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

Abstract

A control device (70) comprises a setting unit (84) and a switch control unit (88). The setting unit sets a control mode for first upper arm switches (SUHa-SWHa), first lower arm switches (SULa-SWLa), second upper arm switches (SUHb-SWHb), and second lower arm switches (SULb-SWLb). The switch control unit controls whether the first upper arm switches, the first lower arm switches, the second upper arm switches, and the second lower arm switches are ON or OFF on the basis of the set control mode. The setting unit sets the control mode such that the switching frequency is randomly changed when at least one of the first upper arm switches, the first lower arm switches, the second upper arm switches, and the second lower arm switches is PWM-driven.

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. 2023-214819, filed on December 20, 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] Patent No. 7235588

[0005] In the above system, noise (for example, electromagnetic noise) from the rotating electrical machine may be generated when the switches included in the inverter are PWM-driven.

[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 reduce noise from the rotating electric machine.

[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 inverter comprises: a setting unit that sets 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 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 based on the set control mode.

[0008] The setting unit sets the control mode so as to randomly change the switching frequency when 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 is PWM driven.

[0009] This makes it possible to prevent the switching frequency from being maintained at a specific frequency, and to spread the spectrum of noise levels of the rotating electrical machine generated in conjunction with switching control, thereby reducing the noise generated by the rotating electrical machine.

[0010] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 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 flowchart of the control processing executed by the control device, FIG. 4 is a diagram showing a control mode of H drive control, FIG. 5 is a diagram showing a control mode of Y drive control, FIG. 6 is a time chart showing an example of a method of randomly changing a carrier frequency, FIG. 7 is a diagram showing a calculation result of frequency characteristics of current ripple and noise level, FIG. 8 is a diagram showing a calculation result of frequency characteristics of current ripple and noise level in a comparative example, FIG. 9 is an overall configuration diagram of a control system according to a second embodiment, FIG. 10 is a flowchart of control processing executed by a control device, FIG. 11 is a diagram showing a control mode of Y drive control, FIG. 12 is an overall configuration diagram of a control system according to a third embodiment, FIG. 13 is a flowchart of control processing executed by a control device, FIG. 14 is a diagram showing a control mode of first Y drive control, FIG. 15 is a diagram showing a control mode of second Y drive control, and FIG. 17 is a diagram showing a control mode of B mode, FIG. 18 is a diagram showing a control mode of C mode, FIG. 19 is a diagram showing a control mode of D mode, FIG. 20 is a diagram showing an example of an on / off pattern and a pulse pattern in a 180° period, FIG. 21 is a diagram showing an example of a mode switching method, FIG. 22 is a diagram showing an example of a mode switching method, FIG. 23 is a diagram showing a control mode of A mode according to a modification of the fourth embodiment, and FIG. 24 is a diagram showing a control mode of A mode according to a modification of the fourth embodiment. 25 is a diagram showing a control mode of the B mode according to a modification of the fourth embodiment, FIG. 26 is a diagram showing a control mode of the B mode according to a modification of the fourth embodiment, FIG. 27 is a diagram showing a control mode of the C mode according to a modification of the fourth embodiment, FIG. 28 is a diagram showing a control mode of the C mode according to a modification of the fourth embodiment, FIG. 29 is a diagram showing a control mode of the D mode according to a modification of the fourth embodiment, FIG. 30 is a diagram showing a control mode of the D mode according to a modification of the fourth embodiment, and FIG.FIG. 32 is a diagram showing a control mode of the first control according to the fifth embodiment, FIG. 33 is a functional block diagram of a carrier generation unit, FIG. 34 is a time chart showing the transition of each waveform when interleaving control is performed, FIG. 35 is a time chart showing the transition of each waveform in the case of Comparative Example 1 in which interleaving control is not performed, FIG. 36 is a diagram showing the calculation results of the frequency characteristics of the current ripple and noise level in Comparative Example 1, FIG. 37 is a diagram showing the calculation results of the frequency characteristics of the current ripple and noise level in Comparative Example 2, FIG. 38 is a diagram showing the calculation results of the frequency characteristics of the current ripple and noise level according to the fifth embodiment, FIG. 39 is a functional block diagram of a carrier generation unit according to a modified example of the fifth embodiment, FIG. 40 is a functional block diagram of a carrier generation unit according to the sixth embodiment, FIG. 41 is a functional block diagram of a carrier generation unit according to the seventh embodiment, and FIG. 42 is a functional block diagram of a carrier generation unit according to the eighth embodiment.

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

[0012] A first embodiment of a control device according to the present disclosure will 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.

[0013] 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.

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

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

[0016] In this embodiment, 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.

[0017] 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.

[0018] 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, it electrically connects the positive terminal of the battery 10 and the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase. On the other hand, when the power switch 14 is turned off, it electrically disconnects the positive terminal of the battery 10 and the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase. The control system 100 also 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] The control system 100 includes a current sensor 60 , a rotation angle sensor 61 , a voltage sensor 62 and a temperature sensor 63 .

[0025] 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.

