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

Abstract

A control device (70) comprises: a request determination unit (89) for determining whether there is a temperature increase request for a system; and a switch control unit (86) for performing ON or OFF control of first upper and lower arm switches (SUHa to SWHa, SULa to SWLa) and second upper and lower arm switches (SUHb to SWHb, SULb to SWLb). When it is determined that there is a temperature increase request, the switch control unit performs temperature increase control in which the total amount of heat generated in a first inverter (20), a second inverter (30), and a rotary electric machine (40) is increased compared to when it is determined that there is no temperature increase request.

Description

Rotating electric machine control device, program, and rotating electric machine control method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-218587, filed on December 25, 2023, the contents of which are incorporated herein by reference.

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

[0003] Conventionally, a system for controlling the drive of a rotating electric machine using two inverters has been known. In this system, a first inverter is electrically connected to first ends of a multi-phase armature winding of the rotating electric machine, and a second inverter is electrically connected to second ends of the armature winding. Drive control of the rotating electric machine is performed by switching control of the first and second inverters, thereby achieving high output and high efficiency of the system. An example of such a technology is disclosed in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2017-175747

[0005] There is still room for improvement in the technology for increasing the amount of heat produced in the above systems.

[0006] A primary object of the present disclosure is to provide a control device, a program, and a control method for a rotating electric machine that can increase the amount of heat generated.

[0007] The present disclosure relates to a control device for a rotating electric machine that is applied to a system including: a rotating electric machine having a multi-phase armature winding; a first inverter having first upper arm switches and first lower arm switches connected in series for the same number of phases, and a series connection of the first upper arm switches and the first lower arm switches connected in parallel to a DC power source; a second inverter having second upper arm switches and second lower arm switches connected in series for the same number of phases; a positive bus bar that electrically connects, in each phase, a high potential side terminal of the first upper arm switch and a high potential side terminal of the second upper arm switch; and a negative bus bar that electrically connects, in each phase, a low potential side terminal of the first lower arm switch and a low potential side terminal of the second lower arm switch. In each phase, the low potential side terminal of the first upper arm switch and the high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding, In each phase, the low potential side terminal of the second upper arm switch and the high potential side terminal of the second lower arm switch are electrically connected to the second end of the armature winding, and the system comprises: a request determination unit that determines whether there is a temperature increase request for the system; and a switch control unit that controls the on / off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch, and when it is determined that there is a temperature increase request, the switch control unit performs temperature increase control, which is the control that increases the total amount of heat generated in the first inverter, the second inverter, and the rotating electric machine compared to when it is determined that there is no temperature increase request.

[0008] According to the present disclosure, the total amount of heat generated in the first inverter, the second inverter, and the rotating electric machine can be increased.

[0009] 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.1 is an overall configuration diagram of a control system according to a first embodiment, FIG. 2 is a diagram showing a cooling device, FIG. 3 is a functional block diagram of control processing executed by a control device, FIG. 4 is a diagram showing areas of Y and H drive control, FIG. 5 is a diagram showing a control mode of H drive control, FIG. 6 is a diagram showing a control mode of Y drive control, FIG. 7 is a flowchart of control processing executed by a control device, FIG. 8 is a diagram showing a change mode of a switching frequency based on an inverter temperature, and FIG. 9 is a diagram showing a change mode of a switching frequency based on a motor temperature. 10 is a time chart showing the transition of phase current when the carrier frequency is high, FIG. 11 is a time chart showing the transition of phase current when the carrier frequency is low, FIG. 12 is a time chart showing an example of a dual heat generation mode, FIG. 13 is a time chart showing an example of normal control, FIG. 14 is a diagram showing current vectors in the dual heat generation mode according to the second embodiment, FIG. 15 is a diagram showing a cooling device according to the third embodiment, FIG. 16 is a diagram showing the relationship between the temperature of each switch module and the allowable temperature, and FIG. 17 is a diagram showing a cooling device according to the fourth embodiment. 18 is a flowchart of the control process executed by the control device, FIG. 19 is a time chart showing the transition of the phase current when the zero-phase sequence signal is not superimposed, FIG. 20 is a time chart showing the transition of the phase current when the zero-phase sequence signal is superimposed in the first mode, FIG. 21 is a time chart showing the transition of the phase current when the zero-phase sequence signal is superimposed in the second mode, FIG. 22 is a time chart showing the transition of the phase current when the zero-phase sequence signal is superimposed in the third mode, and FIG. 23 is a time chart showing the transition of the phase current when the zero-phase sequence signal is superimposed in the sixth mode. 24 is a diagram showing the control mode of Y drive control, FIG. 25 is a diagram showing the overall configuration of a control system according to the seventh embodiment, FIG. 26 is a diagram showing the control mode of first Y drive control, FIG. 27 is a diagram showing the control mode of second Y drive control, FIG. 28 is a diagram showing the control mode of A mode according to the eighth embodiment, FIG. 29 is a diagram showing the control mode of B mode, FIG. 30 is a diagram showing the control mode of C mode, FIG. 31 is a diagram showing the control mode of D mode, and FIG. 32 is a diagram showing an example of a mode switching method.

[0010] 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.

[0011] A first embodiment of a control device according to the present disclosure will be described below with reference to the drawings. The control device of the present embodiment is applied to a control system mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0012] As shown in Fig. 1, the control system 100 includes a battery 10, which is 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.

[0013] 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 .

[0014] 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.

[0015] In this embodiment, each of the switches SUHa to SWLa and SUHb to SWLb is a voltage-controlled semiconductor switching element, more specifically, an IGBT. In this case, the high-potential terminal of each of the switches SUHa to SWLa and SUHb to SWLb is the collector, and the low-potential terminal is the emitter. A freewheel diode is connected in anti-parallel to each of the switches SUHa to SWLb. Specifically, U-, V-, and W-phase first upper-arm diodes DUHa, DVHa, and DWHa are connected in anti-parallel to the U-, V-, and W-phase first upper-arm switches SUHa, SVHa, and SWHa, respectively, and U-, V-, and W-phase first lower-arm diodes DULa, DVLa, and DWLa are connected in anti-parallel to the U-, V-, and W-phase first lower-arm switches SULa, SVLa, and SWLa, respectively. U, V, W-phase second upper-arm diodes DUHb, DVHb, DWHb are connected in anti-parallel to the U, V, W-phase second upper-arm switches SUHb, SVHb, SWHb, and U, V, W-phase second lower-arm diodes DULb, DVLb, DWLb are connected in anti-parallel to the U, V, W-phase second lower-arm switches SULb, SVLb, SWLb.

[0016] The collectors of the first upper arm switches SUHa, SVHa, SWHa for each phase and the collectors of the second upper arm switches SUHb, SVHb, SWHb for each phase are connected via a positive bus 11, which is an electrical path such as a bus bar. The emitters of the first lower arm switches SULa, SVLa, SWLa for each phase and the emitters of the second lower arm switches SULb, SVLb, SWLb for each phase are connected via a negative bus 12, which is an electrical path such as a bus bar. The emitters of the second lower arm switches SULb, SVLb, SWLb for each phase are connected to the negative bus 12.

[0017] The control system 100 includes a power switch 14. The power switch 14 is, for example, a semiconductor switching element or a mechanical relay. The power switch 14 connects the positive bus 11 and the positive terminal of the battery 10. When the power switch 14 is turned on, the positive terminal of the battery 10 is electrically connected to the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase. When the power switch 14 is turned off, the positive terminal of the battery 10 is electrically disconnected from the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase.

[0018] The control system 100 includes a capacitor 15. The capacitor 15 functions as a smoothing capacitor. The capacitor 15 is connected in parallel to the series-connected body of the first upper arm switches SUHa to SWHa of each phase and the first lower arm switches SULa to SWLa of each phase.

[0019] The rotating electric machine 40 is an on-board main engine that serves as a power source for running the vehicle. The rotating electric machine 40 includes a rotor 41 and a stator 50. The rotor 41 is capable of transmitting power to the drive wheels 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 stator 50 includes a U-phase winding 51U, a V-phase winding 51V, and a W-phase winding 51W as armature windings. The phase windings 51U, 51V, and 51W are arranged at intervals of 120 electrical degrees on the stator core that constitutes the stator 50. The phase windings 51U, 51V, and 51W are open windings.

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

[0022] The control system 100 includes a changeover switch 13. The changeover switch 13 is provided on the positive bus 11 (corresponding to the "target bus"). The changeover switch 13 is, for example, a semiconductor switching element or a mechanical relay. When the changeover switch 13 is turned on, the changeover switch 13 electrically connects the collectors of the upper phase arm switches SUHa, SVHa, and SWHa of the first inverter 20 to the collectors of the upper phase arm switches SUHb, SVHb, and SWHb of the second inverter 30. When the changeover switch 13 is turned off, the changeover switch 13 electrically disconnects the collectors of the upper phase arm switches SUHa, SVHa, and SWHa of the first inverter 20 from the collectors of the upper phase arm switches SUHb, SVHb, and SWHb of the second inverter 30.

[0023] The changeover switch 13 may be, for example, an IGBT. In this case, a freewheel diode is connected in anti-parallel to the changeover switch 13. The collector of the IGBT is connected to the first inverter 20 side, and the emitter of the IGBT is connected to the second inverter 30 side.

