Control device for rotary electrical machine, program, and method for controlling rotary electrical machine

Abstract

A control device (70) comprises: a setting unit (85) for setting Y drive control or H drive control; and a determination unit (87) for determining whether or not there is a high possibility that partial discharge will occur between two different phase armature windings (51U-51W). The Y drive control is control in which second upper arm switches (SUHb-SWHb) of respective phases are fixed to ON and second lower arm switches (SULb-SWLb) of the respective phases are fixed to OFF in a state in which changeover switches (QH, QL) are turned off, or the second lower arm switches of the respective phases are fixed to ON and the second upper arm switches of the respective phases are fixed to OFF in a state in which the changeover switch is turned off, and first upper and lower arm switches (SUHa-SWHa, SULa-SWLa) are turned on and off. The H drive control is control in which the first upper and lower arm switches and the second upper and lower arm switches are turned on and off. The setting unit restricts the H drive control when it is determined that there is a high possibility that partial discharge will occur.

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. 2024-007822 filed on January 23, 2024, 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. The drive of the rotating electric machine is controlled by switching control of the first and second inverters. An example of such a technology is disclosed in Patent Document 1.

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

[0005] If the potential difference between the armature windings of two different phases is large, there is a concern that partial discharge may occur between the armature windings of two different phases.

[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 suppress the occurrence of partial discharge.

[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; 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; and a changeover switch provided on a target bus bar that is at least one of the positive bus bar and the negative bus bar, wherein, 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 when the changeover switch is turned on, it electrically connects the first inverter and the second inverter via the target bus, and when turned off, it cuts off the electrical connection between the first inverter and the second inverter via the target bus.

[0008] The present disclosure includes a setting unit that sets Y-drive control or H-drive control as the control mode of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch, and a determination unit that determines whether there is a high possibility of partial discharge occurring between the armature windings of two different phases.

[0009] The Y drive control is a control that fixes the second upper arm switch of each phase on and fixes the second lower arm switch of each phase off when the changeover switch is off, or fixes the second lower arm switch of each phase on and fixes the second upper arm switch of each phase off when the changeover switch is off, and turns the first upper arm switch and the first lower arm switch on and off.

[0010] The H drive control is a control for turning on and off the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch.

[0011] The setting unit of the present disclosure performs processing to restrict the H drive control when the determining unit determines that there is a high possibility of the partial discharge occurring.

[0012] In the H drive control, the potential difference (specifically, the maximum value of the potential difference) between the armature windings of two different phases is larger than in the Y drive control. Therefore, when the H drive control is performed, partial discharges may be more likely to occur between the armature windings of two different phases than when the Y drive control is performed.

[0013] Therefore, the setting unit of the present disclosure performs processing to restrict the H drive control when the determining unit determines that there is a high possibility of partial discharge occurring, thereby making it possible to suppress the occurrence of partial discharge between the armature windings of two different phases.

[0014] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an overall configuration diagram of a control system according to a first embodiment, Fig. 2 is a functional block diagram of control processing executed by a control device, Fig. 3 is a diagram showing a control mode of Y drive control, Fig. 4 is a diagram showing a control mode of H drive control, Fig. 5 is a flowchart of processing executed by the control device, Fig. 6 is a diagram showing first map information, Fig. 7 is a diagram showing second map information, Fig. 8 is a flowchart of processing executed by a control device according to a second embodiment, Fig. 9 is a diagram showing the second map information, and Fig. 10 is a flowchart of processing executed by a control device according to a third embodiment. 10 is a flowchart of the process executed by the control device according to the third embodiment, FIG. 11 is a diagram showing an example of a drive circuit for a switch, FIG. 12 is a diagram showing an example of a drive circuit for a switch, FIG. 13 is a flowchart of the process executed by the control device according to the fourth embodiment, FIG. 14 is a circuit diagram when the device is turned on in a state where the dielectric strength is large, FIG. 15 is a circuit diagram when the device is turned on in a state where the dielectric strength is large, FIG. 16 is a circuit diagram when the device is turned off in a state where the dielectric strength is large, and FIG. 18 is a circuit diagram when the device is turned on when the dielectric strength is large, FIG. 19 is a circuit diagram when the device is turned on when the dielectric strength is large, FIG. 20 is a circuit diagram when the device is turned off when the dielectric strength is large, FIG. 21 is a circuit diagram when the device is turned off when the dielectric strength is large, FIG. 22 is a circuit diagram when the device is turned on when the dielectric strength is small, FIG. 23 is a circuit diagram when the device is turned on when the dielectric strength is small, and FIG. 24 is a circuit diagram when the device is turned on when the dielectric strength is large. FIG. 27 is a circuit diagram when the device is turned on when the dielectric strength is small, FIG. 28 is a circuit diagram when the device is turned off when the dielectric strength is small, FIG. 29 is a circuit diagram when the device is turned off when the dielectric strength is small, FIG. 30 is a flowchart of the process executed by the control device according to the fifth embodiment, and FIG. 31 is a circuit diagram when the device is turned on when the dielectric strength is small,32 is a time chart showing a switching pattern when the dielectric strength is high, FIG. 33 is a flowchart of processing executed by a control device according to a sixth embodiment, FIG. 34 is a time chart showing an example of a switching timing interval for switching the switching state of each phase, FIG. 35 is a diagram showing an example of a method for setting threshold values, FIG. 36 is an overall configuration diagram of a control system according to a seventh embodiment, FIG. 37 is a flowchart of processing executed by a control device, FIG. 38 is an overall configuration diagram of a control system according to another embodiment, and FIG. 39 is a diagram showing a control mode of Y drive control according to another embodiment.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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 .

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The control system 100 includes a changeover switch QH and a diode DH. The changeover switch QH is provided on the positive bus 11 (corresponding to the "target bus"). The changeover switch QH is, for example, a semiconductor switching element or a mechanical relay. In this embodiment, the changeover switch QH is an IGBT. The collector of the changeover switch QH is connected to the first inverter 20 side, and the emitter of the changeover switch QH is connected to the second inverter 30 side. A diode DH is connected in antiparallel to the changeover switch QH.