[0026] 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 temperatures of the first inverter 20 and the second inverter 30. For example, the temperature sensor 63 detects the temperatures of the switches SUHa to SWLa and SUHb to SWLb that constitute each of the inverters 20, 30 as the temperatures of the first and second inverters 20, 30.

[0027] The detection values ​​of the sensors 60 to 63 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.

[0028] 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 3, which will be described later.

[0029] 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.

[0030] The control device 70 controls the selector switch 13, the switches SUHa-SWLa of the first inverter 20, and the switches SUHb-SWLb of the second inverter 30 to turn on or off in order to control the control variable of the rotating electric machine 40 to a command value. With the power switch 14 turned on, the control device 70 controls the selector switch 13 to switch the drive state of the control system 100 between a Y drive state and an H drive state. The control device 70 turns off the selector switch 13, turns on the second upper arm switches SUHb, SVHb, and SWHb of each phase, and turns off the second lower arm switches SULb, SVLb, and SWLb of each phase, thereby placing the control system 100 in the Y drive state. In the Y drive state, the phase windings 51U, 51V, and 51W are Y-connected via the second inverter 30. Meanwhile, the control device 70 turns on the selector switch 13 to place the control system 100 in the H drive state.

[0031] 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.

[0032] 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 .

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The setting unit 84 includes a selection unit 85, a carrier generation unit 86, and a drive signal generation unit 87. The selection unit 85 selects whether the drive state of the control system 100 should be the Y drive state or the H drive state. The selection unit 85 may select which state to use based on, for example, the electrical angular velocity ωr calculated based on the electrical angle θr and the operating point of the rotating electric machine 40 determined by the command torque Trq*.

[0037] The carrier generator 86 generates a carrier signal for generating drive signals for the switches SUHa to SWLa and SUHb to 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.

[0038] The drive signal generating unit 87 generates drive signals for each of the switches SUHa to SWLa, 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.

[0039] Specifically, the drive signal generation unit 87 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. The drive signal generation unit 87 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.

[0040] Based on the generated drive signal, the switch control unit 88 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 on / off of the switches SUHa-SWLa and SUHb-SWLb of the first and second inverters 20 and 30 is controlled in accordance with the drive signal.

[0041] 3 is a flowchart showing the control process of the rotary electric machine 40 executed by the control device 70. The process shown in FIG. 3 is repeatedly executed by the processor 71 of the control device 70, for example, at a predetermined control cycle.

[0042] In step S10, the selection unit 85 selects whether the Y drive state or the H drive state should be used.

[0043] If the H drive state is selected in step S10, the process proceeds to step S11, where the H drive control is set as the control mode for the rotating electric machine 40. When the H drive control is selected, the setting unit 84 PWM-drives the switches SUHa to SWLa of the first inverter 20 and PWM-drives the switches SUHb to SWLb of the second inverter 30, as shown in FIG. 4 . In this embodiment, the frequency of the carrier signal used in the H drive control is a fixed frequency. Therefore, the switching frequencies of the switches SUHa to SWLa and SUHb to SWLb are the same in the H drive control.

[0044] 3, if the Y-drive state is selected in step S10, the process proceeds to step S12, where Y-drive control is set as the control mode for the rotary electric machine 40. When the Y-drive control is selected, the setting unit 84 PWM-drives the switches SUHa to SWLa of the first inverter 20, as shown in FIG. 5. In addition, the setting unit 84 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.

[0045] In step S12, the carrier generating unit 86 randomly changes the frequency of the carrier signal used to generate the drive signals for the switches SUHa to SWLa of the first inverter 20. This randomly changes the switching frequencies of the first upper arm switches SUHa, SVHa, SWHa of each phase and the first lower arm switches SULa, SVLa, SWLa of each phase.

[0046] The method of randomly varying the frequency of the carrier signal may be selected from a variety of methods. The method illustrated in Fig. 6 is a method of randomly varying the frequency fr of the carrier signal around a reference frequency fst.

[0047] For example, the carrier generating unit 86 calculates a random change amount for the reference frequency fst at a predetermined control period based on a counter value that is updated at a predetermined control period and a random carrier table that is information that associates the counter value with the random change amount. The carrier generating unit 86 determines the frequency of the carrier signal used to generate the drive signal by adding the calculated random change amount to the reference frequency fst.

[0048] According to the present embodiment described above in detail, when Y-drive control is executed, it is possible to prevent the switching frequency of each switch SUHa to SWLa of the first inverter 20 from being continuously maintained at a specific frequency. As a result, as shown in FIG. 7 , the frequency of the carrier signal is spread, and the frequency components of the current ripple flowing from the battery 10 to the first inverter 20 that are highly dependent on the frequency of the carrier signal can be reduced. This makes it possible to reduce the frequency components of the noise level (electromagnetic noise level) of the rotating electric machine and the frequency components of the common-mode current that are highly dependent on the frequency of the carrier signal. As a result, the noise generated by the control system 100 can be reduced.

[0049] 8 shows the calculation results of the current ripple and noise level in a comparative example in which the frequency of the carrier signal is fixed in the Y drive control. In the comparative example, the frequency components of the current ripple and noise level, which are highly dependent on the frequency of the carrier signal, cannot be reduced.