[0024] As shown in FIG. 2 , the control system 100 includes a cooling device that cools the first and second inverters 20, 30, the rotating electric machine 40, and the battery 10 when switching control of the first and second inverters 20, 30 is performed to run the vehicle. Specifically, the cooling device includes a circulation path 200 through which coolant circulates, an electric water pump 201, a radiator 202, and an electric fan 203. The water pump 201 is powered and driven to circulate the coolant. In the example shown in FIG. 2 , the first inverter 20, the second inverter 30, the rotating electric machine 40, and the battery 10 are arranged in this order downstream of the water pump 201 in the circulation path 200. Note that the arrangement order of the devices in the circulation path 200 is not limited to the order shown in FIG. 2 .

[0025] A radiator 202 is provided in circulation path 200 between water pump 201 and battery 10. Radiator 202 cools the coolant that flows in via circulation path 200 and supplies the cooled coolant to water pump 201. The coolant that flows into radiator 202 is cooled by wind blown against radiator 202 as the vehicle moves and wind blown against radiator 202 by rotating fan 203. In this embodiment, circulation path 200, the coolant circulating through circulation path 200, and water pump 201 correspond to a "heat transfer unit."

[0026] Returning to the explanation of FIG. 1, the control system 100 includes a current sensor 60 , a rotation angle sensor 61 , a voltage sensor 62 , an inverter temperature sensor 63 , a motor temperature sensor 64 , a water temperature sensor 65 , and a battery temperature sensor 66 .

[0027] The current sensor 60 detects the phase current flowing through each of the phase windings 51U, 51V, and 51W. In this embodiment, the current sensor 60 is provided at one of the ends of each of the phase windings 51U, 51V, and 51W that is closer to the first inverter 20. Hereinafter, the sign of the phase current is defined as positive when the current flows from the first terminal 51Ua, 51Va, and 51Wa of each of the windings 51U, 51V, and 51W to the second terminal 51Ub, 51Vb, and 51Wb, and negative when the current flows from the second terminal 51Ub, 51Vb, and 51Wb to the first terminal 51Ua, 51Va, and 51Wa. Note that the current sensor 60 may also be provided at one of the ends of each of the phase windings 51U, 51V, and 51W that is closer to the second inverter 30.

[0028] The rotation angle sensor 61 is, for example, a resolver, and detects the electrical angle of the rotor 41. The voltage sensor 62 detects the voltage across the capacitor 15. The inverter temperature sensor 63 detects the temperatures of the first inverter 20 and the second inverter 30. For example, the inverter temperature sensor 63 detects the temperatures of the switches SUHa to SWLa and SUHb to SWLb that constitute each inverter 20, 30 as the temperatures of the first and second inverters 20, 30.

[0029] The motor temperature sensor 64 detects the temperature of the rotating electrical machine 40. The motor temperature sensor 64 detects, for example, the temperatures of the armature windings 51U to 51W. The water temperature sensor 65 detects the temperature of the cooling water circulating through the circulation path 200. The battery temperature sensor 66 detects the temperature of the battery 10.

[0030] The detection values ​​of the sensors 60 to 66 are input to a control device 70 included in the control system 100. The control device 70 is an electronic control unit (ECU) that performs various controls of the control system 100, and includes a processor 71 and a storage unit 72 as hardware. In the control 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 70 in FIG. 1.

[0031] The memory unit 72 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 70. The memory provides the processor 71 with a working area for temporary use when the processor 71 performs 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 processor 71, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or a flash memory. The storage stores program information and the like for the processing shown in Figures 3 and 7, which will be described later.

[0032] For example, program information stored on a non-transient physical recording medium is installed in the storage unit 72. 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 72.

[0033] The water pump 201 and the fan 203 may be driven by a control device separate from the control device 70. However, in this embodiment, for convenience, it is assumed that the water pump 201 and the fan 203 are driven by the control device 70.

[0034] In order to control the control variable of the rotary electric machine 40 to the command value, the control device 70 controls the changeover switch 13, the switches SUHa to SWLa of the first inverter 20, and the switches SUHb to SWLb of the second inverter 30 to turn on or off while the power switch 14 is on. In this embodiment, the control variable is torque.

[0035] FIG. 3 is a block diagram showing the control process of the rotating electrical machine 40 executed by the control device 70. As shown in FIG.

[0036] The command value calculation unit 80 calculates a d-axis current command value Id* and a q-axis current command value Iq* in a dq coordinate system based on the command torque Trq* received from a control device that is higher in level than the control device 70. The command value calculation unit 80 may calculate the d- and q-axis current command values ​​Id* and Iq* for performing minimum current maximum torque control of the rotating electric machine 40, for example.

[0037] The two-phase conversion unit 81 calculates the d-axis current value Idr and the q-axis current value Iqr based on the phase currents Iur, Ivr, and Iwr detected by the current sensor 60 and the electrical angle θr detected by the rotation angle sensor 61.

[0038] The current feedback unit 82 calculates a d-axis voltage command value Vd* and a q-axis voltage command value Vq* based on the d- and q-axis current command values ​​Id* and Iq* and the d- and q-axis current values ​​Idr and Iqr. Specifically, the current feedback unit 82 calculates a d-axis current deviation, which is the difference between the d-axis current command value Id* and the d-axis current value Idr, and calculates a d-axis voltage command value Vd* as a manipulated variable for feedback-controlling the calculated d-axis current deviation to zero. The current feedback unit 82 calculates a q-axis current deviation, which is the difference between the q-axis current command value Iq* and the q-axis current value Iqr, and calculates a q-axis voltage command value Vq* as a manipulated variable for feedback-controlling the calculated q-axis current deviation to zero. The feedback control is, for example, proportional-plus-integral control.

[0039] The three-phase converter 83 calculates U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* based on the d- and q-axis voltage command values ​​Vd*, Vq* and the electrical angle θr. The U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* are command values ​​for voltages applied to the U-, V-, and W-phase windings 51U, 51V, and 51W. In this embodiment, the sign of the applied voltage to each phase winding is positive when the potential at the first terminal 51Ua, 51Va, and 51Wa of the winding 51U, 51V, and 51W is higher than the potential at the second terminal 51Ub, 51Vb, and 51Wb of the winding 51U, 51V, and 51W, respectively. The sign is negative when the potential at the second terminal 51Ub, 51Vb, and 51Wb of the winding 51U, 51V, and 51W is higher than the potential at the first terminal 51Ua, 51Va, and 51Wa of the winding 51U, 51V, and 51W.

[0040] The speed calculation unit 84 calculates the rotation speed Nr of the rotor 41 based on the electrical angle θr.

[0041] The selection unit 85 determines whether the drive state of the control system 100 should be Y drive control or H drive control. In the present embodiment, the selection unit 85 selects whether the drive state should be Y drive control or H drive control based on the operating point of the rotating electric machine 40 determined by the calculated rotation speed Nr and command torque Trq* and on the control map information.

[0042] 4 shows an example of 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 command torque Trq*. The control map information is stored in the storage unit 72.

[0043] The selection unit 85 selects Y drive control when it determines that the rotation speed Nr is equal to or less than the determination threshold Jth. On the other hand, the selection unit 85 selects H drive control when it determines that the rotation speed Nr is higher than the determination threshold Jth or when it determines that the rotation speed Nr has exceeded a predetermined speed Nth. The determination threshold Jth increases as the command torque Trq* decreases in the region where the rotation speed Nr is equal to or less than the predetermined speed Nth.

[0044] Returning to the explanation of FIG. 3, the switch control unit 86 generates a carrier signal for generating drive signals for the switches SUHa-SWLa and SUHb-SWLb of the first and second inverters 20 and 30. In this embodiment, the carrier signal is a triangular wave signal with equal increasing and decreasing speeds. The drive signals are comprised of switch on and off commands.

[0045] The switch control unit 86 generates drive signals for the switches SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30 based on the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw*, the power supply voltage Vsr, which is the voltage detected by the voltage sensor 62, and the generated carrier signal.

[0046] Specifically, the switch control unit 86 calculates U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw by normalizing the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* by the power supply voltage Vsr. Specifically, the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw are values ​​obtained by dividing the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* by half the power supply voltage Vsr.

[0047] 5 , the switch control unit 86 performs H drive control by turning on the selector switch 13 to PWM-drive the switches SUHa to SWLa of the first inverter 20 and PWM-drive the switches SUHb to SWLb of the second inverter 30. The switch control unit 86 generates drive signals for the switches SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30 based on a magnitude comparison between the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw and the carrier signal.

[0048] On the other hand, when Y drive control is selected by the selector 85, the switch control unit 86 performs Y drive control by turning off the selector switch 13 and PWM-driving the switches SUHa to SWLa of the first inverter 20, as shown in FIG. 6 . The switch control unit 86 also fixes the upper arm switches SUHb, SVHb, and SWHb of the second inverter 30 to on and fixes the lower arm switches SULb, SVLb, and SWLb of the second inverter 30 to off. This results in a star connection of the phase windings 51U, 51V, and 51W via the second inverter 30. The switch control unit 86 generates drive signals for the switches SUHa to SWLa of the first inverter 20 based on a magnitude comparison between the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw and the carrier signal.

