Rotary electrical machine control device, rotary electrical machine control program, and rotary electrical machine control method

Abstract

Provided is a rotary electrical machine control device (60) that is applied to a system (100) including a rotary electrical machine (40) having multi-phase armature windings (51U, 51V, 51W), a first inverter (20), a second inverter (30), a positive electrode-side bus (11), and a negative electrode-side bus (12), said rotary electrical machine control device comprising: an abnormality detection unit (67, 78) which detects a voltage abnormality in a system voltage (Vsys) between the positive electrode-side bus and the negative electrode-side bus; and a phase operation unit (68, 79) which, when the abnormality detection unit has detected a voltage abnormality, changes the phase difference (Δθ) between a phase (θ1) of each phase voltage applied by the first inverter and a phase (θ2) of each phase voltage applied by the second inverter, in such a manner as to increase the phase difference (Δθ).

Description

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

[0001] This application is based on Japanese Application No. 2023-219444, filed on December 26, 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 control program for a rotating electric machine, 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. 6907171

[0005] In the control device described in the above document, when the modulation rate is equal to or greater than a threshold value, the switching frequency is suppressed by performing phase shift control that changes the phase difference between the phase of the output phase voltage of the first inverter unit and the phase of the output phase voltage of the second inverter unit.

[0006] However, since the phase shift control does not control the current, there is a possibility that the voltage may not be appropriately suppressed during a load dump.

[0007] A primary object of the present disclosure is to provide a control device for a rotating electric machine, a control program for a rotating electric machine, and a control method for a rotating electric machine that can prevent overvoltage during an abnormality.

[0008] A first means for solving the above problem includes 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 side bus bar for 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, a negative side busbar that electrically connects the low potential side terminal of the first lower arm switch and the low potential side terminal of the second lower arm switch; and a control device for a rotating electric machine applied to a system including the negative side busbar, an abnormality detection unit that detects a voltage abnormality in the system voltage between the positive side busbar and the negative side busbar, and a phase operation unit that, when a voltage abnormality is detected by the abnormality detection unit, changes the phase difference between the phase of each phase voltage applied by the first inverter and the phase of each phase voltage applied by the second inverter so as to increase it.

[0009] A second means for solving the above problem includes 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 side bus bar for electrically connecting, 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 positive side bus bar for connecting, in each phase, a high potential side terminal of the first lower arm switch. a negative busbar that electrically connects the low potential side terminal of the first lower arm switch and the low potential side terminal of the second lower arm switch, the control program for a rotating electric machine being executed by a control device of the rotating electric machine that is applied to a system including the positive side busbar and the negative side busbar, and, if a voltage abnormality is detected in the abnormality detection process, executing a phase operation process that changes the phase of each phase voltage applied by the first inverter and the phase of each phase voltage applied by the second inverter so as to increase the phase difference.

[0010] A third means for solving the above problem includes 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 side bus bar for electrically connecting, 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 positive side bus bar for electrically connecting, 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 control method for a rotating electric machine implemented by a rotating electric machine control device applied to a system including a negative side busbar that electrically connects the low potential side terminal of a lower arm switch and the low potential side terminal of the second lower arm switch, the method including: an abnormality detection process that detects a voltage abnormality in the system voltage between the positive side busbar and the negative side busbar; and, if a voltage abnormality is detected in the abnormality detection process, a phase operation process that changes the phase of each phase voltage applied by the first inverter and the phase of each phase voltage applied by the second inverter so as to increase the phase difference.

[0011] According to the above means, when a voltage abnormality is detected, the phase difference between the phase of each phase voltage applied by the first inverter and the phase of each phase voltage applied by the second inverter increases. As the phase difference increases, the phase voltages applied by the first inverter and the phase voltages applied by the second inverter cancel each other out, thereby suppressing the voltage applied to the armature winding. As a result, overcurrents and overvoltages can be suppressed.

[0012] 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 a diagram showing the configuration of a control system, Fig. 2 is a functional block diagram showing functions during current control, Fig. 3 is a functional block diagram showing functions during phase control, Fig. 4 is a diagram showing phase currents when a load dump occurs, Fig. 5 is a diagram showing phase currents when a load dump occurs, Fig. 6 is a flowchart of a phase correction process, Fig. 7 is a diagram showing the relationship between the phase difference and the phase currents during PWM control, Fig. 8 is a diagram showing the relationship between the phase difference and the phase currents during overmodulation control, Fig. 9 is a diagram showing the relationship between the phase difference and the phase currents during square wave control, Fig. 10 is a diagram showing the relationship between the phase difference and the phase currents in a modified example, Fig. 11 is a diagram showing the relationship between the phase difference and the phase currents in a modified example, and Fig. 12 is a diagram showing the relationship between the phase difference and the phase currents in a modified example.

[0013] The present disclosure will now be described with reference to the drawings with respect to a control device, a control program, and a control method for a rotating electric machine. In the embodiments and the modifications, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals. For corresponding and / or associated parts, the description of the embodiments can be referenced.

[0014] The control device 60 for the rotating electric machine 40 of this embodiment is mounted on an electric vehicle such as an electric car or a hybrid car, and is applied to a control system 100 for the rotating electric machine 40 (hereinafter simply referred to as the control system 100).

[0015] As shown in FIG. 1, the control system 100 of this embodiment includes a battery 10, a first inverter 20, a second inverter 30, a rotating electric machine 40, and a control device 60 for the rotating electric machine (hereinafter, in the first embodiment, simply referred to as the control device 60).

[0016] The battery 10 is, for example, a battery pack including a series connection of unit cells, and is a DC power supply in this embodiment. 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.

[0017] 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 .