[0050] Second Embodiment The second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in FIG. 9 , 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.

[0051] 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.

[0052] 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.

[0053] 10 is a flowchart showing the control process of the rotary electric machine 40 executed by the control device 70. The process shown in FIG. 10 is repeatedly executed by the processor 71 of the control device 70, for example, at a predetermined control cycle.

[0054] In this embodiment, in the Y drive control, the lower arm side of the second inverter 30 functions as the neutral point, rather than the upper arm side of the second inverter 30 .

[0055] In detail, if the Y drive state is selected in step S10, the process proceeds to step S13, where, as shown in FIG. 11, the upper arm switches SUHb, SVHb, and SWHb of each phase of the second inverter 30 are fixed to off, and the lower arm switches SULb, SVLb, and SWLb of each phase of the second inverter 30 are fixed to on.

[0056] According to the present embodiment described above, it is possible to achieve the same effects as the first embodiment.

[0057] <Modification of Second Embodiment> When the control device 70 selects the Y-drive control, the control state of each of the switches SUHb to SWLb on the second inverter 30 side may be alternately switched between the state shown in Fig. 11 and the state shown in Fig. 5. In this case, the cycle of the alternate switching 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 integer multiple of the electrical angle cycle.

[0058] Third Embodiment A third embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in Fig. 12 , a configuration is provided in which either the first inverter 20 or the second inverter 30 is selectively disconnected from the battery 10.

[0059] 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."

[0060] 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.

[0061] 13 is a flowchart showing the control process of the rotary electric machine 40 executed by the control device 70. The process shown in FIG. 13 is repeatedly executed by the processor 71 of the control device 70, for example, at a predetermined control cycle.

[0062] If the Y drive state is selected in step S10, the process proceeds to step S14, where control for switching between the first Y drive control and the second Y drive control is executed.

[0063] 14, in a state in which the first power switch 14 is turned on and the second power switch 17 is turned off, the first Y drive control PWM-drives the switches SUHa to SWLa of the first inverter 20. In addition, 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.

[0064] Furthermore, in the carrier generating unit 86, the frequency of the carrier signal used to generate the drive signals for the switches SUHa to SWLa of the first inverter 20 is changed randomly.

[0065] 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.

[0066] 15, in a state in which the first power switch 14 is turned off and the second power switch 17 is turned on, the second Y drive control PWM-drives the switches SUHb to SWLb of the second inverter 30. 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.

[0067] Furthermore, the carrier generating unit 86 randomly changes the frequency of the carrier signal used to generate the drive signals for the switches SUHb to SWLb of the second inverter 30 .

[0068] 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.

[0069] 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.

[0070] 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.

[0071] In the second example, when the control device 70 determines that the temperature of the first inverter 20 detected by the temperature sensor 63 exceeds the first temperature threshold 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 temperature of the first inverter 20 may be, for example, the highest temperature among the temperatures of the switches SUHa to SWLa of the first inverter 20.

[0072] Furthermore, when the control device 70 determines that the temperature of the second inverter 30 detected by the temperature sensor 63 exceeds the second temperature threshold value while the second Y drive control is being executed, the control device 70 switches from the second Y drive control to the first Y drive control. In this case, the temperature of the second inverter 30 may be, for example, the highest temperature among the temperatures of the switches SUHb to SWLb of the second inverter 30. The first temperature threshold value may be the same as or different from the second temperature threshold value.

[0073] According to the present embodiment described above, uneven heat generation in the first inverter 20 and the second inverter 30 can be suppressed.

[0074] Modification of the Third Embodiment The control described in the third embodiment may be applied to the second embodiment. In this case, in the first Y drive control, the second lower arm switches SULb to SWLb for each phase may be fixed on instead of the second upper arm switches SUHb to SWHb for each phase of the second inverter 30. Also, in the second Y drive control, the first lower arm switches SULa to SWLa for each phase may be fixed on instead of the first upper arm switches SUHa to SWHa for each phase of the first inverter 20.

[0075] Fourth Embodiment The fourth embodiment will be described below with reference to the drawings, focusing on the differences from the first to third embodiments. In this embodiment, when H drive control is selected, the switching frequency of the PWM-driven switch is changed randomly. Four modes shown in the following Figures 16 to 19 are used here. Note that the following Figures 16 to 19 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 omitted from the symbols of each component.

[0076] Mode A shown in Figure 16 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 voltage to the winding 51.

[0077] 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. For example, as shown in FIG. 20A, the control device 70 may switch the second upper arm switch SHb on and off at a period that is half the electrical angle period (i.e., a period of 180 electrical degrees, which is half the switching period Tsw).

[0078] Alternatively, the control device 70 may switch the second upper arm switch SHb on and off based on an electrical angle θr and a pulse pattern, which is information in which an on command and an off command are associated with the electrical angle θr, as shown in FIG. 20B. The pulse pattern is a drive signal that is symmetrical about an electrical angle of 180°. The pulse pattern may be designed, for example, to reduce a specific frequency component of the current ripple flowing from the battery 10 to the first inverter 20. For example, the pulse pattern described in Japanese Patent No. 6551297 may be used.

