Rotating electric machine control device

Abstract

In the first control state, which one of the first fault pattern (FP1) and the second fault pattern (FP2) is discriminated, in the second control state, which one of the first lower stage side fault pattern (LF1) and the second lower stage side fault pattern (LF2) is discriminated, which one of the upper stage side arm of the first inverter (11), the lower stage side arm of the first inverter (12), the upper stage side arm of the second inverter (12), and the lower stage side arm of the second inverter (12) is the fault side arm is discriminated based on the discrimination result in the first control state and the discrimination result in the second control state.

Description

TECHNICAL FIELD

[0001] The present application relates to a rotating electric machine control device that drives and controls a rotating electric machine having an open-circuit winding via two inverters. BACKGROUND

[0002] A control device is known that drives and controls a rotating electric machine by switching controlling inverters each having one at both ends of three-phase open-circuit windings of a three-phase alternating-current type rotating electric machine. A technology is disclosed in Japanese Patent Application Publication No. 2014-192950 that enables the rotating electric machine to continue to be driven even in the event of a failure of a switching element of an inverter that drives such three-phase open-circuit windings. Thus, in the event of a failure of a switching element of either of the two inverters, all of the upper-stage switching elements or all of the lower-stage switching elements of the inverter including the failed switching element are set to an on state, and all of the switching elements of the other inverter are set to an off state, the inverter is neutralized, and the rotating electric machine is driven by the other inverter that has not failed.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-192950 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] Here, the detection of the failed switching element can be performed by providing a sensor or the like to each switching element. However, providing a sensor for failure detection to all of the switching elements incurs a cost. Therefore, it is also considered to detect a failure using existing parameters for control. That is, if one switching element fails, the respective phase currents or voltages of the alternating current or the like change, and therefore, the presence or absence of a failure can also be detected based on the respective phase currents or voltages or the like. However, since two inverters are connected to the open-circuit windings, in the event of a failure in either inverter, the current flowing through the open-circuit windings or the phase-to-phase voltage is affected, and thus, it is difficult to determine the switching element that has simply failed.

[0008] In the above documents, no specific technology for determining the switching element that has failed is mentioned. In addition, among failures of switching elements, there are a short-circuit failure in which the switching element always becomes an on state and an open-circuit failure in which the switching element always becomes an off state, and the phenomena caused by each failure are different, and the determination methods are also different. However, no specific technology for distinguishing and determining the above is mentioned in the above documents.

[0009] In view of the above, it is desirable to provide a technology that determines a failure site in a case where one of switching elements of two inverters respectively provided at both ends of an open winding has failed.

[0010] Technical Solution to Problem

[0011] As one mode in view of the above, a rotating electric machine control device of a first mode drives and controls a rotating electric machine having a plurality of phases of open windings independent of each other via a first inverter and a second inverter, the first inverter is connected to one end side of the plurality of phases of open windings, converts electric power between direct current and alternating current of the plurality of phases, the second inverter is connected to the other end side of the plurality of phases of open windings, converts electric power between direct current and alternating current of the plurality of phases, in the first inverter and the second inverter, an arm of one phase of alternating current is configured by a series circuit of an upper side switching element and a lower side switching element, the first inverter and the second inverter are independently controllable, in a case where open circuit failure in which one of the switching elements of one of the first inverter and the second inverter always becomes an open circuit state has occurred, current cumulative values of the plurality of phases of alternating current are respectively accumulated and calculated, occurrence of the open circuit failure is detected based on the positive and negative of each of the current cumulative values, and a site where the open circuit failure has occurred is discriminated, when the first inverter and the second inverter are controlled by hybrid pulse width modulation control that controls in a manner in which a plurality of pulses different in output pattern in a first period of 1 / 2 of an electrical angle are output and a non-active state is continued in a second period of the remaining 1 / 2, in a case where occurrence of the open circuit failure is detected, which one of a first failure mode and a second failure mode is discriminated based on the positive and negative of each of the current cumulative values in a first control state, the first failure mode is a failure side arm in which one of an upper side arm of the first inverter and a lower side arm of the second inverter is the open circuit failure, the second failure mode is a failure side arm in which one of a lower side arm of the first inverter and an upper side arm of the second inverter is the open circuit failure, which one of a first lower side failure mode and a second lower side failure mode is discriminated based on each of the current cumulative values in a second control state different from the first control state, the first lower side failure mode is the lower side arm of the second inverter being the failure side arm, the second lower side failure mode is the lower side arm of the first inverter being the failure side arm, and which one of the upper side arm of the first inverter, the lower side arm of the first inverter, the upper side arm of the second inverter, and the lower side arm of the second inverter is the failure side arm is discriminated based on a result of the discrimination in the first control state and a result of the discrimination in the second control state.

[0012] According to the experiments and simulations by the inventors, it was confirmed that in the case where open-circuit failure of a switching element occurs in one of the two inverters, the three-phase current waveform becomes an asymmetric and distorted waveform. For example, the waveform of the AC current of a certain phase greatly deflects to the positive side, and the waveform of the AC current of a certain phase greatly deflects to the negative side. Moreover, if the AC current is accumulated over a prescribed time, the tendency of the deflection becomes more pronounced. The direction of the deflection differs depending on the position of the switching element of the open-circuit failure. Therefore, if the positive and negative of the current accumulation value is based, it is possible to determine that open-circuit failure has occurred and in which upper and lower side arms of which inverter the open-circuit failure has occurred. In addition, according to the experiments and simulations by the inventors, in the second control state, in the case where open-circuit failure occurs in the upper side arm, detection of the open-circuit failure itself is difficult, but in the case where open-circuit failure occurs in the lower side arm, it is possible to detect the open-circuit failure and determine which inverter has failed. In the first control state, it is possible to detect the open-circuit failure regardless of which of the upper and lower side arms has failed. However, in the first control state, it is possible to determine whether the failure mode is the first failure mode or the second failure mode, but it is not possible to determine which inverter. According to the present structure, in the case where open-circuit failure occurs in the lower side arm, it is possible to determine the failure side arm at least from the determination result in the second control state. In addition, in the case where open-circuit failure occurs in the upper side arm and in the case where open-circuit failure occurs in the lower side arm, it is possible to determine the failure side arm from the determination result in the first control state and the determination result in the second control state. In this way, according to the present structure, it is possible to determine the failure site in the case where open-circuit failure has occurred in one of the switching elements of the two inverters respectively possessed by the two ends of the open-circuit winding.

[0013] Further, as one mode, a rotating electric machine control device that drives and controls a rotating electric machine having a plurality of open-circuit windings independent of each other via a first inverter connected to one end side of the plurality of open-circuit windings and converting electric power between direct current and multi-phase alternating current and a second inverter connected to the other end side of the plurality of open-circuit windings and converting electric power between direct current and multi-phase alternating current, in which an arm of one phase of alternating current is configured by a series circuit of an upper side switching element and a lower side switching element in each of the first inverter and the second inverter, and the first inverter and the second inverter are independently controlled, in the case where an open-circuit failure in which one switching element always becomes an open-circuit state occurs in one of the first inverter and the second inverter, current cumulative values of each phase are calculated by cumulating the multi-phase alternating currents, respectively, in the case where the occurrence of the open-circuit failure is detected based on the positive and negative of each of the current cumulative values, and the position where the open-circuit failure has occurred is discriminated, in the case where the occurrence of the open-circuit failure is detected, which of a first failure mode in which the open-circuit failure has occurred in one of an upper side arm of the first inverter and a lower side arm of the second inverter and a second failure mode in which the open-circuit failure has occurred in one of a lower side arm of the first inverter and an upper side arm of the second inverter is discriminated based on the positive and negative of each of the current cumulative values, thereafter, one of the first inverter and the second inverter is assumed to be a failure inverter in which the open-circuit failure has occurred and is assumed to be an assumed failure inverter, the switching elements of an assumed failure side arm in which the open-circuit failure is assumed to have occurred among the upper side arm and the lower side arm of the assumed failure inverter are set to an on state, and the switching elements of the other non-assumed failure side arm are set to an on state based on the discriminated failure mode, and active short-circuit control is performed, and switching control is performed on the inverter other than the assumed failure inverter, thereafter, in the case where the open-circuit failure is not detected based on the positive and negative of each of the current cumulative values, it is discriminated that the assumed failure inverter is the failure inverter and that the assumed failure side arm is the failure side arm, and in the case where the open-circuit failure is detected, it is discriminated that the inverter other than the assumed failure inverter is the failure inverter and that the failure side arm in the failure inverter is discriminated based on the failure mode.

[0014] According to the configuration, in a case where an open-circuit failure is detected, the assumed failure-side arm is switched and controlled as the assumed failure-side arm in such a manner that the inverter can be controlled even if the assumed failure-side arm has an open-circuit failure. In this state, if the open-circuit failure is not detected again, it is determined that the assumption is correct, and if the open-circuit failure is detected again, it is determined that the assumption is incorrect. Therefore, according to the configuration, the failure-side arm can be determined.

[0015] In addition, in view of the above, as one embodiment, a rotating electric machine control device drives and controls a rotating electric machine having a plurality of open-circuit windings independent of each other via a first inverter and a second inverter, the first inverter is connected to one end side of the plurality of open-circuit windings, converts electric power between direct current and multi-phase alternating current, the second inverter is connected to the other end side of the plurality of open-circuit windings, converts electric power between direct current and multi-phase alternating current, in the first inverter and the second inverter, an arm of one phase of alternating current is configured by a series circuit of an upper-stage side switching element and a lower-stage side switching element, the first inverter and the second inverter can be controlled independently of each other, in a case where a short-circuit failure of one switching element has occurred in one of the first inverter and the second inverter, the inverter in which the short-circuit failure has occurred is set as a failure inverter, a current cumulative value of each phase is calculated by cumulating and calculating an alternating current of each phase respectively, and which one of the upper-stage side arm and the lower-stage side arm of the failure inverter in which the short-circuit failure has occurred is determined based on a positive and negative of each current cumulative value.

[0016] According to experiments and simulations by the inventor, it is confirmed that in a case where a short-circuit failure of a switching element has occurred in one of the two inverters, a three-phase current waveform becomes an asymmetric and distorted waveform. For example, a waveform of an alternating current of one phase is largely deflected to the positive side, and a waveform of an alternating current of one phase is largely deflected to the negative side. Moreover, if the alternating current is cumulated for a predetermined time, the tendency of the deflection is more significantly exhibited. The direction of the deflection differs depending on the position of the switching element in which the short-circuit failure has occurred. Therefore, if the positive and negative of the current cumulative value are based on, which one of the upper-stage side arm and the lower-stage side arm of the failure inverter in which the short-circuit failure has occurred is determined. By determining the failure site, the two inverters can be controlled in a manner not affected by the failure site, and thus the drive of the rotating electric machine can be continued. In this way, according to the configuration, the failure site can be determined in a case where one of the switching elements of the two inverters respectively having both ends of the open-circuit winding has a short-circuit failure.

[0017] Other features and advantages of the rotating electric machine control device will be apparent from the following description of the embodiments with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 is a schematic block diagram of a rotating electric machine drive system.

[0019] Fig. 2 is a simple partial block diagram of a rotating electric machine control device.

[0020] Fig. 3 is a schematic voltage vector diagram of a rotating electric machine in a quadrature vector space

[0021] Fig. 4 is a diagram showing an example of a control region of a rotating electric machine.

[0022] Fig. 5 is a waveform diagram showing an example of voltage commands and switching control signals of hybrid continuous pulse width modulation control (half-cycle continuous pulse).

[0023] Fig. 6 is a waveform diagram showing an example of voltage commands and switching control signals of hybrid discontinuous pulse width modulation control (half-cycle discontinuous pulse).

[0024] Fig. 7 is a waveform diagram showing another example of voltage commands and switching control signals of hybrid continuous pulse width modulation control (half-cycle continuous pulse).

[0025] Fig. 8 is a waveform diagram showing another example of voltage commands and switching control signals of hybrid discontinuous pulse width modulation control (half-cycle discontinuous pulse).

[0026] Fig. 9 is a waveform diagram showing an example of voltage commands and switching control signals of continuous pulse width modulation control.

[0027] Fig. 10 is a waveform diagram showing an example of voltage commands and switching control signals of discontinuous pulse width modulation control.

[0028] Fig. 11 is a waveform diagram showing an example of three-phase AC waveforms in the case where an open-circuit fault has occurred during motoring (low speed).

[0029] Fig. 12 is a waveform diagram showing an example of three-phase AC waveforms in the case where an open-circuit fault has occurred during motoring (high speed).

[0030] Fig. 13 is a waveform diagram showing an example of three-phase AC waveforms in the case where an open-circuit fault has occurred during regeneration (low speed).

[0031] Fig. 14 is a waveform diagram showing an example of three-phase AC waveforms in the case where an open-circuit fault has occurred during regeneration (high speed).

[0032] Fig. 15 is an explanatory diagram of the principle of discriminating the open-circuit failure site.

[0033] Fig. 16 is a waveform chart showing an example of three-phase alternating current waveforms in the case where the first inverter has an open-circuit failure at the time of power running at an ultra-low rotational speed.

[0034] Fig. 17 is a waveform chart showing an example of three-phase alternating current waveforms in the case where the second inverter has an open-circuit failure at the time of power running at an ultra-low rotational speed.

[0035] Fig. 18 is a different chart showing the behavior of three-phase alternating current in the case where an open-circuit failure has occurred at the time of power running at an ultra-low rotational speed and in the case where an open-circuit failure has occurred at the time of power running at a rotational speed faster than the ultra-low rotational speed.

[0036] Fig. 19 is a chart showing an action point in a control region of a rotating electric machine.

[0037] Fig. 20 is a chart showing the relationship between torque command and rotational speed of a rotating electric machine at the time of discriminating a failure site.

[0038] Fig. 21 is a chart showing an example (exchange of pulses) of a regenerative disable action for eliminating distortion of three-phase current waveforms at the time of regeneration in a state where an open-circuit failure has occurred at the lower stage side.

[0039] Fig. 22 is a chart showing another example (exchange of pulses and reversal of definition of direction of alternating current) of a regenerative disable action for eliminating distortion of three-phase current waveforms at the time of regeneration in a state where an open-circuit failure has occurred at the lower stage side.

[0040] Fig. 23 is a chart showing elimination of distortion of three-phase current waveforms by switching control signals of Fig. 21 and Fig. 22

[0041] Fig. 24 is a flowchart showing an example of the outline steps of discriminating the site of occurrence of an open-circuit failure.

[0042] Fig. 25 is a chart showing an example of three-phase alternating current waveforms and cumulative currents capable of discriminating a failure site.

[0043] Fig. 26 is a chart showing an example of three-phase alternating current waveforms and cumulative currents capable of discriminating a failure site.

[0044] Fig. 27 ​is a drawing showing an example of three-phase AC waveforms and accumulated currents when an open-circuit fault occurs during power running at a low speed.

[0045] Fig. 28 is a drawing showing an example of accumulated currents before and after distortion elimination of an AC current.

[0046] Fig. 29 is a drawing showing an example of accumulated currents before and after distortion elimination of an AC current.

[0047] Fig. 30 is a drawing showing an example of accumulated currents when an open-circuit fault occurs during power running at an ultra-low speed, which makes it difficult to determine the fault site.

[0048] Fig. 31 is a drawing showing an example of accumulated currents when an open-circuit fault occurs during power running at an ultra-low speed, which makes it difficult to determine the fault site.

[0049] Fig. 32 is a flowchart showing an example of steps of determining the site of an open-circuit fault.

[0050] Fig. 33 is a flowchart showing an example of steps of first fault site determination processing.

[0051] Fig. 34 is a flowchart showing an example of steps of second fault site determination processing.

[0052] Fig. 35 is a flowchart showing an example of steps of third fault site determination processing.

[0053] Fig. 36 is a waveform chart showing an example of three-phase AC waveforms when an open-circuit fault occurs during power running at a low speed in a noise reduction priority mode.

[0054] Fig. 37 is a waveform chart showing an example of three-phase AC waveforms when an open-circuit fault occurs during power running at a high speed in a noise reduction priority mode.

[0055] Fig. 38 is a waveform chart showing an example of three-phase AC waveforms when an open-circuit fault occurs during regeneration at a low speed in a noise reduction priority mode.

[0056] Fig. 39 is a waveform chart showing an example of three-phase AC waveforms when an open-circuit fault occurs during regeneration at a high speed in a noise reduction priority mode.

[0057] Fig. 40is a flowchart showing an example of the step of identifying the occurrence site of an open-circuit fault in the noise reduction priority mode.

[0058] Fig. 41 is a flowchart showing another example of the step of identifying the occurrence site of an open-circuit fault in the noise reduction priority mode.

[0059] Fig. 42 is a graph showing the behavior of three-phase AC waveforms in the case where an open-circuit fault occurred during motoring and in the case where an open-circuit fault occurred during regeneration in the noise reduction priority mode.

[0060] Fig. 43 is a graph showing an example of a control region of a rotating electric machine.

[0061] Fig. 44 is a graph showing an example of the action points from detection of a short-circuit fault to driving of the rotating electric machine by fail-safe control.

[0062] Fig. 45 is a graph showing an example of the flow of current during shutdown control after detection of a short-circuit fault.

[0063] Fig. 46 is a graph showing an example of the flow of current during shutdown control after detection of a short-circuit fault in a 1-inverter system.

[0064] Fig. 47 is a graph showing an example of the transition of torque command and rotational speed after occurrence of a short-circuit fault, and a three-phase current waveform.

[0065] Fig. 48 is a graph showing another example of the transition of torque command after occurrence of a short-circuit fault.

[0066] Fig. 49 is a flowchart showing an example of the step of determining the position where a short-circuit fault occurred.

[0067] Fig. 50 is a graph showing an example of a cumulative current waveform.

[0068] Fig. 51 is a graph showing an example of a cumulative current waveform.

[0069] Fig. 52 is a graph showing an example of a cumulative current waveform.

[0070] Fig. 53 is a graph showing an example of a cumulative current waveform.

[0071] Fig. 54 is a graph showing an example of a control region of a rotating electric machine of a 1-inverter system.

[0072] Fig. 55 is a graph showing torque command and rotational speed after a short-circuit fault occurs in the 1-inverter system. DETAILED DESCRIPTION

[0073] Hereinafter, an embodiment of a rotating electric machine control device that drives and controls a rotating electric machine having mutually independent multi-phase open-circuit windings via two inverters will be described based on the drawings. Fig. 1 is a schematic block diagram of a rotating electric machine drive system including a rotating electric machine control device 1 (MG-CTRL). The rotating electric machine 80 is a component that becomes a driving force source of a wheel in a vehicle such as an electric automobile, a hybrid automobile, or the like. The rotating electric machine 80 is an open-circuit winding type rotating electric machine having mutually independent multi-phase (three phases in this embodiment) stator coils 8 (open-circuit windings). One inverter 10 that is independently controlled to convert electric power between direct current and multi-phase (three phases in this case) alternating current is connected to both ends of the stator coils 8, respectively. That is, a first inverter 11 (INV1) is connected to one end side of the stator coils 8, and a second inverter 12 (INV2) is connected to the other end side of the stator coils 8. Hereinafter, in a case where it is not necessary to distinguish the first inverter 11 and the second inverter 12, they will be simply referred to as inverters 10.

[0074] The inverter 10 is configured to have a plurality of switching elements 3. The first inverter 11 is configured to have a plurality of first switching elements 31, and the second inverter 12 is configured to have a plurality of second switching elements 32. In a case where it is not necessary to distinguish the first switching elements 31 and the second switching elements 32, they will be simply referred to as switching elements 3. The switching elements 3 use IGBTs (Insulated Gate Bipolar Transistors) or power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). In Fig. 1 In, a manner in which IGBTs are used as the switching elements 3 is exemplified. In this embodiment, the first inverter 11 and the second inverter 12 are inverters 10 of the same circuit structure using the same kind of switching elements 3.

[0075] Each alternating current one-phase arm 3A of the two inverters 10 is configured by a series circuit of an upper-stage side switching element 3H and a lower-stage side switching element 3L. In each switching element 3, a freewheeling diode 35 is connected in parallel in a positive direction from a negative electrode FG to a positive electrode P (a direction from the lower-stage side toward the upper-stage side). Further, in the multi-phase arm 3A, one side including the upper-stage side switching element 3H is referred to as an upper-stage side arm, and one side including the lower-stage side switching element 3L is referred to as a lower-stage side arm.

[0076] Furthermore, in this embodiment, the two inverters 10 are each connected to an independent DC power supply 6. That is, the first floating ground FG1, which serves as the negative terminal FG of the first inverter 11, and the second floating ground FG2, which serves as the negative terminal FG of the second inverter 12, are independent of each other. In addition, a DC link capacitor 4 (smoothing capacitor) is provided between the inverters 10 and the DC power supply 6 to smooth the DC voltage.

[0077] Specifically, the first inverter 11, consisting of a series circuit of a first upper-side switching element 31H and a first lower-side switching element 31L, has a first DC link capacitor 41 (first smoothing capacitor) connected to its DC side and is connected to a first DC power supply 61. Its AC side is connected to one end of the multi-phase stator coil 8, thus converting power between DC and multi-phase AC. The second inverter 12, consisting of a series circuit of a second upper-side switching element 32H and a second lower-side switching element 32L, has a second DC link capacitor 42 (second smoothing capacitor) connected to its DC side and is connected to a second DC power supply 62. Its AC side is connected to the other end of the multi-phase stator coil 8, thus converting power between DC and multi-phase AC.

[0078] In this embodiment, the first DC power supply 61 and the second DC power supply 62 are DC power supplies with the same rated voltage, etc., and the first DC link capacitor 41 and the second DC link capacitor 42 are also capacitors with the same rated capacitance, etc. The rated voltage of the DC power supply 6 is approximately 48 volts to 400 volts. The DC power supply 6 is composed of, for example, secondary batteries (batteries) such as nickel-metal hydride batteries and lithium-ion batteries, and energy storage components such as double-layer capacitors. The rotary motor 80 can function as both a motor and a generator. The rotary motor 80 converts the electricity from the DC power supply 6 into power (power operation) via the inverter 10. Alternatively, the rotary motor 80 converts the rotational driving force transmitted from wheels, etc., into electricity, and charges the DC power supply 6 via the inverter 10 (regeneration).