[0018] The first inverter 20 includes a series connection of a U-phase first upper arm switch SUHa and a U-phase first lower arm switch SULa, a V-phase first upper arm switch SVHa and a V-phase first lower arm switch SVLa, and a W-phase first upper arm switch SWHa and a W-phase first lower arm switch SWLa. Hereinafter, these will be collectively referred to as switches SUHa to SWLa.

[0019] Similarly, the second inverter 30 includes a series connection of a U-phase second upper arm switch SUHb and a U-phase second lower arm switch SULb, a series connection of a V-phase second upper arm switch SVHb and a V-phase second lower arm switch SVLb, and a series connection of a W-phase second upper arm switch SWHb and a W-phase second lower arm switch SWLb. Hereinafter, these will be collectively referred to as switches SUHb to SWLb.

[0020] In this embodiment, voltage-controlled semiconductor switching elements, more specifically, IGBTs, are used as the switches SUHa to SWLa and SUHb to SWLb. In this embodiment, the high-potential terminal of each switch is the collector, and the low-potential terminal is the emitter. Freewheeling diodes DUHa, DVHa, DWHa, DULa, DVLa, DWLa, DUHb, DVHb, DWHb, DULb, DVLb, and DWLb are connected in anti-parallel to the switches SUHa, SVHa, SWHa, SULa, SVLa, SWLa, SUHb, SVHb, SWHb, SULb, SVLb, and SWLb, respectively.

[0021] The collectors of the first upper arm switches SUHa, SVHa, SWHa of each phase and the collectors of the second upper arm switches SUHb, SVHb, SWHb of each phase are electrically connected by a positive bus 11 serving as a high-potential side connecting line such as a bus bar. The emitters of the first lower arm switches SULa, SVLa, SWLa of each phase and the emitters of the second lower arm switches SULb, SVLb, SWLb of each phase are electrically connected by a negative bus 12 serving as a low-potential side connecting line such as a bus bar.

[0022] The positive terminal of the battery 10 is electrically connected to the positive bus 11, and the negative terminal of the battery 10 is electrically connected to the negative bus 12. The battery 10 is electrically connected to the buses 11, 12 on the opposite side of the first inverter 20 from the second inverter 30.

[0023] The rotating electric machine 40 is, for example, a main motor mounted on a vehicle. A rotor 41 of the rotating electric machine 40 is capable of transmitting power to drive wheels (not shown) 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 (for example, neodymium magnets) as field poles.

[0024] The rotating electric machine 40 includes a stator 50. The stator 50 includes armature windings, namely, a U-phase winding 51U, a V-phase winding 51V, and a W-phase winding 51W. The phase windings 51U, 51V, and 51W are arranged with an electrical angle of 120°. The phase windings 51U, 51V, and 51W are open-connected, and both ends of each phase winding 51U, 51V, and 51W are electrically connected to the first inverter 20 or the second inverter 30.

[0025] Specifically, in each phase, first ends 51Ua, 51Va, 51Wa of the windings 51U, 51V, 51W are electrically connected to first upper switches SUHa, SVHa, SWHa and first lower switches SULa, SVLa, SWLa of the corresponding phase. Also, second ends 51Ub, 51Vb, 51Wb of the windings 51U, 51V, 51W are electrically connected to second upper switches SUHb, SVHb, SWHb and second lower switches SULb, SVLb, SWLb of the corresponding phase.

[0026] The control system 100 includes a changeover switch 13. The changeover switch 13 is provided on the positive electrode side bus 11 between the first inverter 20 and the second inverter 30. When the changeover switch 13 is turned on, it electrically connects the first inverter 20 and the second inverter 30, and when turned off, it electrically disconnects the first inverter 20 and the second inverter 30. The changeover switch 13 is controlled by the control device 60. The changeover switch 13 is provided to switch the driving state of the control system 100, as will be described later.

[0027] For example, the changeover switch 13 is a semiconductor switching element such as an IGBT or a relay. When an IGBT is used as the changeover switch 13, a freewheel diode is connected in parallel to the changeover switch 13. In this case, the anode of the freewheel diode is electrically connected to the second inverter 30 side, and the cathode is electrically connected to the first inverter 20 side.

[0028] The control system 100 includes a power switch 14 as a power switch unit, and a capacitor 15. The power switch 14 is, for example, a semiconductor switching element or a relay. The power switch 14 is provided on the positive bus 11 between the positive terminal of the battery 10 and the first inverter 20. When the power switch 14 is turned on, it electrically connects the battery 10 and the rotating electric machine 40, and when it is turned off, it electrically disconnects the battery 10 and the rotating electric machine 40. The power switch 14 is driven by the control device 60.

[0029] A first end of the capacitor 15 is electrically connected to the positive bus 11 between the power switch 14 and the first inverter 20. A second end of the capacitor 15 is electrically connected to the negative bus 12 between the negative terminal of the battery 10 and the first inverter 20.

[0030] The control system 100 includes a current sensor 16 and a rotation angle sensor 17. The current sensor 16 detects phase currents Iu, Iv, and Iw flowing through the respective phase windings 51U, 51V, and 51W. In this embodiment, the current sensor 16 is provided at one of the ends of each phase winding 51U, 51V, and 51W closer to the first inverter 20. The sign of the detected value of the current sensor 16 is positive when the current flows from the first terminal 51Ua, 51Va, and 51Wa of each phase winding 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 16 may also be provided at one of the ends of each phase winding 51U, 51V, and 51W closer to the second inverter 30.

[0031] The rotation angle sensor 17 is, for example, a resolver, and detects the electrical angle θ of the rotor 41. The phase currents Iur, Ivr, and Iwr detected by the current sensor 16 and the electrical angle θr detected by the rotation angle sensor 17 are input to the control device 60.