[0079] In mode A, the control device 70 randomly changes the switching frequency of the first lower arm switch SLa.

[0080] Mode B shown in Figure 17 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 to apply a positive voltage to the winding 51.

[0081] 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 at a period that is half the electrical angle period as shown in Fig. 20(a) above, or may switch the second upper arm switch SHb on and off based on a pulse pattern as shown in Fig. 20(b) above.

[0082] In mode B, the control device 70 randomly changes the switching frequency of the second lower arm switch SLb.

[0083] Mode C shown in Figure 18 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 to apply a positive voltage to the winding 51.

[0084] 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 at a period that is half the electrical angle period as shown in Fig. 20(a) above, or may switch the second lower arm switch SLb on and off based on a pulse pattern as shown in Fig. 20(b) above.

[0085] In mode C, the control device 70 randomly changes the switching frequency of the first upper arm switch SHa.

[0086] Mode D shown in Figure 19 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 voltage to the winding 51.

[0087] 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 at a period that is half the electrical angle period as shown in Fig. 20(a) above, or may switch the first lower arm switch SLa on and off based on a pulse pattern as shown in Fig. 20(b) above.

[0088] In the D mode, the control device 70 randomly changes the switching frequency of the second upper arm switch SHb.

[0089] An example of a method for switching between the modes will be described below.

[0090] 21 , the control device 70 may switch between mode A and mode B at intervals of 180 electrical degrees, thereby reducing the imbalance between the heat generated by the lower arm of the first inverter 20 and the heat generated by the lower arm of the second inverter 30.

[0091] The control device 70 may switch between the C mode and the D mode at intervals of 180 electrical degrees. This reduces the imbalance between the heat generated by the upper arm of the first inverter 20 and the heat generated by the upper arm of the second inverter 30.

[0092] The control device 70 may switch between mode A and mode C at intervals of 180 electrical degrees. This reduces the imbalance between the heat generated on the upper arm side of the first inverter 20 and the heat generated on the lower arm side of the first inverter 20.

[0093] The control device 70 may switch between the B mode and the D mode at intervals of 180 electrical degrees. This reduces the imbalance between the heat generated on the upper arm side of the second inverter 30 and the heat generated on the lower arm side of the second inverter 30.

[0094] The control device 70 may also switch between modes A to D using the method shown in Fig. 22. Fig. 22 is a state transition diagram of each mode.

[0095] 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°.

[0096] [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 temperature sensor 63 exceeds the temperature threshold Tα during control to switch between A mode and B mode, the control device 70 switches to control to switch 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.

[0097] [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 temperature sensor 63 exceeds the temperature threshold Tα during control of switching between the B mode and the D mode, the control device 70 switches to control of switching between the A mode and the B mode. This makes it possible to suppress heat generation in the second upper arm switch SHb.

[0098] [3] If 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 temperature sensor 63 exceeds the temperature threshold Tα during control of switching between A mode and B mode, the control device 70 switches to control of switching between A mode and C mode. This makes it possible to suppress heat generation in the second lower arm switch SLb.

[0099] [4] If 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 temperature sensor 63 exceeds the temperature threshold Tα during control of switching between A mode and C mode, the control device 70 switches to control of switching between A mode and B mode. This makes it possible to suppress heat generation in the first upper arm switch SHa.

[0100] [5] If the control device 70 determines that the detected temperature T2L of the second lower arm switch SLb exceeds the temperature threshold Tα during control of switching between B mode and D mode, the control device 70 switches to control of switching between C mode and D mode. This makes it possible to suppress heat generation in the second lower arm switch SLb.

[0101] [6] If the control device 70 determines that the detected temperature T1H of the first upper arm switch SHa exceeds the temperature threshold Tα during control of switching between C mode and D mode, the control device 70 switches to control of switching between B mode and D mode. This makes it possible to suppress heat generation in the first upper arm switch SHa.

[0102] [7] If the control device 70 determines that the detected temperature T2H of the second upper arm switch SHb exceeds the temperature threshold Tα during control of switching between C mode and D mode, the control device 70 switches to control of switching between A mode and C mode. This makes it possible to suppress heat generation in the second upper arm switch SHb.

[0103] [8] When the control device 70 determines that the detected temperature T1L of the first lower arm switch SLa exceeds the temperature threshold Tα during 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. Note that in the controls [1] to [8] above, the temperature threshold value compared with the switch temperature of the first inverter 20 and the temperature threshold value compared with the switch temperature of the second inverter 30 may be the same value or different values.

[0104] 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.

[0105] <Modification of Fourth Embodiment> In mode A shown in Fig. 16, the control device 70 may PWM-drive the first upper arm switch SHa as shown in Fig. 23 and randomly change the switching frequency of the first upper arm switch SHa. In this case, the control device 70 alternately turns on the first upper arm switch SHa and the first lower arm switch SLa.

[0106] In addition, the control device 70 may perform switching control of the second upper arm switch SHb and the second lower arm switch SLb in mode A shown in Figure 23 based on a pulse pattern as shown in Figure 24, provided that the second upper arm switch SHb and the second lower arm switch SLb are not turned on simultaneously.