[0079] like Fig. 1 As shown, inverter 10 is controlled by rotating motor control device 1. Rotating motor control device 1 can control the first inverter 11 and the second inverter 12 independently (details of the control methods will be described later). Rotating motor control device 1 is constructed with logic circuits such as a microcomputer as its core component. For example, rotating motor control device 1 performs current feedback control using vector control based on the target torque (torque command) of rotating motor 80 provided by other control devices such as vehicle control devices (not shown), and controls rotating motor 80 via inverter 10.

[0080] The actual currents flowing in the stator coils 8 of the respective phases of the rotary electric machine 80 are detected by the current sensors 15, and the magnetic pole position of the rotor of the rotary electric machine 80 at each timing is detected by the rotary sensor 13 such as a resolver. The rotary electric machine control device 1 performs current feedback control using the detection results of the current sensors 15 and the rotary sensor 13. The rotary electric machine control device 1 is configured to have various functional sections for current feedback control, each of which is realized by cooperation of hardware and software (program) such as a microcomputer.

[0081] Fig. 2 The block diagram simply shows the functional sections of a part of the rotary electric machine control device 1. In the vector control method, the actual currents (U-phase current Iu, V-phase current Iv, W-phase current Iw) flowing through the rotary electric machine 80 are coordinate-converted into vector components (d-axis current Id, q-axis current Iq) of the d-axis and the q-axis which are the direction of the magnetic field (magnetic flux) generated by the permanent magnet provided to the rotor of the rotary electric machine 80 and the direction orthogonal to the d-axis (the direction which travels at an electrical angle of π / 2 with respect to the direction of the magnetic field), and feedback control is performed. The rotary electric machine control device 1 performs coordinate conversion by the three-phase / two-phase coordinate conversion section 55 based on the detection results (θ: magnetic pole position, electrical angle) of the rotary sensor 13.

[0082] The current feedback control section 5 (FB) performs feedback control of the rotary electric machine 80 based on the deviation between the current command (d-axis current command Id*, q-axis current command Iq*) based on the torque command of the rotary electric machine 80 and the actual current (d-axis current Id, q-axis current Iq) in the dq-axis orthogonal vector coordinate system, and calculates the voltage command (d-axis voltage command Vd*, q-axis voltage command Vq*). The rotary electric machine 80 is driven via the two inverters 10, the first inverter 11 and the second inverter 12. Therefore, the d-axis voltage command Vd* and the q-axis voltage command Vq* are respectively divided into the first d-axis voltage command Vd1* and the first q-axis voltage command Vq1* for the first inverter 11, and the second d-axis voltage command Vd2* and the second q-axis voltage command Vq2* for the second inverter 12 in the distribution section 53 (DIV).

[0083] As described above, the rotary electric machine control device 1 is capable of controlling the first inverter 11 and the second inverter 12 independently of each other, and has two voltage control sections 7 each of which has a three-phase voltage command calculation section 73 and a modulation section 74 (MOD). That is, the rotary electric machine control device 1 has a first voltage control section 71 which generates the switching control signals (Su1, Sv1, Sw1) for the U-phase, the V-phase, and the W-phase of the first inverter 11, and a second voltage control section 72 which generates the switching control signals (Su2, Sv2, Sw2) for the U-phase, the V-phase, and the W-phase of the second inverter 12. Details will be described later. Figs. 6-7As will be discussed later, the voltage command (Vu1) of the first inverter 11 ** Vv1 ** Vw1 ** The phase difference between the voltage commands (Vu2**, Vv2**, Vw2**) of the second inverter 12 and the voltage commands (Vu2**, Vv2**, Vw2**) is “π”. Therefore, the value obtained by subtracting “π” from the detection result (θ) of the rotation sensor 13 is input to the second voltage control unit 72.

[0084] Furthermore, as described later, the modulation method includes synchronous modulation that is synchronized with the rotation of the rotating motor 80 and asynchronous modulation that is independent of the rotation of the rotating motor 80. Generally, the generation module for the switch control signal based on synchronous modulation (in the case of software, the generation process) is different from the generation module for the switch control signal based on asynchronous modulation. The voltage control unit 7 described above generates the switch control signal based on a voltage command and a carrier wave that is asynchronous with the rotation of the rotating motor 80. However, in this embodiment, for the sake of simplicity, it is assumed that the voltage control unit 7 also generates a switch control signal based on synchronous modulation (for example, the switch control signal in the case of rectangular wave control described later).

[0085] Furthermore, as described above, each arm 3A of the inverter 10 is composed of a series circuit of an upper-side switching element 3H and a lower-side switching element 3L. Fig. 2 Although there is no difference, the switching control signals for each phase are output as both upper-level and lower-level switching control signals. For example, the first U-phase switching control signal Su1, which controls the switching of the U-phase of the first inverter 11, is output as two signals: the first U-phase upper-level switching control signal Su1+ with a "+" appended to the end and the first U-phase lower-level switching control signal Su1- with a "-" appended to the end. Furthermore, when the upper-level switching element 3H and the lower-level switching element 3L constituting each arm 3A are simultaneously turned on, that arm 3A becomes short-circuited. To prevent this, a dead time is provided so that both the upper-level and lower-level switching control signals of each arm 3A are inactive. This dead time is also provided in the voltage control unit 7.

[0086] like Fig. 1As shown, the control terminals of the respective switching elements 3 (gate terminals in the case of IGBTs or FETs) of the inverter 10 are connected to the rotating electric machine control device 1 via the drive circuits 2 (DRVs) and are individually subjected to switching control. The operating voltage (circuit power supply voltage) of the high-voltage system circuit (system connected to the direct-current power supply 6) for driving the rotating electric machine 80, such as the inverter 10, and the low-voltage system circuit (system of operating voltage of 3.3 to 5 volts or so) of the rotating electric machine control device 1 or the like, which is centered on a microcomputer or the like, are greatly different. The drive circuits 2 individually increase the driving ability (for example, voltage amplitude, output current, and the like, which is the ability to make the circuit of the subsequent stage operate) of the drive signals (switching control signals) with respect to the respective switching elements 3 and relay them. The first drive circuit 21 relays the switching control signals to the first inverter 11, and the second drive circuit 22 relays the switching control signals to the second inverter 12.

[0087] Further, the inverter 10 has a circuit that detects abnormalities of the inverter 10, such as the temperature of the switching elements 3, generation of overcurrent, and the like, and the information is supplied to the rotating electric machine control device 1 via the drive circuits 2. These pieces of information can also be determined for the switching elements 3, such as the degree of abnormality in the first inverter 11 and the degree of abnormality in the second inverter 12.

[0088] The rotating electric machine control device 1 is capable of performing both pulse width modulation (PWM) control, which outputs a plurality of pulses of different patterns in one cycle of an electrical angle, and rectangular wave control (1-pulse control (1-P), which outputs one pulse in one cycle of an electrical angle, as a manner of switching (voltage waveform control manner) of the switching elements 3 that constitute the first inverter 11 and the second inverter 12. That is, the rotating electric machine control device 1 is capable of performing the pulse width modulation control and the rectangular wave control as a control manner of the first inverter 11 and the second inverter 12. Further, as described above, the rotating electric machine control device 1 is capable of individually controlling the first inverter 11 and the second inverter 12 in mutually independent control manners.

[0089] In addition, the pulse width modulation has a manner of sinusoidal pulse width modulation (SPWM), continuous pulse width modulation (CPWM) such as space vector pulse width modulation (SVPWM), discontinuous pulse width modulation (DPWM), and the like. Therefore, in the pulse width modulation control that the rotating electric machine control device 1 is capable of performing, the control manner includes continuous pulse width modulation control and discontinuous pulse width modulation control.

[0090] The continuous pulse width modulation is a modulation method in which all of the arms 3A of the multiphase are continuously subjected to pulse width modulation, and the discontinuous pulse width modulation is a modulation method in which the pulse width modulation is performed during a period in which the switching elements of a part of the arms 3A of the multiphase are fixed to the on state or the off state. Specifically, in the discontinuous pulse width modulation, for example, the signal level of the switching control signal of the inverter corresponding to one phase of the three-phase alternating current is sequentially fixed, and the signal levels of the switching control signals of the other two phases are varied. In the continuous pulse width modulation, all of the phases are modulated, and the switching control signal corresponding to a certain phase is not fixed as described above. These modulation methods are determined in accordance with the operation conditions such as the rotational speed, the torque, and the like of the rotating electric machine 80, and the modulation rate (the ratio of the effective value of the line voltage of the three-phase alternating current to the direct current voltage) required to satisfy the operation conditions.

[0091] In the pulse width modulation, the pulses are generated on the basis of the magnitude relationship between the amplitude of the alternating waveform as the voltage command and the amplitude of the waveform of the triangular wave (including the sawtooth wave)-shaped carrier (CA) (refer to, for example, Non-Patent Literature 1). Fig. 7 There are also cases in which the PWM waveform is directly generated by digital operation without comparison with the carrier, but in this case, the amplitude of the alternating waveform as the command value and the amplitude of the carrier waveform also have a correlation relationship.

[0092] In the pulse width modulation based on digital operation, the carrier is determined in accordance with the control period of the rotating electric machine control device 1 such as the operation period of the microcomputer or the operation period of the electronic circuit. That is, even in the case in which the multiphase alternating current is used for the drive of the alternating current rotating electric machine 80, the carrier has a period (asynchronous period) that is not bound to the rotational speed, the rotational angle (electric angle) of the rotating electric machine 80. Therefore, both the carrier and each pulse generated on the basis of the carrier are asynchronous with the rotation of the rotating electric machine 80. Therefore, the modulation methods such as the sinusoidal pulse width modulation and the space vector pulse width modulation are sometimes referred to as asynchronous modulation. In contrast to this, the modulation method in which the pulses are generated in synchronization with the rotation of the rotating electric machine 80 is referred to as synchronous modulation. For example, in the rectangular wave control (rectangular wave modulation), since one pulse is output within one period of the electric angle of the rotating electric machine 80, the rectangular wave modulation is synchronous modulation.

[0093] As described above, as an index indicating the conversion rate from the direct-current voltage to the alternating-current voltage, there is a modulation factor indicating the ratio of the effective value of the line voltage of the multiphase alternating-current voltage with respect to the direct-current voltage. Generally, the maximum modulation factor of the sine wave pulse width modulation control is about 0.61 (≈0.612), and the maximum modulation factor of the space vector pulse width modulation control is about 0.71 (≈0.707). The modulation method having a modulation factor exceeding about 0.71 is called "overmodulation pulse width modulation" as a modulation method in which the modulation factor is generally high. The maximum modulation factor of the "overmodulation pulse width modulation" is about 0.78. This 0.78 is a physically (mathematically) limit value in the electric power conversion from the direct-current to the alternating-current. In the overmodulation pulse width modulation, when the modulation factor reaches 0.78, it becomes a rectangular wave modulation (1-pulse modulation) in which one pulse is output in one cycle of the electric angle. In the rectangular wave modulation, the modulation factor is fixed at the physical limit value, that is, about 0.78. Further, the value of the modulation factor exemplified here is a physically (mathematically) value not considering the dead time.

[0094] The overmodulation pulse width modulation in which the modulation factor is less than 0.78 can also be implemented using the principle of either one of the synchronous modulation method and the asynchronous modulation method. A representative modulation method of the overmodulation pulse width modulation is the discontinuous pulse width modulation. The discontinuous pulse width modulation can also be implemented using the principle of either one of the synchronous modulation method and the asynchronous modulation method. For example, in the case of using the synchronous modulation method, one pulse is output in one cycle of the electric angle in the rectangular wave modulation, but a plurality of pulses are output in one cycle of the electric angle in the discontinuous pulse width modulation. When a plurality of pulses exist in one cycle of the electric angle, the modulation factor decreases because the effective period of the pulse decreases accordingly. Therefore, it is not limited to the modulation factor fixed at about 0.78, and any modulation factor less than 0.78 can be implemented by the synchronous modulation method. For example, in one cycle of the electric angle, 9-pulse modulation (9-Pulses) in which 9 pulses are output, 5-pulse modulation (5-Pulses) in which 5 pulses are output, and the like, multi-pulse modulation (Multi-Pulses) can be performed.

[0095] In addition, the rotating electric machine control device 1 can execute shutdown control (SDN), active short-circuit control (ASC) as fail-safe control in a case where the inverter 10, the rotating electric machine 80 is detected to have an abnormality. The shutdown control is control that changes the switching control signal to all of the switching elements 3 configuring the inverter 10 to an inactive state and makes the inverter 10 into a disconnection state. The active short-circuit control is control that sets either the upper side switching element 3H of all of the arms 3A of the multiphase or the lower side switching element 3L of all of the arms 3A of the multiphase to an on state and sets the other to an off state. Further, a case where the upper side switching element 3H of all of the arms 3A of the multiphase is set to an on state and the lower side switching element 3L of all of the arms 3A of the multiphase is set to an off state is referred to as upper side active short-circuit control (ASC-H). In addition, a case where the lower side switching element 3L of all of the arms 3A of the multiphase is set to an on state and the upper side switching element 3H of all of the arms 3A of the multiphase is set to an off state is referred to as lower side active short-circuit control (ASC-L).

[0096] As shown in the present embodiment, in a case where the inverter 10 is connected to both ends of the stator coil 8, if one of the inverters 10 is short-circuited by the active short-circuit control, the stator coil 8 of the multiphase is short-circuited in the one of the inverters 10. That is, the one of the inverters 10 becomes a neutral point and the stator coil 8 is Y-connected. Therefore, the rotating electric machine control device 1 can realize a mode of controlling the rotating electric machine 80 of the open-circuit winding type via two inverters 10 and a mode of controlling the rotating electric machine 80 of the Y-connected type via one inverter 10 (the inverter 10 on the side that is not subjected to the active short-circuit control).

[0097] Fig. 3 A vector diagram of one operation point in the dq-axis vector coordinate system of the rotating electric machine 80 is illustrated. In the drawing, "V1" indicates a first voltage vector that shows a voltage based on the first inverter 11, and "V2" indicates a second voltage vector that shows a voltage based on the second inverter 12. The voltage that appears in the stator coil 8 that is an open-circuit winding via two inverters 10 corresponds to the difference "V1-V2" between the first voltage vector V1 and the second voltage vector V2. "Va" in the drawing indicates a resultant voltage vector that appears in the stator coil 8. In addition, "Ia" indicates a current that flows through the stator coil 8 of the rotating electric machine 80. As shown in the drawing, when the first inverter 11 and the second inverter 12 are controlled in such a manner that the directions of the vectors of the first voltage vector V1 and the second voltage vector V2 differ by 180 degrees, the resultant voltage vector Va becomes a vector that is obtained by adding the magnitude of the second voltage vector V2 to the direction of the first voltage vector V1. Fig. 3

[0098] ​The following describes the technique for determining the location of a fault when one of the switching elements 3 of the two inverters 10 that constitute the open-circuit winding (stator coil 8) fails, categorizing the fault into open-circuit faults and short-circuit faults. First, the technique for determining the location of a fault when one of the switching elements 3 of the two inverters 10 that constitute the open-circuit winding (stator coil 8) fails is explained.

[0099] In this embodiment, multiple control regions R (refer to) are set corresponding to the operating conditions of the rotary motor 80. Fig. 4 The rotating motor control device 1 controls the inverter 10 in a control mode corresponding to each control area R. Fig. 4 This is an example illustrating the relationship between the rotational speed and torque of a rotary electric machine 80. For example, as... Fig. 4 As shown, the control area R of the rotary motor 80 is provided with a first speed area VR1, a second speed area VR2 where the rotational speed of the rotary motor 80 under the same torque is higher than that of the first speed area VR1, and a third speed area VR3 where the rotational speed of the rotary motor 80 under the same torque is higher than that of the second speed area VR2.

[0100] As described above, the rotating electric motor control device 1 can control the first inverter 11 and the second inverter 12 respectively through multiple control methods with different switching modes. The control methods include pulse width modulation (PWM) control, which outputs multiple pulses with different modes during one cycle of the electrical angle, and control during half a cycle (half a cycle) of the electrical angle (full cycle), i.e., the first period H1 (refer to...). Fig. 5 Multiple pulses with different output modes are generated during the remaining 1 / 2 cycle (half cycle), i.e., the second period H2 (refer to...). Fig. 5 (etc.) in a state of persistent inefficiency (refer to) Figs. 5-8 Hybrid pulse width modulation (MX-PWM) control is used to control the first inverter 11 and the second inverter 12 in the first speed region VR1 and the second speed region VR2.

[0101] Hybrid pulse width modulation control (MX-PWM) includes hybrid continuous pulse width modulation control (MX-CPWM) and hybrid discontinuous pulse width modulation control (MX-DPWM). Details will be described later. In hybrid continuous pulse width modulation control, control is performed in a manner where the second period H2 is continuously inactive, and in the first period H1, pulse width modulation is continuously applied to all arms 3A of the multiphase (see reference). Fig. 5 , Fig. 7The details will be described later. Similarly, the details will be described later, in the mixed discontinuous pulse width modulation control, the second period H2 is controlled in a manner that the non-active state is continued, and the first period H1 is pulse width modulated for the arm 3A of a part of the multiphase, including a period in which the switching element 3 is fixed to the on state or the off state (refer to Fig. 6 , Fig. 8 The details will be described later.

[0102] In the mixed pulse width modulation control, the switching control signal also becomes the non-active state in the second period H2, and therefore, the loss of the inverter 10 is reduced, and in addition, the high-order harmonic current due to the switching operation is also reduced, and therefore, the loss (iron loss) of the rotating electric machine 80 is also reduced. That is, by executing the mixed pulse width modulation control, it is possible to reduce the system loss.

[0103] For example, as shown in Table 1 below, the rotating electric machine control device 1 controls the two inverters 10, the first inverter 11 and the second inverter 12, using the mixed continuous pulse width modulation control (MX-CPWM) described later in the first speed region VR1. In addition, the rotating electric machine control device 1 controls the two inverters 10, the first inverter 11 and the second inverter 12, using the mixed discontinuous pulse width modulation control (MX-DPWM) described later in the second speed region VR2. In addition, the rotating electric machine control device 1 controls the two inverters 10, the first inverter 11 and the second inverter 12, using the rectangular wave in the third speed region VR3. Mi_sys, Mi_inv1, and Mi_inv2 in the table will be described later.

[0104] [Table 1]

[0105] R Mi_sys INV1 Mi_inv1 INV2 Mi_inv2 VR1 M < a MX-CPWM M < a MX-CPWM M < a VR2 a < M < 0.78 MX-DPWM a < M < 0.78 MX-DPWM a < M < 0.78 VR3 M＝0.78 1-Pulse M＝0.78 1-Pulse M＝0.78

[0106] Preferably, the boundary of each control region R (the boundary of the first speed region VR1, the second speed region VR2, and the third speed region VR3) is set in accordance with at least one of the ratio of the line voltage of the multiphase alternating voltage to the direct current voltage and the rotational speed of the rotating electric machine 80 corresponding to the torque of the rotating electric machine 80.

[0107] As Fig. 4 illustrated, the operating condition of the rotating electric machine 80 is generally defined by the relationship between the rotational speed and the torque. The control region R is preferably set based on the rotational speed as one parameter. Here, although it is also possible to set the rotational speed that defines the boundary of the control region R to be constant regardless of the torque, it is more preferable to set the rotational speed that defines the boundary of the control region R to be different values depending on the torque. Thereby, it is possible to drive control the rotating electric machine 80 with high efficiency according to the operating condition of the rotating electric machine 80.

[0108] In addition, for example, in a case where a high output (high rotation speed or high torque) is required for the rotating electric machine 80, in a voltage-type inverter, the requirement is achieved by increasing the DC voltage or increasing the proportion of the DC voltage converted to the alternating voltage. In a case where the DC voltage is constant, the requirement can be achieved by increasing the proportion of the DC voltage converted to the alternating voltage. The proportion can be expressed as the proportion of the effective value of the three-phase alternating current power with respect to the DC power (in the case of the voltage-type inverter, equivalent to the proportion of the effective value of the three-phase alternating voltage with respect to the DC voltage). As described above, in the control mode of controlling the inverter 10, there are various modes in which the proportion varies from low to high.

[0109] As shown in Table 1, when the control regions R are set based on the proportion of the effective value of the three-phase alternating current power with respect to the DC power (modulation ratio) determined in accordance with the requirement for the rotating electric machine 80, the rotating electric machine 80 can be driven and controlled with high efficiency in accordance with the operating conditions of the rotating electric machine 80. Further, in the table, "Mi_inv1" denotes the modulation ratio of the first inverter 11, "Mi_inv2" denotes the modulation ratio of the second inverter 12, and "Mi_sys" denotes the modulation ratio of the entire system.

[0110] In the above Table 1, the modulation ratios corresponding to the respective control regions R are exemplified. In the present embodiment, the terminal-to-terminal voltage "E1" of the first DC power supply 61 and the terminal-to-terminal voltage "E2" of the second DC power supply 62 are the same (both are the voltage "E"). If the effective value on the alternating current side of the first inverter 11 is denoted by "Va_inv1" and the effective value on the alternating current side of the second inverter 12 is denoted by "Va_inv2", the modulation ratio "Mi_inv1" of the first inverter 11 and the modulation ratio "Mi_inv2" of the second inverter 12 are expressed by the following equations (1), (2). In addition, the modulation ratio "Mi_sys" of the entire system is expressed by the following equation (3).

[0111] Mi_inv1 = Va_inv1 / E1 = Va_inv1 / E... (1)

[0112] Mi_inv2 = Va_inv2 / E2 = Va_inv2 / E... (2)

[0113] Mi_sys = (Va_inv1 + Va_inv2) / (E1 + E2)

[0114] = (Va_inv1 + Va_inv2) / 2E... (3)

[0115] For the instantaneous value of the voltage, the instantaneous vector needs to be considered, but if only the modulation ratio is considered, the modulation ratio "Mi_sys" of the system as a whole is "(Mi_inv1+Mi_inv2) / 2" according to the equations (1) to (3). In addition, the modulation ratios corresponding to each control region R are shown as rated values in Table 1. Therefore, in actual control, the range in which the modulation ratio corresponding to each control region R is repeated can also be included, taking into account fluctuations and the like when the control mode changes in the control region R.

[0116] In addition, the modulation ratio "a" shown in Table 1 and the modulation ratio "b" shown in Table 2 described later are set based on the theoretical upper limit value of the modulation ratio in each modulation method, further taking into account the dead time. For example, "a" is around 0.5 to 0.6, and "b" is around 0.25 to 0.3.