[0028] When the changeover switch QH is turned on, it electrically connects the collectors of the upper phase arm switches SUHa, SVHa, SWHa of the first inverter 20 to the collectors of the upper phase arm switches SUHb, SVHb, SWHb of the second inverter 30. On the other hand, when the changeover switch QH is turned off, it electrically disconnects the collectors of the upper phase arm switches SUHa, SVHa, SWHa of the first inverter 20 from the collectors of the upper phase arm switches SUHb, SVHb, SWHb of the second inverter 30.

[0029] The control system 100 includes a current sensor 60 , a rotation angle sensor 61 , a voltage sensor 62 , a temperature sensor 63 , and an air pressure sensor 64 .

[0030] 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.

[0031] 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 temperature sensor 63 detects the temperature of the rotating electric machine 40. For example, the temperature sensor 63 detects the temperatures of the phase windings 51U, 51V, and 51W. The air pressure sensor 64 detects the atmospheric pressure in the installation environment of the control system 100 (specifically, the rotating electric machine 40).

[0032] The detection values ​​of the sensors 60 to 64 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 device 70, the processor 71 and the storage unit 72 are connected to each other via a communication bus 73. 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.

[0033] 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 FIGS. 2 and 5, which will be described later.

[0034] 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.

[0035] FIG. 2 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 the dq coordinate system based on the command torque Trq* received from a higher-level control device than the control device 70 .

[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 setting unit 85 selects whether the drive state of the control system 100 should be Y drive control or H drive control. In the present embodiment, the setting 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, which is determined by the calculated rotation speed Nr and command torque Trq*, and on the control map information. The control map information is information that defines the Y drive control region and the H drive control region in association with the rotation speed Nr and the command torque Trq*. The control map information is stored in the storage unit 72.

[0042] The setting unit 85 generates drive signals for the switches SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30. The drive signals are made up of on and off commands for the switches.

[0043] Specifically, the setting unit 85 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, which is the detected voltage of the voltage sensor 62. 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 1 / 2 of the power supply voltage Vsr.

[0044] 3, the setting unit 85 turns off the selector switch QH and performs PWM driving of the switches SUHa to SWLa of the first inverter 20. The setting unit 85 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. As a result, the phase windings 51U, 51V, and 51W are star-connected via the second inverter 30.

[0045] The setting unit 85 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 Sgc. The carrier signal Sgc is, for example, a triangular wave signal whose gradual increase and decrease rates are equal.

[0046] On the other hand, when the setting unit 85 selects the H drive control, as shown in FIG. 4, the setting unit 85 turns on the changeover switch QH, PWM-drives each of the switches SUHa to SWLa of the first inverter 20, and PWM-drives each of the switches SUHb to SWLb of the second inverter 30.

[0047] Specifically, the setting unit 85 generates drive signals for the switches SUHa-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 first carrier signal Sg1, similar to the Y-drive control. The setting unit 85 generates drive signals for the switches SUHb-SWLb of the second inverter 30 based on a magnitude comparison between the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw and the second carrier signal Sg2, similar to the Y-drive control. The first and second carrier signals Sg1 and Sg2 are, for example, triangular wave signals with equal increasing and decreasing speeds. The frequency, amplitude, and fluctuation center value of the second carrier signal Sg2 are the same as those of the first carrier signal Sg1. The phase difference between the first carrier signal Sg1 and the second carrier signal Sg2 is 180°. In this embodiment, the frequency of the carrier signals Sg1 and Sg2 used in the H drive control is the same as the frequency of the carrier signal Sgc used in the Y drive control.

[0048] The switch control unit 86 includes drive circuits for the switches SUHa to SWLa and SUHb to SWLb. Based on the generated drive signals, the switch control unit 86 controls the charge / discharge currents of the gates of the switches SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30. This controls the on / off states of the switches SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30 in accordance with the drive signals.

[0049] 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.

[0050] Incidentally, the potential difference between the armature windings of two different phases is larger when H drive control is executed than when Y drive control is executed. When H drive control, which increases the potential difference, is executed, if the dielectric strength between the armature windings of two different phases is low, partial discharge is likely to occur between the armature windings of two different phases. If partial discharge occurs, there is a concern that it may accelerate deterioration of the rotating electric machine 40, for example.

[0051] In order to suppress the occurrence of partial discharge, it is also possible to design the rotating electric machine 40 so that it has a dielectric strength that takes into account the above-mentioned potential difference when H drive control is executed. However, in this case, the insulating coating that covers the conductors that make up the armature winding becomes thicker, which may result in a decrease in the output of the rotating electric machine 40, for example.

[0052] Here, the occurrence of partial discharge can be suppressed if the peak value of the surge voltage that occurs when the switching states of the inverters 20 and 30 are changed can be reduced. Therefore, the control device 70 performs processing to reduce the peak value of the surge voltage in a situation where the possibility of partial discharge occurring is high.

[0053] As shown in Fig. 2, the control device 70 includes a determination unit 87. The determination unit 87 determines whether or not there is a high possibility of partial discharge occurring between the armature windings of two different phases. In this embodiment, when the determination unit 87 determines that both the first and second conditions are satisfied, it determines that there is a high possibility of partial discharge occurring due to a decrease in dielectric strength.

[0054] The first condition is that the atmospheric pressure detection value Pr of the atmospheric pressure sensor 64 is lower than the atmospheric pressure threshold value Pth. The atmospheric pressure threshold value Pth may be set to a value less than 1 atmosphere (e.g., 0.6 to 0.7 atmospheres). The second condition is that the temperature detection value Tmr of the temperature sensor 63 is higher than the temperature threshold value Tth.

[0055] The setting unit 85 prohibits the setting of the H drive control when the determining unit 87 determines that there is a high possibility of partial discharge occurring.

[0056] Fig. 5 shows a flowchart of the torque control process of the rotary electric machine 40. The process shown in Fig. 5 is repeatedly executed by the processor 71 of the control device 70, for example, at a predetermined control period.

[0057] In step S10, the command torque Trq* is acquired, and the speed calculation unit 84 calculates the rotation speed Nr.

[0058] In step S11, the determination unit 87 determines whether or not both the first and second conditions are met.

[0059] If it is determined in step S11 that at least one of the first and second conditions is not satisfied, the process proceeds to step S12, where the setting unit 85 selects either the Y drive control or the H drive control based on the command torque Trq*, the rotation speed Nr, and the first map information, which is the control map information.

