connecting or disconnecting one of the first capacitor and the second capacitor that is connected in parallel to the DC power supply, wherein the rotating electric machine system comprises: a discharge resistor (70) connected in parallel to only one of the first capacitor and the second capacitor; and connection switches (QH, QL, RH) that connect or disconnect the discharge resistor to a specific capacitor of the first capacitor and the second capacitor to which the discharge resistor is not connected in parallel; an abnormality determination unit (84) that determines whether an abnormality has occurred in the rotating electric machine system; and a switch operation unit (80, 83) that turns off the power switch and turns on the connection switch when the abnormality determination unit determines that an abnormality has occurred in the rotating electric machine system.

2. The first inverter (20) has first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) connected in series, the number of which corresponds to the number of phases; the second inverter (30) has second upper arm switches (SUHb, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) connected in series, the number of which corresponds to the number of phases; the DC power source (10) is connected in parallel only to the series connection of the first upper arm switches and the first lower arm switches, out of the series connection of the first upper arm switches and the first lower arm switches and the series connection of the second upper arm switches and the second lower arm switches; in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are connected to a first end of the winding; 2. The control device for a rotating electric machine system according to claim 1, wherein in each phase, a low potential side terminal of the second upper arm switch and a high potential side terminal of the second lower arm switch are connected to a second end of the winding, and the rotating electric machine system comprises: a positive side bus (11) connecting, in each phase, the high potential side terminal of the first upper arm switch and the high potential side terminal of the second upper arm switch; and a negative side bus (12) connecting, in each phase, the low potential side terminal of the first lower arm switch and the low potential side terminal of the second lower arm switch, and the connection switch is a switch (QH, QL) provided on a target bus which is at least one of the positive side bus and the negative side bus.

3. A control device for a rotating electric system as described in claim 2, wherein the connection switch allows bidirectional current flow in the target bus when turned on, and prevents bidirectional current flow in the target bus when turned off.

4. A control device for a rotating electric machine system as described in claim 2 or 3, comprising a control unit (80 to 82) that controls the control amount of the rotating electric machine in an H drive state in which switching control of the first upper arm switch, the first lower arm switch, the second upper arm switch and the second lower arm switch is performed when the connection switch is operated on, and wherein the switch operation unit maintains the connection switch in an on operation both before and after it is determined that an abnormality has occurred in the rotating electric machine system when the abnormality determination unit determines that an abnormality has occurred during control of the rotating electric machine in the H drive state.

5. A control device for a rotating electric system as described in claim 2 or 3, wherein when the abnormality determination unit determines that an abnormality has occurred in the rotating electric system, the switch operation unit further turns on an upper arm switch or a lower arm switch of each phase of the inverter connected in parallel to the specific capacitor, of the first inverter and the second inverter.

6. The control device for a rotating electric machine system according to claim 2 or 3, wherein the discharge resistor is connected in parallel only to the first capacitor (15a) of the first and second capacitors, the specific capacitor is the second capacitor (15b), the target bus is the positive bus, diodes (DUHa, DVHa, DWHa) are connected in anti-parallel to the first upper arm switch, and the control unit (80-82) controls a control amount of the rotating electric machine in a Y-drive state in which, with the connection switch turned off, the second upper arm switch of each phase is fixed to an on-operation, the second lower arm switch of each phase is fixed to an off-operation, and switching control of the first upper arm switch and the first lower arm switch is performed, and when it is determined that an abnormality has occurred in the rotating electric machine system during control of the rotating electric machine in the Y-drive state, the switch operation unit maintains the second upper arm switch of each phase in an on-operation throughout the period before and after it is determined that the abnormality has occurred.