[0032] The control system 100 includes a voltage sensor 18 that detects a system voltage Vsys between the positive bus 11 and the negative bus 12. The voltage sensor 18 is connected in parallel with the capacitor 15. That is, a first end of the voltage sensor 18 is electrically connected to the positive bus 11 between the power switch 14 and the first inverter 20. A second end of the voltage sensor 18 is electrically connected to the negative bus 12 between the negative terminal of the battery 10 and the first inverter 20. The detection result of the voltage sensor 18 is input to the control device 60. When the power switch 14 is turned on, the system voltage Vsys matches the power supply voltage of the battery 10, and when the power switch 14 is turned off, the system voltage Vsys matches the voltage across the capacitor 15.

[0033] The control device 60 is primarily composed of a microcomputer including a processing unit 60a such as a CPU and a storage unit 60b such as various types of memory. The functions provided by the microcomputer can be provided by software stored in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof. For example, when the microcomputer is provided by electronic circuits, which are hardware, the functions can be provided by digital circuits including numerous logic circuits or analog circuits. For example, the processing unit 60a of the microcomputer executes programs stored in a non-transitory tangible storage medium (non-transitory tangible storage medium) that serves as the storage unit 60b. The programs include, for example, control programs that realize the functions shown in Figures 2 and 3. Execution of a program (e.g., a control program) results in the execution of a method (e.g., a control method) corresponding to the program. The storage unit 60b is, for example, a non-volatile memory. The programs stored in the storage unit 60b can be downloaded and updated via a communication network such as the Internet, for example, via OTA (Over the Air).

[0034] The control device 60 has a function of switching the drive state of the control system 100 between a Y drive state and an H drive state by controlling the selector switch 13. The control device 60 sets the control system 100 to the Y drive state (first mode) by turning off the selector switch 13, turning on the second upper arm switches SUHb, SVHb, and SWHb of each phase, and turning off the lower arm switches SULb, SVLb, and SWLb of each phase. In the Y drive state, the phase windings 51U, 51V, and 51W are Y-connected via the second inverter 30. On the other hand, the control device 60 sets the control system 100 to the H drive state (second mode) by turning on the selector switch 13.

[0035] In the Y drive state, the control device 60 controls the switching of the switches SUHa to SWLa in the first inverter 20. In addition, in the H drive state, the control device 60 controls the switching of both the switches SUHa to SWLa in the first inverter 20 and the switches SUHb to SWLb in the second inverter 30. By appropriately switching between the Y drive state and the H drive state and executing switching control, the control system 100 can be made to have a high output and high efficiency.

[0036] The control device 60 has various functions for executing current control and phase control. These controls are executed at least in the H drive state. The control device 60 selects and executes either phase control or current control based on the operating conditions of the rotating electric machine 40. For example, the control device 60 executes current control when the modulation factor of the inverters 20, 30 is less than a predetermined threshold and PWM control is performed. On the other hand, the control device 60 executes phase control when the modulation factor of the inverters 20, 30 is equal to or greater than a predetermined threshold and overmodulation control or square wave control is performed. Note that the current control corresponds to current feedback control, and the phase control corresponds to torque feedback control.

[0037] First, the functions for executing current control will be described with reference to Fig. 2. Current control is performed when PWM control is performed. Note that PWM control is performed, for example, when the modulation rate is less than a threshold value and in a low rotation range, low output range, etc. Fig. 2 is a functional block diagram for explaining various functions for realizing current control. Note that the various functions of the control device 60 are realized, for example, by the arithmetic processing unit 60a executing a program stored in the storage unit 60b.

[0038] As shown in FIG. 2, the control device 60 includes a current command generating unit 61, a dq conversion unit 62, a current control unit 63, a UVW conversion unit 64, and a modulation unit 65 as functions for executing current control.

[0039] The current command generating unit 61 receives a torque command value Trq* from a higher-level control device than the control device 60. Based on the received torque command value Trq*, the current command generating unit 61 calculates a d-axis current command value Id* and a q-axis current command value Iq* in a dq coordinate system using a torque-dq map or the like. Hereinafter, the d-axis current command value Id* and the q-axis current command value Iq* may be collectively referred to as d- and q-axis current command values ​​Id* and Iq*.

[0040] The dq converter 62 receives the phase currents Iur, Ivr, and Iwr detected by the current sensor 16 and the electrical angle θr detected by the rotation angle sensor 17. The dq converter 62 calculates a d-axis current value Idr and a q-axis current value Iqr based on the detected phase currents Iur, Ivr, and Iwr and the electrical angle θr. The d-axis current value Idr and the q-axis current value Iqr may be collectively referred to as the d- and q-axis current values ​​Idr and Iqr.

[0041] The current control unit 63 receives the difference between the d-axis and q-axis current command values ​​Id* and Iq* and the d-axis and q-axis current values ​​Idr and Iqr. More specifically, the current control unit 63 receives the 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 input d-axis current deviation to zero. The current control unit 63 also receives the 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 input q-axis current deviation to zero. The feedback control is, for example, proportional-plus-integral control.

[0042] The d- and q-axis voltage command values ​​Vd* and Vq* and the detected electrical angle θr are input to the UVW converter 64. Based on the input d- and q-axis voltage command values ​​Vd* and Vq* and the electrical angle θr, the UVW converter 64 calculates a U-phase voltage command value Vu*, a V-phase voltage command value Vv*, and a W-phase voltage command value Vw*. Hereinafter, these may be collectively referred to as the respective phase voltage command values ​​Vu*, Vv*, and Vw*.