[0107] In mode B shown in Fig. 17, the control device 70 may PWM-drive the second upper arm switch SHb as shown in Fig. 25 and randomly change the switching frequency of the second upper arm switch SHb. In this case, the control device 70 alternately turns on the second upper arm switch SHb and the second lower arm switch SLb.

[0108] In addition, the control device 70 may perform switching control of the first upper arm switch SHa and the first lower arm switch SLa in mode B shown in Figure 25 based on a pulse pattern as shown in Figure 26, provided that the first upper arm switch SHa and the first lower arm switch SLa are not turned on simultaneously.

[0109] In the C mode shown in Fig. 18, the control device 70 may PWM-drive the first lower arm switch SLa as shown in Fig. 27 and randomly change the switching frequency of the first lower arm switch SLa. In this case, the control device 70 alternately turns on the first upper arm switch SHa and the first lower arm switch SLa.

[0110] In addition, the control device 70 may perform switching control of the second upper arm switch SHb and the second lower arm switch SLb in mode C shown in Figure 27 based on a pulse pattern as shown in Figure 28, provided that the second upper arm switch SHb and the second lower arm switch SLb are not turned on simultaneously.

[0111] In the D mode shown in Fig. 19, the control device 70 may PWM-drive the second lower arm switch SLb as shown in Fig. 29 and randomly change the switching frequency of the second lower arm switch SLb. In this case, the control device 70 alternately turns on the second upper arm switch SHb and the second lower arm switch SLb.

[0112] In addition, the control device 70 may perform switching control of the first upper arm switch SHa and the first lower arm switch SLa in the D mode shown in Figure 29 based on a pulse pattern as shown in Figure 30, provided that the first upper arm switch SHa and the first lower arm switch SLa are not turned on simultaneously.

[0113] Fifth Embodiment The fifth embodiment will be described below with reference to the drawings, focusing on the differences from the first to third embodiments. In this embodiment, when H drive control is selected, the control device 70 performs interleaved control. Here, the control shown in the following Figures 31 and 32 is used. For convenience, the following Figures 31, 32, etc. 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.

[0114] The setting unit 84 of the control device 70 sets, as the control mode, a control that switches between the first control and the second control.

[0115] 31 , the first control is a control for PWM driving the first upper arm switch SHa and the second lower arm switch SLb in order to apply a positive voltage to the winding 51. In the first control, the carrier generating unit 86 randomly changes the frequency of the carrier signal used to generate the drive signals for the first upper arm switch SHa and the second lower arm switch SLb.

[0116] In the first control, the first lower arm switch SLa and the first upper arm switch SHa may be alternately turned on or may be fixed to off. In the first control, the second upper arm switch SHb and the second lower arm switch SLb may be alternately turned on or may be fixed to off.

[0117] 32, the second control is a control for PWM driving the second upper arm switch SHb and the first lower arm switch SLa in order to apply a negative voltage to the winding 51. In the second control, the carrier generating unit 86 randomly changes the frequency of the carrier signal used to generate the drive signals for the second upper arm switch SHb and the first lower arm switch SLa.

[0118] In the second control, the first upper arm switch SHa and the first lower arm switch SLa may be alternately turned on or may be fixed to off. In the second control, the second lower arm switch SLb and the second upper arm switch SHb may be alternately turned on or may be fixed to off.

[0119] The setting unit 84 sets the phase difference β between the on-timing of the first upper arm switch SHa and the on-timing of the second lower arm switch SLb in the first control and the phase difference β between the on-timing of the second upper arm switch SHb and the on-timing of the first lower arm switch SLa in the second control to an electrical angle of 180°. This setting method will be described below using Figures 33 and 34 using the first control as an example.

[0120] FIG. 33 is an example of a functional block diagram of the carrier generation unit 86.

[0121] The counter generating unit 90 outputs a counter value that is updated at a predetermined control period.

[0122] The random value generator 91 calculates the random change ΔR at a specified cycle based on the input counter value and the random carrier table. The specified cycle is, for example, a cycle of 180°, 360°, 540°, or 720° electrical angle.

[0123] The first adder 92A calculates the frequency of the first carrier signal Sg1 (hereinafter referred to as the first carrier frequency fr1) by adding the calculated random change ΔR to the reference frequency fst. The first carrier frequency fr1 is a carrier signal used to generate a drive signal for the first upper arm switch SHa of the first inverter 20. The first carrier frequency fr1 is updated at a specified cycle.

[0124] The second adder 92B calculates the frequency of the second carrier signal Sg2 (hereinafter referred to as the second carrier frequency fr2) by adding the calculated random change ΔR to the reference frequency fst. The second carrier frequency fr2 is a carrier signal used to generate a drive signal for the second lower arm switch SLb of the second inverter 30. The second carrier frequency fr2 is updated at regular intervals.