[0117] Here, with reference to Figs. 5-8 For the characteristic hybrid pulse width modulation control (MX-PWM) in the present embodiment, an example of the waveforms of the voltage command (Vu1**, Vu2**) of the U phase and the upper side switch control signal (Su1+, Su2+) of the U phase is shown. In addition, regarding the lower side switch control signal Su2- of the second U phase and the V phase and the W phase, the illustration is omitted. Fig. 5 and Fig. 7 An example of the waveforms of the hybrid continuous pulse width modulation control (MX-CPWM) is shown. Fig. 6 and Fig. 8 An example of the waveforms of the hybrid discontinuous pulse width modulation control (MX-DPWM) is shown.

[0118] In Fig. 5 and Fig. 6 , an example of the carrier CA of the first inverter 11, that is, the first carrier CA1, the carrier CA of the second inverter 12, that is, the second carrier CA2, the U phase voltage command common to the first inverter 11 and the second inverter 12, that is, the common U phase voltage command Vu ** , the first U phase upper side switch control signal Su1+, and the second U phase upper side switch control signal Su2+ is shown. Regarding the first U phase lower side switch control signal Su1-, the second U phase lower side switch control signal Su2-, and the V phase and the W phase, the illustration is omitted (the same applies to other control methods).

[0119] For example, the first carrier CA1 varies between "0.5 < CA1 < 1", the second carrier CA2 varies between "0 < CA2 < 0.5", and the voltage command (V**) can vary between "0 < V** < 1". By comparison of the carriers CA (the first carrier CA1 and the second carrier CA2) and the voltage command (V**), in a case where the voltage command is above the carrier CA, the switch control signal is "1", and in a case where the voltage command is less than the carrier CA, the switch control signal is "0". The comparison logic with respect to the carrier CA and the voltage command (V**) is also the same in the following description.

[0120] As shown in FIG. 1, the first carrier CA1 and the second carrier CA2 are half the amplitude of the voltage command (V**) allowed. In general pulse width modulation, the amplitude of the carrier CA is equal to the amplitude of the voltage command allowed, and the carrier CA in hybrid pulse width modulation can be called a half carrier. By using such a half carrier, in the first period H1 (half cycle) of 1 / 2 cycle of the electrical angle (full cycle), since such a half carrier crosses the voltage command (V**), a plurality of pulses of different output patterns are output as the switch control signal. In the remaining 1 / 2 cycle, that is, the second period H2 (half cycle), since the half carrier does not cross the voltage command (V**), the switch control signal is output in a manner that the non-active state is continued. Fig. 5 Fig. 6 As shown in FIG. 1, the first carrier CA1 and the second carrier CA2 are half the amplitude of the voltage command (V**) allowed. In general pulse width modulation, the amplitude of the carrier CA is equal to the amplitude of the voltage command allowed, and the carrier CA in hybrid pulse width modulation can be called a half carrier. By using such a half carrier, in the first period H1 (half cycle) of 1 / 2 cycle of the electrical angle (full cycle), since such a half carrier crosses the voltage command (V**), a plurality of pulses of different output patterns are output as the switch control signal. In the remaining 1 / 2 cycle, that is, the second period H2 (half cycle), since the half carrier does not cross the voltage command (V**), the switch control signal is output in a manner that the non-active state is continued.

[0121] In addition, in hybrid discontinuous pulse width modulation control, as shown in FIG. 2, in the second period H2, a pulse that becomes active state partially is also output as the switch control signal. This is because the modulation rate of the underlying discontinuous pulse width modulation is greater than that of continuous pulse width modulation. The pulse that becomes active state in the second period H2 is output near the center of the amplitude of the voltage command (V**), near the inflection point of the voltage command (V**). As shown in FIG. 2, even in hybrid discontinuous pulse width modulation control, it can be said that the second period H2 is output in a manner that the non-active state is continued. In addition, when the second period H2 is set as a period in which the switch control signal is only the non-active state (a period less than 1 / 2 cycle), and the first period H1 is set as a period in which the second period H2 is not included in one cycle (a period of 1 / 2 cycle or more), the hybrid pulse width modulation can be defined in the following manner. Hybrid pulse width modulation control can also be controlled in a manner that a plurality of pulses of different output patterns are output in the first period H1 of 1 / 2 cycle of the electrical angle or more, and the non-active state is continued in the remaining period of 1 cycle of the electrical angle, that is, the second period H2. Fig. 6 Fig. 6

[0122] Fig. 7 Fig. 8 ​​​​The different ways of mixing continuous pulse width modulation control and hybrid discontinuous pulse width modulation control are shown. Fig. 5 and Fig. 6 The generated switching control signals are the same. In Fig. 7 and Fig. 8 An example of the first inverter 11 carrier CA, i.e., the first carrier CA1, the carrier CA of the second inverter 12, i.e., the second carrier CA2, the U-phase voltage command of the first inverter 11, i.e., the first U-phase voltage command Vu1**, the U-phase voltage command of the second inverter 12, i.e., the second U-phase voltage command Vu2**, the first U-phase upper side switching control signal Su1+, and the second U-phase upper side switching control signal Su2+ is shown. For example, the first carrier CA1 and the second carrier CA2 vary between "0.5 < CA < 1", and the voltage command (V**) can vary between "0 ≤ V** ≤ 1". The phases of the first carrier CA1 and the second carrier CA2 differ by 180 degrees (π). In addition, the phases of the first U-phase voltage command Vu1** and the second U-phase voltage command Vu2** also differ by 180 degrees (π).

[0123] As shown in Fig. 7 and Fig. 8 , the amplitudes of the first carrier CA1 and the second carrier CA2 are half of the amplitudes allowed by the voltage command (V**). Therefore, Fig. 7 and Fig. 8 The carriers CA in the ways shown in

[0124] Fig. 5 and Fig. 6 are also half carriers. By using such half carriers, in the first period H1, which is 1 / 2 of the electrical angle (or more than 1 / 2), different multiple pulses are output as switching control signals because such half carriers cross the voltage command (V**). In the remaining period of the cycle, i.e., the second period H2, because the half carriers do not cross the voltage command (V**), the switching control signals are output in a continuous non-active state. Fig. 7 Fig. 8 The ways shown in

[0125] As described with reference to Figs. 5-8 ​The hybrid pulse width modulation control generates a plurality of pulses based on a carrier wave CA, i.e., a half carrier wave (first carrier wave CA1, second carrier wave CA2) having a wave height of 1 / 2 of a range of variation of an instruction value (voltage instruction, in the above example, U-phase voltage instruction (Vu** = Vu1** = Vu2**), Vu1**, Vu2**)) and the instruction value. In the present embodiment, as a manner of hybrid pulse width modulation control, both a double half carrier wave single reference manner and a double half carrier wave double reference manner are exemplified.

[0126] In the double half carrier wave single reference manner, as described with reference to Fig. 5 and Fig. 6 , a pulse for the first inverter 11 is generated based on a first half carrier wave (first carrier wave CA1) set on one of a higher voltage side or a lower voltage side (in this case, the higher voltage side) than the center of the amplitude of the instruction value (common U-phase voltage instruction Vu**) and the instruction value (common U-phase voltage instruction Vu**) common to the first inverter 11 and the second inverter 12. In this manner, in the present embodiment, a pulse for the second inverter 12 is generated based on a second half carrier wave (second carrier wave CA2) set on the other of the higher voltage side or the lower voltage side (in this case, the lower voltage side) than the center of the amplitude of the instruction value (common U-phase voltage instruction Vu**) and the instruction value (common U-phase voltage instruction Vu**) in the same phase as the first half carrier wave (first carrier wave CA1).

[0127] In the double half carrier wave double reference manner, as described with reference to Fig. 7 and Fig. 8 , a pulse for the first inverter 11 is generated based on a first half carrier wave (first carrier wave CA1) set on one of a higher voltage side or a lower voltage side (in this case, the higher voltage side) than the center of the amplitude of the instruction value (first U-phase voltage instruction Vu1**, second U-phase voltage instruction Vu2**) and a first instruction value (first U-phase voltage instruction Vu1**) for the first inverter 11. In this manner, in the present embodiment, a pulse for the second inverter 12 is generated based on a second half carrier wave (second carrier wave CA2) set on the same side (higher voltage side) as the first half carrier wave (first carrier wave CA1) in a phase different by 180 degrees from the first half carrier wave (first carrier wave CA1) and a second instruction value (second U-phase voltage instruction Vu2**) for the second inverter 12 in a phase different by 180 degrees from the first instruction value (first U-phase voltage instruction Vu1**).

[0128] Further, as described later with reference to Table 2, in the first speed region VR1 and the second speed region VR2, sometimes the inverter 10 is controlled not by hybrid pulse width modulation control but by pulse width modulation control. Fig. 9An example is shown where, in the first speed region VR1, both the first inverter 11 and the second inverter 12 are controlled by continuous pulse width modulation (PWM) control, including the first U-phase voltage command Vu1**, the second U-phase voltage command Vu2**, the carrier CA, the first U-phase upper-side switch control signal Su1+, and the second U-phase upper-side switch control signal Su2+. Additionally... Fig. 10 An example is shown where, in the second speed region VR2, both the first inverter 11 and the second inverter 12 are controlled by discontinuous pulse width modulation control, the first U-phase voltage command Vu1**, the second U-phase voltage command Vu2**, the carrier CA, the first U-phase upper-side switch control signal Su1+, and the second U-phase upper-side switch control signal Su2+ are shown.

[0129] When both the first inverter 11 and the second inverter 12 are under switching control, the first U-phase voltage command Vu1** and the second U-phase voltage command Vu2** are approximately 180 degrees out of phase. For example, the maximum amplitude of the U-phase voltage is "(4 / 3)E", and the maximum amplitude of the line voltage is "2E" (see also...). Fig. 3 (Vector diagram). Furthermore, the first DC power supply 61 and the second DC power supply 62 are independent, and the first DC voltage E1 of the first DC power supply 61 and the second DC voltage E2 of the second DC power supply 62 can also be different values. For example, to be precise, the maximum amplitude of the U-phase voltage is "(2 / 3)E1)+(2 / 3)E2", but for ease of understanding, it is set to "E1=E2=E" in this specification. Equal power is supplied from both inverters 10 to the rotating motor 80. At this time, the same voltage command (V**) with a phase difference of 180 degrees (π) is provided to both inverters 10.

[0130] However, when the inverter 10 is switched on and off, there is a possibility that pulsating components overlapping with the fundamental frequency of the alternating current can generate audible noise. When the two inverters 10 are controlled by different types of pulses, pulsations corresponding to each pulse are generated, potentially increasing the audible noise. This is especially true when the rotating motor 80 operates at low speeds, increasing the likelihood that the frequency of the pulsating components (or their sideband frequencies) will be included in the audible noise band. Therefore, the control method of the rotating motor 80, i.e., the control method of the inverter 10, should preferably be appropriately set according to the operating conditions to balance high system efficiency with reduced audible noise.

[0131] The rotating electric machine control device 1 of this embodiment has a loss reduction priority mode (efficiency priority mode) and a noise reduction priority mode as control modes for the rotating electric machine 80, and can switch between the loss reduction priority mode and the noise reduction priority mode. In the loss reduction priority mode, as described above with reference to Table 1, the rotating electric machine control device 1 uses hybrid pulse width modulation control to control the switching of the inverter 10. In the noise reduction priority mode, as shown in Table 2 below, the rotating electric machine control device 1 uses pulse width modulation control to control the switching of the inverter 10.

[0132] [Table 2]

[0133]

[0134]

[0135] When the inverter 10 is switched on and off, there is a possibility that a pulsating component overlapping with the fundamental frequency of the alternating current generates audible noise. This is especially true when the rotating motor 80 operates at low speeds, increasing the likelihood that the frequency of the pulsating component (or its sideband frequencies) is contained within the audible frequency band. In hybrid pulse width modulation, such as... Figs. 5-8 As shown, during the half-cycle of the electrical angle, since the two inverters 10 are controlled in different pulse forms, pulsations corresponding to each pulse are generated, which may increase the noise in the audible frequency band. In the first speed region VR1 and the second speed region VR2, where the rotational speed of the rotating motor 80 is relatively low, the noise accompanying the vehicle's movement (such as the sound of tires touching the road surface) is also relatively low. Therefore, if the noise output from one of the driven inverters 10 is in the audible frequency band, the noise may be easily heard by the user.

[0136] For example, when the vehicle starts or decelerates towards a stop, considering that noise in the audible frequency band is easily heard by the user, a noise reduction priority mode is preferred. When the vehicle is running stably, a loss reduction priority mode is preferred. In addition, these modes can also be selected by the user through operation (setting switches, including input from touch panels, etc.).

[0137] In the noise reduction priority mode, in the first speed region VR1 and the second speed region VR2 where the rotating motor 80 rotates at relatively low speeds, the first inverter 11 and the second inverter 12 are controlled by pulse width modulation (PWM) control instead of hybrid pulse width modulation (HPWM) control. Since the currents flowing through the two inverters 10 in the stator coil 8 are approximately 180 degrees out of phase, the phase difference of the currents containing pulsating components is also approximately 180 degrees. Therefore, at least a portion of the pulsating components can cancel each other out, reducing noise in the audible frequency band.

[0138] However, the switching elements 3 constituting the inverter 10 have a short-circuit failure in which the switching element 3 always becomes an on state, and an open-circuit failure in which the switching element 3 always becomes an off state. For example, in a case where a rotary electric machine having a generally Y-shaped connection type stator coil is driven by one inverter, if a short-circuit failure or an open-circuit failure occurs, shutdown control in which all of the switching elements of the inverter are set to an off state, active short-circuit control in which the upper side switching elements of all of the arms of the multiphase are set to an on state or the lower side switching elements of all of the arms of the multiphase are set to an on state, or the like is performed, and the vehicle is stopped.

[0139] However, as in the present embodiment, in a case where the rotary electric machine 80 having the mutually independent multiphase open-circuit windings as the stator coils 8 is driven and controlled via the first inverter 11 and the second inverter 12, the rotary electric machine 80 can be driven and controlled via one inverter 10 of the first inverter 11 and the second inverter 12. As described above, if one of the inverters 10 is short-circuited by the active short-circuit control, the stator coils 8 of the multiphase are short-circuited in the one inverter 10, the one inverter 10 becomes a neutral point, and the stator coils 8 are Y-connected. Therefore, the rotary electric machine control device 1 can realize a mode in which the Y-connected rotary electric machine 80 is controlled via one inverter 10 (the inverter 10 on the side that is not subjected to the active short-circuit control).

[0140] In a case where the rotary electric machine is driven by one inverter, if a short-circuit failure or an open-circuit failure occurs, the vehicle that uses the rotary electric machine as a driving force source needs to be stopped. However, as in the present embodiment, in a case where the rotary electric machine 80 is driven by two inverters 10, even if a short-circuit failure or an open-circuit failure occurs, the vehicle can continue to travel within a certain limit range without stopping the vehicle that uses the rotary electric machine 80 as a driving force source. For example, it is possible to travel to the current destination such as a home or a repair factory.

[0141] For example, in a case where a short-circuit failure has occurred in one of the inverters 10, in the upper side arm and the lower side arm, it is sufficient to perform the active short-circuit control in which all of the switching elements 3 of the arm on the side including the switching element 3 in which the short-circuit failure has occurred are set to an on state and all of the switching elements 3 of the arm on the other side are set to an off state. By setting all of the switching elements 3 of the arm on the side including the switching element 3 in which the short-circuit failure has occurred to an on state, it is possible to use the switching element 3 in which the short-circuit failure has occurred as a switching element 3 in which no failure has occurred.

[0142] In addition, in the case where an open-circuit failure has occurred in one of the inverters 10, in the upper side arm and the lower side arm, it is sufficient to perform active short-circuit control by setting all of the switching elements 3 of the arm on the side including the switching element 3 in which the open-circuit failure has occurred to the on state and setting all of the switching elements 3 of the arm on the side not including the switching element 3 in which the open-circuit failure has occurred to the off state. By setting all of the switching elements 3 of the arm on the side including the switching element 3 in which the open-circuit failure has occurred to the off state, it is possible to use the switching element 3 in which the open-circuit failure has occurred as a switching element 3 in which no failure has occurred.

[0143] Therefore, at least it is necessary to determine which of the first inverter 11 and the second inverter 12 the switching element 3 in which the failure has occurred belongs to and which of the upper side arm and the lower side arm it belongs to. More preferably, it is possible to determine which of the phases in the multiphase the switching element 3 in which the failure has occurred is.

[0144] Hereinafter, a description will be given of the manner in which the rotary electric machine 80 is driven by the fail-safe control to determine the switching element 3 in which the open-circuit failure has occurred and to continue the running of the vehicle after the determination in the case where an open-circuit failure has occurred in one of the switching elements 3 constituting the first inverter 11 and the second inverter 12 (in the case where a one-phase open-circuit failure has occurred).

[0145] Figs. 11-14 (Fig. 9 and Fig. 10 described later Figs. 36-39 ) are waveform charts showing an example of three-phase alternating current waveforms (U-phase current Iu, V-phase current Iv, W-phase current Iw) in the case where an open-circuit failure has occurred. Fig. 11 and Fig. 12 (Fig. 11 and Fig. 12 described later Fig. 36 and Fig. 37 ) show three-phase alternating current waveforms in the case where an open-circuit failure has occurred at the time of motoring, Fig. 13 and Fig. 14 (Fig. 13 and Fig. 14 described later Fig. 38 and Fig. 39 ) show three-phase alternating current waveforms in the case where an open-circuit failure has occurred at the time of regeneration. Figs. 11-14 (Fig. 15 and Fig. 16 described later Figs. 36-39 ) collectively show waveforms in the case where an open-circuit failure has occurred in the switching element 3 of the U-phase. In addition, Figs. 11-14 (Fig. 17 and Fig. 18 described later Figs. 36-39 ) collectively show waveforms in the case where an open-circuit failure has occurred in the switching element 3 of the upper side (HIGHSIDE) of the first inverter 11, waveforms in the case where an open-circuit failure has occurred in the switching element 3 of the lower side (LOWSIDE) of the first inverter 11, waveforms in the case where an open-circuit failure has occurred in the switching element 3 of the upper side (HIGHSIDE) of the second inverter 12, and waveforms in the case where an open-circuit failure has occurred in the switching element 3 of the lower side (LOWSIDE) of the second inverter 12. In addition, with respect toFig. 11 of Fig. 12 (and relative to) Fig. 36 of Fig. 37 This shows the case where the rotary motor 80 rotates at a higher speed relative to the same torque. Fig. 13 of Fig. 14 (and relative to) Fig. 38 of Fig. 39 The diagram shows the case where the rotary motor 80 rotates at a higher speed under the same torque.

[0146] like Fig. 11 and Fig. 12 As shown, if an open-circuit fault occurs during power operation, the three-phase AC waveforms will become asymmetrical and distorted on both the upstream and downstream sides of the first inverter 11 and the second inverter 12. Furthermore, the three-phase AC waveforms are identical when an open-circuit fault occurs on the upstream side of the first inverter 11 and when an open-circuit fault occurs on the downstream side of the second inverter 12, and vice versa.

[0147] On the other hand, such as Fig. 13 and Fig. 14 As shown, during regeneration, when an open-circuit fault occurs on the lower side of the first inverter 11 and the second inverter 12, the three-phase AC waveform becomes an asymmetrical and distorted waveform. However, when an open-circuit fault occurs on the upper side of the first inverter 11 and the second inverter 12, the three-phase AC waveform is approximately symmetrical and almost undistorted.

[0148] That is, such as Fig. 15 As shown, during power operation (refer to...) Figs. 16-18 (Except for the power operation at ultra-low speeds described later), regardless of where an open circuit fault occurs, the three-phase AC waveform will indicate an abnormality. The abnormality can be broadly categorized as follows: Fig. 15 The diagram shows two fault modes, FP1 and FP2. During regeneration, when an open-circuit fault occurs only on the downstream side of the first inverter 11 and the second inverter 12, the three-phase AC waveform exhibits anomalies. These anomalies can be broadly categorized as follows: Fig. 15 The two lower-level fault modes LF are shown: the first lower-level fault mode LF1 and the second lower-level fault mode LF2.

[0149] The first failure mode FP1 is a failure mode FP when either of the upper side arm of the first inverter 11 and the lower side arm of the second inverter 12 is a failure side arm in which an open circuit failure has occurred. The second failure mode FP2 is a failure mode FP when either of the lower side arm of the first inverter 11 and the upper side arm of the second inverter 12 is a failure side arm. The first lower side failure mode LF1 is a lower side failure mode LF when the lower side arm of the second inverter is a failure side arm. The second lower side failure mode LF2 is a lower side failure mode LF when the lower side arm of the first inverter is a failure side arm.

[0150] As shown in Fig. 15 , the shapes of the failure mode FP and the lower side failure mode LF are different in that a part is repeated. Therefore, if the state of the three-phase alternating current waveform at the time of motoring and the state of the three-phase alternating current waveform at the time of regeneration are compared, it is possible to discriminate in which inverter 10 the open circuit failure has occurred on the upper side and the lower side (where the failure side arm is) in the case where the open circuit failure is detected.

[0151] Specifically, in the case where the first failure mode FP1 is detected at the time of motoring and no abnormality is detected in the three-phase alternating current waveform at the time of regeneration, it is possible to discriminate that the open circuit failure has occurred on the upper side (inv1-HIGHSIDE) of the first inverter 11. In the case where the first failure mode FP1 is detected at the time of motoring and the first lower side failure mode LF1 is detected at the time of regeneration, it is possible to discriminate that the open circuit failure has occurred on the lower side (inv2-LOWSIDE) of the second inverter 12. In addition, in the case where the second failure mode FP2 is detected at the time of motoring and no abnormality is detected in the three-phase alternating current waveform at the time of regeneration, it is possible to discriminate that the open circuit failure has occurred on the upper side (inv2-HIGHSIDE) of the second inverter 12. In the case where the second failure mode FP2 is detected at the time of motoring and the second lower side failure mode LF2 is detected at the time of regeneration, it is possible to discriminate that the open circuit failure has occurred on the lower side (inv1-LOWSIDE) of the first inverter 11.