[0049] Based on the generated drive signal, the switch control unit 86 controls the charge / discharge current of the gates of the switches SUHa-SWLa and SUHb-SWLb of the first and second inverters 20 and 30. As a result, the switches SUHa-SWLa and SUHb-SWLb of the first and second inverters 20 and 30 are controlled to be turned on or off in accordance with the drive signal.

[0050] The switching patterns of the switches of the inverters 20, 30, which are switched in accordance with the drive signal in the H drive control, are shifted in phase by 120° in electrical angle in each phase. Also, the switching pattern of the switches of the first inverter 20, which is switched in accordance with the drive signal in the Y drive control, is shifted in phase by 120° in electrical angle in each phase.

[0051] The request determination unit 89 determines whether or not there is a temperature increase request for the control system 100. In this embodiment, the request determination unit 89 determines that there is a temperature increase request when it determines that the battery temperature Tbat detected by the battery temperature sensor 66 is lower than the target temperature Tbtgt.

[0052] When the control device 70 determines that there is a temperature increase request, it performs temperature increase control to increase the total amount of heat generated by the first inverter 20, the second inverter 30, and the rotating electrical machine 40. The control device 70 drives the water pump 201 to transfer the heat generated by the temperature increase control to the battery 10, which is the target for temperature increase, via the coolant in the circulation path 200. The control device 70 continues the temperature increase control, for example, until the battery temperature Tbat reaches the target temperature Tbtgt. The temperature increase control quickly increases the temperature of the battery 10, thereby shortening the charging time of the battery 10 using an external charger, for example.

[0053] 7 shows a flowchart of the control process of the rotary electric machine 40 executed by the control device 70. The process shown in FIG. 7 is repeatedly executed by the processor 71 of the control device 70, for example, at a predetermined control cycle.

[0054] In step S10, the command torque Trq* is acquired, and the speed calculation unit 84 calculates the rotation speed Nr.

[0055] In step S11, the selection unit 85 selects either the Y drive control or the H drive control based on the command torque Trq* and the rotation speed Nr.

[0056] In step S12, the request determination unit 89 determines whether or not there is a temperature increase request.

[0057] If it is determined that there is no temperature increase request, the process proceeds to step S12, where the switching control of the first inverter 20 and the second inverter 30 is performed in accordance with the control mode selected in step S11.

[0058] On the other hand, if it is determined in step S12 that a temperature increase request has been made, the process proceeds to step S14, where it is determined whether the temperature detected by the motor temperature sensor 64 (hereinafter referred to as the motor temperature Tmt) is equal to or lower than a motor temperature threshold value Tmα (corresponding to the "first threshold value"). In this embodiment, the motor temperature Tmt is the temperature of each of the phase windings 51U, 51V, 51W. The motor temperature threshold value Tmα is, for example, the upper limit allowable temperature of each of the phase windings 51U, 51V, 51W that can maintain the reliability of each of the phase windings 51U, 51V, 51W. Note that the motor temperature Tmt compared with the motor temperature threshold value Tmα may be, for example, the maximum or average value of the temperatures of each of the phase windings 51U, 51V, 51W.

[0059] If it is determined in step S14 that the motor temperature Tmt exceeds the motor temperature threshold Tmα, the process proceeds to step S15, where it is determined whether the inverter temperature Tinv detected by the inverter temperature sensor 63 is equal to or lower than the inverter temperature threshold Tinα (corresponding to the "second threshold"). The inverter temperature Tinv may be, for example, the higher of the temperature of the first inverter 20 (hereinafter referred to as the first inverter temperature Tinv1) and the temperature of the second inverter 30 (hereinafter referred to as the second inverter temperature Tinv2), or the average value of the inverter temperatures Tinv1 and Tinv2. The inverter temperature threshold Tinα is, for example, the upper limit temperature allowable for the first and second inverters 20, 30 at which the reliability of the first and second inverters 20, 30 can be maintained.

[0060] If it is determined in step S15 that the inverter temperature Tinv exceeds the inverter temperature threshold value Tinα, the process proceeds to step S13 to prohibit the execution of each heat generation mode, which will be described later.

[0061] On the other hand, if it is determined in step S15 that the inverter temperature Tinv is equal to or lower than the inverter temperature threshold value Tinα, the process proceeds to step S16.

[0062] In step S16, an inverter heat generation mode is executed in which the inverter switching frequency fc is set higher than the inverter switching frequency in step S13. Specifically, the frequency of the carrier signal is increased. This increases the inverter switching loss to a level higher than the inverter switching loss in step S13, thereby increasing the amount of heat generated by the inverter. As a result, the total amount of heat generated by the first and second inverters 30 and the rotating electric machine 40 increases. This increases the amount of heat transferred to the battery 10, allowing the battery 10 to quickly heat up.

[0063] If Y drive control is selected in step S11, the switching frequency of each switch SUHa to SWLa of the first inverter 20 is increased in step S16. On the other hand, if H drive control is selected in step S11, the switching frequency of each switch SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30 is increased in step S16.

[0064] The increment Δfup of the switching frequency set in step S16 relative to the switching frequency set in step S13 may be set smaller as the inverter temperature Tinv increases, as shown in Fig. 8. This makes it possible to prevent the inverter from overheating.

[0065] If it is determined in step S14 that the motor temperature Tmt is equal to or lower than the motor temperature threshold Tmα, the process proceeds to step S17, where it is determined whether the inverter temperature Tinv is equal to or lower than the inverter temperature threshold Tinα. If it is determined in step S17 that the inverter temperature Tinv exceeds the inverter temperature threshold Tinα, the process proceeds to step S18.

[0066] In step S18, a motor heat generation mode is executed in which the inverter switching frequency fc is set lower than the inverter switching frequency in step S13. Specifically, the frequency of the carrier signal is lowered. As a result, as shown in FIGS. 10 and 11 , the fluctuation amount of the component of the current flowing through each phase winding 51U, 51V, 51W that depends on the carrier signal frequency increases. As a result, the iron loss of the rotating electric machine 40 is increased above the iron loss of the rotating electric machine 40 in step S13, and the amount of heat generated by the rotating electric machine 40 increases. This increases the total amount of heat generated by the first and second inverters 30 and the rotating electric machine 40.

[0067] If Y drive control is selected in step S11, the switching frequency of each switch SUHa to SWLa of the first inverter 20 is reduced in step S18. On the other hand, if H drive control is selected in step S11, the switching frequency of each switch SUHa to SWLa and SUHb to SWLb of the first and second inverters 20, 30 is reduced in step S18.

[0068] The decrease Δfdown of the switching frequency set in step S18 with respect to the switching frequency set in step S13 may be set smaller as the inverter temperature Tinv increases, as shown in Fig. 9. This makes it possible to prevent the rotating electrical machine 40 from becoming overheated.

[0069] If it is determined in step S17 that the inverter temperature Tinv is equal to or lower than the inverter temperature threshold value Tinα, the process proceeds to step S19. In step S19, a dual heat generation mode is executed to increase the amount of heat generated by the first and second inverters 20, 30 and the amount of heat generated by the rotating electric machine 40. In this embodiment, this heat generation mode alternates between a first control for applying a positive voltage to each phase winding 51U, 51V, 51W and a second control for applying a negative voltage to each phase winding 51U, 51V, 51W by PWM driving the switches of the first and second inverters 20, 30. The dual heat generation mode will now be described with reference to FIG. 12 .

[0070] FIG. 12 shows the transition of each waveform. FIG. 12 shows the waveform for only one phase in the control system 100. Therefore, the symbols U, V, and W that identify the phase have been removed from the symbols for each component. In FIG. 12, (a) shows the transition of the carrier signal Sg and the normalized command value Duty. (b) shows the transition of the first voltage V1, which is the voltage on the first inverter 20 side of the winding. (c) shows the transition of the second voltage V2, which is the voltage on the second inverter 30 side of the winding. In FIG. 12, fc is the frequency of the carrier signal Sg, and Tc is one period of the carrier signal Sg. One period Tc of the carrier signal Sg is equal to one switching period Tsw of the switches SUHa to SWLa and SUHb to SWLb of each inverter 20, 30.

[0071] In the first control, the control device 70 turns on the first upper arm switch SHa and the second lower arm switch SLb and turns off the first lower arm switch SLa and the second upper arm switch SHb, thereby applying the positive voltage (+Vsr) of the battery 10 to the windings.

[0072] In the second control, the control device 70 turns on the second upper arm switch SHb and the first lower arm switch SLa and turns off the second lower arm switch SLb and the first upper arm switch SHa, thereby applying the negative voltage (−Vsr) of the battery 10 to the windings.

[0073] This increases the fluctuation amount of the voltage difference across each phase winding 51U, 51V, 51W, thereby increasing the iron loss of the rotating electric machine 40 and the switching loss of the first and second inverters 20, 30. As a result, the amount of heat generated by the first and second inverters 20, 30 and the amount of heat generated by the rotating electric machine 40 can be increased.

[0074] 13 shows an example of a control mode when the H drive control selected in step S11 is executed in step S13. In FIG. 13, (a) shows the transitions of the first and second carrier signals Sg1 and Sg2 and the normalized command value Duty. (b) shows the transitions of the first voltage V1, and (c) shows the transitions of the second voltage V2.