[0060] 6 shows the first map information. The first map information defines an operating region of the rotating electrical machine 40, surrounded by the first maximum torque line Ltmax1, the second maximum torque line Ltmax2, the first line L1, the second line L2, the axis of the rotational speed Nr (hereinafter referred to as the horizontal axis), and the axis of the command torque Trq* (hereinafter referred to as the vertical axis). The first and second maximum torque lines Ltmax1 and Ltmax2 define the maximum torque Tmax, which is the maximum value of the command torque Trq*, and extend along the horizontal axis (specifically, extend parallel to the horizontal axis). The first maximum torque line Ltmax1 is a line extending from the vertical axis. The second maximum torque line Ltmax2 is a line extending from one end of the first maximum torque line Ltmax1 along the horizontal axis (specifically, extend parallel to the horizontal axis).

[0061] The first line L1 extends from one end of the second maximum torque line Ltmax2 and decreases in value on the vertical axis as the rotational speed Nr increases. The second line L2 extends along the vertical axis from one end of the first line L1 to the horizontal axis (specifically, extends parallel to the vertical axis). The value on the horizontal axis of the second line L2 is the maximum rotational speed Nmax, which is the maximum value of the rotational speed Nr.

[0062] The judgment threshold Jth is made up of a first threshold line J1 and a second threshold line J2. The first threshold line J1 is a line extending along the first line L1 from the boundary between the first maximum torque line Ltmax1 and the second maximum torque line Ltmax2. The first threshold line J1 is a line extending such that the value on the vertical axis decreases as the rotation speed Nr increases. The second threshold line J2 is a line extending from one end of the first threshold line J1 along the second line L2 (specifically, extending parallel to the second line L2). The value on the horizontal axis of the second threshold line J2 is a judgment speed Nth (>0) that is lower than the maximum rotation speed Nmax.

[0063] The region of the operating range where the rotation speed Nr is equal to or less than the judgment threshold Jth is the Y drive control region, while the region of the operating range where the rotation speed Nr exceeds the judgment threshold Jth is the H drive control region.

[0064] The setting unit 85 selects Y-drive control when it determines that the operating point determined from the command torque Trq* and rotation speed Nr acquired in step S10 is in the Y-drive control region. In this embodiment, the Y-drive control is performed so that the field-weakening current flowing through the phase windings 51U, 51V, 51W is set to 0. On the other hand, the setting unit 85 selects H-drive control when it determines that the operating point is in the H-drive control region.

[0065] If it is determined in step S11 that both the first and second conditions are met, the process proceeds to step S13, where the control map information is switched from the first map information to the second map information.

[0066] 7 shows the second map information. In the second map information, the length of the second maximum torque line Ltmax2 is shorter than the length of the second maximum torque line Ltmax2 in the first map information. In the second map information, the operating region of the rotating electrical machine 40 is defined by the first maximum torque line Ltmax1, the second maximum torque line Ltmax2, the third line L3, the fourth line L4, the horizontal axis, and the vertical axis. This operating region is entirely within the Y drive control region. Therefore, in step S13, a restriction is imposed that prohibits the setting of H drive control, and Y drive control is selected.

[0067] The third line L3 extends from one end of the second maximum torque line Ltmax2 along the first line L1. The fourth line L4 extends from one end of the third line L3 to the horizontal axis along the second line L2 (specifically, extends parallel to the second line L2). The value of the fourth line L4 on the horizontal axis is higher than the threshold speed Nth and lower than the maximum rotation speed Nmax.

[0068] In the second map information, the determination threshold Jth is the same as the determination threshold Jth in the first map information. The area surrounded by the determination threshold Jth, the second maximum torque line Ltmax2, the third line L3, the fourth line L4, and the horizontal axis is defined as the field-weakening area. The field-weakening area is the area of ​​the operating area defined by the second map information that is higher than the determination threshold Jth. The area of ​​the operating area that is equal to or lower than the determination threshold Jth is defined as the normal area.

[0069] If the setting unit 85 determines that the operating point determined from the command torque Trq* and rotational speed Nr obtained in step S10 is in the normal region, it performs Y drive control to set the field-weakening current flowing through each phase winding 51U, 51V, 51W to 0.

[0070] On the other hand, when the setting unit 85 determines that the operating point is in the field-weakening region, it performs Y-drive control, which causes a field-weakening current to flow through the phase windings 51U, 51V, and 51W. If the rotating electric machine 40 is a salient-pole machine, the field-weakening current can increase the torque of the rotating electric machine 40 and the rotation speed Nr when the operating point is in a region where H-drive control should be performed.

[0071] According to the present embodiment described above, the H drive control is prohibited in a situation where the possibility of partial discharge occurring is high, which makes it possible to suppress an increase in the peak value of the surge voltage that occurs when the switching state is changed, and thus to suppress the occurrence of partial discharge.

[0072] Second Embodiment A second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the second map information is different from the second map information of the first embodiment, and the method of restricting H drive control is changed.

[0073] Fig. 8 shows a flowchart of the torque control process for the rotary electric machine 40. The process shown in Fig. 8 is repeatedly executed by the processor 71, for example, at a predetermined control period.

[0074] If the determination in step S11 is affirmative, the process proceeds to step S14, where the control map information is switched from the first map information to the second map information.

[0075] 9 shows the second map information of this embodiment. In the second map information, the line defining the high-torque side of the boundaries of the H drive control region has been changed from the second maximum torque line Ltmax2 and the first line L1 to a first change line Lc1. The first change line Lc1 extends from the midpoint of the first threshold line J1 to one end of the second line L2. The region surrounded by the first change line Lc1, the second line L2, the horizontal axis, and the determination threshold Jth is the H drive control region in the second map information.

[0076] The first change line Lc1 extends so that the value on the vertical axis decreases as the rotation speed Nr increases. The first change line Lc1 is located on the low torque side of the first line L1. Therefore, in step S14, a constraint is imposed that the high torque side of the boundary of the H drive control region is shifted toward the low torque side relative to the first map information. As a result, the magnitude of the current vectors flowing through the phase windings 51U, 51V, and 51W during H drive control can be reduced. This reduces the increase in the peak value of surge voltages that occur when the switching state is changed, thereby suppressing the occurrence of partial discharges.

[0077] Third Embodiment A third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, a process for restricting H drive control is executed by reducing the switching speed of the first and second inverters 20, 30.