[0152] Fig. 16 and Fig. 17 show three-phase alternating current waveforms in the case where the rotational speed of the rotating electric machine 80 is low and an open circuit failure has occurred at an ultra-low rotational speed, as compared with Fig. 11 and Fig. 13 both show three-phase alternating current waveforms in the case where an open circuit failure has occurred at the time of motoring. Fig. 16 and Fig. 17 both show three-phase alternating current waveforms in the case where an open circuit failure has occurred at the time of motoring. Fig. 16 show waveforms in the case where the switching element 3 of the U phase of the upper side or the lower side of the first inverter 11 has an open circuit failure, Fig. 17 show waveforms in the case where the switching element 3 of the U phase of the upper side or the lower side of the second inverter 12 has an open circuit failure.Fig. 16 and Fig. 17 The waveforms of three different rotational speeds (RS1, RS2, RS3), the waveforms of the case where the open-circuit failure occurs in the upper-stage side (HIGHSIDE) switching element 3, and the waveforms of the case where the open-circuit failure occurs in the lower-stage side (LOWSIDE) switching element 3 are collectively shown in a matrix form. In addition, the rotational speeds are "RS1 < RS2 < RS3", and the rotational speed of "RS3" which is the highest among the three is compared with Fig. 11 and Fig. 13 The ultra-low rotational speed is also lower than the rotational speed of the rotary electric machine 80.

[0153] As in the case of the regeneration, as shown in FIG. 6, in the case where the open-circuit failure occurs in the lower-stage side of the first inverter 11 and the second inverter 12, the three-phase alternating current waveforms become asymmetric and distorted waveforms, but in the case where the open-circuit failure occurs in the upper-stage side of the first inverter 11 and the second inverter 12, the three-phase alternating current waveforms are approximately symmetric and almost no distortion occurs. That is, as shown in FIG. 7, when the rotational speed is reduced to the ultra-low rotational speed, the state of the three-phase alternating current waveforms in the case where the open-circuit failure occurs changes. Since the operation of the three-phase alternating current waveforms at the ultra-low rotational speed is the same as in the case of the regeneration, if the states of the three-phase alternating current waveforms at the time of the motoring at the ultra-low rotational speed and at the time of the motoring at a higher speed than the ultra-low rotational speed are compared, as described with reference to FIG. 6, it is possible to discriminate in which one of the upper-stage side and the lower-stage side of the inverters 10 the open-circuit failure occurs in the case where the open-circuit failure is detected. Fig. 16 and Fig. 17 Fig. 18 Fig. 15

[0154] Fig. 19 The operation points in the control region of the rotary electric machine 80 are shown. In addition, Fig. 19 The control region "Rs" in FIG. 8 indicates a single-inverter control region Rs when the rotary electric machine 80 is controlled by one inverter 10, and "Rd" indicating the entire control region indicates a double-inverter control region Rd when the rotary electric machine 80 is controlled by two inverters 10.

[0155] For example, in the case where the open-circuit failure is detected in the motoring at the first operation point P1 outside the single-inverter control region Rs, by moving the operation point to the second operation point P2 on the regeneration side, as described with reference to FIG. 6, it is possible to discriminate the site where the open-circuit failure occurs. Fig. 15 Fig. 20 The relationship between the torque command and the rotational speed of the rotary electric machine 80 is shown. At the time tl when the open-circuit failure is detected in the motoring at the first operation point P1, the torque command is changed from the motoring torque to the regeneration torque. By the regeneration control, the rotational speed of the rotary electric machine 80 is reduced between the time tl and the time t2, and at the time t2, the rotational speed of the rotary electric machine 80 is reduced to the rotational speed of the single-inverter control region Rs. ​​​​

[0156] When the site where the open-circuit failure has occurred is determined, in the single-inverter control region Rs, by actively short-circuiting the one inverter 10 on the side where the failure has occurred, the rotary electric machine 80 can be driven and controlled via the other inverter 10 where no failure has occurred. The third operation point P3 is lower in rotational speed than the original first operation point PI, but can output the same torque, so that the travel of the vehicle can be continued within certain limits.

[0157] Here, although detailed description is omitted, in the case where the open-circuit failure is detected in the motoring, the site where the open-circuit failure has occurred can also be determined without moving the operation point to the regenerative side as described above, for example, by reducing the rotational speed to an ultra-low rotational speed by shutdown control or the like. Details will be described later with reference to Fig. 34

[0158] However, as described above, in the case where the open-circuit failure is detected in the motoring at the first operation point PI outside the single-inverter control region Rs, the operation point is moved to the second operation point P2 on the regenerative side, and in the case where the rotational speed of the rotary electric machine 80 is reduced by regenerative operation, when the failure site is the lower-stage side, the three-phase alternating current waveform is in a distorted state. When the waveform is distorted, high-order harmonic components occur, and there are cases where the DC power supply 6 or the DC link capacitor 4 or the like is consumed, or other equipment is affected by electromagnetic noise, or audible noise is generated. Therefore, it is preferable to suppress the distortion in the current waveform at the time of regeneration.

[0159] As described above, in the case where the open-circuit failure has occurred on the upper-stage side, the three-phase alternating current hardly becomes distorted at the time of regeneration. Therefore, in the present embodiment, the distortion of the three-phase alternating current is eliminated by changing the switching pattern. Fig. 21 and Fig. 22 Switching control signals for eliminating the distortion of the three-phase current waveform at the time of regeneration in a state where an open-circuit failure has occurred are shown. Fig. 21 Switching control signals in a first case (case 1) are shown, Fig. 22 Switching control signals in a second case (case 2) are shown.

[0160] In the first case, first, the switching control signals of the upper-stage side and the switching control signals of the lower-stage side of the first inverter 11 are exchanged, and the switching control signals of the upper-stage side and the switching control signals of the lower-stage side of the second inverter 12 are exchanged. Further, the switching control signals of the first inverter 11 and the switching control signals of the second inverter 12 are exchanged. That is, in the first case, the switching pattern of the upper-stage arm of the first inverter 11 and the switching pattern of the lower-stage arm of the second inverter 12 are exchanged, and the switching pattern of the lower-stage arm of the first inverter 11 and the switching pattern of the upper-stage arm of the second inverter are exchanged. ​

[0161] In the second case, as in the first case, first, the switching control signals of the upper side and the lower side of the first inverter 11 are exchanged. Then, the direction of the current flowing through the stator coil 8 is exchanged. For example, in the three-phase two-phase coordinate conversion section 55 shown in the drawing, the positive and negative of the three-phase current are simply reversed. That is, in the second case, the switching mode of the upper side arm and the switching mode of the lower side arm of the first inverter 11 are exchanged, and the switching mode of the upper side arm and the switching mode of the lower side arm of the second inverter 12 are exchanged, and further, the positive and negative of the multiphase alternating current (Iu, Iv, Iw) are reversed. Fig. 2

[0162] Fig. 23 The three-phase current waveforms at the time of regeneration in the state where the open-circuit fault has occurred in the upper side (left) and the three-phase current waveforms after the distortion has been eliminated by the switching control signals of the first case (case 1) and the switching control signals of the second case (case 2) in the state where the open-circuit fault has occurred in the lower side (upper and lower right) are shown. As shown in the drawing, even in the case where the open-circuit fault has occurred in the upper side, the three-phase alternating current is a waveform in which almost no distortion has occurred, as in the case where the open-circuit fault has occurred in the lower side. In this way, the control that adjusts the waveform at the time of regeneration is called a regeneration failure operation. Fig. 23

[0163] Fig. 24 An example of the outline steps of the occurrence site of the open-circuit fault is shown. When the occurrence of the open-circuit fault (OPEN-FAIL) is detected (#5), the rotating electric machine control device 1 determines whether the rotation speed of the rotating electric machine 80 is a rotation speed at which regeneration (ReGEN) is possible (#6). As described above, in the present embodiment, after the open-circuit fault site is determined, the drive control of the rotating electric machine 80 is continued by one inverter 10 in which no fault has occurred. In the case where regeneration is performed, in order to reduce the rotation speed of the rotating electric machine 80, in the case where the rotation speed of the rotating electric machine 80 is low, the rotating electric machine 80 can be decelerated to a stop.

[0164] Therefore, the rotating electric machine control device 1 determines whether the rotation speed of the rotating electric machine 80 is a rotation speed at which regeneration is possible in step #6, and in the case where regeneration is possible, a first fault site determination process (#10) accompanied by regeneration is executed. On the other hand, in the case where regeneration is not possible, after the deceleration process (#8) that decelerates the rotation speed of the rotating electric machine 80 to the above-described ultra-low rotation speed is executed, a second fault site determination process (#20) not accompanied by regeneration is executed. In addition, at the time of step #6, in the case where the rotation speed of the rotating electric machine 80 is already the ultra-low rotation speed, further deceleration is not necessary. In the deceleration process of step #8, as described with reference to FIG. 6, the rotation speed of the rotating electric machine 80 is decelerated to the ultra-low rotation speed, and the switching control signals of the upper side and the lower side of the inverter 10 are exchanged. Fig. 34 ​​As will be described later, the determination process (#81) including the rotational speed is executed. Therefore, the deceleration process of Step #8 is not necessarily accompanied by deceleration.

[0165] When the open-circuit failure site is determined in the first failure site determination process (#10) or the second failure site determination process (#20), the rotating electric machine control device 1 drives and controls the rotating electric machine 80 via the non-failed inverter 10 in the single-inverter control region Rs as described above (#60: 1-inv drive). Further, as will be described later with reference to Fig. 32 and Fig. 35 As will be described later, the open-circuit failure site can also be determined by the third failure site determination process (#30).

[0166] Hereinafter, the principle of determining the site where the open-circuit failure has occurred based on the three-phase current waveform will be described with reference to the flowchart of Figs. 25-31 Figs. 32-35 The sequence of determining the site where the open-circuit failure has occurred will be described with reference to the flowchart of

[0167] As will be described later with reference to Figs. 11-14 , Fig. 16 , Fig. 17 When the open-circuit failure occurs, the three-phase alternating current waveform is distorted and becomes an asymmetric waveform. For example, when the open-circuit failure occurs on the upper stage side of the first inverter 11 (or the lower stage side of the second inverter 12), as will be described later with reference to Fig. 11 , the waveform becomes a waveform in which the U-phase current Iu is deflected to the negative side and the V-phase current Iv and the W-phase current Iw are deflected to the positive side. Here, if the three-phase currents (the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw) are integrated over a predetermined time (for example, 200 [ms]), the U-phase integrated current ∑Iu, the V-phase integrated current ∑Iv, and the W-phase integrated current ∑Iw can be obtained, as will be described later with reference to Fig. 25

[0168] The U-phase integrated current ∑Iu, the V-phase integrated current ∑Iv, and the W-phase integrated current ∑Iw significantly show the distortion of the three-phase alternating current waveform, and by using them, the site where the open-circuit failure has occurred can be determined. Further, when integrating the currents, if the integration is started from the peak value of each alternating current, the error due to the shift of the integrated value can be suppressed.

[0169] Fig. 25 and Fig. 26 An example of the three-phase alternating current waveform and the integrated current by which the site where the open-circuit failure has occurred can be determined is shown in Fig. 27 An example of the three-phase alternating current waveform and the integrated current by which the determination of the failure site is difficult is shown in Fig. 28 and Fig. 29 As described above, the integrated current before the distortion of the alternating current during regeneration is eliminated and the integrated current after the distortion is eliminated are shown. Further,​​Fig. 30 and Fig. 31 An example of the cumulative current when an open-circuit failure occurs during power running at an ultra-low rotation speed is shown. Fig. 30 An example of the cumulative current when it is difficult to determine the failure site is shown, Fig. 31 An example of the cumulative current when it is possible to determine the failure site is shown.

[0170] In addition, Fig. 25 , Fig. 27 , Fig. 30 An example when the upper-side switching element 3H of the U phase of the first inverter 11 has an open-circuit failure is shown, Fig. 26 , Fig. 28 , Fig. 31 An example when the lower-side switching element 3L of the U phase of the first inverter 11 has an open-circuit failure is shown. In addition, Fig. 29 An example when the lower-side switching element 3L of the U phase of the second inverter 12 has an open-circuit failure is shown. Fig. 25 , Fig. 26 , Fig. 30 , Fig. 31 is a waveform during power running, Figs. 27-29 is a waveform during regeneration. Furthermore, Fig. 25 , Fig. 26 , Fig. 30 , Fig. 31 The dotted line in Fig. 28 and Fig. 29 indicates the timing when the open-circuit failure occurs.

[0171] As shown in Fig. 25 , when the upper-side switching element 3H of the U phase of the first inverter 11 is controlled by the hybrid pulse width modulation control in a state of an open-circuit failure during power running, the three-phase current waveforms become asymmetric and distorted waveforms. The waveforms become such that the U-phase current Iu is deflected to the negative side, and the V-phase current Iv and the W-phase current Iw are deflected to the positive side. Here, the rotating electric machine control device 1 accumulates the three-phase currents (the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw) for a predetermined time (for example, 200 [ms]). The U-phase cumulative current ∑Iu obtained by accumulating the U-phase current Iu deflected to the negative side increases to the negative side (the value decreases, and the waveform drops) as shown in Fig. 25 . In addition, the V-phase cumulative current ∑Iv and the W-phase cumulative current ∑Iw obtained by accumulating the V-phase current Iv and the W-phase current Iw deflected to the positive side increase to the positive side (the waveforms rise).

[0172] The rotating electric machine control device 1 sets a predetermined cumulative threshold value on the positive side and the negative side, determines that an open-circuit failure has occurred in a case where the cumulative threshold value exceeds the positive side or the negative side, and can determine the occurrence mode of the open-circuit failure. Here, the cumulative threshold value on the positive side is set to "Ith+", and the cumulative threshold value on the negative side is set to "Ith-". In Fig. 25 In the illustrated mode, the occurrence of an open-circuit failure is determined when the following condition is satisfied. This condition is set to the first mode.

[0173] (∑Iu < Ith-) && (∑Iv > Ith+) && (∑Iw > Ith+)

[0174] In addition, this condition is satisfied in a case where the lower-side switching element 3L of the U phase of the second inverter 12 has an open-circuit failure, in addition to a case where the upper-side switching element 3H of the U phase of the first inverter 11 has an open-circuit failure.

[0175] As Fig. 26 indicated, in a case where the lower-side switching element 3L of the U phase of the first inverter 11 is controlled by the hybrid pulse width modulation control in a state where an open-circuit failure has occurred, the three-phase current wave is also formed as an asymmetric and distorted waveform. The waveform becomes a waveform in which the U phase current Iu is deflected to the positive side, and the V phase current Iv and the W phase current Iw are deflected to the negative side. The U phase cumulative current ∑Iu obtained by accumulating the U phase current Iu deflected to the positive side increases (the waveform rises) to the positive side as indicated in Fig. 26 indicated. In addition, the V phase cumulative current ∑Iv and the W phase cumulative current ∑Iw obtained by accumulating the V phase current Iv and the W phase current Iw deflected to the negative side increase (the values decrease, and the waveforms fall) to the negative side. In Fig. 26 In the illustrated mode, the occurrence of an open-circuit failure is determined when the following condition is satisfied.

[0176] This condition is set to the second mode.

[0177] (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw < Ith-)

[0178] In addition, this condition is satisfied in a case where the upper-side switching element 3H of the U phase of the second inverter 12 has an open-circuit failure, in addition to a case where the lower-side switching element 3L of the U phase of the first inverter 11 has an open-circuit failure.

[0179] The conditions under which an open-circuit fault occurs in the twelve switching elements 3 constituting the first inverter 11 and the second inverter 12 are shown in Table 3 below, and there are six types, from the first mode to the sixth mode. In the following description, each switching element 3 uses the three-phase identification symbol (U, V, W), the identification number of the first inverter 11 and the second inverter 12 (1, 2), and the identification symbols (H, L) of the upper-side switching element 3H and the lower-side switching element 3L. For example, if it is the upper-side switching element 3H of the U phase of the first inverter 11, it is marked as "U1H", and if it is the lower-side switching element 3L of the W phase of the second inverter 12, it is marked as "W2L".

[0180] [Table 3]

[0181]

[0182]

[0183] Fig. 27 The diagram shows the accumulated current during regeneration via hybrid pulse width modulation control when an open-circuit fault occurs in the upper-side switching element 3H of phase U of the first inverter 11. (Example:) Fig. 14 As shown, the distortion of the three-phase AC waveform is very small. The U-phase current Iu deflects slightly to the negative side, the V-phase current Iv deflects slightly to the positive side, but the W-phase current Iw deflects almost nothing. Therefore, as... Fig. 27 As shown, the cumulative current ∑Iu of phase U tends to increase towards the negative side (value decreases, waveform declines), and the cumulative current ∑Iv of phase V tends to increase towards the positive side (waveform rises), but the cumulative current ∑Iw of phase W shows almost no increase or decrease on either the positive or negative side. Therefore, even after time has passed, the cumulative current ∑Iw of phase W does not meet any of the conditions in modes 1 to 6 shown in Table 3, and does not meet the detection conditions for an open-circuit fault. Therefore, in the case of an open-circuit fault occurring in the upstream switching element 3H, no abnormality was detected during regeneration (refer to...). Fig. 15 wait).

[0184] Fig. 28 The diagram shows the accumulated current during regeneration via hybrid pulse width modulation control when an open-circuit fault occurs in the downstream switching element 3L of the U-phase of the first inverter 11. (Example:) Fig. 13 and Fig. 14 As shown, the waveforms are such that the U-phase current Iu deflects to the positive side, while the V-phase currents Iv and Iw deflect to the negative side. The cumulative U-phase current ∑Iu is obtained by accumulating the positively deflected U-phase current Iu. Fig. 28increases (the value decreases, the waveform drops). In addition, the V-phase cumulative current ∑Iv and the W-phase cumulative current ∑Iw, which are obtained by cumulating the V-phase current Iv and the W-phase current Iw that deflect to the negative side, increase toward the positive side (the waveform rises). As with the second mode at the time of motoring, the following holds true, and it is determined that an open-circuit failure has occurred.

[0185] (∑Iu > Ith+ ) && (∑Iv < Ith- ) && (∑Iw < Ith- )

[0186] Thereafter, as described with reference to Fig. 21 and Fig. 22 , when the regenerative failure operation is performed by switching the switching control signals in order to eliminate distortion, the state in which the upper-side switching element 3H of the U-phase of the first inverter 11 has an open-circuit failure at the time of regeneration is equivalent (the same tendency is shown). Therefore, the increase in the cumulative currents toward the positive and negative sides is also eliminated. Fig. 27

[0187] The cumulative current at the time of regeneration by the mixed pulse width modulation control of the lower-side switching element 3L of the U-phase of the second inverter 12 in the state in which an open-circuit failure has occurred is shown. As shown in Fig. 29 and Fig. 13 , the waveform in which the U-phase current Iu deflects to the negative side, and the V-phase current Iv and the W-phase current Iw deflect to the positive side is obtained. The U-phase cumulative current ∑Iu, which is obtained by cumulating the U-phase current Iu that deflects to the negative side, increases toward the negative side (the value decreases, the waveform drops) as shown in Fig. 14 . In addition, the V-phase cumulative current ∑Iv and the W-phase cumulative current ∑Iw, which are obtained by cumulating the V-phase current Iv and the W-phase current Iw that deflect to the positive side, increase toward the positive side (the waveform rises). Therefore, as with the first mode at the time of motoring, the following holds true, and it is determined that an open-circuit failure has occurred. Fig. 29 (∑Iu < Ith- ) && (∑Iv > Ith+ ) && (∑Iw > Ith+ )

[0188] Thereafter, as described with reference to

[0189] and Fig. 21 , if the regenerative failure operation is performed by switching the switching control signals in order to eliminate distortion, the state in which the upper-side switching element 3H of the U-phase of the second inverter 12 has an open-circuit failure at the time of regeneration is equivalent. Therefore, the increase in the cumulative currents toward the positive and negative sides is also eliminated. Fig. 22 At the time of regeneration, the conditions that hold true when the six switching elements 3 of the lower side of the first inverter 11 and the second inverter 12 have open-circuit failures are shown in Table 4 below, and there are six kinds from the first mode to the sixth mode. The numbers and the logic expressions of the respective modes are the same as those of Table 3.

[0190]

[0191] ​[Table 4]

[0192] Mode Determination condition Faulty site 1 (∑Iu < Ith- ) && (∑Iv > Ith+) && (∑Iw > Ith+) U2L 2 (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw < Ith-) U1L 3 (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw > Ith+) V2L 4 (∑Iu < Ith-) && (∑Iv > Ith+) && (∑Iw < Ith-) V1L 5 (∑Iu > Ith+) && (∑Iv > Ith+) && (∑Iw < Ith-) W2L 6 (∑Iu < Ith-) && (∑Iv < Ith-) && (∑Iw > Ith+) W1L

[0193] If Table 3 and Table 4 are combined, as shown in Table 5 below, it is possible to determine in which one of the twelve switching elements an open-circuit failure has occurred.

[0194] [Table 5]

[0195]

[0196] Fig. 30 The cumulative currents at the time of motoring at an ultra-low rotational speed by the hybrid pulse width modulation control in a state where the upper-stage side switching element 3H of the U phase of the first inverter 11 has an open-circuit failure are shown. As shown in Fig. 16 and Fig. 17 , the three-phase alternating current waveforms hardly have distortion. Therefore, as shown in Fig. 30 , the U phase cumulative current ∑Iu, the V phase cumulative current ∑Iv, and the W phase cumulative current ∑Iw hardly increase and decrease on the positive side and the negative side. Therefore, even over time, the W phase cumulative current ∑Iw does not satisfy any of the conditions of the patterns 1 to 6 shown in Table 3 or Table 4, and does not satisfy the detection condition of the open-circuit failure.

[0197] Fig. 31 The cumulative currents at the time of motoring at an ultra-low rotational speed by the hybrid pulse width modulation control in a state where the lower-stage side switching element 3L of the U phase of the first inverter 11 has an open-circuit failure are shown. As shown in Fig. 16 and Fig. 17 , the three-phase current waveforms become asymmetric and distorted waveforms. They become waveforms in which the U phase current Iu is deflected to the positive side, and the V phase current Iv and the W phase current Iw are deflected to the negative side. The U phase cumulative current ∑Iu obtained by cumulating the U phase current Iu deflected to the positive side increases (the waveform rises) to the positive side as shown in Fig. 31 . In addition, the V phase cumulative current ∑Iv and the W phase cumulative current ∑Iw obtained by cumulating the V phase current Iv and the W phase current Iw deflected to the negative side increase (the values decrease, and the waveforms fall) to the negative side. In Fig. 31 the illustrated mode, when the following condition is satisfied, it is determined that an open-circuit failure has occurred. This condition is the same as the second pattern of Table 3 and Table 4.