[0075] The amplitude of the first and second carrier signals Sg1 and Sg2 is half that of the carrier signal Sg shown in Figure 12. The amplitude, period, and phase of the first carrier signal Sg1 are the same as those of the second carrier signal Sg2. The minimum value (0) of the first carrier signal Sg1 is the same as the maximum value (0) of the second carrier signal Sg2.

[0076] In the example shown in Figure 13, the control device 70 controls the switches of the first and second inverters 20, 30 so that a first period L1 in which the positive voltage of the battery 10 and zero voltage are alternately applied to the winding, and a second period L2 in which the negative voltage of the battery 10 and zero voltage are alternately applied to the winding, occur alternately.

[0077] The control device 70 alternately turns on the first upper arm switch SHa and the first lower arm switch SLa while fixing the second upper arm switch SHb to OFF and the second lower arm switch SLb to ON during the first period L1. The control device 70 alternately turns on the second upper arm switch SHb and the second lower arm switch SLb while fixing the first upper arm switch SHa to OFF and the first lower arm switch SLa to ON during the second period L2. The control shown in Figure 13 results in a smaller fluctuation in the voltage difference across each phase winding 51U, 51V, 51W than the control shown in Figure 12.

[0078] According to the present embodiment described above, the total amount of heat generated by the first and second inverters 20, 30 and the rotating electrical machine 40 can be increased.

[0079] Second Embodiment A second embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the processing content of the dual heat generation mode in step S19 in FIG. 7 is changed.

[0080] Specifically, when it is determined that there is a temperature increase request, the control device 70 increases the reactive current (specifically, the d-axis current) that does not contribute to torque generation of the rotating electrical machine 40 more than in the control in step S13, compared to when it is determined that there is no temperature increase request. The dual heat generation mode will be described below with reference to FIG. 14.

[0081] Fig. 14 is a diagram showing a dq coordinate system. Fig. 14 shows the equal torque line Lt and the MTPA line. The MTPA line is a line determined by a combination of the d-axis and q-axis current command values ​​Id* and Iq* for minimum current maximum torque control of the rotating electric machine 40. In the dq coordinate system, the negative side of the d-axis is a field weakening region.

[0082] In Figure 14, P1 is a reference point indicating the tip of the current vector determined in the control of step S13. The current vector is determined by the d- and q-axis currents. Reference point P1 exists on the MTPA line. P2 and P3 are heat generation increase points that are shifted from reference point P1 on the equal torque line Lt that passes through reference point P1. Heat generation increase point P2 is a point shifted to the negative side of the d-axis from reference point P1, and heat generation increase point P3 is a point shifted to the positive side of the d-axis from reference point P1.

[0083] In the dual heat generation mode, the control device 70 controls the on / off of the switches of the first and second inverters 20, 30 so that the tip of the current vector is at either the heat generation increasing point P2 or P3. The dual heat generation mode of this embodiment can be applied to either the Y drive control or the H drive control.

[0084] By locating the heat generation increase point on the equal torque line Lt passing through the reference point P1, it is possible to prevent the torque of the rotating electric machine 40 from deviating from the command torque Trq* when the dual heat generation mode is executed.

[0085] According to the present embodiment described above, the total amount of heat generated by the first and second inverters 20, 30 and the rotating electrical machine 40 can be increased.

[0086] Third Embodiment A third embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the process of the inverter heat generation mode in step S16 in FIG. 7 is changed.

[0087] FIG. 15 shows the configuration of the first and second inverters 20 and 30 and their vicinity in the cooling device shown in FIG.

[0088] The circulation path 200 includes an inlet pipe 210, an outlet pipe 220, and a plurality of connection pipes 230. The inlet pipe 210 and the outlet pipe 220 are long. The coolant that has been cooled by the radiator 202 flows into the inlet pipe 210.

[0089] The inlet pipe 210 and the outlet pipe 220 are connected by a plurality of connection pipes 230. As a result, the cooling water that flows in from the inlet pipe 210 flows to the outlet pipe 220 via each connection pipe 230.

[0090] The first inverter 20 includes first U-, V-, and W-phase modules M1U, M1V, and M1W. The first U-phase module M1U is a modular component in which U-phase first upper and lower arm switches SUHa and SULa are housed in a case. The first V-phase module M1V is a modular component in which V-phase first upper and lower arm switches SVHa and SVLa are housed in a case. The first W-phase module M1W is a modular component in which W-phase first upper and lower arm switches SWHa and SWLa are housed in a case.

[0091] The second inverter 30 includes second U-, V-, and W-phase modules M2U, M2V, and M2W. The second U-phase module M2U is a modular component in which U-phase second upper and lower arm switches SUHb and SULb are housed in a case. The second V-phase module M2V is a modular component in which V-phase second upper and lower arm switches SVHb and SVLb are housed in a case. The second W-phase module M2W is a modular component in which W-phase second upper and lower arm switches SWHb and SWLb are housed in a case.

[0092] Each of the modules M1U to M2W is disposed between adjacent connection pipes 230 in the longitudinal direction of the inlet pipe 210 and the outlet pipe 220. This allows each of the modules M1U to M2W to be cooled.

[0093] In this embodiment, the first U-, V-, and W-phase modules M1U, M1V, and M1W and the second U-, V-, and W-phase modules M2U, M2V, and M2W are arranged in this order from the upstream side in the direction of coolant flow. Therefore, as shown in Figure 16, the degree of cooling and the temperature decrease in the order of M1U, M1V, M1W, M2U, M2V, and M2W. As a result, the margin for the allowable upper limit temperature Tlim of the switches increases in the order of M1U, M1V, M1W, M2U, M2V, and M2W.

[0094] Therefore, the control device 70 sets the switching frequency (specifically, the frequency of the carrier signal Sg) of the first U-phase module M1U, which is cooled most upstream among the first U-, V-, and W-phase modules M1U, M1V, and M1W, to be higher than the switching frequencies of the first V- and W-phase modules M1V and M1W. The control device 70 also sets the switching frequency of the first V-phase module M1V to be higher than the switching frequency of the first W-phase module M1W.

[0095] The control device 70 sets the switching frequency (specifically, the frequency of the carrier signal Sg) of the second U-phase module M2U, which is cooled most upstream among the second U-, V-, and W-phase modules M2U, M2V, and M2W, higher than the switching frequencies of the second V- and W-phase modules M2V and M2W. The control device 70 also sets the switching frequency of the second V-phase module M2V higher than the switching frequency of the second W-phase module M2W.

[0096] Increasing the switching frequency increases the amount of heat generated by the switch. By relatively increasing the switching frequency of the switch with a large margin for the allowable upper limit temperature, it is possible to effectively increase the amount of heat generated in both the heat generation mode while avoiding an overheating state of the first and second inverters 20, 30.

[0097] Fourth Embodiment A fourth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the process content of the inverter heat generation mode is changed to a process of increasing the on-resistance of the switch.

[0098] 17 is a flowchart showing the control process of the rotary electric machine 40 executed by the control device 70. The process shown in FIG. 17 is repeatedly executed by the processor 71, for example, at a predetermined control cycle.

[0099] If the determination in step S15 is affirmative, the process proceeds to step S20, where an inverter heat generation mode is selected, and control is performed to lower the gate voltage of the switch to be turned on to increase the on-resistance. Specifically, if Y drive control is selected in step S11, the gate voltage of the PWM-driven switch of the first inverter 20 and the gate voltage of the switch fixed on in the second inverter 30 are lowered below the gate voltage when Y drive control is performed in step S13. On the other hand, if H drive control is selected in step S11, the gate voltage of the PWM-driven switch of the first and second inverters 20, 30 are lowered below the gate voltage when H drive control is performed in step S13.

[0100] This increases the amount of heat generated by the switch with increased on-resistance.

[0101] Fifth Embodiment A fifth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the processing content of the dual heat generation mode is changed to processing for flowing a zero-phase current.

[0102] FIG. 18 is a block diagram showing the control process of the rotating electrical machine 40 executed by the control device 70.

[0103] The zero-phase signal generating unit 87 generates a zero-phase signal V0* for controlling the zero-phase current flowing through the U, V, and W-phase windings 51U, 51V, and 51W to a target value, and outputs the signal to the U, V, and W-phase superimposing units 88U, 88V, and 88W.

[0104] U, V, W phase superimposing units 88U, 88V, 88W add a common zero-phase sequence signal V0* to U, V, W phase voltage command values ​​Vu*, Vv*, Vw* and output the result to switch control unit 86. Switch control unit 86 generates drive signals using "Vu*+V0*, Vv*+V0*, Vw*+V0*." In the dual heat generation mode, switch control unit 86 generates drive signals for performing H drive control so as to pass zero-phase sequence current through each phase winding 51U, 51V, 51W to increase the amount of heat generated.

[0105] Next, several setting modes of the zero-phase-sequence signal V0* will be described with reference to Fig. 19 to Fig. 22. Fig. 19 shows the transition of the phase voltage command values ​​Vu*, Vv*, and Vw* when the zero-phase-sequence signal V0* is 0.

[0106] The first mode will be described. As shown in Fig. 20, the zero-phase-sequence signal generator 87 outputs a DC zero-phase-sequence signal V0* that is smaller in amplitude than the phase voltage command values ​​Vu*, Vv*, and Vw*. This causes a DC zero-phase-sequence current to flow through the phase windings 51U, 51V, and 51W, thereby increasing the amount of heat generated in the first and second inverters 20 and 30 and the rotating electric machine 40.