[0125] As can be seen from Figure 33, the first carrier frequency fr1 and the second carrier frequency fr2 are the same frequency. Furthermore, the first carrier signal Sg1 and the second carrier signal Sg2 have the same maximum value Cmax and the same minimum value Cmin. Furthermore, the phase difference between the first carrier signal Sg1 and the second carrier signal Sg2 is set to an electrical angle of 180°.

[0126] The drive signal generator 87 compares the first carrier signal Sg with the normalized command value Duty to generate a drive signal for the first upper arm switch SHa. The drive signal generator 87 also compares the common normalized command value Duty, obtained by comparing the first carrier signal Sg1, with the second carrier signal Sg2 to generate a drive signal for the second lower arm switch SLb.

[0127] Figure 34 shows the transitions of each waveform during interleaved control. In Figure 34, (a) shows the transitions of first carrier signal Sg1 and standardized command value Duty, (b) shows the transitions of first voltage V1, which is the voltage on the first inverter 20 side of winding 51, (c) shows the transitions of second carrier signal Sg2 and standardized command value Duty, and (d) shows the transitions of second voltage V2, which is the voltage on the second inverter 30 side of winding 51. The standardized command value Duty in (a) and the standardized command value in (b) are the same value.

[0128] 10(e) shows the change in the voltage difference ΔV obtained by subtracting the second voltage V2 from the first voltage V1, and FIG. 10(f) shows the change in the current Iph flowing from the battery 10 to the first inverter 20.

[0129] 35 shows the transition of each waveform in Comparative Example 1, where interleave control is not performed. In the Comparative Example, the phase difference between the first carrier signal Sg1 and the second carrier signal Sg2 is set to zero.

[0130] Figure 36 shows the calculation results of the frequency characteristics of current ripple and electromagnetic noise when Comparative Example 1 shown in Figure 35 is executed. On the other hand, Figure 37 shows the calculation results of Comparative Example 2 when interleaved control is executed but the first and second carrier frequencies fr1 and fr2 are set to a common fixed frequency.

[0131] In comparison with Comparative Examples 1 and 2, according to this embodiment, as shown in FIG. 38, the peak frequencies of the current ripple and noise level can be increased by about twice that of Comparative Example 1, and the peak values ​​of the current ripple and noise level can be significantly reduced.

[0132] Modification of the Fifth Embodiment Taking the first control as an example, the control device 70 may use a common carrier signal for generating the drive signal for the first upper arm switch SHa and the drive signal for the second lower arm switch SLb. In this case, the control device 70 may calculate a normalized command value to be compared with the carrier signal to generate the drive signal for the second lower arm switch SLb as "1-Duty."

[0133] The control device 70 may set the phase difference β in the first and second controls to a value other than 180°, such as "150°≦β≦210°", "170°≦β≦190°", or "175°≦β≦185°".

[0134] As shown in FIG. 39, the carrier generating section 86 may include, instead of the counter generating section 90 and the random value generating section 91, a signal generating section 93 that generates an M-sequence signal as a random change ΔR.

[0135] Sixth Embodiment The sixth embodiment will be described below with reference to the drawings, focusing on differences from the fifth embodiment. In this embodiment, interleaving control is not performed, and the phase difference between the first carrier signal Sg1 and the second carrier signal Sg2 is zero. The setting unit 84 randomly changes the switching frequencies of the first upper arm switch SHa and the second lower arm switch SLb in the first control and the switching frequencies of the second upper arm switch SHb and the first lower arm switch SLa in the second control, centered around the reference frequency fst. The setting unit 84 sets the random change in the switching frequency relative to the reference frequency fst in the first control to different values ​​from the random change in the switching frequency relative to the reference frequency fst in the second control.

[0136] FIG. 40 is an example of a functional block diagram of the carrier generation unit 86.

[0137] The first random value generation unit 94A calculates a first random change ΔR1 at a predetermined control period based on the input counter value and the random carrier table.

[0138] The first adder 92A calculates the first carrier frequency fr1 by adding the calculated first random change ΔR1 to the reference frequency fst.

[0139] The second random value generation unit 94B calculates a second random change amount ΔR2 that randomly changes with respect to the first random change amount ΔR1 at a predetermined control period based on the input counter value and the random carrier table.

[0140] The second adder 92B calculates the second carrier frequency fr2 by adding the calculated second random change ΔR2 to the reference frequency fst.

[0141] According to this embodiment, it is possible to improve the effect of diffusing the frequency components of the current ripple, and it is possible to improve the effect of reducing the current ripple and noise.

[0142] Seventh Embodiment The seventh embodiment will be described below with reference to the drawings, focusing on differences from the fifth embodiment. In this embodiment, interleaving control is not performed, and the phase difference between the first carrier signal Sg1 and the second carrier signal Sg2 is 0. The setting unit 84 differentiates the reference frequency used to calculate the first carrier frequency fr1 from the reference frequency used to calculate the second carrier frequency fr2.

[0143] FIG. 41 is an example of a functional block diagram of the carrier generation unit 86.

[0144] The first adder 92A calculates the first carrier frequency fr1 by adding the calculated random change ΔR to the first reference frequency fst1. The second adder 92B calculates the first carrier frequency fr1 by adding the calculated random change ΔR to the second reference frequency fst2. The second reference frequency fst2 and the first reference frequency fst1 are different frequencies.