[0198] (∑Iu > Ith+ ) && (∑Iv < Ith- ) && (∑Iw < Ith- )

[0199] During ultra-low speed power operation, the conditions under which an open-circuit fault occurs in the six switching elements 3 on the lower-level side of the first inverter 11 and the second inverter 12 are shown in Table 6 below, which includes six modes from the first mode to the sixth mode. The numbering and logic formula of each mode are the same as those in Tables 3 and 4, and Table 6 is the same as that in Table 4.

[0200] [Table 6]

[0201] Mode Determination condition Faulty site 1 (∑Iu < Ith-) && (∑Iv > Ith+) && (∑Iw < Ith-) U2L 2 (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw < Ith-) U1L 3 (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw > Ith+) V2L 4 (∑Iu < Ith-) && (∑Iv > Ith+) && (∑Iw < Ith-) V1L 5 (∑Iu > Ith+) && (∑Iv > Ith+) && (∑Iw < Ith-) W2L 6 (∑Iu < Ith-) && (∑Iv < Ith-) && (∑Iw > Ith+) W1L

[0202] If Tables 3 and 6 are combined, then as shown in Table 7 below, it is possible to determine which of the twelve switching elements has an open-circuit fault. This is the same as in Table 5.

[0203] [Table 7]

[0204]

[0205]

[0206] The following is for reference Figs. 32 to 35 The flowchart illustrates the steps for identifying the faulty arm. Fig. 32 An example of the entire process for identifying the faulty arm is shown. Fig. 33 An example of the steps in the first fault location identification process (#10) is shown. Fig. 34 An example of the steps for the second fault location identification process (#20) is shown. Fig. 35 An example of the steps for the third fault location identification process (#30) is shown.

[0207] As mentioned above, in order to detect open-circuit faults and identify the faulty arm, it is necessary to calculate the cumulative value of the AC current, i.e., the cumulative current. Therefore, the accumulation of AC current (phase current) begins (#1). As mentioned above, for example, the AC current (Iu, Iv, Iw) of 200 [ms] is accumulated and the cumulative current (∑Iu, ∑Iv, ∑Iw) is calculated.

[0208] In the next step #2, it is determined whether an overcurrent state (OC) is present. This is based on the inventors' experiments and simulations, for example... Fig. 19As shown in the high output region Roc, it is confirmed that the instantaneous value of the three-phase alternating current is a very large value in the case where the open circuit failure occurs in the operation region where the output torque of the rotating electric machine 80 is large and the rotational speed is also high. In such a case, overcurrent is detected by the not-shown overcurrent detection sensor possessed by the inverter 10 or the rotating electric machine 80, and the detection result is transmitted to the rotating electric machine control device 1. In response to the overcurrent, since the priority order is high, the rotating electric machine control device 1 restricts other control and preferentially executes control for eliminating the overcurrent state. Here, the rotating electric machine control device 1 executes the shutdown control (SDN) or the active short circuit control (ASC) (#3a), and reduces the rotational speed of the rotating electric machine 80 (#3: deceleration process). The rotating electric machine control device 1 resumes the normal control (torque control) (#3b, #3c) when the rotational speed reaches the target speed (for example, the rotational speed at which the operation point is outside the high output region Roc).

[0209] Next, it is determined whether the operation state of the rotating electric machine 80 is the power running (PWR) or the regeneration (ReGEN) (#4). In the case of the regeneration, the process proceeds to #1, and the description is made with reference to Fig. 35 As described later, the third failure site discrimination process (#30) is executed. In the case where the rotating electric machine 80 is performing the power running, it is determined whether the open circuit failure (OPEN-FAIL) is detected (#5). Here, it is determined whether one of the determination conditions of the six patterns shown in Table 3 is satisfied, and in the case where one is satisfied, it is detected that the open circuit failure has occurred. Further, the control state of the rotating electric machine 80 at the time of the step #5 corresponds to the first control state. In addition, here, the case where the open circuit failure is detected in the first operation point P1 shown in Fig. 2 is described. The description is made with reference to Fig. 19 Fig. 40 and Fig. 41 described later #3, #5.

[0210] When it is determined that the open circuit failure has occurred, it is next determined whether the rotating electric machine 80 can regenerate (ReGEN) (#6). As described above, in the present embodiment having two inverters 10, in the case where the open circuit failure has occurred, the rotating electric machine 80 is also controlled to continue the vehicle travel. When the rotating electric machine 80 is caused to regenerate, since the rotating electric machine 80 is decelerated, in the case where the travel speed of the vehicle is low and the rotational speed of the rotating electric machine 80 is also low, it is possible that the rotating electric machine 80 stops and the vehicle also stops due to the regeneration. That is, it is difficult to continue the vehicle travel. In the step #6, for example, it is determined whether the rotational speed of the rotating electric machine 80 is equal to or higher than a first prescribed rotational speed which is prescribed in advance.

[0211] ​In a case where the rotational speed of the rotary electric machine 80 is equal to or higher than the first prescribed rotational speed, the rotary electric machine control device 1 sets a regenerative torque (ReGEN-TR) (#7) and executes the first fault site discrimination processing (#10). With the setting of the regenerative torque, the operating point of the rotary electric machine 80 moves from the first operating point Pl shown in FIG. 8 to a second operating point P2. The rotary electric machine control device 1, after determining the fault side arm by executing the first fault site discrimination processing (#10), executes the single-inverter drive control (1-inv drive) (#61 (#60)) in which the rotary electric machine 80 is driven by one inverter 10. Fig. 19 In a case where the rotational speed of the rotary electric machine 80 is equal to or higher than the first prescribed rotational speed, the rotary electric machine control device 1 sets a regenerative torque (ReGEN-TR) (#7) and executes the first fault site discrimination processing (#10). With the setting of the regenerative torque, the operating point of the rotary electric machine 80 moves from the first operating point Pl shown in FIG. 8 to a second operating point P2. The rotary electric machine control device 1, after determining the fault side arm by executing the first fault site discrimination processing (#10), executes the single-inverter drive control (1-inv drive) (#61 (#60)) in which the rotary electric machine 80 is driven by one inverter 10.

[0212] In a case where the rotational speed of the rotary electric machine 80 is less than the first prescribed rotational speed, the second fault site discrimination processing (#20) is executed in step #6. As described with reference to Figs. 16 to 18 、 Fig. 30 、 Fig. 31 Table 6 and Table 7, the second fault site discrimination processing (#20) is processing accompanying the power running at an ultra-low rotational speed. That is, the second fault site discrimination processing (#20) is executed at a rotational speed lower than the second prescribed rotational speed. Therefore, before the second fault site discrimination processing (#20), the processing of setting the rotational speed of the rotary electric machine 80 to the second prescribed rotational speed (ultra-low speed side prescribed speed) is executed (#8). The rotary electric machine control device 1, after determining the fault side arm by executing the second fault site discrimination processing (#20), executes the single-inverter drive control (1-inv drive) (#62 (#60)) in which the rotary electric machine 80 is driven by one inverter 10.

[0213] Next, the first fault site discrimination processing (#10) will be described with reference to Fig. 33 In the first fault site discrimination processing (#10), first, it is determined whether an open-circuit fault is detected in the regenerative state (second control state) (#11). Here, it is determined whether one of the determination conditions of the six patterns shown in Table 4 is satisfied, and in a case where one is satisfied, it is detected that an open-circuit fault has occurred.

[0214] In a case where it is determined in step #11 that an open-circuit fault has occurred, as described with reference to Figs. 21 to 23 In order to eliminate distortion or deflection of the waveform of the alternating current (Iu, Iv, Iw) in regeneration, the regeneration failure operation (#12) is executed. With the normal regeneration or the regeneration accompanying the regeneration failure operation, the rotational speed of the rotary electric machine 80 is reduced, and the operating point moves into the single-inverter control region Rs. In step #13a (#13) after step #12, it is determined whether the operating point of the rotary electric machine 80 is within the single-inverter control region Rs. If the operating point is not within the single-inverter control region Rs, deceleration based on regeneration (#14a (#14)) is continued until it is determined that the operating point is within the single-inverter control region Rs.

[0215] In a case where the operation point enters the single-inverter control region Rs, it is determined whether the failure mode FP at the time of detection of the open failure in step #5 is the first failure mode FP1 (#15a (#15)). In a case where the failure mode FP is the first failure mode FP1, the failure side arm is the upper stage side arm of the first inverter 11 (inv1: H) or the lower stage side arm of the second inverter 12 (inv2: L). In step #11, since the open failure is also detected in regeneration, the failure side arm is the lower stage side arm of the second inverter 12 (inv2: L). Therefore, in step #16a (#16), the failure site (FAIL) is set to the lower stage side arm of the second inverter 12 (inv2-LOW).

[0216] The rotating electric machine control device 1 moves the operation point to the third operation point P3 through zero Newton control (0Nm) that controls the output torque of the rotating electric machine 80 to be zero, controls the second inverter 12 in which the open failure has occurred in the lower stage side arm through upper stage side active short-circuit control (ASC-H), and controls the first inverter 11 through pulse width modulation control (#17a (#17)). Then, it is restored from regeneration to motoring (#18a (#18)), and single-inverter drive control (1-inv drive) that drives the rotating electric machine 80 through one inverter 10 is executed (#61 (#60)).

[0217] The paths from step #15a (#15) to steps #16b (#16), #17b (#17), #18b (#18), #61 (#60) are also the same, and thus detailed explanation is omitted. In addition, the paths from step #11 to steps #13b (#13), #14b (#14), #15b (#15), #16c (#16), #17c (#17), #18c (#18), #61 (#60), and the paths from step #15b (#15) to steps #16d (#16), #17d (#17), #18d (#18), #61 (#60) are also the same, and thus detailed explanation is omitted.

[0218] Further, as described with reference to Fig. 21 , Fig. 22 , Fig. 28 , Fig. 29When the regeneration failure operation is executed, distortion and deflection of the alternating current (Iu, Iv, Iw) are also suppressed, and deflection of the cumulative current (∑Iu, ∑Iv, ∑Iw) also becomes small. Therefore, the determination condition at the time of regeneration described with reference to Table 4 is also not satisfied. Therefore, the cumulative current (∑Iu, ∑Iv, ∑Iw) used in the determination in steps #15, #16 is preferably a value obtained before the regeneration failure operation is executed in step #12 (for example, a value obtained at the time of determination in step #11). Alternatively, it is preferable to execute the determination in steps #15, #16 before the regeneration failure operation.

[0219] Next, the second failure site determination processing (#20) will be described with reference to Fig. 34 The second failure site determination processing (#20) will be described. As described with reference to Fig. 32 Before the second failure site determination processing (#20), the super low speed side prescribed speed setting processing (#8) of setting the rotational speed of the rotary electric machine 80 to a second prescribed rotational speed (super low speed side prescribed speed) is executed. In the super low speed side prescribed speed setting processing, first, it is determined whether the rotational speed of the rotary electric machine 80 is lower than or equal to the second prescribed rotational speed (super low speed side prescribed speed) (#81). In the case where the rotational speed is higher than the super low speed side prescribed speed, the rotational speed of the rotary electric machine 80 is decelerated by the shutdown control (SDN), the active short-circuit control (ASC), and the zero Newton control (0Nm) (#82). In the case where the rotational speed of the rotary electric machine 80 is lower than or equal to the second prescribed rotational speed (super low speed side prescribed speed), the control mode of the rotary electric machine 80 is set to the torque mode (#83). That is, in the case where the control for deceleration of step #82 is not performed, the torque mode is continued, and in the case where the control for deceleration is performed, the torque mode is returned to.

[0220] The rotary electric machine control device 1 determines whether an open circuit failure is detected in a state where the rotary electric machine 80 is operated at a rotational speed lower than the second prescribed rotational speed (super low speed side prescribed speed) (power running at a super low rotational speed (second control state)). Here, it is determined whether one of the determination conditions of the six modes shown in Table 6 is satisfied, and in the case where one is satisfied, it is detected that an open circuit failure has occurred.

[0221] In the case where it is determined in step #21 that the open-circuit failure has occurred, it is determined whether the failure pattern FP at the time when the open-circuit failure is detected in step #5 is the first failure pattern FP1 (#25a (#25)). In the case where the failure pattern FP is the first failure pattern FP1, the failure side arm is the upper stage side arm of the first inverter 11 (inv1: H) or the lower stage side arm of the second inverter 12 (inv2: L). In step #21, since the open-circuit failure is detected also in the power running at the ultra-low speed, the failure side arm is the lower stage side arm of the second inverter 12 (inv2: L). Therefore, in step #26a (#26), the failure site (FAIL) is set to the lower stage side arm of the second inverter 12 (inv2-LOW).

[0222] The rotating electric machine control device 1 controls the second inverter 12 in which the open-circuit failure has occurred in the lower stage side arm by the upper stage side active short-circuit control (ASC-H) and controls the first inverter 11 by the pulse width modulation control (#27a (#27)). Then, the power running at the ultra-low speed is recovered to the normal power running (#28a (#28)), and the single-inverter drive control (1-inv drive) by which the rotating electric machine 80 is driven by one inverter 10 is executed (#62 (#60)).

[0223] The paths from step #25a (#25) to steps #26b (#26), #27b (#27), #28b (#28), #62 (#60) are also the same, and detailed explanation is omitted. In addition, the paths from step #21 to steps #25b (#25), #26c (#26), #27c (#27), #28c (#28), #62 (#60) and the paths from step #25b (#25) to steps #26d (#26), #27d (#27), #28d (#28), #62 (#60) are also the same, and detailed explanation is omitted.

[0224] Next, the third failure site determination processing (#30) will be described with reference to FIG. 12. Fig. 35 The third failure site determination processing (#30) will be described. As described above, in the case where the failure site is the lower stage side arm of the second inverter 12 (inv2-LOW), the failure site is determined in step #30. Fig. 32As shown, the third failure site discrimination processing (#30) is branched and executed before the open failure discrimination processing in the first control state of Step #5. The third failure site discrimination processing (#30) is executed in the regeneration of the rotary electric machine 80, and corresponds to the failure discrimination processing in the second control state. However, the third failure site discrimination processing (#30) is executed independently of the failure discrimination processing in the first control state. As described above, in the case where the inverter 10 is switched by the hybrid pulse width modulation control, even if an open failure occurs in the upper side arm, distortion of the AC waveform occurring at the time of regeneration is small, and thus it is difficult to detect the occurrence of the open failure. Therefore, in the third failure site discrimination processing (#30), the occurrence of the open failure is detected only in the case where the open failure has occurred in the lower side arm, and the inverter 10 in which the failure has occurred is discriminated. In addition, when the operation state of the rotary electric machine 80 is switched to the motoring, the open failure detection in the first control state can be performed. Therefore, the third failure site discrimination processing is executed in order to rapidly detect that the open failure has occurred in at least the lower side arm in the regeneration of the rotary electric machine 80 and determine the failure site.

[0225] In the third failure site discrimination processing (#30), first, it is determined whether the open failure is detected in the regeneration state (the second control state) (#31). In the third failure site discrimination processing, it is also determined whether one of the determination conditions of the six patterns shown in Table 4 is satisfied, and in the case where one is satisfied, it is detected that the open failure has occurred. Here, it is detected that the lower side failure pattern LF is occurring. As described above, in the case where the open failure has occurred in the upper side arm, in the third failure site discrimination processing (#30), neither the detection of the failure nor the discrimination of the failure site can be performed.

[0226] In the case where it is determined that the open failure has occurred in Step #31, as described with reference to Figs. 21 to 23 In order to eliminate the distortion or the deflection of the waveform of the AC current (Iu, Iv, Iw) in the regeneration, the regeneration failure operation is executed (#32). By the execution of the regeneration failure operation, the rotation speed of the rotary electric machine 80 is reduced, and the operation point is moved into the single inverter control region Rs. In Step #33 after Step #32, it is determined whether the operation point of the rotary electric machine 80 is in the single inverter control region Rs. If the operation point is not in the single inverter control region Rs, the deceleration based on the regeneration is continued (#34) until it is determined that the operation point is in the single inverter control region Rs.

[0227] In a case where the operation point enters the single-inverter control region Rs, it is determined which of the lower-side arm of the first inverter 11 and the lower-side arm of the second inverter 12 has an open-circuit failure. Here, it is determined whether the detection phase of the open-circuit failure is the second inverter 12 (#35). As described above with reference to Table 4, the rotary electric machine control device 1 can determine the switching element 3 in which the open-circuit failure has occurred, depending on which of the determination conditions of the six modes is satisfied. That is, it is known whether the open-circuit failure has occurred in the first inverter 11 or in the second inverter 12.

[0228] When the open-circuit failure has occurred in the second inverter 12, in step #36a (#36), the failure site (FAIL) is set to the lower-side arm (inv2-LOW) of the second inverter 12. In addition, when the open-circuit failure has occurred in the first inverter 11, in step #36b (#36), the failure site (FAIL) is set to the lower-side arm (inv1-LOW) of the first inverter 11.

[0229] In a case where the open-circuit failure has occurred in the second inverter 12, the rotary electric machine control device 1 controls the second inverter 12 in which the open-circuit failure has occurred in the lower-side arm by upper-side active short-circuit control (ASC-H), and controls the first inverter 11 by pulse width modulation control (#37a (#37)). Then, single-inverter drive control (1-inv drive) by one inverter 10 to drive the rotary electric machine 80 is executed (#63 (#60)). In addition, in a case where the open-circuit failure has occurred in the first inverter 11, the rotary electric machine control device 1 controls the first inverter 11 in which the open-circuit failure has occurred in the lower-side arm by upper-side active short-circuit control (ASC-H), and controls the second inverter 12 by pulse width modulation control (#37b (#37)). Then, single-inverter drive control (1-inv drive) by one inverter 10 to drive the rotary electric machine 80 is executed (#63 (#60)).

[0230] Further, the control method in the single-inverter drive control (#60) is not limited to the continuous pulse width modulation control (CPWM) and the discontinuous pulse width modulation control (DPWM), but can be a rectangular wave control (1-Pulse). These are examples, and the modulation form can be any form. Here, the hybrid pulse width modulation control makes the switching control signal non-active in the second period H2, thereby enabling reduction of system loss. By setting the mutually different periods to the second period H2 in the first inverter 11 and the second inverter 12, as a whole, it is possible to realize a state in which continuous switching by a plurality of pulses is performed. However, in the single-inverter drive control, since only one inverter 10 is switched, in the hybrid pulse width modulation control, distortion of the alternating current waveform can occur. Therefore, the single-inverter drive control is preferably performed by the pulse width modulation control or the rectangular wave control which outputs a plurality of pulses different in pattern in one cycle of the electrical angle. However, as the control method, it is also permissible to select the hybrid pulse width modulation control (MX-PWM).

[0231] Further, as described with reference to Fig. 21 , Fig. 22 , Fig. 28 , Fig. 29 and the like, when the regeneration failure operation is performed, distortion and deflection of the alternating current (Iu, Iv, Iw) are also suppressed, and deflection of the cumulative current (∑Iu, ∑Iv, ∑Iw) also becomes small. Therefore, the determination condition at the time of regeneration described with reference to Table 4 is also not established. Therefore, as with the first fault site discrimination processing (#10), the cumulative current (∑Iu, ∑Iv, ∑Iw) used in the determination in step #35 is preferably a value obtained before the regeneration failure operation is performed in step #32 (for example, a value obtained at the time of determination in step #31). Alternatively, it is preferable to perform the determination in step #35 before the regeneration failure operation.

[0232] As described above, the rotating electric machine control device 1 calculates the current cumulative values (∑Iu, ∑Iv, ∑Iw) of each of the multiphase alternating currents (Iu, Iv, Iw) by accumulating each of the multiphase alternating currents (Iu, Iv, Iw) in the case where an open-circuit failure (one-phase open-circuit failure) in which one of the switching elements 3 always becomes an open-circuit state occurs, detects the occurrence of the open-circuit failure based on the positive and negative of each of the current cumulative values (∑Iu, ∑Iv, ∑Iw), and discriminates the site where the open-circuit failure has occurred. In the case where the first inverter 11 and the second inverter 12 are controlled by the hybrid pulse width modulation control, the rotating electric machine control device 1 discriminates which of the first failure mode FP1 and the second failure mode FP2 is the failure mode FP based on the positive and negative of each of the current cumulative values (∑Iu, ∑Iv, ∑Iw) in the first control state (power running). Also, the rotating electric machine control device 1 discriminates which of the first lower-stage side failure mode LF1 and the second lower-stage side failure mode LF2 is the lower-stage side failure mode LF based on each of the current cumulative values (∑Iu, ∑Iv, ∑Iw) in the second control state (regeneration / power running at an ultra-low rotational speed) different from the first control state (power running). Also, the rotating electric machine control device 1 discriminates which of the upper-stage side arm of the first inverter 11, the lower-stage side arm of the first inverter 11, the upper-stage side arm of the second inverter 12, and the lower-stage side arm of the second inverter 12 is the failure side arm based on the discrimination result in the first control state and the discrimination result in the second control state.

[0233] Further, in the above embodiment, a manner in which the discrimination in the second control state is performed after the discrimination in the first control state is exemplified with reference to Fig. 32 However, the order of the first control state and the second control state can be reversed. Also, the discrimination based on the discrimination result in the first control state and the discrimination result in the second control state includes a case where there is no discrimination result in the first control state. In a case where there is no discrimination result in the first control state and the discrimination in the second control state is the lower-stage side failure mode LF, the lower-stage side arm of the second inverter 12 is determined to be the failure side arm by the first lower-stage side failure mode LF1, and the lower-stage side arm of the first inverter 11 is determined to be the failure side arm by the second lower-stage side failure mode LF2. As for a case where there are both the discrimination result in the first control state and the discrimination result in the second control state, reference is made to Fig. 15 As described above.