[0107] The second aspect will be described. As shown in FIG. 21 , the zero-phase signal generator 87 outputs an AC zero-phase signal V0* that fluctuates with the same period as the periods of the phase voltage command values ​​Vu*, Vv*, and Vw*. Specifically, the zero-phase signal generator 87 outputs a zero-phase signal V0* that makes the amplitudes of the U- and V-phase voltage command values ​​Vu* and Vv* larger than the amplitude of the W-phase voltage command value Vw*. As shown in FIG. 15 , the U- and V-phase modules, which are arranged upstream relative to the W-phase module, have a larger degree of cooling. Therefore, even if the amplitude of the voltage command value corresponding to a phase with a larger degree of cooling is increased, the module of the phase whose amplitude is increased can be prevented from overheating.

[0108] The third aspect will be described. As shown in Fig. 22, the zero-phase-sequence signal generator 87 outputs an AC zero-phase-sequence signal V0* that fluctuates at a frequency three times the frequency of the phase voltage command values ​​Vu*, Vv*, and Vw*. This makes it possible to increase the amplitude of the phase currents flowing through the phase windings 51U, 51V, and 51W as uniformly as possible.

[0109] According to the present embodiment described above, heat can be generated effectively by passing a zero-phase current.

[0110] Sixth Embodiment The sixth embodiment will be described below with reference to the drawings, focusing on differences from the first to fifth embodiments. In this embodiment, as shown in FIG. 23 , the control system 100 includes a second changeover switch 16 in addition to the first changeover switch 13. The second changeover switch 16 is provided on the negative bus 12 (corresponding to the “target bus”). The second changeover switch 16 is, for example, a semiconductor switching element or a mechanical relay. When the second changeover switch 16 is turned on, it electrically connects the emitters of the lower arm switches SULa, SVLa, and SWLa of the first inverter 20 to the emitters of the lower arm switches SULb, SVLb, and SWLb of the second inverter 30. On the other hand, when the second changeover switch 16 is turned off, it electrically disconnects the emitters of the lower arm switches SULa, SVLa, SWLa of the first inverter 20 from the emitters of the lower arm switches SULb, SVLb, SWLb of the second inverter 30.

[0111] The second changeover switch 16 may be, for example, an IGBT. In this case, a freewheeling diode is connected in anti-parallel to the second changeover switch 16. The collector of the IGBT is connected to the second inverter 30 side, and the emitter of the IGBT is connected to the first inverter 20 side.

[0112] In this embodiment, when the control device 70 selects the H drive control, it turns on the first changeover switch 13 and the second changeover switch 16. On the other hand, when the control device 70 selects the Y drive control, it turns off the first changeover switch 13 and the second changeover switch 16.

[0113] The control device 70 switches between upper arm neutral point control and lower arm neutral point control when performing Y drive control among the normal control, inverter heat generation mode, motor heat generation mode, and dual heat generation mode in step S13.

[0114] The upper arm neutral point control is a control in which, with the first and second changeover switches 13 and 16 turned off, the second upper arm switches SUHb to SWHb of each phase are fixed on and the second lower arm switches SULb to SWLb of each phase are fixed off, and the first upper and lower arm switches SUHa and SULa are PWM driven (see Figure 6 above).

[0115] As shown in FIG. 24, the lower arm neutral point control is a control in which, with the first and second changeover switches 13, 16 turned off, the second lower arm switches SULb to SWLb of each phase are fixed on and the second upper arm switches SUHb to SWHb of each phase are fixed off, and the first upper and lower arm switches SUHa to SWHa are PWM driven. Note that the control device 70 may set the switching cycle between the upper arm neutral point control and the lower arm neutral point control to, for example, one electrical angle cycle of the rotating electric machine 40, or to multiple electrical angle cycles, or to a cycle that is not an integral multiple of the electrical angle cycle.

[0116] According to the present embodiment described above, it is possible to prevent the second inverter 30 from generating heat unevenly in either the upper or lower arm.

[0117] Seventh Embodiment A seventh embodiment will now be described with reference to the drawings, focusing on differences from the first to fifth embodiments. In this embodiment, as shown in Fig. 25 , a configuration is provided in which either the first inverter 20 or the second inverter 30 is selectively disconnected from the battery 10.

[0118] More specifically, the control system 100 includes a second power switch 17 in addition to the first power switch 14. The second power switch 17 is, for example, a semiconductor switching element or a mechanical relay. The second power switch 17 connects the positive terminal of the battery 10 to the collectors of the upper arm switches SUHb, SVHb, and SWHb of each phase of the second inverter 30. When the second power switch 17 is turned on, it electrically connects the positive terminal of the battery 10 to the collectors of the upper arm switches SUHb, SVHb, and SWHb of each phase. When the second power switch 17 is turned off, it electrically disconnects the positive terminal of the battery 10 from the collectors of the upper arm switches SUHb, SVHb, and SWHb of each phase. In this embodiment, the first power switch 14 and the second power switch 17 correspond to a "connection switching unit."

[0119] In this embodiment, the capacitor 15 is connected in parallel to the battery 10. When the H drive control is selected, the control device 70 turns on the first power switch 14 and turns off the second power switch 17.

[0120] When performing Y drive control in the normal control, inverter heat generation mode, motor heat generation mode, or dual heat generation mode in step S13, the control device 70 performs control to switch between the first Y drive control and the second Y drive control.

[0121] 26, the first Y drive control is a control for PWM driving each of the switches SUHa to SWLa of the first inverter 20 in a state where the first power switch 14 is turned on and the second power switch 17 is turned off. Also, the upper arm switches SUHb, SVHb, and SWHb of the second inverter 30 are fixed on, and the lower arm switches SULb, SVLb, and SWLb of the second inverter 30 are fixed off.

[0122] When the first power switch 14 is turned on and the second power switch 17 is turned off, the first mode is entered in which the battery 10 and the first inverter 20 are electrically connected and the battery 10 and the second inverter 30 are electrically disconnected.

[0123] 27, the second Y drive control is a control for PWM driving the switches SUHb to SWLb of the second inverter 30 when the first power switch 14 is turned off and the second power switch 17 is turned on. Also, the upper arm switches SUHa, SVHa, and SWHa of the first inverter 20 are fixed on, and the lower arm switches SULa, SVLa, and SWLa of the second inverter 30 are fixed off.

[0124] When the first power switch 14 is turned off and the second power switch 17 is turned on, the battery 10 and the second inverter 30 are electrically connected and the battery 10 and the first inverter 20 are electrically disconnected, entering a second mode.

[0125] According to the present embodiment described above, uneven heat generation in the first inverter 20 and the second inverter 30 can be suppressed.

[0126] The control device 70 can switch between the first Y drive control and the second Y drive control in various ways. Two examples will be described below.

[0127] In the first example, the control device 70 may alternate between the first Y-drive control and the second Y-drive control at a predetermined cycle. In this case, the predetermined cycle may be, for example, one electrical angle cycle of the rotating electric machine 40, multiple electrical angle cycles, or a cycle that is not an integral multiple of the electrical angle cycle.

[0128] In the second example, when the control device 70 determines that the first inverter temperature Tinv1 exceeds the inverter temperature threshold Tinα during execution of the first Y drive control, the control device 70 switches from the first Y drive control to the second Y drive control. In this case, the first inverter temperature Tinv1 may be, for example, the highest temperature among the temperatures of the switches SUHa to SWLa of the first inverter 20.

[0129] Furthermore, when the control device 70 determines that the second inverter temperature Tinv2 exceeds the inverter temperature threshold Tinα during execution of the second Y drive control, the control device 70 switches from the second Y drive control to the first Y drive control. In this case, the second inverter temperature Tinv2 may be, for example, the highest temperature among the temperatures of the switches SUHb to SWLb of the second inverter 30.

[0130] Eighth Embodiment The eighth embodiment will now be described with reference to the drawings, focusing on differences from the first to fifth embodiments. In this embodiment, when performing H drive control, the control device 70 switches between four modes shown in Figures 28 to 31 among the normal control in step S13, the inverter heat generation mode, the motor heat generation mode, and the dual heat generation mode. Note that Figures 28 to 31 below show the configuration of only one phase in the control system 100. For this reason, the symbols U, V, and W that identify the phase have been deleted from the symbols of each component.

[0131] Mode A shown in Figure 28 corresponds to the first lower arm control, and is a control in which the first upper arm switch SHa and the second lower arm switch SLb are fixed off and the first lower arm switch SLa is PWM driven to apply a negative polarity voltage to the winding 51.

[0132] In mode A, the control device 70 turns on the second upper arm switch SHb for at least a part of one switching period Tsw. The control device 70 may switch the second upper arm switch SHb on and off, for example, at a period that is ½ of the electrical angle period (i.e., a period of 180 electrical degrees, which is ½ of the switching period Tsw).

[0133] In addition, in mode A, the control device 70 may PWM drive the first upper arm switch SHa so as to alternately turn on the first upper arm switch SHa and the first lower arm switch SLa.

[0134] Mode B shown in Figure 29 corresponds to second lower arm control, and is a control in which the first lower arm switch SLa and the second upper arm switch SHb are fixed off and the second lower arm switch SLb is PWM driven in order to apply a positive voltage to the winding 51.