[0145] According to this embodiment, the frequency components of the current ripple can be diffused more effectively, and the current ripple and noise can be reduced more effectively. Furthermore, the counter generator 90 and the random value generator 91 are used in common to generate the first and second carrier frequencies fr1 and fr2. This reduces the processing load on the control device 70.

[0146] Eighth Embodiment An eighth embodiment will now be described with reference to the drawings, focusing on differences from the sixth embodiment. In this embodiment, the setting unit 84 uses different reference frequencies to calculate the first carrier frequency fr1 and the second carrier frequency fr2.

[0147] FIG. 42 is an example of a functional block diagram of the carrier generation unit 86.

[0148] The first adder 92A calculates the first carrier frequency fr1 by adding the calculated first random change ΔR1 to the first reference frequency fst1. The second adder 92B calculates the second carrier frequency fr2 by adding the calculated second random change ΔR2 to the second reference frequency fst2. The second reference frequency fst2 and the first reference frequency fst1 are different frequencies.

[0149] According to this embodiment, the effect of diffusing the frequency components of the current ripple can be further improved, and the effect of reducing the current ripple and noise can be further improved.

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

[0151] In the sixth to eighth embodiments, the carrier generation unit 86 may be provided with a signal generation unit 93 that generates the M sequence signal shown in FIG. 39 as a random change amount ΔR, instead of the counter generation unit and the random carrier table.

[0152] 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.

[0153] The control system does not need to be provided with a changeover switch. In this case, the control system is a system that is always in the H drive state.

[0154] The carrier signal is not limited to a triangular wave signal, but may be, for example, a sawtooth wave signal.

[0155] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0156] The rotating electric machine is not limited to a permanent magnet field type synchronous machine, and may be, for example, an induction machine.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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 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 connection 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 side bus (11) electrically connecting a high potential terminal of the first upper arm switch and a high potential terminal of the second upper arm switch in each phase; and a negative side bus (12) electrically connecting a low potential terminal of the first lower arm switch and a low potential terminal of the second lower arm switch in each phase. a control device (70) for a rotating electric machine applicable to a system including: in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding; in each phase, a low potential side terminal of the second upper arm switch and a high potential side terminal of the second lower arm switch are electrically connected to a second end of the armature winding; a setting unit (84) that sets a 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 switch control unit (88) that controls on / off of the first upper arm switch, the first lower arm switch, the second upper arm switch and the second lower arm switch based on the set control mode, wherein the setting unit sets the control mode such that a switching frequency is randomly changed when 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 is PWM driven.

2. A control device for a rotating electric machine as described in claim 1, further comprising a changeover switch (13, 16) provided on a target bus which is at least one of the positive bus and the negative bus, the changeover switch electrically connecting the first inverter and the second inverter via the target bus when turned on and cutting off the electrical connection between the first inverter and the second inverter via the target bus when turned off, the setting unit sets Y-drive control as the control mode, the Y-drive control being a control which 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 PWM-drives the first upper arm switch and the first lower arm switch, and the setting unit randomly changes the switching frequency of the first upper arm switch and the first lower arm switch in the Y-drive control.

3. A connection switching unit (14, 17) is provided 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, 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, and the Y drive control is a first Y drive control that is executed in a state in which the connection switching unit is set to the first mode, and the setting unit sets control for switching between the first Y drive control and the second Y drive control as the control mode, and the second Y drive control is a control for fixing the first upper arm switch of each phase on and fixing the first lower arm switch of each phase off when the connection switching unit is set to the second mode and the changeover switch is turned off, or a control for fixing the first lower arm switch of each phase on and fixing the first upper arm switch of each phase off when the connection switching unit is set to the second mode and the changeover switch is turned off, 3. The control device for a rotating electric machine according to claim 2, wherein the second Y drive control is a control for PWM driving the second upper arm switch and the second lower arm switch, and the setting unit randomly changes a switching frequency of the second upper arm switch and the second lower arm switch in the second Y drive control.

4. A control device for a rotating electric machine as described in claim 1, wherein the setting unit sets, as the control mode, control for switching between first lower arm control and second lower arm control, the first lower arm control is control for PWM driving the first lower arm switch to apply a negative voltage to the armature winding, and the second lower arm control is control for PWM driving the second lower arm switch to apply a positive voltage to the armature winding, and the setting unit randomly varies a switching frequency of the first lower arm switch in the first lower arm control, and randomly varies a switching frequency of the second lower arm switch in the second lower arm control.

5. A control device for a rotating electric machine as described in claim 4, wherein the setting unit sets, as the control mode, control for switching between the first lower arm control, the second lower arm control, the first upper arm control, and the second upper arm control, the first upper arm control is control for PWM driving the first upper arm switch to apply a positive voltage to the armature winding, and the second upper arm control is control for PWM driving the second upper arm switch to apply a negative voltage to the armature winding, and the setting unit randomly varies a switching frequency of the first upper arm switch in the first upper arm control, and randomly varies a switching frequency of the second upper arm switch in the second upper arm control.