[0234] Further, in the case where the open-circuit failure occurs in the upper side arm and the first control state does not exist, the failure side arm in which the open-circuit failure occurs is not determined. However, in this case, even if the rotating electric machine 80 regenerates and the open-circuit failure occurs in the upper side arm at the time of regeneration, the alternating currents (Iu, Iv, Iw) do not become distorted. Therefore, since there is almost no influence, there is no problem even if the open-circuit failure is not detected. After that, when the rotating electric machine 80 is motoring, the open-circuit failure is detected. At this time, as a result of the determination in the first control state, the first failure mode FP1 or the second failure mode FP2 is determined. At the time of regeneration before motoring, since the determination result in the second control state (no lower side failure mode LF) has been obtained, the rotating electric machine control device 1 is able to determine the failure side arm on the basis of the determination result in the first control state and the determination result in the second control state. Of course, after the open-circuit failure is detected in motoring, further motoring at an ultra-low speed or regeneration can be performed, the determination result in the second control state is newly obtained, and then the failure side arm can be determined on the basis of the determination result in the first control state and the determination result in the second control state.

[0235] In addition, as described above, the rotating electric machine control device 1 has the loss reduction priority mode and the noise reduction priority mode as the control modes of the rotating electric machine 80. As described above with reference to Table 2, in the noise reduction priority mode, both the first inverter 11 and the second inverter 12 are driven by the normal pulse width modulation control, instead of the hybrid pulse width modulation control. The behavior of the three-phase alternating current in the case where the open-circuit failure occurs when both the first inverter 11 and the second inverter 12 are driven in the noise reduction priority mode is different from the behavior described with reference to Figs. 9 to 12. Figs. 11 to 14

[0236] Figs. 36 to 39 With Figs. 11 to 14 the same, a waveform chart showing an example of the three-phase alternating current waveform (U-phase current Iu, V-phase current Iv, W-phase current Iw) in the case where the open-circuit failure occurs in the noise reduction priority mode (i.e., the case where both the inverters 10 are controlled by the pulse width modulation control). Fig. 36 and Fig. 37 With Fig. 11 and Fig. 12 With the same, a waveform chart showing an example of the three-phase alternating current waveform in the case where the open-circuit failure occurs at the time of motoring, Fig. 38 and Fig. 39 With Fig. 13 and Fig. 14 With the same, a waveform chart showing an example of the three-phase alternating current waveform in the case where the open-circuit failure occurs at the time of regeneration. With Figs. 11 to 14 the same, Figs. 36 to 39 With the same, a waveform chart showing an example of the three-phase alternating current waveform in the case where the open-circuit failure occurs at the time of motoring, Figs. 11 to 14 With the same, a waveform chart showing an example of the three-phase alternating current waveform in the case where the open-circuit failure occurs at the time of motoring, Figs. 36 to 39 ​The waveforms of the case where the open-circuit failure occurs in the switching element 3 of the upper side (HIGHSIDE) of the first inverter 11, the waveforms of the case where the open-circuit failure occurs in the switching element 3 of the lower side (LOWSIDE) of the first inverter 11, the waveforms of the case where the open-circuit failure occurs in the switching element 3 of the upper side (HIGHSIDE) of the second inverter 12, and the waveforms when the open-circuit failure occurs in the switching element 3 of the lower side (LOWSIDE) of the second inverter 12 are shown in a matrix. In addition, the same as the waveforms with respect to Fig. 11 Fig. 12 Fig. 36 Fig. 37 The case where the rotational speed of the rotating electric machine 80 is higher at the same torque is shown. The same as the waveforms with respect to Fig. 13 Fig. 14 Fig. 38 Fig. 39 The case where the rotational speed of the rotating electric machine 80 is higher at the same torque is shown.

[0237] The same as the waveforms with respect to Fig. 11 Fig. 12 The same as the waveforms with respect to Fig. 36 Fig. 37 If the open-circuit failure occurs at the time of motoring, the three-phase alternating current waveforms become asymmetric and distorted waveforms regardless of the upper side or the lower side of the first inverter 11 and the second inverter 12. In addition, the three-phase alternating current waveforms are the same waveforms in the case where the open-circuit failure occurs in the upper side of the first inverter 11 and in the case where the open-circuit failure occurs in the lower side of the second inverter 12, and are the same waveforms in the case where the open-circuit failure occurs in the lower side of the first inverter 11 and in the case where the open-circuit failure occurs in the upper side of the second inverter 12.

[0238] In addition, as shown in Fig. 38 Fig. 39 In the case where the open-circuit failure occurs at the time of regeneration, the three-phase alternating current waveforms become asymmetric and distorted waveforms regardless of the upper side or the lower side of the first inverter 11 and the second inverter 12. In addition, the three-phase alternating current waveforms are the same waveforms in the case where the open-circuit failure occurs in the upper side of the first inverter 11 and in the case where the open-circuit failure occurs in the lower side of the second inverter 12, and are the same waveforms in the case where the open-circuit failure occurs in the lower side of the first inverter 11 and in the case where the open-circuit failure occurs in the upper side of the second inverter 12.

[0239] In the loss reduction priority mode (i.e., the case where the two inverters 10 are controlled by the hybrid pulse width modulation control), as shown in Fig. 13 Fig. 14 ​​​​​​​​​​As shown, in the case where an open-circuit failure occurs on the lower-stage side of the first inverter 11 and the second inverter 12 at the time of regeneration, the three-phase alternating-current waveform is an asymmetric and distorted waveform, but in the case where an open-circuit failure occurs on the upper-stage side of the first inverter 11 and the second inverter 12, the three-phase alternating-current waveform is a substantially symmetric and hardly distorted waveform.

[0240] That is, in the loss reduction priority mode, as shown in Fig. 15 , at the time of motoring (except at the time of ultra-low rotation speed), the three-phase alternating-current waveform shows abnormality regardless of where the open-circuit failure occurs, and the abnormality mode is roughly classified into Fig. 15 the first failure mode FP1 and the second failure mode FP2 as shown. On the other hand, at the time of regeneration, the three-phase alternating-current waveform shows abnormality only in the case where an open-circuit failure occurs on the lower-stage side of the first inverter 11 and the second inverter 12. Therefore, if the states of the three-phase alternating-current waveform at the time of motoring and at the time of regeneration are compared, it is possible to discriminate in which one of the upper-stage side and the lower-stage side of the inverter 10 the open-circuit failure occurs in the case where the open-circuit failure is detected (see also Tables 3 to 5 and refer to the above description thereof).

[0241] However, in the noise reduction priority mode, as shown in Fig. 42 , at the time of motoring and at the time of regeneration, the states of the three-phase alternating-current waveform show the same tendency. That is, in either of the time of motoring and the time of regeneration, in the case where an open-circuit failure occurs, it is possible to discriminate the first failure mode FP1 or the second failure mode FP2 as the failure mode FP. Therefore, it is not possible to discriminate in which one of the upper-stage side and the lower-stage side of the inverter 10 the open-circuit failure occurs. Therefore, the rotating electric machine control device 1 assumes one of the first inverter 11 and the second inverter 12 as the failure inverter, and on the basis of the assumption, drives and controls the rotating electric machine 80 via the inverter 10 which is assumed not to have failed in the single-inverter control region Rs (1-inv drive).

[0242] After that, if no abnormality (open-circuit failure) is detected, it is assumed to be correct, and thus the inverter 10 assumed to be failure is determined as the failure inverter. On the other hand, in the case where abnormality (open-circuit failure) is further detected, the assumption is incorrect, and thus the inverter 10 not assumed to be failure is determined as the failure inverter. Also, in the state where the correct failure inverter is determined, the rotating electric machine 80 is driven and controlled via the inverter 10 (normal inverter) which has not failed in the single-inverter control region Rs (1-inv drive).

[0243] Hereinafter, the description will be made with reference to the flowchart of Fig. 40 . As described above with reference to Fig. 36 , Fig. 37 and Fig. 42That is, even in the case where the inverter 10 is switched by the usual pulse width modulation control instead of the hybrid pulse width modulation control, it is possible to discriminate the failure mode FP by detecting the open-circuit failure in the first control state (step #5). Therefore, here, the processing after step #5 is explained.

[0244] First, in step #41, it is determined whether or not the operation point of the rotating electric machine 80 is within the single-inverter control region Rs. If the operation point is not within the single-inverter control region Rs, deceleration based on, for example, shutdown control (SDN), active short-circuit control (ASC), zero Newton control (0Nm) is executed (#42) until it is determined that the operation point is within the single-inverter control region Rs. In the case where the operation point is the single-inverter control region Rs, the control mode of the rotating electric machine 80 is set to the torque mode (#43). That is, in the case where the control for deceleration of step #42 is not executed, the torque mode is continued, and in the case where the control for deceleration is executed, the torque mode is returned to.

[0245] The failure mode FP at the time when the open-circuit failure is detected in step #5 is the first failure mode FP1 or the second failure mode FP2. Therefore, it is not clear in which inverter 10 of the first inverter 11 and the second inverter 12 the open-circuit failure has occurred. Therefore, it is assumed that the rotating electric machine control device 1 has occurred in one of the inverters 10. That is, the rotating electric machine control device 1 sets one of the first inverter 11 and the second inverter 12 as the assumed failure inverter as the assumed failure inverter and the other inverter 10 as the assumed normal inverter as the assumed normal inverter (#51). Here, the first inverter 11 is set as the assumed normal inverter (NORMAL) and the second inverter 12 is set as the assumed failure inverter (OPEN-FAIL). Of course, this assumption can be the reverse.

[0246] For example, if the failure mode FP at the time when the open-circuit failure is detected in step #5 is the first failure mode FP1, the failure side arm is the upper stage side arm of the first inverter 11 or the lower stage side arm of the second inverter 12. In step #51, since the second inverter 12 is set as the assumed failure inverter, it is assumed that the failure side arm is the lower stage side arm of the second inverter 12. That is, the lower stage side arm of the second inverter 12 is set as the assumed failure side arm.

[0247] In step #52, it is determined whether the open-fault (OPEN-FAIL) occurred in the upper side arm or the lower side arm, based on the assumed faulty inverter set in step #51 and the fault pattern FP determined in step #5. Here, since the faulty side arm is the lower side arm, the rotating electric machine control device 1 controls the second inverter 12 by the upper side active short-circuit control (ASC-H) and controls the first inverter 11 by the pulse width modulation control (#53a (#53)).

[0248] When starting the switching of the inverter 10 based on the new control mode, the re-accumulation of the phase currents is started (#54a (#54). That is, the accumulated values of the three-phase currents (Iu, Iv, Iw) are reset once, and the accumulated currents (∑Iu, ∑Iv, ∑Iw) are calculated again. Next, in step #55a (#55), it is determined whether the open-fault is detected based on these accumulated currents (∑Iu, ∑Iv, ∑Iw). Here, in the case where the open-fault is detected, there is an error in the assumption in step #51 and step #52. That is, it is determined that the faulty side arm is not the lower side arm of the second inverter 12, but the upper side arm of the first inverter 11, which is the other side of the first fault pattern FP1.

[0249] The rotating electric machine control device 1 sets the fault site (FAIL) to the upper side arm (inv1-HIGH) of the first inverter 11 (#56a (#56)). Then, the rotating electric machine control device 1 controls the first inverter 11 in which the open-fault occurred in the upper side arm by the lower side active short-circuit control (ASC-L) and controls the second inverter 12 by the pulse width modulation control (#57a (#57). Then, the single-inverter drive control (1-inv drive) by which the rotating electric machine 80 is driven by one inverter 10 is executed (#65 (#60)).

[0250] If the open-fault is not detected in step #55a (#55), the assumption in step #51 and step #52 is correct. That is, as assumed, it is determined that the faulty side arm is the lower side arm of the second inverter 12. The fault site (FAIL) is set to be the lower side arm (inv2-LOW) of the second inverter 12 (#56b (#56)). Then, the rotating electric machine control device 1 controls the second inverter 12 in which the open-fault occurred in the lower side arm by the upper side active short-circuit control (ASC-H) and controls the first inverter 11 by the pulse width modulation control (#57b (#57). Then, the single-inverter drive control (1-inv drive) by which the rotating electric machine 80 is driven by one inverter 10 is executed (#65 (#60)).

[0251] The path from step #52 to step #53b (#53), #54b (#54), #55b (#55), #56c (#56), #57c (#57), #65a (#60) is also the same as that of step #53a (#53), #54a (#54), #55a (#55), #56b (#56), #57b (#57), #65a (#60), and thus the detailed description is omitted. In addition, the path from step #55b (#55) to step #56d (#56), #57d (#27), #65a (#60) is also the same as that of step #55a (#55), #56c (#56), #57c (#57), #65a (#60), and thus the detailed description is omitted. In addition, in the noise reduction priority mode, the inverter 10 is switched by the normal pulse width modulation control. Therefore, when the single inverter drive control (1-inv drive) is executed, the control mode can not be changed from the hybrid pulse width modulation control to the normal pulse width modulation control.

[0252] Thus, even in the case where the control mode of the inverter 10 is not the hybrid pulse width modulation control, the rotary electric machine control device 1 can determine whether the failure mode FP of the open circuit failure is the first failure mode FP1 or the second failure mode FP2 based on the positive or negative of each current cumulative value (∑Iu, ∑Iv, ∑Iw), and then assume one of the first inverter 11 and the second inverter 12 as the failure inverter as the assumed failure inverter. Then, the rotary electric machine control device 1 performs the active short-circuit control by setting all of the switching elements 3 of the assumed failure side arm to the open state and setting all of the switching elements 3 of the other non-assumed failure side arm to the closed state in the upper stage side arm and the lower stage side arm of the assumed failure inverter based on the determined failure mode FP, and performs the switching control on the inverter 10 different from the assumed failure inverter (assumed normal inverter). Thereafter, the rotary electric machine control device 1 determines that the assumed failure inverter is the failure inverter and determines that the assumed failure side arm is the failure side arm based on the positive or negative of each current cumulative value (∑Iu, ∑Iv, ∑Iw) in the case where the open circuit failure is not detected. In the case where the open circuit failure is detected, the rotary electric machine control device 1 determines the inverter 10 different from the assumed failure inverter as the failure inverter and determines the failure side arm in the failure inverter based on the failure mode FP.

[0253] Further, the method of the assumed failure inverter described with reference to the flowchart of Fig. 40 of course also applies to the case where the control mode is the hybrid pulse width modulation control.

[0254] In addition, in the above, the method of assuming one of the first inverter 11 and the second inverter 12 as the failure inverter to determine the failure inverter and determine the failure site is exemplified. However, as shown in the flowchart of Fig. 41 , after the control mode is changed from the pulse width modulation control to the hybrid pulse width modulation control, the method of determining the failure inverter and determining the failure site by referring to Figs. 32 to 34The first failure site determination process (#10) or the second failure site determination process (#20) determines the failure inverter and determines the failure site.

[0255] That is, in a case where the rotating electric machine control device 1 does not control the two inverters 10 by the hybrid pulse width modulation control but controls the two inverters 10 by the pulse width modulation control in which the plurality of pulses of different patterns are output in the second period H2 and the plurality of pulses of different patterns are output in one cycle of the electrical angle or the rectangular wave control in which one pulse is output in one cycle of the electrical angle, when the occurrence of the open-circuit failure is detected in the first control state, in the first control state, the failure pattern FP is determined, and thereafter, the control mode of the two inverters 10 is changed to the hybrid pulse width modulation control, in the second control state, it is determined whether it is the lower-stage side failure pattern LF, and thereafter, the failure side arm is determined on the basis of the determination result in the first control state and the determination result in the second control state.

[0256] As described above, in the noise reduction priority mode, the first failure pattern FP1 or the second failure pattern FP2 can be determined as the failure pattern FP when the open-circuit failure occurs in either of the motoring and the regeneration. Therefore, in the noise reduction priority mode, the first control state includes the motoring and the regeneration. That is, the first control state before the control mode is changed to the hybrid pulse width modulation control includes the motoring and the regeneration. As with the loss reduction priority mode, the second control state after the control mode is changed to the hybrid pulse width modulation control is the regeneration or the motoring at the super low rotation speed.

[0257] As described above, according to the present embodiment, the failure site can be determined in a case where the open-circuit failure occurs in one of the switching elements 3 of the two inverters 10 respectively provided at both ends of the stator coil 8 constituting the open-circuit winding.

[0258] Next, a technique of determining the failure site in a case where the short-circuit failure occurs in one of the switching elements 3 of the two inverters 10 respectively provided at both ends of the stator coil 8 constituting the open-circuit winding (stator coil 8) will be described.

[0259] In the present embodiment, a plurality of control regions R (refer to Fig. 43 corresponding to the operation conditions of the rotating electric machine 80 are set, and the rotating electric machine control device 1 controls the inverter 10 in the control mode corresponding to each control region R. Fig. 43 An example of the relationship between the rotation speed of the rotating electric machine 80 and the torque is shown. For example, as shown in Fig. 43As shown, as the control region R of the rotary electric machine 80, a first speed region VR1, a second speed region VR2 in which the rotational speed of the rotary electric machine 80 at the same torque T is higher than in the first speed region VR1, and a third speed region VR3 in which the rotational speed of the rotary electric machine 80 at the same torque T is higher than in the second speed region VR2 are set.

[0260] For example, as shown in Table 8 below, the rotary electric machine control device 1 controls both of the first inverter 11 and the second inverter 12 in the first speed region VR1 by continuous pulse width modulation control (CPWM). In addition, the rotary electric machine control device 1 controls both of the first inverter 11 and the second inverter 12 in the second speed region VR2 by discontinuous pulse width modulation control (DPWM). In addition, the rotary electric machine control device 1 controls both of the first inverter 11 and the second inverter 12 in the third speed region VR3 by rectangular wave control. Mi_sys, Mi_inv1, and Mi_inv2 in the table will be described later.

[0261]

Table 8

[0262] R Mi_sys INV1 Mi_inv1 INV2 Mi_inv2 VR1 M < X CPWM M < X CPWM M < X VR2 X ≤ M < 0.78 DPWM X ≤ M < 0.78 DPWM X ≤ M < 0.78 VR3 M＝0.78 1-Pulse M＝0.78 1-Pulse M＝0.78

[0263] The boundary of each control region R (the boundary of the first speed region VR1, the second speed region VR2, and the third speed region VR3) is preferably set in accordance with at least one of the ratio of the rotational speed of the rotary electric machine 80 to the direct current voltage and the ratio of the effective value of the line voltage of the multiphase alternating current voltage to the direct current voltage (either the command value or the converted value based on the output voltage) corresponding to the torque of the rotary electric machine 80.

[0264] As Fig. 43 As exemplified, the operating condition of the rotary electric machine 80 is often defined by the relationship between the rotational speed and the torque. The control region R can be set based on one parameter, the rotational speed. Here, the rotational speed that defines the boundary of the control region R can also be set to be constant regardless of the torque, but it is more preferable to set the rotational speed that defines the boundary of the control region R to be different values depending on the torque. Thereby, the rotary electric machine 80 can be driven and controlled with high efficiency according to the operating condition of the rotary electric machine 80.

[0265] Further, for example, in a case where a high output (high rotation speed or high torque) is required for the rotating electric machine 80, in a voltage-type inverter, the requirement is fulfilled by increasing the DC voltage or increasing the proportion of the DC voltage converted to the AC voltage. In a case where the DC voltage is constant, the requirement can be fulfilled by increasing the proportion of the DC voltage converted to the AC voltage. The proportion can be expressed as the proportion of the effective value of the three-phase AC power with respect to the DC power (in the case of the voltage-type inverter, equivalent to the proportion of the effective value of the three-phase AC voltage with respect to the DC voltage). As described above, in the control mode of controlling the inverter 10, various modes exist from low to high in the proportion.

[0266] As shown in Table 8, if the control regions R are set based on the proportion of the effective value of the three-phase AC with respect to the DC (modulation ratio) decided in accordance with the requirement for the rotating electric machine 80, the rotating electric machine 80 can be driven and controlled with high efficiency in accordance with the operating conditions of the rotating electric machine 80. Further, in the table, "Mi_inv1" indicates the modulation ratio of the first inverter 11, "Mi_inv2" indicates the modulation ratio of the second inverter 12, and "Mi_sys" indicates the modulation ratio of the entire system.

[0267] In the above-described Table 8, the modulation ratios corresponding to the respective control regions R are exemplified. In the present embodiment, the terminal-to-terminal voltage "E1" of the first DC power supply 61 and the terminal-to-terminal voltage "E2" of the second DC power supply 62 are the same (both are the voltage "E"). If the effective value on the AC side of the first inverter 11 is set as "Va_inv1" and the effective value on the AC side of the second inverter 12 is set as "Va_inv2", the modulation ratio "Mi_inv1" of the first inverter 11 and the modulation ratio "Mi_inv2" of the second inverter 12 are expressed by the following described Equations (1), (2). Further, the modulation ratio "Mi_sys" of the entire system is expressed by the following Equation (3).

[0268] Mi_inv1 = Va_inv1 / E1 = Va_inv1 / E... (1)

[0269] Mi_inv2 = Va_inv2 / E2 = Va_inv2 / E... (2)

[0270] Mi_sys = (Va_inv1 + Va_inv2) / (E1 + E2) = (Va_inv1 + Va_inv2) / 2E... (3)

[0271] For the instantaneous value of the voltage, the instantaneous vector needs to be considered, but simply considering the modulation factor, the modulation factor "Mi_sys" of the system as a whole is "(Mi_inv1+Mi_inv2) / 2" according to the equations (1) to (3). Further, in Table 8, the modulation factors corresponding to the respective control regions R are shown as rated values. Therefore, at the time of actual control, a range in which the modulation factors corresponding to the respective control regions R are repeated can also be included, taking into account fluctuations and the like when the control mode changes in the control region R.

[0272] Further, the modulation factor "X" is set based on a theoretical upper limit value (approximately 0.707) of the modulation factor using continuous pulse width modulation (space vector pulse width modulation), further taking into account the dead time. The modulation factor "X" is appropriately set based on experiments or simulations and the like (for example, 0.3 or less).