7. The control device for a rotating electric machine system according to claim 2 or 3, wherein the discharge resistor is connected in parallel only to the first capacitor (15a) of the first and second capacitors, the specific capacitor is the second capacitor (15b), the target bus is the negative bus, diodes (DULa, DVLa, DWLa) are connected in anti-parallel to the first lower arm switch, and the control unit (80-82) controls a control amount of the rotating electric machine in a Y drive state in which, with the connection switch turned off, the second lower arm switch of each phase is fixed to an on operation, the second upper arm switch of each phase is fixed to an off operation, and switching control of the first upper arm switch and the first lower arm switch is performed, and when it is determined that an abnormality has occurred in the rotating electric machine system during control of the rotating electric machine in the Y drive state, the switch operation unit maintains the second lower arm switch of each phase in an on operation throughout the period before and after it is determined that the abnormality has occurred.

8. A control device for a rotating electric machine system according to any one of claims 1 to 3, wherein the rotating electric machine system is mounted on a vehicle, and the abnormality determination unit determines whether or not a collision has occurred in the vehicle to determine whether or not an abnormality has occurred in the rotating electric machine system.

9. A control device for a rotating electric system according to any one of claims 1 to 3, wherein the rotating electric system comprises a series switch (Ka) connected in series to the discharge resistor on the high potential side or low potential side of the discharge resistor, and the switch operation unit turns off the series switch when the abnormality determination unit determines that no abnormality has occurred in the rotating electric system, and turns on the series switch when the abnormality determination unit determines that an abnormality has occurred in the rotating electric system.

10. A program applied to a rotating electric machine system (100, 110) including: a first inverter (20, 120) of multiple phases connected in parallel to a first capacitor (15a); a second inverter (30, 130) of multiple phases connected in parallel to a second capacitor (15b); a rotating electric machine (40, 140) having windings (51U, 51V, 51W, 151U, 151V, 151W, 152U, 152V, 152W) connected to the first inverter and the second inverter, the number of windings corresponding to the number of phases; a DC power supply (10, 10a, 10b) connected in parallel to at least one of the first capacitor and the second capacitor; and a power switch (MH, MHa, MHb) for connecting or disconnecting one of the first capacitor and the second capacitor that is connected in parallel to the DC power supply, wherein the rotating electric machine system comprises: a discharge resistor (70) connected in parallel to only one of the first capacitor and the second capacitor; and connection switches (QH, QL, RH) that connect or disconnect the discharge resistor to a specific capacitor of the first capacitor and the second capacitor to which the discharge resistor is not connected in parallel, wherein the program causes a processor (60a) to execute processes including: an abnormality determination process that determines whether an abnormality has occurred in the rotating electric machine system; and a switch operation process that turns off the power switch and turns on the connection switch when it is determined by the abnormality determination process that an abnormality has occurred in the rotating electric machine system.

11. A method for controlling a rotating electric machine system (100, 110) comprising: a first inverter (20, 120) of multiple phases connected in parallel to a first capacitor (15a); a second inverter (30, 130) of multiple phases connected in parallel to a second capacitor (15b); a rotating electric machine (40, 140) having windings (51U, 51V, 51W, 151U, 151V, 151W, 152U, 152V, 152W) connected to the first inverter and the second inverter, the number of windings corresponding to the number of phases; a DC power supply (10, 10a, 10b) connected in parallel to at least one of the first capacitor and the second capacitor; and a power switch (MH, MHa, MHb) for connecting or disconnecting one of the first capacitor and the second capacitor that is connected in parallel to the DC power supply, wherein the rotating electric machine system comprises: a discharge resistor (70) connected in parallel to only one of the first capacitor and the second capacitor; and connection switches (QH, QL, RH) that connect or disconnect the discharge resistor to a specific capacitor of the first capacitor and the second capacitor to which the discharge resistor is not connected in parallel, the control method comprising: an abnormality determination step that determines whether an abnormality has occurred in the rotating electric machine system; and a switch operation step that turns off the power switch and turns on the connection switch when it is determined by the abnormality determination step that an abnormality has occurred in the rotating electric machine system.

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