[0078] Fig. 10 shows a flowchart of the torque control process of the rotary electric machine 40. The process shown in Fig. 10 is repeatedly executed by the processor 71, for example, at a predetermined control period.

[0079] In step S20, the command torque Trq* is acquired, and the speed calculation unit 84 calculates the rotation speed Nr.

[0080] In step S21, the setting unit 85 determines whether the operating point determined from the command torque Trq* and rotation speed Nr is in the Y drive control region or the H drive control region, based on the acquired command torque Trq* and rotation speed Nr and the first map information shown in Figure 6.

[0081] If it is determined in step S21 that the operating point is in the region of Y drive control, the process proceeds to step S22, where Y drive control is performed.

[0082] On the other hand, if it is determined in step S21 that the operating point is in the H drive control region, the process proceeds to step S23, where the determination unit 87 determines whether or not both the first and second conditions are met.

[0083] If it is determined in step S23 that at least one of the first and second conditions is not met, the process proceeds to step S24, where H drive control is performed.

[0084] If it is determined in step S23 that both the first and second conditions are met, the process proceeds to step S25, where H drive control is performed to slow down the switching speed when turning on and off the switches SUHa to SWLb of each inverter 20, 30, compared to steps S24 and S22. This reduces the peak value of surge voltages that occur when the switching state is changed. As a result, partial discharges can be suppressed even when the dielectric strength is low.

[0085] An example of a drive circuit that reduces the switching speed will now be described.

[0086] First, the first example will be described. The drive circuit in the first example reduces the switching speed by changing the resistance value of the gate resistor. A specific example of the drive circuit is shown in FIG. 11. The drive circuits for the switches SUHa to SWLb of the first and second inverters 20 and 30 basically have the same configuration. SW shown in FIG. 11 is the switch of the inverter.

[0087] The drive circuit includes a voltage source 90, a charging switch 91, a first charging resistor 92A, and a second charging resistor 92B. A first end of a series connection of first and second charging resistors 92A and 92B is connected to the positive terminal of the voltage source 90 via the charging switch 91. A gate of a switch SW is connected to a second end of the series connection of the first and second charging resistors 92A and 92B.

[0088] The drive circuit includes a first discharge resistor 93A, a second discharge resistor 93B, and a discharge switch 94. A gate of a switch SW is connected to a first end of the series connection of the first and second discharge resistors 93A and 93B. A negative terminal of a voltage source 90 and an emitter of the switch SW are connected to a second end of the series connection of the first and second discharge resistors 93A and 93B via the discharge switch 94.

[0089] The drive circuit includes a charge bypass switch 95 and a discharge bypass switch 96. The charge bypass switch 95 is connected in parallel to the first charge resistor 92A. The discharge bypass switch 96 is connected in parallel to the first discharge resistor 93A.

[0090] When the drive signal is an ON command, the setting unit 85 performs a charging process. The charging process is a process of turning on the charging switch 91 and turning off the discharging switch 94. According to the charging process, the gate voltage of the switch SW becomes equal to or higher than the threshold voltage of the switch SW, and the switch SW is turned on.

[0091] When the drive signal is an OFF command, the setting unit 85 performs a discharge process. The discharge process is a process of turning off the charge switch 91 and turning on the discharge switch 94. By performing the discharge process, the gate voltage of the switch SW becomes less than the threshold voltage Vth, and the switch SW is turned off.

[0092] The setting unit 85 turns on the charge bypass switch 95 in the charging process of steps S22 and S24 in Fig. 10. This reduces the gate resistance connecting the voltage source 90 and the gate of the switch SW, and the switching speed when the switch SW is turned on becomes high. On the other hand, the setting unit 85 turns off the charge bypass switch 95 in the charging process of step S25 in Fig. 10. This increases the gate resistance connecting the voltage source 90 and the gate of the switch SW, and the gate charge current decreases. As a result, the switching speed when the switch SW is turned on becomes low.

[0093] The setting unit 85 turns on the discharge bypass switch 96 in the discharge processing of steps S22 and S24. This reduces the gate resistance value connecting the gate and emitter of the switch SW, and the switching speed when the switch SW is turned off becomes high. On the other hand, the setting unit 85 turns off the discharge bypass switch 96 in the discharge processing of step S25. This increases the gate resistance value connecting the gate and emitter of the switch SW, and the gate discharge current decreases. As a result, the switching speed when the switch SW is turned off becomes low.

[0094] Next, a second example will be described. The drive circuit of the second example reduces the switching speed by changing the output voltage of the voltage source. A specific example of the drive circuit is shown in FIG.

[0095] The drive circuit includes a first voltage source 101, a charge switch 91, a charge resistor 92, a discharge resistor 93, a discharge switch 94, and a second voltage source 102. The gate of switch SW is connected to the negative terminal of second voltage source 102 via discharge resistor 93 and discharge switch 94. The positive terminal of second voltage source 102 is connected to the negative terminal of first voltage source 101 and the emitter of switch SW. The first voltage source 101 and second voltage source 102 can vary their output voltages.

[0096] In the charging process of steps S22 and S24 in Fig. 10, the setting unit 85 sets the output voltage of the first voltage source 101 to a first charging voltage VcH. On the other hand, in the charging process of step S25 in Fig. 10, the setting unit 85 sets the output voltage of the first voltage source 101 to a second charging voltage VcL (<VcH) that is lower than the first charging voltage VcH. This reduces the gate charging current. As a result, the switching speed of the switch SW in the charging process of step S25 is slower than the switching speed of the switch SW in the charging process of steps S22 and S24.

[0097] In the discharge process of steps S22 and S24, the setting unit 85 sets the output voltage of the second voltage source 102 to the first discharge voltage VdH. On the other hand, in the discharge process of step S25, the setting unit 85 sets the output voltage of the second voltage source 102 to a second discharge voltage VdL (<VdH) that is lower than the first discharge voltage VdH. This reduces the gate discharge current. As a result, the switching speed of the switch SW in the discharge process of step S25 is slower than the switching speed of the switch SW in the discharge process of steps S22 and S24.

[0098] Although the driving circuit that reduces both the turn-on and turn-off switching speeds has been described, the driving circuit may also reduce either the turn-on or turn-off switching speed.