[0043] The phase voltage command values ​​Vu*, Vv*, and Vw* are command values ​​for the phase voltages Vu, Vv, and Vw. In this embodiment, the signs of the phase voltages Vu, Vv, and Vw are positive when the potentials of the first terminals 51Ua, 51Va, and 51Wa of the windings 51U, 51V, and 51W are higher than the potentials of the second terminals 51Ub, 51Vb, and 51Wb of the windings 51U, 51V, and 51W, respectively, and negative when the potentials of the second terminals 51Ub, 51Vb, and 51Wb of the windings 51U, 51V, and 51W are higher than the potentials of the first terminals 51Ua, 51Va, and 51Wa of the windings 51U, 51V, and 51W.

[0044] The modulator 65 receives the phase voltage command values ​​Vu*, Vv*, and Vw* and the system voltage Vsys. The modulator 65 generates operation signals for the switches SUHa to SWLa of the first inverter 20 and operation signals for the switches SUHb to SWLb of the second inverter 30 based on the phase voltage command values ​​Vu*, Vv*, and Vw*, the system voltage Vsys, and a carrier signal. The carrier signal is, for example, a triangular wave signal. Based on the generated operation signals, switching control of the first inverter 20 and the second inverter 30 is performed. Note that phase correction may be performed by phase correctors 66a and 66b before the operation signals (switching signals) are input to the first inverter 20 and the second inverter 30. The phase correctors 66a and 66b will be described later.

[0045] Next, phase control will be described. This phase control is performed when overmodulation control or square wave control is performed. Square wave control is mainly used for the purpose of increasing the output power of the rotating electric machine 40 and reducing losses under operating conditions where the modulation rate is equal to or higher than a threshold value and the output voltage of each inverter 20, 30 is high, such as in high rotation ranges and high output ranges. On the other hand, overmodulation control is performed in medium rotation ranges and medium output ranges, etc., where the modulation rate is equal to or higher than a threshold value.

[0046] 3 is a functional block diagram for explaining various functions for realizing phase control. As shown in FIG. 3, the control device 60 includes, as functions for executing phase control, a current command generating unit 71, a dq conversion unit 72, a torque estimating unit 73, an amplitude control unit 74, a phase control unit 75, a modulation unit 76, and the like.

[0047] The current command generator 71 receives the torque command value Trq* and the electrical angular velocity ω obtained by time-differentiating the electrical angle θr as input, and calculates a d-axis current command value Id*. The current command generator 71 may be configured in the same manner as the current command generator 61. The dq transformer 72, like the dq transformer 62, calculates a d-axis current value Idr and a q-axis current value Iqr based on the respective phase currents Iur, Ivr, Iwr and the electrical angle θr.

[0048] The torque estimation unit 73 calculates the torque estimation value Te based on the d-axis current value Idr and the q-axis current value Iqr converted by the dq conversion unit 72. The torque estimation value Te is calculated based on, for example, map information or mathematical formula information that associates the d-axis current value Idr, the q-axis current value Iqr, and the torque estimation value Te.

[0049] The amplitude control unit 74 receives the deviation between the d-axis current command value Id* and the d-axis current value Idr, and, based on the deviation, calculates a voltage amplitude command Va, which is a command value for the amplitude of the output voltage vector of each inverter 20, 30. The voltage amplitude command Va is defined as the square root of the sum of the square of the d-axis voltage, which is the d-axis component of the output voltage vector in the dq coordinate system, and the square of the q-axis voltage, which is the q-axis component.

[0050] The phase control unit 75 receives the deviation between the torque command value Trq* and the torque estimate value Te, and, based on the deviation, calculates a voltage phase command Vθ that is a command value for the phase of the output voltage vector of each of the inverters 20, 30. For example, the phase control unit 75 calculates the voltage phase command Vθ using a PI feedback method based on the deviation of the torque estimate value Te from the torque command value Trq*.

[0051] The modulator 76 generates operation signals for the switches SUHa to SWLa of the first inverter 20 and operation signals for the switches SUHb to SWLb of the second inverter 30 based on the voltage amplitude command Va, the voltage phase command Vθ, and the system voltage Vsys. For example, the modulator 76 calculates phase voltage command values ​​Vu*, Vv*, and Vw* based on the voltage amplitude command Va, the voltage phase command Vθ, and the system voltage Vsys, and generates the operation signals by PWM control based on a magnitude comparison between a signal obtained by normalizing the calculated phase voltage command values ​​Vu*, Vv*, and Vw* with the system voltage Vsys and a carrier signal such as a triangular wave signal. Alternatively, for example, the modulator 76 may refer to pulse pattern information, which is map information, and generate the operation signals based on the voltage amplitude command Va, the voltage phase command Vθ, and the system voltage Vsys. Note that the phases may be corrected by the phase correctors 77a and 77b before the operation signals are input to the first inverter 20 and the second inverter 30. The phase correctors 77a and 77b will be described later.

[0052] However, phase control may not be able to effectively respond to a load dump. This will be explained in detail below. First, the occurrence of a load dump and general control when a load dump occurs will be explained. When an abnormality is detected in the control system 100 or an electrical load (not shown) supplied with power from the control system, the power switch 14 is turned off (opened). At this time, if regenerative power generation is being performed by the rotating electric machine 40 (especially at maximum power generation), power from the rotating electric machine 40 will no longer be charged to the battery 10, and a high voltage will be generated (a load dump will occur). This high voltage will be charged to the capacitor 15, causing the system voltage Vsys between the positive bus 11 and the negative bus 12 to rise. If the system voltage Vsys continues to rise and becomes an overvoltage, elements such as the capacitor 15 will be destroyed. To deal with this, for example, when the system voltage Vsys reaches the upper limit voltage OVH, the inverters 20 and 30 are shut down and the switches SUHa to SWLa and SUHb to SWLb are all turned off.