6. A control device for a rotating electric machine as described in claim 1, wherein the setting unit sets, as the control mode, control for switching between first upper arm control and second upper arm control, the first upper arm control is control for PWM driving the first upper arm switch to apply a positive voltage to the armature winding, and the second upper arm control is control for PWM driving the second upper arm switch to apply a negative voltage to the armature winding, and the setting unit randomly varies a switching frequency of the first upper arm switch in the first upper arm control, and randomly varies a switching frequency of the second upper arm switch in the second upper arm control.

7. A control device for a rotating electric machine as described in claim 4 or 5, wherein the first lower arm control is a control that drives the second upper arm switch based on a pulse pattern that is information in which on commands and off commands are related to the electrical angle of the rotating electric machine, and the second lower arm control is a control that drives the first upper arm switch based on the pulse pattern.

8. A control device for a rotating electric machine as described in claim 5 or 6, wherein the first upper arm control is a control that drives the second lower arm switch based on a pulse pattern that is information in which on commands and off commands are associated with the electrical angle of the rotating electric machine, and the second upper arm control is a control that drives the first lower arm switch based on the pulse pattern.

9. The setting unit sets, as the control mode, a control for switching between a first control for PWM driving the first upper arm switch and the second lower arm switch to apply a positive voltage to the armature winding, and a second control for PWM driving the second upper arm switch and the first lower arm switch to apply a negative voltage to the armature winding; the setting unit sets a phase difference between an on-timing of the first upper arm switch and an on-timing of the second lower arm switch in the first control, and a phase difference between an on-timing of the second upper arm switch and an on-timing of the first lower arm switch in the second control, to a value of 150° or more and 210° or less in electrical angle; the setting unit randomly varies a switching frequency of the first upper arm switch and the second lower arm switch in the first control, and a switching frequency of the second upper arm switch and the first lower arm switch in the second control, centered around a reference frequency; The control device for a rotating electric machine according to claim 1 , wherein a random change (ΔR) of a switching frequency with respect to the reference frequency (fst) in each of the first control and the second control is set to a common value.

10. The control device for a rotating electric machine as described in claim 1, wherein the setting unit sets, as the control mode, a control that switches between a first control for PWM driving the first upper arm switch and the second lower arm switch to apply a positive voltage to the armature winding, and a second control for PWM driving the second upper arm switch and the first lower arm switch to apply a negative voltage to the armature winding, and the setting unit randomly varies a switching frequency of the first upper arm switch and the second lower arm switch in the first control and a switching frequency of the second upper arm switch and the first lower arm switch in the second control around a reference frequency (fst), and sets a random change amount (ΔR1) of the switching frequency relative to the reference frequency in the first control and a random change amount (ΔR2) of the switching frequency relative to the reference frequency in the second control to different values.

11. The control device for a rotating electric machine as described in claim 1, wherein the setting unit sets, as the control mode, a control that switches between a first control for PWM driving the first upper arm switch and the second lower arm switch to apply a positive voltage to the armature winding, and a second control for PWM driving the second upper arm switch and the first lower arm switch to apply a negative voltage to the armature winding, and the setting unit randomly varies a switching frequency of the first upper arm switch and the second lower arm switch in the first control around a first reference frequency (fst1), randomly varies a switching frequency of the second upper arm switch and the first lower arm switch in the second control around a second reference frequency (fst2) different from the first reference frequency, and sets a common value (ΔR) for a random change in the switching frequency relative to the first reference frequency in the first control and a random change in the switching frequency relative to the second reference frequency in the second control.

12. The control device for a rotating electric machine as described in claim 1, wherein the setting unit sets, as the control mode, a control that switches between a first control for PWM driving the first upper arm switch and the second lower arm switch to apply a positive voltage to the armature winding, and a second control for PWM driving the second upper arm switch and the first lower arm switch to apply a negative voltage to the armature winding, and the setting unit randomly varies a switching frequency of the first upper arm switch and the second lower arm switch in the first control around a first reference frequency (fst1), randomly varies a switching frequency of the second upper arm switch and the first lower arm switch in the second control around a second reference frequency (fst2) different from the first reference frequency, and sets a random change amount (ΔR1) of the switching frequency relative to the first reference frequency in the first control and a random change amount (ΔR2) of the switching frequency relative to the second reference frequency in the second control to different values.

13. A program applied to a system including: 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 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 side bus (11) 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 in each phase; and a negative side bus (12) 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 in each phase, A program for causing a processor (71) to execute a setting process for setting 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 process for controlling 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 based on the set control mode, wherein the setting process sets the control mode such that a switching frequency is randomly changed when 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 is PWM driven.

14. 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 connection 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 side bus (11) 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 in each phase; and a negative side bus (12) 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 in each phase. a control method for a rotating electric machine applicable to a system including: in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding; and in each phase, a low potential side terminal of the second upper arm switch and a high potential side terminal of the second lower arm switch are electrically connected to a second end of the armature winding; a setting step of setting 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 step of controlling 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 based on the set control mode, wherein in the setting step, the control mode is set such that a switching frequency is randomly changed when 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 is PWM driven.

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