[0135] In mode B, the control device 70 turns on the first upper arm switch SHa for at least a part of one switching period Tsw. The control device 70 may, for example, switch the second upper arm switch SHb on and off in a period that is half the electrical angle period, or may switch the second upper arm switch SHb on and off based on a pulse pattern.

[0136] In addition, in mode B, the control device 70 may PWM drive the second upper arm switch SHb so as to alternately turn on the second upper arm switch SHb and the second lower arm switch SLb.

[0137] Mode C shown in Figure 30 corresponds to the first upper arm control, and is a control in which the first lower arm switch SLa and the second upper arm switch SHb are fixed off and the first upper arm switch SHa is PWM driven in order to apply a positive voltage to the winding 51.

[0138] In mode C, the control device 70 turns on the second lower arm switch SLb for at least a part of one switching period Tsw. For example, the control device 70 may switch the second lower arm switch SLb on and off in a period that is half the electrical angle period, or may switch the second lower arm switch SLb on and off based on a pulse pattern.

[0139] In addition, in mode C, the control device 70 may PWM drive the first lower arm switch SLa so as to alternately turn on the first upper arm switch SHa and the first lower arm switch SLa.

[0140] Mode D shown in Figure 31 corresponds to second upper arm control, and is a control in which the first upper arm switch SHa and the second lower arm switch SLb are fixed off and the second upper arm switch SHb is PWM driven to apply a negative polarity voltage to the winding 51.

[0141] In the D mode, the control device 70 turns on the first lower arm switch SLa for at least a part of one switching period Tsw. For example, the control device 70 may switch the first lower arm switch SLa on and off in a period that is half the electrical angle period, or may switch the first lower arm switch SLa on and off based on a pulse pattern.

[0142] In addition, in the D mode, the control device 70 may PWM drive the second lower arm switch SLb so as to alternately turn on the second upper arm switch SHb and the second lower arm switch SLb.

[0143] The control device 70 may switch between modes A to D using the method shown in Fig. 32. Fig. 32 is a state transition diagram of each mode.

[0144] The control device 70 selects and executes one of the following controls: control for switching between A mode and B mode every 180°; control for switching between B mode and D mode every 180°; control for switching between A mode and C mode every 180°; and control for switching between C mode and D mode every 180°.

[0145] [1] When the control device 70 determines that the temperature T1L of the first lower arm switch SLa (for example, the highest temperature among the temperatures of the first lower arm switches SULa to SWLa of each phase) detected by the inverter temperature sensor 63 exceeds the inverter temperature threshold Tinα during control of switching between A mode and B mode, the control device 70 switches to control of switching between B mode and D mode. This suppresses heat generation in the first lower arm switch and prevents the first lower arm switch SLa from becoming overheated.

[0146] [2] When the control device 70 determines that the temperature T2H of the second upper arm switch SHb (for example, the highest temperature among the temperatures of the second upper arm switches SUHa to SWHa of each phase) detected by the inverter temperature sensor 63 exceeds the inverter temperature threshold Tinα during the execution of control for switching between the B mode and the D mode, the control device 70 switches to control for switching between the A mode and the B mode. This makes it possible to suppress heat generation in the second upper arm switch SHb.

[0147] [3] When the control device 70 determines that the temperature T2L of the second lower arm switch SLb (for example, the highest temperature among the temperatures of the second lower arm switches SULb to SWLb of each phase) detected by the inverter temperature sensor 63 exceeds the inverter temperature threshold Tinα during the execution of control for switching between A mode and B mode, the control device 70 switches to control for switching between A mode and C mode. This makes it possible to suppress heat generation in the second lower arm switch SLb.

[0148] [4] When the control device 70 determines that the temperature T1H of the first upper arm switch SHa (for example, the highest temperature among the temperatures of the first upper arm switches SUHa to SWHa of each phase) detected by the inverter temperature sensor 63 exceeds the inverter temperature threshold Tinα during the execution of control for switching between A mode and C mode, the control device 70 switches to control for switching between A mode and B mode. This makes it possible to suppress heat generation in the first upper arm switch SHa.

[0149] [5] If the control device 70 determines that the detected temperature T2L of the second lower arm switch SLb exceeds the inverter temperature threshold Tinα during the execution of the control for switching between the B mode and the D mode, the control device 70 switches to the control for switching between the C mode and the D mode. This makes it possible to suppress heat generation in the second lower arm switch SLb.

[0150] [6] When the control device 70 determines that the detected temperature T1H of the first upper arm switch SHa exceeds the inverter temperature threshold Tinα during the execution of the control for switching between the C mode and the D mode, the control device 70 switches to the control for switching between the B mode and the D mode. This makes it possible to suppress heat generation in the first upper arm switch SHa.

[0151] [7] When the control device 70 determines that the detected temperature T2H of the second upper arm switch SHb exceeds the inverter temperature threshold Tinα during the execution of the control for switching between the C mode and the D mode, the control device 70 switches to the control for switching between the A mode and the C mode. This makes it possible to suppress heat generation in the second upper arm switch SHb.

[0152] [8] If the control device 70 determines that the detected temperature T1L of the first lower arm switch SLa exceeds the inverter temperature threshold Tinα during the execution of control for switching between A mode and C mode, the control device 70 switches to control for switching between C mode and D mode. This makes it possible to suppress heat generation in the first lower arm switch SLa.

[0153] According to the present embodiment described above, it is possible to prevent a particular switch in the first and second inverters 20, 30 from becoming overheated.

[0154] Other Embodiments The above-described embodiments may be modified as follows.

[0155] The target to be heated by the temperature rise control may be, for example, the coolant in the circulation path 200. If the vehicle is equipped with an air conditioning system that uses the coolant as a heat source for heating the passenger compartment, the temperature of the heating heat source can be quickly raised by the temperature rise control. In this case, the control device 70 may determine that a temperature rise request exists when, for example, it determines that the detected value Thw of the water temperature sensor 65 is lower than the target temperature.

[0156] The heat transfer unit is not limited to a unit that uses cooling water as a cooling fluid, and may be, for example, an air-cooled unit that uses gas (air) as a cooling fluid, or may be a metal heat sink. When a heat sink is used as the heat transfer unit, for example, the first and second inverters 20, 30 and the battery 10 may be provided on the heat sink.

[0157] The carrier signal is not limited to a triangular wave signal, but may be, for example, a sawtooth wave signal.

[0158] In each of the above embodiments, the control device 70 may perform PWM driving based on space vector modulation instead of PWM driving based on a magnitude comparison between the command value and the carrier signal.

[0159] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0160] The rotating electric machine is not limited to a permanent magnet field type synchronous machine, and may be, for example, an induction machine.

[0161] The rotating electric machine is not limited to a three-phase one, but may be a two-phase one or a four-phase or more phase one.

[0162] The semiconductor switches constituting the first inverter and the second inverter are not limited to IGBTs, but may be, for example, N-channel MOSFETs. In this case, the high-potential terminal of the switch is the drain, and the low-potential terminal is the source. Each switch also has a body diode.

[0163] 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.

[0164] The control unit and method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with 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 executed by a computer.