[0273] However, the switching element 3 constituting the inverter 10 sometimes has a short-circuit failure in which the switching element 3 is always in an on state, or an open-circuit failure in which the switching element 3 is always in an off state. For example, as shown in FIG. 6, in a case where the rotary electric machine 80B having a Y-shaped connection type stator coil 8B is driven by one inverter 10B, if a short-circuit failure or an open-circuit failure occurs, the vehicle stops by performing shutdown control in which all of the switching elements 3B of the inverter 10B are set to an off state, or active short-circuit control in which the upper-stage switching element 3H of all of the arms 3A of the multiphase is set to an on state or the lower-stage switching element 3L of all of the arms 3A of the multiphase is set to an on state. Fig. 46

[0274] However, as in the present embodiment, in a case where the rotary electric machine 80 having mutually independent multiphase open-circuit windings as stator coils 8 is driven and controlled via the first inverter 11 and the second inverter 12, the rotary electric machine 80 can be driven and controlled via one inverter 10 of the first inverter 11 and the second inverter 12. As described above, if one of the inverters 10 is short-circuited by the active short-circuit control, the stator coils 8 of the multiphase are short-circuited in the one inverter 10, the one inverter 10 becomes a neutral point, and the stator coils 8 are Y-connected. Therefore, the rotary electric machine control device 1 can realize a mode in which the rotary electric machine 80 that is Y-connected is controlled via one inverter 10 (the inverter 10 on the side that is not subjected to the active short-circuit control).

[0275] ​In the case where the rotary electric machine 80B is driven by one inverter 10B, if a short-circuit failure or an open-circuit failure occurs, it is necessary to stop the vehicle in which the rotary electric machine 80B is a driving force source. However, in the case where the rotary electric machine 80 is driven by two inverters 10 as in the present embodiment, even if a short-circuit failure or an open-circuit failure occurs, it is possible to continue the travel of the vehicle within a certain limit range without stopping the vehicle in which the rotary electric machine 80 is a driving force source. For example, it is possible to travel to the current destination such as a home or a repair factory.

[0276] For example, in the case where a short-circuit failure has occurred in one inverter 10, it is possible to execute the active short-circuit control by setting all of the switching elements 3 of the arm on one side including the switching element 3 in which the short-circuit failure has occurred among the upper-stage side arm and the lower-stage side arm to the on state and setting all of the switching elements 3 of the arm on the other side to the off state. By setting all of the switching elements 3 of the arm on one side including the switching element 3 in which the short-circuit failure has occurred to the on state, it is possible to use the switching element 3 in which the short-circuit failure has occurred as a switching element 3 in which no failure has occurred.

[0277] In addition, in the case where an open-circuit failure has occurred in one inverter 10, it is possible to execute the active short-circuit control by setting all of the switching elements 3 of the arm on one side not including the switching element 3 in which the open-circuit failure has occurred among the upper-stage side arm and the lower-stage side arm to the on state and setting all of the switching elements 3 of the arm on the other side including the switching element 3 in which the open-circuit failure has occurred to the off state. By setting all of the switching elements 3 of the arm on one side including the switching element 3 in which the open-circuit failure has occurred to the off state, it is possible to use the switching element 3 in which the open-circuit failure has occurred as a switching element 3 in which no failure has occurred.

[0278] Therefore, it is necessary to at least determine which one of the first inverter 11 and the second inverter 12 the switching element 3 in which the failure has occurred belongs to and which one of the upper-stage side arm and the lower-stage side arm the switching element 3 in which the failure has occurred belongs to. More preferably, it is sufficient to determine which one of the phases the switching element 3 in which the failure has occurred is.

[0279] Hereinafter, a case where an open-circuit failure has occurred in one of the switching elements 3 configuring the first inverter 11 and the second inverter 12 (a case where one-phase open-circuit failure has occurred) will be described. The switching element 3 in which the open-circuit failure has occurred is determined, and the rotary electric machine 80 is driven by the fail-safe control in such a manner that the travel of the vehicle can be continued after the determination.

[0280] Fig. 44 An example of the action points from the detection of the short-circuit failure to the driving of the rotary electric machine 80 by the fail-safe control is shown in the control region of the rotary electric machine 80. In addition, Fig. 44The control region "Rs" in the drawing indicates a single-inverter control region Rs when the rotary electric machine 80 is controlled by one inverter 10, and "Rd" indicating the entirety of the control regions indicates a double-inverter control region Rd when the rotary electric machine 80 is controlled by two inverters 10. "K" indicates a schematic boundary between the single-inverter control region Rs and the double-inverter control region Rd in the present embodiment. Here, the rotational speed of "K" can be set to be constant regardless of the torque, but as shown in Fig. 44

[0281] Fig. 45 The flow of current when the shutdown control is executed to bring all the switching elements 3 of the first inverter 11 and the second inverter 12 to the off state in a state where the upper-side switching element 3H (31H) of the U-phase arm 3u of the first inverter 11 is in a short-circuit fault state is exemplified. Fig. 46 The flow of current when the shutdown control is executed to bring all the switching elements 3 of the inverter 10B to the off state in a state where the upper-side switching element 3H of the U-phase arm 3u is in a short-circuit fault state in a system (1-inverter system) that drives a rotary electric machine 80B having a stator coil 8B that is Y-shaped via one inverter 10B is exemplified.

[0282] For example, consider a case where a short-circuit fault has occurred at the first operating point Q1 shown in Fig. 44 In addition, in the case where a short-circuit fault has occurred, since an overcurrent flows in the inverter 10 in which the short-circuit fault has occurred, the case where a short-circuit fault can have occurred in the inverter 10 is transmitted to the rotary electric machine control device 1 via the drive circuit 2 by the overcurrent detection circuit. At this time, it is not necessary to determine the switching element 3 in which a short-circuit fault can have occurred. It is only necessary to determine in which one of the first inverter 11 and the second inverter 12 a short-circuit fault has occurred.

[0283] As shown in Fig. 44 The first operating point Q1 is an operating point at which the rotational speed is relatively high. Therefore, even in the case where a short-circuit fault is detected and the shutdown control is executed on the first inverter 11 and the second inverter 12, the rotary electric machine 80 continues to rotate by the inertial force, and a large back electromotive force (BEMF) is generated by the rotation thereof. When this back electromotive force exceeds the voltage on the direct-current side of the inverter 10 (the direct-current link voltage Vdc), the current flows from the rotary electric machine 80 to the direct-current power supply 6 side.

[0284] As described above, Fig. 45 ​A state in which the upper side switching element 3H (31H) of the U-phase arm 3u of the first inverter 11 has a short-circuit failure and is controlled to be shut down is shown. Each arm 3A of the second inverter 12 can only pass a current on a path based on the freewheeling diode 35. Therefore, only in a case where the counter electromotive voltage exceeds the direct current link voltage Vdc of the second inverter 12 (the terminal-to-terminal voltage of the second direct current power supply 62), a current can flow into the second direct current power supply 62 to form a current loop, and a current can flow into the first inverter 11 and the second inverter 12. Details will be described later, and in a case where a current loop can be formed, the switching element 3 in which a short-circuit failure has occurred can be determined based on a phase current (here, three-phase currents lu, lv, lw).

[0285] On the other hand, for example, as shown in Fig. 44 , in a case where the first operation point Q1 is "Q1'" at which the rotational speed is lower, sometimes the counter electromotive voltage does not exceed the direct current link voltage Vdc. In a case where the counter electromotive voltage does not exceed the direct current link voltage Vdc of the second inverter 12 (the terminal-to-terminal voltage of the second direct current power supply 62), a current loop cannot be formed on the second inverter 12 side, and a current cannot flow in the first inverter 11 and the second inverter 12.

[0286] Further, as shown in Fig. 46 , in the 1-inverter system, the upper side switching element 3H (31H) of the U-phase arm 3u has a short-circuit failure, and thus a current loop can be formed. Therefore, as long as the counter electromotive voltage is generated slightly, a current can flow in the inverter 10B.

[0287] As described above, in a case where the first operation point Q1 is "Q1'", since the counter electromotive voltage does not exceed the direct current link voltage Vdc, a current loop is not formed, and thus the switching element 3 in which a short-circuit failure has occurred cannot be determined based on a phase current (here, three-phase currents lu, lv, lw). Therefore, as will be described later, the operation point is moved to the single inverter control region Rs. For example, the fourth operation point Q4 shown in Fig. 44 is moved to. Also, the rotating electric machine control device 1 does not form a current loop by shut down control, but forms a current loop by driving control of the rotating electric machine 80 in a torque control mode in which a torque command is provided, and determines the switching element 3 in which a short-circuit failure has occurred based on a phase current (here, three-phase currents lu, lv, lw).

[0288] Fig. 47 A torque command, a change in rotational speed, and a three-phase current waveform in this case are exemplified. The rotating electric machine 80 detects occurrence of a short-circuit failure at a time tl at which the rotating electric machine 80 rotates at a first rotational speed RS1 based on a first torque command T1 (first operation point Q1 (Q1')) (refer to Fig. 44). The deceleration of the rotating electric machine 80 is started at time t3, and the rotational speed is reduced to the second rotational speed RS2 at time t5. At this time, it is preferable to reduce the rotational speed of the rotating electric machine 80 by, for example, shutdown control. Further, as shown in FIG. 10, the torque command can also be reduced to "zero" at this time. In this case, the operation point moves from the first operation point Ql (Ql') to a third operation point Q3 via a second operation point Q2 (Q2'). When the rotational speed is reduced to the second rotational speed RS2, the rotating electric machine control device 1 performs torque control on the rotating electric machine 80 using a second torque command T2 that is smaller than the first torque command Tl (time t7 to time t9). Thereby, the operation point moves from the third operation point Q3 to a fourth operation point Q4. Fig. 47

[0289] As shown in FIG. 10, the waveform of the three-phase current (Iu, Iv, Iw) in the torque control performed from time t7 to time t9 is an asymmetric and distorted waveform. The rotating electric machine control device 1 determines the switching element 3 in which the short-circuit failure is occurring, based on the three-phase current (Iu, Iv, Iw) from time t7 to time t9. Details will be described later, but in a case where the back electromotive voltage exceeds the direct-current link voltage Vdc, the waveform of the three-phase current (Iu, Iv, Iw) also becomes an asymmetric and distorted waveform. Therefore, even in a case where the back electromotive voltage exceeds the direct-current link voltage Vdc, the rotating electric machine control device 1 determines the switching element 3 in which the short-circuit failure occurs, based on the three-phase current (Iu, Iv, Iw). Fig. 47

[0290] If the switching element 3 in which the short-circuit failure occurs is determined, the rotating electric machine control device 1 drives and controls the rotating electric machine 80 in the single-inverter control region Rs to cause the vehicle to travel. For example, the operation point is moved from the fourth operation point Q4 to a fifth operation point Q5. The torque command at the fifth operation point Q5 is the first torque command Tl that is the same as the torque command at the first operation point Ql. Therefore, although the rotational speed of the rotating electric machine 80 is reduced, the same torque as before the short-circuit failure can be output to drive the rotating electric machine 80, and the vehicle can continue to travel.

[0291] Further, in Fig. 47 , a manner in which the torque command is changed from the second torque command T2 to the first torque command Tl is exemplified, but as Fig. 48 is exemplified, the torque command can be changed from zero to the first torque command Tl after the torque command is temporarily changed to "zero" from the second torque command T2.

[0292] Fig. 49 ​​The flowchart illustrates an example of the steps for determining the location of a short-circuit fault. When a short-circuit fault is detected in either the first inverter 11 or the second inverter 12 by a current detection circuit or the like, the rotating electric machine control device 1 determines that a single-phase short-circuit fault has occurred (S1). As described above, the rotating electric machine control device 1 identifies which inverter 10 of the first inverter 11 and the second inverter 12 has experienced a short-circuit fault. First, it performs shutdown control on the inverter 10 that experienced the short-circuit fault, i.e., the faulty inverter (inv(fail)) (S2). Next, the rotating electric machine control device 1 also performs shutdown control on the inverter 10 that did not experience a short-circuit fault, i.e., the normal inverter (inv(normal)) (S3).

[0293] Next, the rotary motor control device 1 determines whether the back electromotive force (BEMF) exceeds the DC link voltage Vdc (S4). Since there is a linear relationship between the back electromotive force and the rotational speed of the rotary motor 80, the rotary motor control device 1 can also make this determination based on the rotational speed of the rotary motor 80. That is, the rotary motor control device 1 can also determine whether the rotational speed of the rotary motor 80 is above a predetermined speed. If the speed is above the predetermined speed, the rotary motor control device 1 can determine that the back electromotive force (BEMF) exceeds the DC link voltage Vdc. Furthermore, this determination can also be performed based on the modulation rate. For example, if the modulation rate is above a predetermined modulation rate, the rotary motor control device 1 can determine that the back electromotive force (BEMF) exceeds the DC link voltage Vdc.

[0294] When the back electromotive force (BEMF) exceeds the DC link voltage Vdc, as referenced Fig. 45 The rotating motor control device 1 determines whether the short-circuit faulty switching element 3 is an upper-level or lower-level arm based on the three-phase currents (Iu, Iv, Iw). That is, the rotating motor control device 1 performs fault-level discrimination processing (S5). Furthermore, after fault discrimination processing (S5), the rotating motor control device 1 performs deceleration processing (S50) by reducing the speed of the rotating motor 80 through shutdown control. Additionally, since the first inverter 11 and the second inverter 12 of the inverter 10 were shut down in steps S2 and S3, it is permissible to continue shutdown control in step S50.

[0295] In a case where the back electromotive force (BEMF) does not exceed the DC link voltage Vdc, or after the failure level discrimination processing of step S5 is executed, the rotating electric machine control device 1 determines whether the current operation point is in the single-inverter control region Rs. That is, it is determined whether the rotating electric machine 80 can be driven by one inverter 10 (S6). In a case where one-inverter driving cannot be performed, the deceleration processing of step S50 is continued to decelerate the rotating speed of the rotating electric machine 80. Thus, even if the operation point is outside the single-inverter control region Rs, the rotating speed of the rotating electric machine 80 is reduced during the repetition of step S6 and step S50, and the determination condition of step S6 is satisfied.

[0296] In a case where the operation point of the rotating electric machine 80 is in the single-inverter control region Rs, the rotating electric machine control device 1 determines whether the failure level has been determined (S7). If the failure level has been determined through step S5, step S10 described later is entered. On the other hand, in a case where step S5 is not passed, or even if step S5 is passed, the failure level is not determined, step S8 is entered.

[0297] Step S8 is executed, for example, at the third operation point Q3 described above, and the second torque command T2 is set as the torque command. Next, the rotating electric machine control device 1 discriminates, for example, at the fourth operation point Q4, whether the short-circuit failure-occurring switching element 3 is the upper-stage side arm or the lower-stage side arm, on the basis of the three-phase currents (Iu, Iv, Iw). That is, the rotating electric machine control device 1 executes the failure level discrimination processing (S9).

[0298] In step S10 after step S7 or step S9, it is determined whether the failure level is the upper stage. In step S5 or step S9, whether the short-circuit failure-occurring switching element 3 is the upper-stage side arm or the lower-stage side arm is discriminated on the basis of the three-phase currents (Iu, Iv, Iw) until step S10. Therefore, on the basis of these discrimination results, the rotating electric machine control device 1 determines whether the failure level is the upper stage or the lower stage.

[0299] In a case where the failure level is the upper stage, the rotating electric machine control device 1 executes the upper-stage side active short-circuit control (ASC-H) for the failure inverter (inv(fail)) and the pulse width modulation control (PWM) for the normal inverter (inv(normal)) (S11H (S11)). In addition, in a case where the failure level is the lower stage, the rotating electric machine control device 1 executes the lower-stage side active short-circuit control (ASC-L) for the failure inverter (inv(fail)) and the pulse width modulation control (PWM) for the normal inverter (inv(normal)) (S11L (S11)). These steps S11 are executed at the fifth operation point Q5 in Fig. 44

[0300] ​Further, the rotating electric machine control device 1 outputs information of the failure level in which the short-circuit failure occurs to a higher-level control device or the like, not shown (S12). Specifically, information of the failed inverter (the first inverter 11 or the second inverter 12) and information of whether it is the upper-stage side arm or the lower-stage side arm are output. Further, information of which phase in the multiphase it is can also be output.

[0301] Further, in the manner described above with reference to Fig. 49 the failure level determination processing in step S9 is executed. However, even if the back electromotive force (BEMF) exceeds the DC link voltage Vdc, it is not obstructive for the rotating electric machine control device 1 to reduce the rotating speed of the rotating electric machine 80 until the operating point reaches the single-inverter control region Rs and then execute the failure level determination processing (S9) by setting the torque command in step S8.

[0302] Further, in the manner described above with reference to Fig. 49 the failure level determination processing in step S9 is executed. However, even if the back electromotive force (BEMF) exceeds the DC link voltage Vdc, it is not obstructive for the rotating electric machine control device 1 to reduce the rotating speed of the rotating electric machine 80 until the operating point reaches the single-inverter control region Rs and then execute the failure level determination processing (S9) by setting the torque command in step S8.

[0303] Further, in the manner described above with reference to Fig. 49 the failure level determination processing in step S9 is executed. However, even if the back electromotive force (BEMF) exceeds the DC link voltage Vdc, it is not obstructive for the rotating electric machine control device 1 to reduce the rotating speed of the rotating electric machine 80 until the operating point reaches the single-inverter control region Rs and then execute the failure level determination processing (S9) by setting the torque command in step S8.

[0304] Next, the principle of determining the short-circuit failure of the switching element 3 will be described with reference to Figs. 50 to 53 Fig. 50 and Fig. 51 are diagrams illustrating the principle of determination in the failure level determination processing in step S9 in Fig. 49 Fig. 50 shows a case where the upper-stage side switching element 3H of the U phase of the first inverter 11 has a short-circuit failure, Fig. 51 shows a case where the lower-stage side switching element 3L of the U phase of the first inverter 11 has a short-circuit failure. Fig. 52 and Fig. 53 are diagrams illustrating the principle of determination in the failure level determination processing in step S5 in Fig. 49 Fig. 52 shows a case where the upper-stage side switching element 3H of the U phase of the first inverter 11 has a short-circuit failure,​​​Fig. 53 A case where the lower-side switching element 3L of the U phase of the first inverter 11 has a short-circuit failure is shown.

[0305] The rotating electric machine control device 1 accumulates the three-phase alternating currents respectively, and calculates the current accumulation values of the respective phases, based on the positive and negative of the respective current accumulation values, to determine which one of the upper-side arm and the lower-side arm of the inverter that has a short-circuit failure. Here, the inverter that has a short-circuit failure is the first inverter 11. In addition, the three-phase alternating currents are the three-phase currents (U-phase current Iu, V-phase current Iv, W-phase current Iw). In addition, the current accumulation values of the respective phases are the U-phase accumulated current ∑Iu, the V-phase accumulated current ∑Iv, and the W-phase accumulated current ∑Iw.

[0306] As Fig. 47 illustrated, when the torque control (pulse width modulation control) is executed in a state where the upper-side switching element 3H of the U phase of the first inverter 11 has a short-circuit failure, the three-phase current waveforms become asymmetrical and distorted waveforms. As Fig. 47 and Fig. 50 illustrated, the waveforms become waveforms in which the U-phase current Iu is largely deflected to the positive side, and the V-phase current Iv and the W-phase current Iw are largely deflected to the negative side. Here, the rotating electric machine control device 1 accumulates the three-phase currents (U-phase current Iu, V-phase current Iv, W-phase current Iw) for a predetermined time (for example, 200 [ms]). The U-phase accumulated current ∑Iu obtained by accumulating the deflection of the U-phase current Iu largely deflected to the positive side increases (the waveform rises) to the positive side as Fig. 50 illustrated. In addition, the V-phase accumulated current ∑Iv and the W-phase accumulated current ∑Iw obtained by accumulating the V-phase current Iv and the W-phase current Iw largely deflected to the negative side increase (the values decrease, and the waveforms drop) to the negative side.

[0307] The rotating electric machine control device 1 sets a predetermined accumulation threshold value on the positive side and the negative side, and determines that a short-circuit failure has occurred when the accumulation threshold value exceeds either the positive side or the negative side, and is able to determine the occurrence mode of the short-circuit failure. Here, the accumulation threshold value on the positive side is set to "Ith+", and the accumulation threshold value on the negative side is set to "Ith-". In Fig. 50 the illustrated manner, the occurrence of a short-circuit failure is determined when the following condition is satisfied. This condition is set to the first mode.

[0308] (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw < Ith-)

[0309] In addition, this condition is satisfied not only in the case where the upper-side switching element 3H of the U phase of the first inverter 11 has a short-circuit failure, but also in the case where the lower-side switching element 3L of the U phase of the second inverter 12 has a short-circuit failure.

[0310] In addition, in the case where the torque control (pulse width modulation control) is executed in the state where the lower-stage side switching element 3L of the U phase of the first inverter 11 has a short-circuit failure, as shown in FIG. 10, the three-phase current waveforms also become asymmetric and distorted waveforms. As shown in FIG. 10, the U phase current Iu becomes a waveform greatly deflected to the negative side, and the V phase current Iv and the W phase current Iw become waveforms greatly deflected to the positive side. The U phase cumulative current ∑Iu obtained by accumulating the U phase current Iu greatly deflected to the negative side gradually increases (the value decreases, and the waveform drops) to the negative side as shown in FIG. 10. In addition, the V phase cumulative current ∑Iv and the W phase cumulative current ∑Iw obtained by accumulating the V phase current Iv and the W phase current Iw greatly deflected to the positive side increase (the waveforms rise) to the positive side. In the mode illustrated in FIG. 10, the occurrence of the short-circuit failure is determined when the following condition is satisfied. This condition is set as the second mode. Fig. 51 Fig. 51 Fig. 51 Fig. 51

[0311] (∑Iu < Ith- ) && (∑Iv > Ith+) && (∑Iw > Ith+)

[0312] In addition, this condition is satisfied not only in the case where the lower-stage side switching element 3L of the U phase of the first inverter 11 has a short-circuit failure, but also in the case where the upper-stage side switching element 3H of the U phase of the second inverter 12 has a short-circuit failure.

[0313] The conditions satisfied when the twelve switching elements 3 constituting the first inverter 11 and the second inverter 12 have short-circuit failures are shown in Table 9 below, and there are six kinds from the first mode to the sixth mode. In the following description, each switching element 3 uses a three-phase identification symbol (U, V, W), an identification number of the first inverter 11 and the second inverter 12 (1, 2), and an identification symbol of the upper-stage side switching element 3H and the lower-stage side switching element 3L (H, L), and for example, if it is the upper-stage side switching element 3H of the U phase of the first inverter 11, it is marked as "U1H", and if it is the lower-stage side switching element 3L of the W phase of the second inverter 12, it is marked as "W2L".