[0099] Fourth Embodiment A fourth embodiment will be described below with reference to the drawings, focusing on differences from the third embodiment. In this embodiment, a process for changing the switching order of the first and second inverters 20, 30 is executed as a process for restricting the H drive control.

[0100] In this embodiment, in both Y and H drive control, the switching speed of the first upper and lower arm switches SUHa to SWLa of each phase is set higher than the switching speed of the second upper and lower arm switches SUHb to SWLb of each phase.

[0101] 13 is a flowchart showing the torque control process for the rotary electric machine 40. The process shown in FIG. 13 is repeatedly executed by the processor 71, for example, at a predetermined control period.

[0102] If it is determined in step S21 that the operating point is in the Y drive control area, the process proceeds to step S26, where Y drive control is performed.

[0103] If it is determined in step S23 that at least one of the first and second conditions is not satisfied, the process proceeds to step S27, where H drive control is performed under conditions where the dielectric strength is relatively high. If it is determined in step S23 that both the first and second conditions are satisfied, the process proceeds to step S28, where H drive control is performed under conditions where the dielectric strength is relatively low.

[0104] First, the H drive control in step S27 will be described using Figures 14 to 21. Note that Figures 14 to 21 and Figures 22 to 29 described below show the configuration for 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 for each component.

[0105] 14 to 17 will be used to describe a case where a current flows in the "negative" direction through the armature winding 51. As shown in FIGS. 14 and 15, the setting unit 85 generates a drive signal that switches on the first lower arm switch SLa after switching on the second upper arm switch SHb. This allows current to flow through the armature winding 51 by turning on the first lower arm switch SLa, which has a switching speed relatively higher than that of the second upper arm switch SHb, and reduces switching loss.

[0106] 16 and 17, the setting unit 85 generates a drive signal that switches off the first lower arm switch SLa and then switches off the second upper arm switch SHb. As a result, the current flow through the armature winding 51 can be interrupted by turning off the first lower arm switch SLa, which has a switching speed relatively higher than that of the second upper arm switch SHb, and switching loss can be reduced.

[0107] 18 to 21 will be used to describe the case where a current flows in the "forward" direction through the armature winding 51. As shown in Figures 18 and 19, the setting unit 85 generates a drive signal that switches on the first upper arm switch SHa after switching on the second lower arm switch SLb. This allows current to flow through the armature winding 51 by turning on the first upper arm switch SHa, which has a switching speed relatively faster than that of the second lower arm switch SLb, and reduces switching loss.

[0108] 20 and 21, the setting unit 85 generates a drive signal that switches off the first upper arm switch SHa and then switches off the second lower arm switch SLb. As a result, the current flow through the armature winding 51 can be interrupted by turning off the first upper arm switch SHa, which has a switching speed relatively higher than that of the second lower arm switch SLb, and switching loss can be reduced.

[0109] Next, the H drive control in step S28 will be described with reference to FIGS.

[0110] 22 to 25 will be used to describe a case where a current flows in the "negative" direction through the armature winding 51. As shown in FIGS. 22 and 23, the setting unit 85 generates a drive signal that switches on the first lower arm switch SLa and then switches on the second upper arm switch SHb. This causes a current to flow through the armature winding 51 by turning on the second upper arm switch SHb, which has a switching speed relatively slower than that of the first lower arm switch SLa. As a result, although there is a restriction that switching loss increases more than in step S27, the peak value of the surge voltage generated by turn-on can be reduced, and the occurrence of partial discharge can be suppressed.

[0111] 24 and 25, the setting unit 85 generates a drive signal that switches off the second upper arm switch SHb and then switches off the first lower arm switch SLa. This turns off the second upper arm switch SHb, which has a switching speed relatively slower than that of the first lower arm switch SLa, thereby interrupting the flow of current through the armature winding 51. As a result, the peak value of the surge voltage that occurs when the second upper arm switch SHb is turned off can be reduced.

[0112] 26 to 29 will be used to describe the case where a current flows in the "forward" direction through the armature winding 51. As shown in FIGS. 26 and 27, the setting unit 85 generates a drive signal that switches on the first upper arm switch SHa and then switches on the second lower arm switch SLb. This causes a current to flow through the armature winding 51 by turning on the second lower arm switch SLb, which has a switching speed relatively slower than that of the first upper arm switch SHa. As a result, the peak value of the surge voltage that occurs when the switch is turned on can be reduced.

[0113] 28 and 29, the setting unit 85 generates a drive signal that switches off the second lower arm switch SLb and then switches off the first upper arm switch SHa. This turns off the second lower arm switch SLb, which has a switching speed relatively slower than that of the first upper arm switch SHa, thereby interrupting the flow of current through the armature winding 51. As a result, the peak value of the surge voltage that occurs when the second lower arm switch SLb is turned off can be reduced.

[0114] In the processes described with reference to FIGS. 14 to 29, the setting unit 85 may determine the direction of the phase current of each phase based on the detection value of the current sensor 60, for example.

[0115] According to the present embodiment described above, the peak value of the surge voltage can be reduced, and the occurrence of partial discharge can be suppressed.

[0116] Fifth Embodiment A fifth embodiment will be described below with reference to the drawings, focusing on differences from the fourth embodiment. In this embodiment, a process for changing the switching frequencies of the first and second inverters 20, 30 is executed as a process for restricting the H drive control.

[0117] In this embodiment as well, in both Y and H drive control, the switching speed of the first upper and lower arm switches SUHa to SWLa of each phase is set higher than the switching speed of the second upper and lower arm switches SUHb to SWLb of each phase.

[0118] 30 shows a flowchart of the torque control process of the rotary electric machine 40. The process shown in FIG. 30 is repeatedly executed by the processor 71, for example, at a predetermined control period.

[0119] If it is determined in step S23 that at least one of the first and second conditions is not met, the process proceeds to step S29, where H drive control is performed under conditions where the dielectric strength is relatively high. If it is determined in step S23 that both the first and second conditions are met, the process proceeds to step S30, where H drive control is performed under conditions where the dielectric strength is relatively low.

[0120] First, the H drive control in step S29 will be described with reference to Fig. 31. Note that Fig. 31 and Fig. 32, which will be described later, show waveforms for only one phase in the control system 100. For this reason, the symbols U, V, and W that identify the phases have been omitted from the symbols of each component.