[0165] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A rotating electric machine (40) having a multi-phase armature winding (51U to 51W); a first inverter (20) having first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) connected in series for the number of phases, the series-connected body of the first upper arm switches and the first lower arm switches being connected in parallel to a DC power source (10); a second inverter (30) having second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) connected in series for the number of phases; a positive bus (11) for each phase electrically connecting a high potential side terminal of the first upper arm switch and a high potential side terminal of the second upper arm switch; and a negative bus (12) for each phase electrically connecting a low potential side terminal of the first lower arm switch and a low potential side terminal of the second lower arm switch. a request determination unit (89) that determines whether or not there is a temperature increase request for the system; and a switch control unit (86) that controls the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch to be turned on or off, and when it is determined that there is a temperature increase request, the switch control unit performs temperature increase control, which is the control that increases the total amount of heat generated in the first inverter, the second inverter, and the rotating electric machine compared to when it is determined that there is no temperature increase request.[Configuration 2] The control device for a rotary electric machine according to Configuration 1, wherein the switch control unit performs, as the temperature rise control, control to PWM drive at least one of the second upper arm switch and the first lower arm switch to apply a negative voltage to the armature winding, and control to PWM drive at least one of the first upper arm switch and the second lower arm switch to apply a positive voltage to the armature winding. [Configuration 3] The control device for a rotary electric machine according to claim 1 or 2, wherein, as the temperature rise control, when it is determined that there is a temperature rise request, the switch control unit performs, as the temperature rise control, control to PWM drive at least one of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch so as to increase a reactive current that does not contribute to torque generation of the rotary electric machine more than when it is determined that there is no temperature rise request. [Configuration 4] The control device for a rotating electric machine according to claim 1 or 2, wherein the switch control unit performs the temperature rise control by PWM driving at least one of the second upper arm switch and the first lower arm switch, and at least one of the first upper arm switch and the second lower arm switch, so as to pass a zero-phase current through the armature winding of each phase. [Configuration 5] The control device for a rotary electric machine according to Configuration 4, wherein the system includes: a circulation path (200) for a cooling fluid that absorbs heat generated in the rotary electric machine, the first inverter, and the second inverter; and a pump (201) that circulates the cooling fluid through the circulation path, and the switch control unit performs the temperature rise control to satisfy the following conditions: a zero-phase sequence current is caused to flow through the armature winding of each phase such that a current amplitude of the armature winding of a phase of the first upper and lower arm switch of each phase that is cooled on the most upstream side of the circulation path is larger than a current amplitude of the armature winding of a phase of the switch that is cooled on the most downstream side of the circulation path, and a zero-phase sequence current is caused to flow through the armature winding of each phase such that a current amplitude of the armature winding of a phase of the second upper and lower arm switch of each phase that is cooled on the most upstream side of the circulation path is larger than a current amplitude of the armature winding of a phase of the switch that is cooled on the most downstream side of the circulation path.[Configuration 6] The control device for a rotating electric machine according to any one of Configurations 2 to 5, wherein the switch control unit performs the temperature increase control when it is determined that the temperature (Tmt) of the rotating electric machine is equal to or lower than a first threshold (Tmα) and that an inverter temperature (Tinv) that is the temperature of either the first inverter or the second inverter is equal to or lower than a second threshold (Tinα). [Configuration 7] The control device for a rotating electric machine according to any one of Configurations 1 to 6, wherein the switch control unit increases a switching frequency in the temperature increase control when it is determined that there is a temperature increase request compared to when it is determined that there is no temperature increase request. [Configuration 8] The control device for a rotating electric machine according to Configuration 7, wherein the switch control unit performs the temperature increase control when it is determined that the temperature of the rotating electric machine exceeds a first threshold (Tmα) and that an inverter temperature (Tinv) that is the temperature of either the first inverter or the second inverter is equal to or lower than a second threshold (Tinα). [Configuration 9] The control device for a rotating electric machine according to Configuration 7 or 8, wherein the switch control unit reduces an increase in switching frequency (Δfup) in the temperature rise control when the inverter temperature is high compared to when the inverter temperature is low. [Configuration 10] The control device for a rotating electric machine according to any one of Configurations 7 to 9, wherein the system includes: a circulation path (200) for cooling fluid that absorbs heat generated in the rotating electric machine, the first inverter, and the second inverter, and a pump (201) that circulates the cooling fluid through the circulation path, and the switch control unit performs the temperature rise control to satisfy the following conditions: a phase switching frequency of the switch that is cooled on the most upstream side of the circulation path, out of the first upper and lower arm switches of each phase, is set to be higher than a phase switching frequency of the switch that is cooled on the most downstream side of the circulation path, out of the second upper and lower arm switches of each phase, is set to be higher than a phase switching frequency of the switch that is cooled on the most upstream side of the circulation path.[Configuration 11] The control device for a rotating electric machine according to any one of configurations 1 to 10, wherein, when it is determined that there is a temperature increase request, the switch control unit reduces the gate voltage of the switch to be turned on among the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch compared to when it is determined that there is no temperature increase request. [Configuration 12] The control device for a rotating electric machine according to any one of configurations 1 to 6, wherein, when it is determined that there is a temperature increase request, the switch control unit reduces a switching frequency in the temperature increase control compared to when it is determined that there is no temperature increase request. [Configuration 13] The control device for a rotating electric machine according to configuration 12, wherein, when it is determined that there is a temperature increase request, the switch control unit performs the temperature increase control when it is determined that the temperature of the rotating electric machine is equal to or lower than a first threshold (Tmα) and an inverter temperature (Tinv), which is the temperature of either the first inverter or the second inverter, exceeds a second threshold (Tinα). [Configuration 14] The control device for a rotary electric machine according to configuration 12 or 13, wherein the switch control unit reduces a decrease in switching frequency (Δfdown) in the temperature rise control when the temperature of the rotary electric machine is high compared to when the temperature of the rotary electric machine is low. [Configuration 15] The control device for a rotary electric machine according to any one of configurations 1 to 14, wherein the switch control unit performs, as the temperature rise control, control of switching between: first lower-arm control that PWM-drives the first lower-arm switch to apply a negative voltage to the armature winding, second lower-arm control that PWM-drives the second lower-arm switch to apply a positive voltage to the armature winding, first upper-arm control that PWM-drives the first upper-arm switch to apply a positive voltage to the armature winding, and second upper-arm control that PWM-drives the second upper-arm switch to apply a negative voltage to the armature winding.[Configuration 16] A changeover switch (13, 16) is provided on a target busbar that is at least one of the positive busbar and the negative busbar, the changeover switch electrically connects the first inverter and the second inverter via the target busbar when turned on, and cuts off the electrical connection between the first inverter and the second inverter via the target busbar when turned off, the switch control unit performs control to switch between upper arm neutral point control and lower arm neutral point control as the temperature rise control, the upper arm neutral point control is control to fix the second upper arm switch of each phase to on and fix the second lower arm switch of each phase to off when the changeover switch is off, and to PWM drive the first upper arm switch and the first lower arm switch, The control device for a rotating electric machine according to any one of configurations 1 to 14, wherein the lower arm neutral point control is a control that fixes the second lower arm switch of each phase to on and fixes the second upper arm switch of each phase to off when the changeover switch is off, and PWM drives the first upper arm switch and the first lower arm switch.[Configuration 17] A power supply system including: a changeover switch (13, 16) provided on a target busbar that is at least one of the positive busbar and the negative busbar; and a connection changeover unit (14, 17) that changes over between a first mode in which the DC power supply and the first inverter are electrically connected and the DC power supply and the second inverter are electrically disconnected, and a second mode in which the DC power supply and the second inverter are electrically connected and the DC power supply and the first inverter are electrically disconnected, wherein the changeover switch electrically connects the first inverter and the second inverter via the target busbar when turned on, and cuts off the electrical connection between the first inverter and the second inverter via the target busbar when turned off, and the switch control unit performs control to change over between first Y drive control and second Y drive control as the temperature rise control, and the first Y drive control is the second Y drive control is a control for PWM driving the first upper arm switch and the first lower arm switch, when the connection switching unit is set to the first mode and the changeover switch is turned off, fixing the second upper arm switch of each phase on and fixing the second lower arm switch of each phase off, or when the connection switching unit is set to the second mode and the changeover switch is turned off, fixing the second lower arm switch of each phase on and fixing the second upper arm switch of each phase off, and PWM driving the first upper arm switch and the first lower arm switch, and the second Y drive control is a control for PWM driving the first upper arm switch and the first lower arm switch, when the connection switching unit is set to the second mode and the changeover switch is turned off, fixing the first upper arm switch of each phase on and fixing the first lower arm switch of each phase off, or when the connection switching unit is set to the second mode and the changeover switch is turned off, fixing the first lower arm switch of each phase on and fixing the first upper arm switch of each phase off, and The control device for a rotating electric machine according to any one of configurations 1 to 14, wherein the second upper arm switch and the second lower arm switch are controlled to be PWM driven.[Configuration 18] The control device for a rotating electric machine according to any one of Configurations 1 to 17, wherein the request determination unit determines that there is a temperature increase request when it determines that the temperature (Tbat) of the DC power supply is lower than a target temperature (Tbtgt).

[0166] 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 rotating electrical machine (40) having a multi-phase armature winding (51U to 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SUL a to SWLa) corresponding to the number of phases, with the series connection of the first upper arm switch and the first lower arm switch being connected in parallel to a DC power supply (10), a second inverter (30) having a number of series-connected second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) corresponding to the number of phases, in each phase, a positive bus bar (11) electrically connecting the high potential side terminals of the first upper arm switch and the second upper arm switch, and in each phase, a negative bus bar (12) electrically connecting the low potential side terminals of the first lower arm switch and the second lower arm switch. In a control device (70) for a rotating electrical machine applied to a system comprising: in each phase, the low potential side terminal of the first upper arm switch and the high potential side terminal of the first lower arm switch are electrically connected to the first end of the armature winding; in each phase, the low potential side terminal of the second upper arm switch and the high potential side terminal of the second lower arm switch are electrically connected to the second end of the armature winding; a request determination unit (89) for determining whether there is a temperature rise requirement for the system; and a switch control unit (86) for controlling the on or off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch. The switch control unit performs a temperature rise control, which is a control for increasing the total heat generated in the first inverter, the second inverter, and the rotating electrical machine, when it is determined that there is a temperature rise requirement, compared to when it is determined that there is no temperature rise requirement. A control device for a rotating electrical machine.

2. The control device for a rotating electrical machine according to claim 1, wherein the switch control unit performs a control for switching between a control for PWM driving at least one of the second upper arm switch and the first lower arm switch to apply a negative voltage to the armature winding and a control for PWM driving at least one of the first upper arm switch and the second lower arm switch to apply a positive voltage to the armature winding as the temperature rise control.

3. The switch control unit, as the temperature increase control, when it is determined that there is a temperature increase request, controls at least one of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch to perform PWM driving so as to increase the idle current that does not contribute to the torque generation of the rotating electrical machine more than when it is determined that there is no temperature increase request. The control device for a rotating electrical machine according to claim 1 or 2.

4. The switch control unit, as the temperature increase control, controls at least one of the second upper arm switch and the first lower arm switch and at least one of the first upper arm switch and the second lower arm switch to perform PWM driving so as to cause a zero-phase current to flow through the armature winding of each phase. The control device for a rotating electrical machine according to claim 1 or 2.