[0053] This does not pose much of a problem when current control is being performed, but can pose a problem when phase control is being performed. Hereinafter, how the phase current and phase voltage change during each control will be described with reference to FIGS. 4 and 5 . FIG. 4 shows an example (comparison example) during current control, and FIG. 5 shows an example (comparison example) during phase control. The upper sections of FIGS. 4 and 5 show the system voltage Vsys, the middle sections show the phase currents Iu, Iv, and Iw, and the lower sections show the U-phase current Iu and U-phase voltage Vu. The V-phase and W-phase are not specifically shown, but are similar to the U-phase.

[0054] As shown in FIG. 4 , when the power switch 14 is turned off based on the detection of an abnormality (time T1), a load dump occurs and the system voltage Vsys rises. However, even if the system voltage Vsys rises, the current control controls the d- and q-axis currents Id and Iq to manipulate the phase and amplitude of each phase voltage (e.g., the U-phase voltage Vu). Therefore, overcurrents can be prevented from flowing through the rotating electric machine 40 until the system voltage Vsys reaches the upper limit voltage OVH. Even if the system voltage Vsys reaches the upper limit voltage OVH, the inverters 20 and 30 are shut down, and the phase currents Iu, Iv, and Iw flowing through the phase windings 51U, 51V, and 51W of the rotating electric machine 40 flow into the capacitor 15, the system voltage Vsys does not rise significantly because no overcurrents are flowing. As a result, damage to various elements can be prevented.

[0055] On the other hand, when phase control is being performed, as shown in FIG. 5 , when the power switch 14 is turned off based on the detection of an abnormality (time T1), a load dump occurs, and the system voltage Vsys rises. In this case, phase control controls only the phase of each phase voltage (e.g., the U-phase voltage Vu), not its amplitude. In other words, torque is controlled by controlling only the phase, and the d-axis and q-axis currents Id and Iq are not directly controlled. Therefore, the phase currents Iu, Iv, and Iw may increase before the system voltage Vsys reaches the upper limit voltage OVH. As shown in FIG. 5 , the increase in the phase currents Iu, Iv, and Iw may result in overcurrents, which may destroy elements. Even when the system voltage Vsys reaches the upper limit voltage OVH and is shut down (time T2), the overcurrents Iu, Iv, and Iw flow into the capacitor 15. As a result, the system voltage Vsys may continue to increase after shutdown, reaching an overvoltage Vh, potentially destroying elements.

[0056] Therefore, in this embodiment, when a load dump occurs, the phase difference between the phase of each phase voltage applied by the first inverter 20 and the phase of each phase voltage applied by the second inverter 30 is increased to suppress the phase currents Iu, Iv, and Iw. This will be explained in detail below.

[0057] First, the case where phase control is performed will be described. As shown in Fig. 3, in addition to the functions described above, the control device 60 includes an abnormality detection unit 78, a phase operation unit 79, and phase correction units 77a and 77b.

[0058] The abnormality detection unit 78 receives the system voltage Vsys and calculates the rate of change of the system voltage Vsys. The rate of change of the system voltage Vsys is, for example, the rate of increase or decrease per unit time. It may also be the time derivative of the system voltage Vsys. If the abnormality detection unit 78 determines that the system voltage Vsys is increasing at a rate of increase equal to or greater than a predetermined rate of increase, it detects that an abnormality has occurred and notifies the phase operation unit 79 of this fact.

[0059] When an abnormality is detected, the phase manipulation unit 79 determines to increase the phase difference Δθ between the phase θ1 of the phase voltage applied by the first inverter 20 and the phase θ2 of the phase voltage applied by the second inverter 30. Then, the phase manipulation unit 79 sets the phase difference Δθ according to the magnitude of the system voltage Vsys. For example, the phase difference Δθ is set to be larger as the system voltage Vsys increases. Note that the phase difference Δθ may be set to any value greater than 0 degrees and equal to or less than the maximum value. The maximum value of the phase difference Δθ is 180 degrees.

[0060] Then, the phase manipulation unit 79 calculates a phase correction value θ1a for the phase θ1 of each phase voltage applied by the first inverter 20 and a phase correction value θ2a for the phase θ2 of each phase voltage applied by the second inverter 30 so as to achieve the set phase difference Δθ. Note that, as long as the set phase difference Δθ is achieved, only the phase θ1 may be advanced (or delayed), only the phase θ2 may be advanced (or delayed), or one of the phases θ1 and θ2 may be advanced and the other delayed.

[0061] The phase corrector 77a of the first inverter 20 receives a phase correction value θ1a and, based on the phase correction value θ1a, shifts (corrects) the phases of the operation signals of the switches SUHa to SWLa so that the phase θ1 of each phase voltage applied by the first inverter 20 shifts by the phase correction value θ1a. Similarly, the phase corrector 77b of the second inverter 30 receives a phase correction value θ2a and, based on the phase correction value θ2a, shifts (corrects) the phases of the operation signals of the switches SUHb to SWLb so that the phase θ2 of each phase voltage applied by the second inverter 30 shifts by the phase correction value θ2a. Each of the inverters 20, 30 performs switching control based on the phase-corrected operation signals received from the phase correctors 77a, 77b.

[0062] Next, the case where current control is performed will be described. As shown in Fig. 2, in addition to the functions described above, the control device 60 includes an abnormality detection unit 67, a phase operation unit 68, and phase correction units 66a and 66b.

[0063] The abnormality detection unit 67 receives the system voltage Vsys and detects an abnormality, similar to the abnormality detection unit 78. When an abnormality is detected, the phase manipulation unit 68 calculates the phase correction value θ1a and the phase correction value θ2a, similar to the phase manipulation unit 79.