[0121] 31 shows the transition of the switching states of the first upper and lower arm switches SHa and SLa and the transition of the switching states of the second upper and lower arm switches SHb and SLb, where Tsw represents one switching period of each of the switches SHa, SLa, SHb, and SLb, and fsw represents the switching frequency (=1 / Tsw) of each of the switches SHa, SLa, SHb, and SLb.

[0122] The setting unit 85 sets the switching frequency of the first upper and lower arm switches SHa, SLa to be higher than the switching frequency of the second upper and lower arm switches SHb, SLb in each phase. In the example shown in Fig. 31 , the setting unit 85 generates a drive signal that switches the switching states of the second upper and lower arm switches SHb, SLb at intervals of 180 electrical degrees and switches the switching states of the first upper and lower arm switches SHa, SLa at intervals of shorter than 180 electrical degrees.

[0123] The switching frequency of the second upper and lower arm switches SHb and SLb, which have a relatively low switching speed, is set lower than the switching frequency of the first upper and lower arm switches SHa and SLa, which have a relatively high switching speed, thereby reducing the switching loss of the second inverter 30.

[0124] Next, the H drive control in step S30 will be described with reference to FIG.

[0125] The setting unit 85 sets the switching frequency of the first upper and lower arm switches SHa and SLa to be lower than the switching frequency of the second upper and lower arm switches SHb and SLb in each phase. In the example shown in Fig. 31 , the setting unit 85 generates drive signals that switch the switching states of the first upper and lower arm switches SHa and SLa at intervals of 180 electrical degrees and that switch the switching states of the second upper and lower arm switches SHb and SLb at intervals shorter than 180 electrical degrees.

[0126] The switching frequency of the first upper and lower arm switches SHa and SLa, which have a relatively high switching speed, is set lower than the switching frequency of the second upper and lower arm switches SHb and SLb, which have a relatively low switching speed, thereby reducing the peak value of surge voltage that occurs in the first inverter 20 when the switching state is changed, and suppressing the occurrence of partial discharge.

[0127] Sixth Embodiment A sixth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, a process for restricting the H drive control is performed by lengthening the interval between the switching states of the first and second inverters 20, 30.

[0128] 33 shows a flowchart of the torque control process of the rotary electric machine 40. The process shown in FIG. 33 is repeatedly executed by the processor 71, for example, at a predetermined control period.

[0129] In step S40, the command torque Trq* is acquired, and the speed calculation unit 84 calculates the rotation speed Nr.

[0130] In step S41, the setting unit 85 determines whether the operating point determined from the command torque Trq* and rotation speed Nr is in the Y drive control region or the H drive control region, based on the acquired command torque Trq* and rotation speed Nr and the first map information shown in Figure 6.

[0131] If it is determined in step S41 that the operating point is in the region of Y drive control, the process proceeds to step S42, where Y drive control is performed.

[0132] On the other hand, if it is determined in step S41 that the operating point is in the H drive control region, the process proceeds to step S43, where the determination unit 87 determines whether or not both the first and second conditions are met.

[0133] If it is determined in step S43 that at least one of the first and second conditions is not met, the process proceeds to step S44, where H drive control is performed under conditions where the dielectric strength is relatively high. On the other hand, if it is determined in step S43 that both the first and second conditions are met, the process proceeds to step S45, where H drive control is performed under conditions where the dielectric strength is relatively low.

[0134] First, the H drive control in step S44 will be described.

[0135] The setting unit 85 generates drive signals for the first upper and lower arm switches SUHa to SWLa of each phase and the second upper and lower arm switches SUHb to SWLb of each phase under the condition that the interval Δt between adjacent switching timings is equal to or greater than a threshold value α. The threshold value α is, for example, several microseconds, and is specifically set to "1.5 μsec≦α≦4 μsec," "1.5 μsec≦α≦3 μsec," or "2 μsec≦α≦3 μsec."

[0136] Here, among the switches SUHa to SWLb (12 switches) of the first and second inverters 20 and 30, two switches whose switching states are adjacent in time are referred to as switches A and B. The intervals between the adjacent switching times include: the interval between the timing at which switch A is turned off and the timing at which switch B is turned off; the interval between the timing at which switch A is turned on and the timing at which switch B is turned on; the interval between the timing at which switch A is turned off and the timing at which switch B is turned on; and the interval between the timing at which switch A is turned on and the timing at which switch B is turned off. The combinations of switches A and B are: two of the six switches constituting the first inverter 20; two of the six switches constituting the second inverter 30; or one of the six switches constituting the first inverter 20 and one of the six switches constituting the second inverter 30.

[0137] 34 shows an example in which the first switch and the second switch are switched off consecutively in time when the combination of the first and second switches constitutes the first inverter 20. In FIG. 34( a), "GU=H" indicates that the U-phase first upper arm switch SUHa is turned on, and "GU=L" indicates that the U-phase first upper arm switch SUHa is turned off. In FIG. 34( b), "GV=H" indicates that the V-phase first upper arm switch SVHa is turned on, and "GV=L" indicates that the V-phase first upper arm switch SVHa is turned off. In FIG. 34( c), "GW=H" indicates that the W-phase first upper arm switch SWHa is turned on, and "GW=L" indicates that the W-phase first upper arm switch SWHa is turned off.

[0138] 34, Δt1 indicates the interval between the timing at which the U-phase first upper arm switch SUHa is switched off and the timing at which the V-phase first upper arm switch SVHa is switched off, and Δt2 indicates the interval between the timing at which the V-phase first upper arm switch SVHa is switched off and the timing at which the W-phase first upper arm switch SWHa is switched off.

[0139] Next, the H drive control in step S45 will be described, focusing on the differences from step S44.

[0140] The setting unit 85 sets the threshold value α to be longer than the threshold value α used in step S44, thereby lengthening the time interval at which the surge voltage reaches its peak value and suppressing the occurrence of partial discharge.

[0141] In step S45, the setting unit 85 may set the threshold value α to be longer as the detected air pressure value Pr is lower or the detected temperature value Tmr is higher, as shown in Fig. 35. This makes it possible to effectively suppress the occurrence of partial discharge.

[0142] <Modification of Sixth Embodiment> In step S45, the setting unit 85 may perform either a process of increasing the threshold value α as the detected air pressure value Pr decreases, or a process of increasing the threshold value α as the detected temperature value Tmr increases.