5. The system includes a circulation path (200) of a cooling fluid that absorbs heat generated in the rotating electrical machine, the first inverter, and the second inverter, and a pump (201) that circulates the cooling fluid through the circulation path. The switch control unit satisfies the condition of causing a zero-phase current to flow through the armature winding of each phase such that the current amplitude of the armature winding of the phase of the switch cooled on the most upstream side of the circulation path among the first upper and lower arm switches of each phase is larger than the current amplitude of the armature winding of the phase of the switch cooled on the most downstream side of the circulation path, and the condition of causing a zero-phase current to flow through the armature winding of each phase such that the current amplitude of the armature winding of the phase of the switch cooled on the most upstream side of the circulation path among the second upper and lower arm switches of each phase is larger than the current amplitude of the armature winding of the phase of the switch cooled on the most downstream side of the circulation path, and performs the temperature increase control. The control device for a rotating electrical machine according to claim 4.

6. When the switch control unit determines that the temperature (Tmt) of the rotating electrical machine is equal to or lower than a first threshold value (Tma) and the inverter temperature (Tinv), which is the temperature of either the first inverter or the second inverter, is equal to or lower than a second threshold value (Tina), the switch control unit performs the temperature increase control. The control device for a rotating electrical machine according to claim 2.

7. The control device for a rotating electrical machine according to claim 1 or 2, wherein when it is determined that there is a temperature increase request, the switch control unit increases the switching frequency in the temperature increase control compared to when it is determined that there is no temperature increase request.

8. The control device for a rotating electrical machine according to claim 7, wherein when the temperature of the rotating electrical machine exceeds a first threshold value (Tmα) and the inverter temperature (Tinv), which is the temperature of either the first inverter or the second inverter, is equal to or lower than a second threshold value (Tinα), the temperature increase control is performed.

9. The control device for a rotating electrical machine according to claim 8, wherein when the inverter temperature is high, the switch control unit reduces the increase amount (Δfup) of the switching frequency in the temperature increase control compared to when the inverter temperature is low.

10. The system includes a circulation path (200) of a cooling fluid that absorbs heat generated in the rotating electrical machine, the first inverter, and the second inverter, and a pump (201) that circulates the cooling fluid through the circulation path. The switch control unit performs the temperature increase control so as to satisfy the condition that the switching frequency of the phase of the switch cooled on the most upstream side of the circulation path among the first upper and lower arm switches of each phase is higher than the switching frequency of the phase of the switch cooled on the most downstream side of the circulation path, and the condition that the switching frequency of the phase of the switch cooled on the most upstream side of the circulation path among the second upper and lower arm switches of each phase is higher than the switching frequency of the phase of the switch cooled on the most downstream side of the circulation path. The control device for a rotating electrical machine according to claim 7.

11. The control device for a rotating electrical machine according to claim 1 or 2, wherein when it is determined that there is a temperature increase request, the switch control unit reduces the gate voltage of the switch that is turned on among the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch compared to when it is determined that there is no temperature increase request.

12. The control device for a rotating electrical machine according to claim 1 or 2, wherein when it is determined that there is a temperature increase request, the switch control unit reduces the switching frequency in the temperature increase control compared to when it is determined that there is no temperature increase request.

13. The control device for a rotating electrical machine according to claim 12, wherein when the switch control unit determines that the temperature of the rotating electrical machine is equal to or lower than a first threshold value (Tmα) and the inverter temperature (Tinv), which is the temperature of either the first inverter or the second inverter, exceeds a second threshold value (Tinα), the switch control unit performs the temperature increase control.

14. The control device for a rotating electrical machine according to claim 12, wherein when the temperature of the rotating electrical machine is high, the switch control unit makes the decrease amount (Δfdown) of the switching frequency in the temperature increase control smaller than when the temperature of the rotating electrical machine is low.

15. The control device for a rotating electrical machine according to claim 1 or 2, wherein as the temperature increase control, the switch control unit performs control to switch between: a first lower arm control for PWM driving the first lower arm switch to apply a negative voltage to the armature winding; a second lower arm control for PWM driving the second lower arm switch to apply a positive voltage to the armature winding; a first upper arm control for PWM driving the first upper arm switch to apply a positive voltage to the armature winding; and a second upper arm control for PWM driving the second upper arm switch to apply a negative voltage to the armature winding.

16. A switching switch (13, 16) is provided on a target busbar which is at least one of the positive electrode side busbar and the negative electrode side busbar. When the switching switch is turned on, the first inverter and the second inverter are electrically connected via the target busbar. When the switching switch is turned off, the electrical connection between the first inverter and the second inverter via the target busbar is cut off. The switch control unit performs control to switch between upper arm neutral point control and lower arm neutral point control as the temperature increase control. The upper arm neutral point control is control in which, in a state where the switching switch is turned off, the second upper arm switches of each phase are fixed on and the second lower arm switches of each phase are fixed off, and the first upper arm switch and the first lower arm switch are PWM-driven. The lower arm neutral point control is control in which, in a state where the switching switch is turned off, the second lower arm switches of each phase are fixed on and the second upper arm switches of each phase are fixed off, and the first upper arm switch and the first lower arm switch are PWM-driven. The control device for a rotating electrical machine according to claim 1 or 2.

17. A changeover switch (13, 16) provided in a target busbar which is at least one of the positive electrode side busbar and the negative electrode side busbar; a connection changeover unit (14, 17) for switching between a first mode in which the DC power supply and the first inverter are electrically connected and the DC power supply and the second inverter are electrically disconnected, or a second mode in which the DC power supply and the second inverter are electrically connected and the DC power supply and the first inverter are electrically disconnected; the changeover switch, when turned on, electrically connects the first inverter and the second inverter via the target busbar, and when turned off, disconnects the electrical connection between the first inverter and the second inverter via the target busbar; the switch control unit performs control to switch between first Y drive control and second Y drive control as the temperature increase control; the first Y drive control is control in which, when the connection changeover unit is set to the first mode and the changeover switch is turned off, the second upper arm switches of each phase are fixed on and the second lower arm switches of each phase are fixed off, or when the connection changeover unit is set to the second mode and the changeover switch is turned off, the second lower arm switches of each phase are fixed on and the second upper arm switches of each phase are fixed off, and the first upper arm switch and the first lower arm switch are PWM-driven; the second Y drive control is control in which, when the connection changeover unit is set to the second mode and the changeover switch is turned off, the first upper arm switches of each phase are fixed on and the first lower arm switches of each phase are fixed off, or when the connection changeover unit is set to the second mode and the changeover switch is turned off, the first lower arm switches of each phase are fixed on and the first upper arm switches of each phase are fixed off, and the second upper arm switch and the second lower arm switch are PWM-driven. The control device for a rotating electrical machine according to claim 1 or 2.

18. When the requirement determination unit determines that the temperature (Tbat) of the DC power supply is lower than the target temperature (Tbtgt), it determines that there is a temperature increase requirement. The control device for a rotating electrical machine according to claim 1 or 2.

19. A rotating electrical machine (40) having a multi-phase armature winding (51U to 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) corresponding to the number of phases, and the series connection of the first upper arm switches and the first lower arm switches being connected in parallel to a DC power supply (10); a second inverter (30) having a number of series-connected second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) corresponding to the number of phases; a positive bus bar (11) electrically connecting the high-potential side terminals of the first upper arm switches and the high-potential side terminals of the second upper arm switches in each phase; a negative bus bar (12) electrically connecting the low-potential side terminals of the first lower arm switches and the low-potential side terminals of the second lower arm switches in each phase; in a program applied to a system comprising: in each phase, the low-potential side terminal of the first upper arm switch and the high-potential side terminal of the first lower arm switch being electrically connected to the first end of the armature winding; in each phase, the low-potential side terminal of the second upper arm switch and the high-potential side terminal of the second lower arm switch being electrically connected to the second end of the armature winding; a processor (71) having: a process for determining whether there is a temperature rise requirement for the system; a switch control process for controlling the on or off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch; and in the switch control process, when it is determined that there is a temperature rise requirement, performing a temperature rise control, which is the control for increasing the total heat generated in the first inverter, the second inverter, and the rotating electrical machine, more than when it is determined that there is no temperature rise requirement.

20. A rotating electrical machine (40) having a multi-phase armature winding (51U to 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SUL a to SWLa) corresponding to the number of phases, and a series connection of the first upper arm switch and the first lower arm switch being connected in parallel to a DC power supply (10); a second inverter (30) having a number of series-connected second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) corresponding to the number of phases; a positive bus bar (11) electrically connecting the high-potential side terminals of the first upper arm switch and the second upper arm switch in each phase; and a negative bus bar (12) electrically connecting the low-potential side terminals of the first lower arm switch and the second lower arm switch in each phase. In a control method for a rotating electrical machine applied to a system comprising: in each phase, the low-potential side terminal of the first upper arm switch and the high-potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding; in each phase, the low-potential side terminal of the second upper arm switch and the high-potential side terminal of the second lower arm switch are electrically connected to a second end of the armature winding; a determination step of determining whether there is a temperature rise requirement for the system; and a control step of controlling the on or off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch. The control step includes performing a temperature rise control, which is a control for increasing the total heat generated in the first inverter, the second inverter, and the rotating electrical machine, when it is determined that there is a temperature rise requirement, compared to when it is determined that there is no temperature rise requirement.

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