[0064] The phase corrector 66a of the first inverter 20 receives the phase correction value θ1a and, based on the phase correction value θ1a, shifts the phase of the operation signal of each of the switches SUHa to SWLa so that the phase θ1 of each phase voltage applied by the first inverter 20 shifts by the phase correction value θ1a. The phase corrector 66b of the second inverter 30 receives the phase correction value θ2a and, based on the phase correction value θ2a, shifts the phase of the operation signal of each of the switches SUHb to SWLb so that the phase θ2 of each phase voltage applied by the second inverter 30 shifts by the phase correction value θ1a. Each of the inverters 20, 30 performs switching control based on the phase-corrected operation signals received from the phase correctors 66a, 66b.

[0065] Next, a flowchart of the phase correction process will be described with reference to FIG. 6. The phase correction process is executed at predetermined intervals during phase control and current control. The phase correction process is realized by the arithmetic processing unit 60a of the control device 60 executing a control program stored in the storage unit 60b. The phase correction process realizes a method for controlling a rotating electric machine.

[0066] The control device 60 inputs the system voltage Vsys and calculates the rate of change of the system voltage Vsys (step S101). Then, the control device 60 determines whether the calculated rate of change is equal to or greater than a predetermined increase rate (step S102). If the result of this determination is negative, the phase correction process ends. Note that steps S101 and S102 correspond to the abnormality detection process performed by the abnormality detection units 67 and 78.

[0067] On the other hand, if the determination result in step S102 is positive, the control device 60 sets the phase difference Δθ so as to increase the phase difference Δθ (step S103).Then, the control device 60 calculates a phase correction value θ1a for the phase θ1 of each phase voltage applied by the first inverter 20 and a phase correction value θ2a for the phase θ2 of each phase voltage applied by the second inverter 30 so as to achieve the set phase difference Δθ (step S104).

[0068] The control device 60 shifts the phases of the operation signals of the switches SUHa-SWLa and SUHb-SWLb based on the calculated phase correction values ​​θ1a and θ2a (step S105). Then, the phase correction process ends. Note that steps S103 and S104 correspond to the phase manipulation process performed by the phase manipulation units 68 and 79.

[0069] The operation when the above phase correction is performed will be described with reference to Figs. 7 to 9. Fig. 7 illustrates the operation when PWM control (current control) is performed. Fig. 8 illustrates the operation when overmodulation control (phase control). Fig. 9 illustrates the operation when square wave control (phase control).

[0070] The upper rows of FIGS. 7 to 9(a) show the U-phase voltage (hereinafter referred to as INV1_U) applied from the first inverter 20 and the U-phase voltage (hereinafter referred to as INV2_U) applied from the second inverter 30 under normal conditions. The lower rows of FIGS. 7 to 9(a) show the applied voltage (hereinafter referred to as applied voltage_U) applied to the U-phase winding 51U under normal conditions. The upper rows of FIGS. 7 to 9(b) show INV1_U and INV2_U under abnormal conditions (when the system voltage Vsys rises). The lower rows of FIGS. 7 to 9(b) show the applied voltage_U under abnormal conditions (when the system voltage Vsys rises). While FIGS. 7 to 9 illustrate the U-phase, the same applies to the V-phase and W-phase.

[0071] 7(a) and 7(b), when PWM control is performed and an abnormality is detected, the phase difference Δθ increases, causing a difference in the timing at which the switches are turned on in the first inverter 20 and the second inverter 30, reducing the applied voltage _U. As a result, the U-phase current also decreases.

[0072] 8(a) and 8(b), when overmodulation control is performed and an abnormality is detected, the phase difference Δθ increases, causing a difference in the timing at which the switches of the first inverter 20 and the second inverter 30 are turned on, and the applied voltage _U decreases. As a result, the U-phase current also decreases.

[0073] 9(a) and 9(b), when square wave control is performed and an abnormality is detected, the phase difference Δθ increases, causing a difference in the timing at which the switches are turned on in the first inverter 20 and the second inverter 30, thereby reducing the applied voltage _U. As a result, the U-phase current also decreases.

[0074] According to the above embodiment, the following effects are achieved.

[0075] When an abnormality in the system voltage Vsys is detected, the phase manipulation units 68, 79 change the phase difference Δθ between the phase θ1 of the output phase voltage of each phase applied by the first inverter 20 and the phase θ2 of the output phase voltage of each phase applied by the second inverter 30 so as to increase it. This makes it possible to suppress the occurrence of an overcurrent even if a load dump occurs, and also to prevent the system voltage Vsys (the voltage between the terminals of the capacitor 15) from becoming an overvoltage after the inverters 20, 30 are shut down. This makes it possible to suppress element damage.

[0076] The abnormality detection units 67 and 78 detect an abnormality when the rate of change of the system voltage Vsys is equal to or greater than a predetermined rate of increase, thereby enabling the abnormality to be detected quickly before the system voltage Vsys reaches the upper limit voltage OVH.

[0077] The phase operation units 68, 79 increase the phase difference Δθ as the system voltage Vsys increases. The greater the phase difference Δθ, the more the magnitude of the voltage applied to each phase winding 51U, 51V, 51W can be reduced, and therefore, even if the system voltage Vsys increases, overcurrent can be effectively reduced.

[0078] In phase control that does not directly control the d- and q-axis currents Id and Iq, if an abnormality in the system voltage Vsys is detected, the phase operation unit 68 increases the phase difference Δθ to suppress the applied voltage. Thus, even in phase control that does not directly control the d- and q-axis currents Id and Iq, even if a load dump occurs, it is possible to suppress overvoltage and prevent element damage.

[0079] In the current control, when an abnormality in the system voltage Vsys is detected, the phase manipulation unit 79 increases the phase difference Δθ to suppress the applied voltage, which allows the applied voltage to be suppressed more quickly and reliably than when the phase difference Δθ is not increased.

[0080] (Modifications) Hereinafter, modifications in which the configuration of the above embodiment is partially changed will be described.