[0143] Seventh Embodiment A seventh embodiment will be described below with reference to the drawings, focusing on differences from the first to sixth embodiments. In this embodiment, as shown in FIG. 36 , a control system 100 includes a navigation device 65.

[0144] Map information including road information linked to altitude is stored in a memory unit (e.g., storage) of the navigation device 65. The navigation device 65 receives current position information of the vehicle detected by a GPS sensor (not shown) provided in the control system 100. The navigation device 65 is configured to be able to communicate with the control device 70.

[0145] 37 shows a flowchart of the torque control process of the rotary electric machine 40. The process shown in FIG. 37 is repeatedly executed by the processor 71, for example, at a predetermined control period.

[0146] After the process of step S10 is completed, in step S15, the determining unit 87 acquires map information and the current position information of the vehicle from the navigation device 65.

[0147] In step S16, the determining unit 87 calculates the altitude He of the road on which the vehicle is currently located based on the information acquired in step S15.

[0148] In step S17, the determination unit 87 determines whether or not both the first and second conditions are satisfied. The first condition in this embodiment is that the calculated altitude He is higher than an altitude threshold Hth (corresponding to a "determination threshold").

[0149] The processes in steps S15 to S17 can also be applied to the second to sixth embodiments.

[0150] Other Embodiments The above-described embodiments may be modified as follows.

[0151] As shown in Fig. 38, the control system 100 may include a second changeover switch QL in addition to the first changeover switch QH. The second changeover switch QL is provided on the negative bus 12 (corresponding to the "target bus"). The second changeover switch QL is, for example, a semiconductor switching element or a mechanical relay. In this embodiment, the second changeover switch QL is an IGBT. A freewheel diode DL is connected in anti-parallel to the second changeover switch QL. The collector of the second changeover switch QL is connected to the second inverter 30 side, and the emitter of the second changeover switch QL is connected to the first inverter 20 side.

[0152] When the second changeover switch QL is turned on, it electrically connects the emitters of the lower phase arm switches SULa, SVLa, SWLa of the first inverter 20 to the emitters of the lower phase arm switches SULb, SVLb, SWLb of the second inverter 30. When the second changeover switch QL is turned off, it electrically disconnects the emitters of the lower phase arm switches SULa, SVLa, SWLa of the first inverter 20 from the emitters of the lower phase arm switches SULb, SVLb, SWLb of the second inverter 30.

[0153] When the control device 70 selects the H drive control, it turns on the first changeover switch QH and the second changeover switch QL. On the other hand, when the control device 70 selects the Y drive control, it turns off the first changeover switch QH and the second changeover switch QL.

[0154] 39, in the Y drive control, the control device 70 may fix the upper arm switches SUHb, SVHb, and SWHb of the second inverter 30 to OFF and fix the lower arm switches SULb, SVLb, and SWLb of the second inverter 30 to ON. In this case, the lower arm side of the second inverter 30 functions as a neutral point.

[0155] In each of the above embodiments, the condition for determining whether or not the dielectric strength is relatively low may be either the first or second condition, rather than both the first and second conditions.

[0156] The carrier signal is not limited to a triangular wave signal, but may be, for example, a sawtooth wave signal.

[0157] 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.

[0158] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0159] The rotating electric machine is not limited to a permanent magnet field type synchronous machine, and may be, for example, an induction machine.

[0160] 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.

[0161] 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.

[0162] The inverter, rotating electric machine, and control device may be installed in a moving body other than a vehicle, such as an aircraft or a ship. If the moving body is an aircraft, the rotating electric machine serves as a power source for the aircraft's flight, and if the moving body is a ship, the rotating electric machine serves as a power source for the ship's navigation.

[0163] In addition, in the seventh embodiment, when the moving body is an aircraft, the judgment unit 87 acquires altitude information of the aircraft, and uses, as the first condition, the condition that the acquired altitude is higher than the altitude threshold value (corresponding to the "judgment threshold value").

[0164] Furthermore, the inverter, rotating electrical machine, and control device may be mounted on a vehicle other than a moving object.

[0165] 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.

[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 first upper arm switches (SUHa to SWHa) and first lower arm switches (SUL a to SWLa) connected in series, 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 second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) connected in series, 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, and a switching switch (QH) provided on a target bus bar which is at least one of the positive bus bar and the negative bus bar,In a control device (70) of a rotating electrical machine applied to a system including [[QL]], 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 (51Ua to 51Wa) 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 (51Ub to 51Wb) of the armature winding. The switching switch, when turned on, electrically connects the first inverter and the second inverter via the target bus, and when turned off, cuts off the electrical connection between the first inverter and the second inverter via the target bus. A setting unit (85) that sets Y drive control or H drive control as the control modes of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch, and a determination unit (87) that determines whether or not partial discharge is likely to occur between the armature windings of two different phases. The Y drive control is a control in which, with the switching switch turned off, the second upper arm switch of each phase is fixed on and the second lower arm switch of each phase is fixed off, or with the switching switch turned off, the second lower arm switch of each phase is fixed on and the second upper arm switch of each phase is fixed off, and the first upper arm switch and the first lower arm switch are turned on and off. The H drive control is a control in which the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch are turned on and off. The setting unit performs a process of restricting the H drive control when the determination unit determines that the partial discharge is likely to occur. A control device for a rotating electrical machine.

2. In the H drive control, the setting unit sets the switching speed of the first upper arm switch and the first lower arm switch to be higher than the switching speed of the second upper arm switch and the second lower arm switch. In the H drive control, when current flows through the armature winding in the direction from the second end to the first end, after switching the second upper arm switch to on, the first lower arm switch is switched to on, and then, after switching the first lower arm switch to off, the second upper arm switch is switched to off. In the H drive control, when current flows through the armature winding in the direction from the first end to the second end, after switching the second lower arm switch to on, the first upper arm switch is switched to on, and then, after switching the first upper arm switch to off, the second lower arm switch is switched to off. When it is determined that there is a high possibility of partial discharge occurring and current flows through the armature winding in the direction from the second end to the first end, as the restrictive process, in the H drive control, after switching the first lower arm switch to on, the second upper arm switch is switched to on, and then, after switching the second upper arm switch to off, the first lower arm switch is switched to off. When it is determined that there is a high possibility of partial discharge occurring and current flows through the armature winding in the direction from the first end to the second end, as the restrictive process, in the H drive control, after switching the first upper arm switch to on, the second lower arm switch is switched to on, and then, after switching the second lower arm switch to off, the first upper arm switch is switched to off. The control device for a rotating electrical machine according to claim 1, which performs the above-described process.

3. In the H drive control, the setting unit sets the switching speed of the first upper arm switch and the first lower arm switch to be higher than that of the second upper arm switch and the second lower arm switch, and sets the switching frequency of the first upper arm switch and the first lower arm switch to be higher than that of the second upper arm switch and the second lower arm switch. When it is determined that there is a high possibility of partial discharge occurring, as the restricting process, in the H drive control, a process of setting the switching frequency of the first upper arm switch and the first lower arm switch to be lower than that of the second upper arm switch and the second lower arm switch is performed. The control device for a rotating electrical machine according to claim 1.

4. When it is determined that there is a high possibility of partial discharge occurring, the setting unit, as the restricting process, performs a process of prohibiting the setting of the H drive control and setting the Y drive control. The control device for a rotating electrical machine according to claim 1.

5. When it is determined that the operating point defined by the rotational speed of the rotor (41) of the rotating electrical machine and the torque of the rotating electrical machine is in the region of the Y drive control, the setting unit sets the Y drive control as the control mode. When it is determined that the operating point is in the region of the H drive control, the setting unit sets the H drive control as the control mode. When it is determined that there is a high possibility of partial discharge occurring, even when the operating point is in the region of the H drive control, while setting the Y drive control as the control mode, the first upper arm switch and the first lower arm switch are turned on and off so as to allow a weakening field current to flow through the armature winding. The control device for a rotating electrical machine according to claim 4.

6. When the setting unit determines that the operating point defined by the rotational speed of the rotor (41) of the rotating electrical machine and the torque of the rotating electrical machine is in the region of the Y drive control, the setting unit sets the Y drive control as the control mode. When the operating point is determined to be in the region of the H drive control, the setting unit sets the H drive control as the control mode. When it is determined that the partial discharge is likely to occur, as the restricting process, the control device for a rotating electrical machine according to claim 1 performs a process of shifting the boundary on the high torque side among the boundaries of the region of the H drive control to the low torque side.

7. When the setting unit determines that the partial discharge is likely to occur, as the restricting process, the setting unit performs a process of reducing the switching speed of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch in the H drive control to be lower than the switching speed of the first upper arm switch and the first lower arm switch in the Y drive control. The control device for a rotating electrical machine according to claim 1.

8. In the H drive control, the setting unit imposes a condition that the interval between temporally adjacent switching timings among the switching timings of the switching states of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch is equal to or greater than a threshold value, and turns on and off the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch. When it is determined that the partial discharge is likely to occur, as the restricting process, the setting unit performs a process of making the threshold value longer than when it is not determined that the partial discharge is likely to occur. The control device for a rotating electrical machine according to claim 1.

9. When the setting unit determines that the partial discharge is likely to occur, the setting unit makes the threshold value longer as the atmospheric pressure around the system is lower. The control device for a rotating electrical machine according to claim 8.

10. When the setting unit determines that the partial discharge is likely to occur, the setting unit makes the threshold value longer as the temperature of the rotating electrical machine is higher. The control device for a rotating electrical machine according to claim 8 or 9.

11. The determination unit determines that there is a high possibility of partial discharge occurring when it determines that at least one of the conditions that the temperature of the rotating electrical machine exceeds a temperature threshold value and that the atmospheric pressure around the system is below an atmospheric pressure threshold value is satisfied. The control device for a rotating electrical machine according to any one of claims 1 to 8.

12. The system is mounted on a moving body, and the determination unit determines that there is a high possibility of partial discharge occurring on the condition that it determines that the altitude or height of the moving body exceeds a determination threshold value. The control device for a rotating electrical machine according to any one of claims 1 to 8.

13. 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) equal to the number of phases, with 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) equal to the number of phases; a positive bus bar (11) electrically connecting the high-potential terminals of the first upper arm switches and the high-potential terminals of the second upper arm switches in each phase; a negative bus bar (12) electrically connecting the low-potential terminals of the first lower arm switches and the low-potential terminals of the second lower arm switches in each phase; a switching switch (QH) provided on a target bus bar that is at least one of the positive bus bar and the negative bus bar,In a program applied to a system including [[QL]], 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; the switching switch, when turned on, electrically connects the first inverter and the second inverter via the target bus, and when turned off, cuts off the electrical connection between the first inverter and the second inverter via the target bus; the processor (71) is caused to execute a setting process of setting Y drive control or H drive control as the control mode of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch, and a determination process of determining whether partial discharge is likely to occur between the armature windings of two different phases; the Y drive control is a control in which, with the switching switch turned off, the second upper arm switch of each phase is fixed on and the second lower arm switch of each phase is fixed off, or with the switching switch turned off, the second lower arm switch of each phase is fixed on and the second upper arm switch of each phase is fixed off, and the first upper arm switch and the first lower arm switch are turned on and off; the H drive control is a control in which the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch are turned on and off; in the setting process, when it is determined by the determination process that the partial discharge is likely to occur, a process of restricting the H drive control is performed. Program., 14. A rotating electric 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 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, and a switching switch (QH) provided on a target bus bar which is at least one of the positive bus bar and the negative bus bar.In a method for controlling a rotating electrical machine applied to a system including a first inverter (V1), a second inverter (V2), a target bus (QL), etc., 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; the changeover switch, when turned on, electrically connects the first inverter and the second inverter via the target bus, and when turned off, cuts off the electrical connection between the first inverter and the second inverter via the target bus; as control modes of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch, there is a setting step of setting Y drive control or H drive control; there is a determination step of determining whether or not partial discharge is likely to occur between the armature windings of two different phases; the Y drive control is, with the changeover switch turned off, fixing the second upper arm switch of each phase to on and fixing the second lower arm switch of each phase to off, or fixing the second lower arm switch of each phase to on and fixing the second upper arm switch of each phase to off, and controlling the first upper arm switch and the first lower arm switch to be turned on and off; the H drive control is a control for turning on and off the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch; in the setting step, when it is determined by the determination step that the partial discharge is likely to occur, a process of restricting the H drive control is performed. A method for controlling a rotating electrical machine.

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