[0081] In the above embodiment, the phase difference Δθ may be gradually increased. In this case, the speed at which the phase difference Δθ is increased may be increased as the system voltage Vsys increases.

[0082] In the above embodiment, even if an abnormality occurs during current control, the phase difference Δθ does not need to be increased because overcurrent and overvoltage can be suppressed by current control alone.

[0083] In the above embodiment, the phase control and the current control may be different between the first inverter 20 and the second inverter 30. For example, when the modulation factor of the first inverter 20 is equal to or greater than a threshold value and the modulation factor of the second inverter 30 is less than the threshold value, phase control (overmodulation control or square wave control) may be performed on the first inverter 20, and current control (PWM control) may be performed on the second inverter 30. Similarly, when the modulation factor of the first inverter 20 is less than the threshold value and the modulation factor of the second inverter 30 is equal to or greater than the threshold value, current control (PWM control) may be performed on the first inverter 20, and phase control (overmodulation control or square wave control) may be performed on the second inverter 30.

[0084] Even when the inverters 20, 30 are controlled differently, if an abnormality in the system voltage Vsys is detected, a phase difference correction may be performed to increase the phase difference Δθ.

[0085] FIG. 10 shows an example in which PWM control is performed in the first inverter 20 and overmodulation control is performed in the second inverter 30. The upper part of FIG. 10(a) shows INV1_U and INV2_U under normal conditions, and the lower part of FIG. 10(a) shows the applied voltage _U under normal conditions. The upper part of FIG. 10(b) shows INV1_U and INV2_U under abnormal conditions, and the lower part of FIG. 10(b) shows the applied voltage _U under abnormal conditions. Comparing FIG. 10(a) and FIG. 10(b) reveals that even when PWM control and overmodulation control are performed, the applied voltage _U decreases as the phase difference Δθ increases. As a result, the U-phase current also decreases.

[0086] FIG. 11 shows an example in which PWM control is performed in the first inverter 20 and square wave control is performed in the second inverter 30. The upper part of FIG. 11(a) shows INV1_U and INV2_U under normal conditions, and the lower part of FIG. 11(a) shows the applied voltage _U under normal conditions. The upper part of FIG. 11(b) shows INV1_U and INV2_U under abnormal conditions, and the lower part of FIG. 11(b) shows the applied voltage _U under abnormal conditions. Comparing FIG. 11(a) and FIG. 11(b) reveals that even when PWM control and square wave control are performed, the applied voltage _U decreases as the phase difference Δθ increases. As a result, the U-phase current also decreases.

[0087] FIG. 12 shows an example in which overmodulation control is performed in the first inverter 20 and square wave control is performed in the second inverter 30. The upper part of FIG. 12(a) shows INV1_U and INV2_U under normal conditions, and the lower part of FIG. 12(a) shows applied voltage_U under normal conditions. The upper part of FIG. 12(b) shows INV1_U and INV2_U under abnormal conditions, and the lower part of FIG. 12(b) shows applied voltage_U under abnormal conditions. Comparing FIG. 12(a) and FIG. 12(b) reveals that even when PWM control and square wave control are performed, the applied voltage_U decreases as the phase difference Δθ increases. As a result, the U-phase current also decreases.

[0088] In the above embodiment, the modulation factor is assumed to be a value obtained by dividing the amplitude of each phase voltage command value Vu*, Vv*, Vw* by "system voltage Vsys / 2." However, the modulation factor may be a value obtained by dividing the amplitude of the fundamental wave component of the voltage applied to each phase (output phase voltage) by each inverter 20, 30 by "voltage of battery 10 (or system voltage Vsys) / 2." Note that the modulation factor may be calculated for each inverter 20, 30.

[0089] In the above embodiment, the Y drive state and the H drive state can be selected, but it may be configured so that only the H drive state can be implemented. In this case, the changeover switch 13 is not necessary.

[0090] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0091] The following describes characteristic configurations extracted from the above-described embodiments.

[0092] [Configuration 1] A rotating electric machine (40) having a multi-phase armature winding (51U, 51V, 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, and a series connection of the first upper arm switches and the first lower arm switches 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 device (60) for a rotating electric machine applied to a system including the above-mentioned inverter, the control device comprising: an abnormality detection unit (67, 78) that detects a voltage abnormality in a system voltage (Vsys) between the positive bus bar and the negative bus bar; and a phase operation unit (68, 79) that, when a voltage abnormality is detected by the abnormality detection unit, changes a phase difference (Δθ) between a phase (θ1) of each phase voltage applied by the first inverter and a phase (θ2) of each phase voltage applied by the second inverter so as to increase the phase difference (Δθ).

[0093] [Configuration 2] The control device for a rotating electric machine according to Configuration 1, wherein the abnormality detection unit detects an abnormality when a voltage increase rate of the system voltage is equal to or greater than a predetermined increase rate.

[0094] [Configuration 3] The control device for a rotating electric machine according to Configuration 1 or 2, wherein the phase operation unit increases the phase difference or increases the speed at which the phase difference is increased as the system voltage increases or as an increase rate of the system voltage increases.

[0095] [Configuration 4] A control device for a rotating electric machine according to any one of Configurations 1 to 3, comprising: a torque estimation unit (73) that estimates a torque estimation value (Te) from a phase current detection value of the armature winding of each phase; and a phase control unit (75) that performs phase control that controls the phase of an applied voltage to the armature winding based on a deviation between a torque command value (Trq*) and the torque estimation value, wherein the phase operation unit increases the phase difference when an abnormality is detected by the abnormality detection unit during phase control by the phase control unit.

[0096] [Configuration 5] A control device for a rotating electric machine according to any one of configurations 1 to 4, comprising: a current command generation unit (61) that generates a current command value from a torque command value; and a current control unit (63) that performs current control that controls the amplitude and phase of a voltage applied to the armature winding based on a deviation between a detected value of a phase current flowing through the armature winding and the current command value, wherein the phase operation unit increases the phase difference even when an abnormality is detected by the abnormality detection unit during current control by the current control unit.

[0097] [Configuration 6] The control device for a rotating electric machine according to Configuration 5, wherein the phase operation unit increases the phase difference when a voltage abnormality is detected in a case where at least one of the first inverter and the second inverter is phase-controlled by the phase control unit and the other is current-controlled by the current control unit.

[0098] [Configuration 7] A rotating electric machine (40) having a multi-phase armature winding (51U, 51V, 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, and a series connection of the first upper arm switches and the first lower arm switches 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 program for a rotating electric machine executed by a control device (60) for a rotating electric machine applied to a system including the above-mentioned inverter, the control program causing the rotating electric machine to execute an abnormality detection process that detects a voltage abnormality in a system voltage (Vsys) between the positive bus bar and the negative bus bar, and a phase operation process that, when a voltage abnormality is detected in the abnormality detection process, changes the phase difference (Δθ) between the phase (θ1) of each phase voltage applied by the first inverter and the phase (θ2) of each phase voltage applied by the second inverter so as to increase the phase difference (Δθ).

[0099] [Configuration 8] A rotating electric machine (40) having a multi-phase armature winding (51U, 51V, 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, and a series connection of the first upper arm switches and the first lower arm switches 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 implemented by a control device (60) for a rotating electric machine applied to a system including the above-mentioned inverter, the control method including: an abnormality detection process for detecting a voltage abnormality in a system voltage (Vsys) between the positive busbar and the negative busbar; and a phase operation process for changing a phase difference (Δθ) between a phase (θ1) of each phase voltage applied by the first inverter and a phase (θ2) of each phase voltage applied by the second inverter so as to increase the phase difference (Δθ) when a voltage abnormality is detected in the abnormality detection process.

[0100] 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, 51V, 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) corresponding to the number of phases, 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, and a negative bus bar (12) electrically connecting the low-potential side terminals of the first lower arm switches and the low-potential side terminals of the second lower arm switches in each phase. In a control device (60) for a rotating electrical machine applied to a system (100), an abnormality detection unit (67, 78) for detecting a voltage abnormality of a system voltage (Vsys) between the positive bus bar and the negative bus bar, and a phase operation unit (68, 79) for changing so as to expand a phase difference (Δθ) between a phase (θ1) of each phase voltage applied by the first inverter and a phase (θ2) of each phase voltage applied by the second inverter when a voltage abnormality is detected by the abnormality detection unit. A control device for a rotating electrical machine.

2. The control device for a rotating electrical machine according to claim 1, wherein the abnormality detection unit detects an abnormality when a voltage increase rate of the system voltage is equal to or higher than a predetermined increase rate.

3. The control device for a rotating electrical machine according to claim 2, wherein the phase operation unit increases the phase difference, or increases the speed at which the phase difference is expanded, as the system voltage is higher or the voltage increase rate of the system voltage is higher.

4. A torque estimation unit (73) for estimating a torque estimation value (Te) from a phase current detection value of the armature winding of each phase, and a phase control unit (75) for performing phase control to control a phase of an applied voltage applied to the armature winding based on a deviation between a torque command value (Trq*) and the torque estimation value. The phase operation unit expands the phase difference when an abnormality is detected by the abnormality detection unit during the phase control by the phase control unit. The control device for a rotating electrical machine according to claim 3.

5. A current command generation unit (61) that generates a current command value from a torque command value, and a current control unit (63) that performs current control to control the amplitude and phase of an applied voltage applied to the armature winding based on a deviation between a detected value of a phase current flowing through the armature winding and the current command value. The phase operation unit expands the phase difference even when an abnormality is detected by the abnormality detection unit during the current control by the current control unit. The control device for a rotating electrical machine according to claim 4.

6. The phase operation unit expands the phase difference when a voltage abnormality is detected in a case where at least one of the first inverter and the second inverter is phase-controlled by the phase control unit and the other is current-controlled by the current control unit. The control device for a rotating electrical machine according to claim 5.

7. A control program for a rotating electrical machine implemented by a control device (60) for a rotating electrical machine applied to a system including a rotating electrical machine (40) having a plurality of phases of armature windings (51U, 51V, 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) corresponding to the number of phases, and the series-connected body 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), a positive electrode side bus bar (11) that electrically connects the high potential side terminals of the first upper arm switches in each phase and the high potential side terminals of the second upper arm switches, and a negative electrode side bus bar (12) that electrically connects the low potential side terminals of the first lower arm switches in each phase and the low potential side terminals of the second lower arm switches. The control program includes an abnormality detection process for detecting a voltage abnormality of a system voltage (Vsys) between the positive electrode side bus bar and the negative electrode side bus bar, and a phase operation process for changing the phase difference (Δθ) between the phase (θ1) of each phase voltage applied by the first inverter and the phase (θ2) of each phase voltage applied by the second inverter so as to expand the phase difference when a voltage abnormality is detected in the abnormality detection process.

8. A rotating electrical machine (40) having a multi-phase armature winding (51U, 51V, 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, and 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 control method for a rotating electrical machine implemented by a control device (60) of the rotating electrical machine applied to a system comprising: an abnormality detection process for detecting a voltage abnormality of a system voltage (Vsys) between the positive bus bar and the negative bus bar; and a phase operation process for changing the phase difference (Δθ) between the phase (θ1) of each phase voltage applied by the first inverter and the phase (θ2) of each phase voltage applied by the second inverter so as to expand the phase difference when a voltage abnormality is detected in the abnormality detection process.

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