[0314]

Table 9

[0315] Mode Determination condition Faulty site 1 (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw < Ith-) U1H, U2L 2 (∑Iu < Ith-) && (∑Iv > Ith+) && (∑Iw > Ith+) U1L, U2H 3 (∑Iu < Ith-) && (∑Iv > Ith+) && (∑Iw < Ith-) V1H, V2L 4 (∑Iu > Ith+) && (∑Iv < Ith-) && (∑Iw > Ith+) V1L, V2H 5 (∑Iu < Ith-) && (∑Iv < Ith-) && (∑Iw > Ith+) W1H, W2L 6 (∑Iu > Ith+) && (∑Iv > Ith+) && (∑Iw < Ith-) W1L, W2H

[0316] As described above, in step S1 of FIG. 10, it is determined which inverter 10 of the first inverter 11 and the second inverter 12 has a short-circuit failure. Therefore, in step S2 of FIG. 10, the upper-stage side switching element 3H of the U phase of the inverter 10 in which the short-circuit failure has occurred is controlled to be turned off. Figure 49 Figure 49 ​​​​​In step S9, if which one of the first to sixth patterns is the condition that is determined to be true, it is possible to determine in which upper side arm or lower side arm of which inverter 10 a short-circuit failure has occurred. For example, in a case where a short-circuit failure has occurred in the first inverter 11 and the condition of the fourth pattern is satisfied, it is determined that a short-circuit failure is occurring in the lower side arm of the first inverter 11. In the present embodiment, it is also determined which switching element 3 in the lower side arm has a short-circuit failure. In this example, it is determined that the lower side switching element 3L(V1L) of the V-phase of the first inverter 11 has a short-circuit failure.

[0317] As described above, step S9 is executed in a case where the rotational speed of the rotary electric machine 80 is less than the prescribed rotational speed (or less than the prescribed modulation rate). The rotary electric machine control device 1 performs torque control on the first inverter 11 and the second inverter 12 on the basis of a torque command that is lower than a prescribed torque (for example, the second torque command T2) that is prescribed in advance. Figure 44 and Figure 47 The rotary electric machine control device 1 then determines in which one of the upper side arm and the lower side arm of the inverter in which a short-circuit failure has occurred on the basis of the positive or negative of each of the current cumulative values (the U-phase cumulative current ∑Iu, the V-phase cumulative current ∑Iv, and the W-phase cumulative current ∑Iw) during the torque control.

[0318] In this way, in a case where the first inverter 11 is the inverter in which a short-circuit failure has occurred, in a case where the current cumulative value of one phase among the plurality of current cumulative values (the U-phase cumulative current ∑Iu, the V-phase cumulative current ∑Iv, and the W-phase cumulative current ∑Iw) is positive and the current cumulative values of the other phases are negative, it is determined that a short-circuit failure has occurred in the upper side arm of the inverter in which a short-circuit failure has occurred (Table 9: patterns 1, 3, 5), and in a case where the current cumulative value of one phase among the plurality of current cumulative values is negative and the current cumulative values of the other phases are positive, it is determined that a short-circuit failure has occurred in the lower side arm of the inverter in which a short-circuit failure has occurred (Table 9: patterns 2, 4, 6). In addition, in a case where the second inverter 12 is the inverter in which a short-circuit failure has occurred, in a case where the current cumulative value of one phase among the plurality of current cumulative values is positive and the current cumulative values of the other phases are negative, it is determined that a short-circuit failure has occurred in the lower side arm of the inverter in which a short-circuit failure has occurred (Table 9: patterns 1, 3, 5), and in a case where the current cumulative value of one phase among the plurality of current cumulative values is negative and the current cumulative values of the other phases are positive, it is determined that a short-circuit failure has occurred in the upper side arm of the inverter in which a short-circuit failure has occurred (Table 9: patterns 2, 4, 6).

[0319] The same applies to the case where the rotational speed of the rotary electric machine 80 is equal to or higher than the prescribed rotational speed (or equal to or higher than the prescribed modulation rate). In the case where the rotational speed of the rotary electric machine 80 is equal to or higher than the prescribed rotational speed, the rotary electric machine control device 1 executes the shutdown control that brings all the switching elements 3 of both the first inverter 11 and the second inverter 12 into the off state. Also, the rotary electric machine control device 1 discriminates which of the upper side arm and the lower side arm of the faulty inverter has a short-circuit failure on the basis of the positive and negative of each current cumulative value in the process of executing the shutdown control.

[0320] In the case where the upper side switching element 3H (U1H) of the U phase of the first inverter 11 has a short-circuit failure and the shutdown control is executed, even in the case where the rotational speed of the rotary electric machine 80 is equal to or higher than the prescribed rotational speed, the three-phase current waveforms become asymmetrical and distorted waveforms. As shown in FIG. 18, they become waveforms in which the U phase current Iu greatly deflects to the positive side, and the V phase current Iv and the W phase current Iw greatly deflect to the negative side. The U phase cumulative current ∑Iu obtained by cumulating the U phase current Iu that greatly deflects to the positive side increases (the waveform rises) to the positive side as shown in FIG. 19. Also, the V phase cumulative current ∑Iv and the W phase cumulative current ∑Iw obtained by cumulating the V phase current Iv and the W phase current Iw that greatly deflect to the negative side increase (the values decrease, and the waveforms fall) to the negative side. This tendency is the same as in the manner shown in FIG. 17. In the manner shown in FIG. 18, the occurrence of a short-circuit failure is determined when the conditions below are satisfied. The conditions are the same as the first pattern shown in Table 9 described above. Figure 52 Figure 52 Figure 50 Figure 52 In the manner shown in FIG. 18, the occurrence of a short-circuit failure is determined when the conditions below are satisfied. The conditions are the same as the first pattern shown in Table 9 described above.

[0321] (∑Iu > Ith+ ) && (∑Iv < Ith- ) && (∑Iw < Ith- )

[0322] As described above, the conditions are satisfied not only in the case where the upper side switching element 3H (U1H) of the U phase of the first inverter 11 has a short-circuit failure, but also in the case where the lower side switching element 3L (U2L) of the U phase of the second inverter 12 has a short-circuit failure.

[0323] Also, even in the case where the shutdown control is executed in the state where the lower side switching element 3L (U1L) of the U phase of the first inverter 11 has a short-circuit failure, the three-phase current waveforms become asymmetrical and distorted waveforms as shown in the lower part of FIG. 22. As shown in FIG. 23, they become waveforms in which the U phase current Iu greatly deflects to the negative side, and the V phase current Iv and the W phase current Iw greatly deflect to the positive side. The U phase cumulative current ∑Iu obtained by cumulating the U phase current Iu that greatly deflects to the negative side increases (the waveform rises) to the negative side as shown in FIG. 24. Also, the V phase cumulative current ∑Iv and the W phase cumulative current ∑Iw obtained by cumulating the V phase current Iv and the W phase current Iw that greatly deflect to the positive side increase (the values decrease, and the waveforms fall) to the positive side. This tendency is the same as in the manner shown in FIG. 21. In the manner shown in FIG. 23, the occurrence of a short-circuit failure is determined when the conditions below are satisfied. The conditions are the same as the second pattern shown in Table 9 described above. Figure 53 Figure 53 Figure 53 ​​​​​increases (value decreases, waveform drops). In addition, V-phase cumulative current ∑Iv and W-phase cumulative current ∑Iw, which are obtained by cumulating V-phase current Iv and W-phase current Iw that are largely deflected to the positive side, increase (waveform rises) to the positive side. This tendency is the same as that shown in Figure 51 In the same manner as shown in Figure 53 In the same manner as shown in

[0324] (∑Iu < Ith- ) && (∑Iv > Ith+) && (∑Iw > Ith+)

[0325] In the same manner as described above, this condition is established in the case where a short-circuit fault occurs in the upper-stage side switching element 3H (U2H) of the U phase of the second inverter 12, in addition to the case where a short-circuit fault occurs in the lower-stage side switching element 3L (U1L) of the U phase of the first inverter 11.

[0326] In this way, in the case where the rotational speed of the rotary electric machine 80 is equal to or higher than the prescribed rotational speed, in step S5, the switching element 3 in which a short-circuit fault has occurred can be determined in accordance with the condition of Table 9 described above.

[0327] As described above, according to the present embodiment, in the case where a short-circuit fault has occurred in one of the switching elements 3 of the two inverters 10 that are respectively provided at both ends of the open-circuit winding, the switching element 3 in which a fault has occurred can be determined. Moreover, control of the rotary electric machine 80 can be continued without using the switching element 3 in which a fault has occurred.

[0328] Here, in the first inverter 11 and the second inverter 12, the inverter 10 other than the fault inverter is taken as a normal inverter, one side of the upper-stage side arm and the lower-stage side arm of the fault inverter in which a short-circuit fault has occurred is taken as a fault side arm, and the other side is taken as a non-fault side arm. The rotary electric machine control device 1 performs active short-circuit control that sets all of the switching elements 3 of the fault side arm of the fault inverter to an on state and sets all of the switching elements 3 of the non-fault side arm to an off state, and performs single-inverter drive control that drives the rotary electric machine 80 via the normal inverter.

[0329] For example, as described above, in the case where a short-circuit fault occurs in the upper side switching element 3H (31H) of the U phase of the first inverter 11, the first inverter 11 is a fault inverter, and the second inverter 12 is a normal inverter. Also, the upper side arm of the first inverter 11 is a fault side arm, and the lower side arm of the first inverter 11 is a non-fault side arm. The rotating electric machine control device 1 performs upper side active short-circuit control (ASC-H) that sets all of the switching elements 3 of the upper side arm of the first inverter 11 to an on state, sets all of the switching elements 3 of the lower side arm of the first inverter 11 to an off state, and drives the rotating electric machine 80 via the second inverter 12.

[0330] Figure 54 An example of a control region of the rotating electric machine 80B of the one-inverter system as a comparative example is shown. In addition, Figure 55 The torque command and the rotational speed of the rotating electric machine 80B after a short-circuit fault occurs in the one-inverter system are shown. When a short-circuit fault occurs in the rotating electric machine 80B at the time tf while the rotating electric machine 80B is operating at the first operation point Q1, shutdown control is immediately performed at the time t0 by short-circuit detection. In order to cope with a large current that flows by performing the shutdown control, active short-circuit control is immediately performed at the time tl. By the active short-circuit control, the rotational speed of the rotating electric machine 80B is reduced, and at the time tz, the rotational speed of the rotating electric machine 80B becomes "zero", and the rotating electric machine 80B stops. That is, the rotating electric machine 80B is controlled so as to pass the second operation point Q2 toward the origin Q0. In this way, in the one-inverter system, in the case where a short-circuit fault occurs, the drive of the rotating electric machine 80B cannot be continued, and the running of the vehicle cannot be continued.

[0331] However, according to the present embodiment, as described above, the fault site can be determined in the case where a short-circuit fault occurs in one of the switching elements 3 of the two inverters 10 that are respectively provided at both ends of the open-circuit winding.

[0332] (Summary of Embodiment)

[0333] Next, a summary of the rotating electric machine control device (1) described above is briefly described.

[0334] (1-1) As one mode, a rotary electric machine control device (1) controls a rotary electric machine (80) having mutually independent multi-phase open-circuit windings (8) via a first inverter (11) and a second inverter (12), wherein the first inverter (11) is connected to one end side of the multi-phase open-circuit windings (8), converts electric power between direct current and multi-phase alternating current, the second inverter (12) is connected to the other end side of the multi-phase open-circuit windings (8), converts electric power between direct current and multi-phase alternating current, in each of the first inverter (11) and the second inverter (12), an arm (3A) of one phase of alternating current is configured by a series circuit of an upper-stage side switching element (3H) and a lower-stage side switching element (3L), the first inverter (11) and the second inverter (12) are independently controlled, in a case where an open-circuit failure in which one switching element (3) always becomes an open-circuit state occurs in one of the first inverter (11) and the second inverter (12), multi-phase alternating currents (Iu, Iv, Iw) are respectively accumulated and current accumulation values (∑Iu, ∑Iv, ∑Iw) of the phases are calculated, the occurrence of the open-circuit failure is detected based on the positive and negative of each of the current accumulation values (∑Iu, ∑Iv, ∑Iw), and the position where the open-circuit failure has occurred is discriminated, when the two inverters, the first inverter (11) and the second inverter (12), are controlled by a hybrid pulse width modulation control that controls in a manner in which a plurality of pulses different in output pattern in one of 1 / 2 periods of an electric angle, that is, a first period, and a non-active state is continued in the remaining 1 / 2 period, that is, a second period, in a case where the occurrence of the open-circuit failure is detected, which one of a first failure pattern (FP1) and a second failure pattern (FP2) is discriminated based on the positive and negative of each of the current accumulation values (∑Iu, ∑Iv, ∑Iw) in a first control state, the first failure pattern (FP1) being that one of an upper-stage side arm of the first inverter (11) and a lower-stage side arm of the second inverter (12) is a failure side arm in which the open-circuit failure has occurred, the second failure pattern (FP2) being that one of the lower-stage side arm of the first inverter (11) and the upper-stage side arm of the second inverter (12) is the failure side arm, which one of a first lower-stage side failure pattern (LF1) and a second lower-stage side failure pattern (LF2) is discriminated based on each of the current accumulation values (∑Iu, ∑Iv, ∑Iw) in a second control state different from the first control state, the first lower-stage side failure pattern being that the lower-stage side arm of the second inverter is the failure side arm, the second lower-stage side failure pattern being that the lower-stage side arm of the first inverter is the failure side arm, and which one of the first control state and the second control state is selected based on the discrimination result in the first control state and the discrimination result in the second control state,determining which one of the upper arm of the first inverter, the lower arm of the first inverter, the upper arm of the second inverter, and the lower arm of the second inverter is the fault side arm.

[0335] According to the experiments and simulations by the inventors, it was confirmed that in the case where the open-circuit failure of the switching element (3) occurs in one of the two inverters (10), the three-phase current waveform becomes an asymmetric and distorted waveform. For example, the waveform of the alternating current of a certain phase is greatly deflected to the positive side, and in addition, the waveform of the alternating current of a certain phase is greatly deflected to the negative side. Also, when the alternating currents (Iu, Iv, Iw) are accumulated over a prescribed time, the tendency of the deflection becomes more pronounced. The direction of the deflection differs depending on the position of the switching element (3) in which the open-circuit failure occurs. Therefore, if the positive and negative of the current accumulation value (∑Iu, ∑Iv, ∑Iw) are based, it is possible to determine that the open-circuit failure has occurred and in which one of the upper arm and the lower arm of which inverter (10) the open-circuit failure has occurred. In addition, according to the experiments and simulations by the inventors, in the second control state, in the case where the open-circuit failure occurs in the upper arm, the detection of the open-circuit failure itself is difficult, but in the case where the open-circuit failure occurs in the lower arm, the open-circuit failure can be detected and it is possible to determine which inverter (10) the failure is in. In the first control state, the open-circuit failure can be detected regardless of which one of the upper arm and the lower arm it occurs in. However, in the first control state, it is possible to determine whether the failure pattern (FP) is the first failure pattern (FP1) or the second failure pattern (FP2), but it is not possible to determine which inverter (10) it is. According to the present structure, in the case where the open-circuit failure occurs in the lower arm, it is possible to determine the fault side arm at least from the determination result in the second control state. In addition, in the case where the open-circuit failure occurs in the upper arm and in the case where the open-circuit failure occurs in the lower arm, as long as the determination result in the first control state and the determination result in the second control state are based, it is possible to determine the fault side arm. In this way, according to the present structure, it is possible to determine the failure site in the case where the open-circuit failure of one of the switching elements (3) of the two inverters (10) respectively having the open-circuit winding (8) at both ends occurs.

[0336] (1-2) Preferably, the rotating electric machine control device (1) determines that the lower side arm of the second inverter (12) is the fault side arm in a case where it is determined to be the first fault pattern (FP1) in the first control state and to be the first lower side fault pattern (LF) in the second control state, determines that the upper side arm of the first inverter (11) is the fault side arm in a case where it is determined to be the first fault pattern (FP1) in the first control state and to be not the lower side fault pattern (LF) in the second control state, determines that the lower side arm of the first inverter is the fault side arm in a case where it is determined to be the second fault pattern (FP2) in the first control state and to be the lower side fault pattern (LF) in the second control state, and determines that the upper side arm of the second inverter (12) is the fault side arm in a case where it is determined to be the second fault pattern (FP2) in the first control state and to be not the lower side fault pattern (LF) in the second control state.

[0337] According to this structure, the fault side arm can be appropriately determined on the basis of the determination results of the fault pattern (FP) determined in the first control state and whether it is the lower side fault pattern (LF) determined in the second control state.

[0338] (1-3) In addition, preferably, in the rotating electric machine control device (1), the first fault pattern (FP1) is determined in a case where the current cumulative value of one phase is negative and the current cumulative values of the other phases are positive among the plurality of current cumulative values (∑Iu, ∑Iv, ∑Iw), and the second fault pattern (FP2) is determined in a case where the current cumulative value of one phase is positive and the current cumulative values of the other phases are negative among the plurality of current cumulative values (∑Iu, ∑Iv, ∑Iw).

[0339] It is confirmed through experiments and simulations by the inventor that the alternating current of the phase including the switching element (3) in which the open circuit fault has occurred is deflected in a different tendency from the alternating currents of the other phases in the first control state. Therefore, the fault site can be determined on the basis of the tendency of the deflection as described above.

[0340] (1-4) In addition, preferably, in the rotating electric machine control device (1), the first lower side fault pattern (LF1) is determined in a case where the current cumulative value of one phase is negative and the current cumulative values of the other phases are positive among the plurality of current cumulative values (∑Iu, ∑Iv, ∑Iw), and the second lower side fault pattern (LF2) is determined in a case where the current cumulative value of one phase is positive and the current cumulative values of the other phases are negative among the plurality of current cumulative values (∑Iu, ∑Iv, ∑Iw).

[0341] According to the experiments and simulations by the inventor, it is confirmed that the alternating current of the phase including the open-circuit failure of the switching element (3) is deflected in a different tendency from the alternating current of the other phases in the second control state. Therefore, it is possible to determine the failure site according to the deflection tendency as described above.

[0342] (1-5) In addition, preferably, the first control state is motoring in which the rotational speed of the rotary electric machine (80) is equal to or higher than a first prescribed rotational speed, and the second control state is regeneration.

[0343] According to the experiments and simulations by the inventor, it is confirmed that, in the case of an open-circuit failure, when the switching control of the inverter (10) is performed by hybrid pulse width modulation control, the behavior of the alternating current (Iu, Iv, Iw) is different between motoring and regeneration. Therefore, by making the first control state motoring and making the second control state regeneration, it is possible to appropriately determine the failure side arm.

[0344] (1-6) In addition, preferably, in the rotary electric machine control device (1), in the case where the second control state is regeneration and the occurrence of the open-circuit failure is detected in the second control state, a regeneration disable operation of suppressing the distortion of the alternating current (Iu, Iv, Iw) of the plurality of phases due to the open-circuit failure is performed.

[0345] According to the experiments and simulations by the inventor, in the case where the upper side arm has an open-circuit failure, in the second control state, the waveform of the alternating current (Iu, Iv, Iw) does not greatly distort. Therefore, even if the upper side arm has an open-circuit failure, in the second control state, under certain conditions, there is room to control the inverter 10 as in the case where no open-circuit failure has occurred. According to the present structure, by performing the regeneration disable operation of suppressing the distortion of the alternating current (Iu, Iv, Iw) of the plurality of phases due to the open-circuit failure, even if an open-circuit failure occurs, it is possible to control the inverter (10) as in the case where no open-circuit failure has occurred.

[0346] (1-7) Here, preferably, the regeneration failure operation switches the switching pattern of the upper side arm of the first inverter (11) and the switching pattern of the lower side arm of the second inverter (12), and switches the switching pattern of the lower side arm of the first inverter (11) and the switching pattern of the upper side arm of the second inverter (12), or switches the switching pattern of the upper side arm and the switching pattern of the lower side arm of the first inverter (11), and switches the switching pattern of the upper side arm and the switching pattern of the lower side arm of the second inverter (12), thereby inverting the positive and negative of the multiphase alternating currents (Iu, Iv, Iw) to each other.

[0347] According to the inventor's experiments and simulations, in the second control state, the waveforms of the alternating currents (Iu, Iv, Iw) do not greatly distort in the case where the upper side arm is open-circuit faulted. According to the present structure, by switching the upper side arm and the lower side arm, it is possible to set the faulted side arm, which is open-circuit faulted, as the upper side arm, and thereby it is possible to obtain the alternating currents (Iu, Iv, Iw) whose distortion is suppressed.

[0348] (1-8) Here, preferably, the rotation speed of the rotating electric machine (80) is reduced by the regeneration.

[0349] According to the present structure, by reducing the rotation speed of the rotating electric machine 80 by the regeneration operation for discriminating the fault site, it is possible to shorten the lead time until the next control using one inverter (10) to drive the rotating electric machine 80 or the like after the fault site is discriminated.

[0350] (1-9) In addition, preferably, the first control state is a motoring in which the rotation speed of the rotating electric machine (80) is equal to or higher than a first prescribed rotation speed, and the second control state is a motoring in which the rotation speed of the rotating electric machine (80) is lower than a second prescribed rotation speed that is lower than the first prescribed rotation speed.

[0351] According to the inventor's experiments and simulations, it is confirmed that in the case where the open-circuit fault occurs, when the inverter (10) is switched controlled by the hybrid pulse width modulation control, even in the same motoring, the behavior of the alternating currents (Iu, Iv, Iw) differs depending on the rotation speed. In particular, it is confirmed that in the case where the rotation speed is low, the behavior becomes the same as the regeneration. Therefore, by setting the first control state to be the motoring and setting the second control state to be the motoring based on the rotation speed that is lower than the first control state, it is possible to appropriately discriminate the faulted side arm.

[0352] (1-10) Further preferably, in the rotating electric machine control device (1), in the first control state, the occurrence of the open-circuit failure is detected and the failure pattern (FP) is discriminated, thereafter, in the second control state, the lower-stage side failure pattern (LF) is discriminated, and thereafter, the failure side arm is discriminated based on the discrimination result of the first control state and the discrimination result of the second control state.

[0353] According to this structure, by sequentially executing the control realizing the first control state and the control realizing the second control state, the failure side arm can be appropriately discriminated.

[0354] (1-11) Further preferably, in the rotating electric machine control device (1), after the occurrence of the open-circuit failure is detected and the failure pattern (FP) is discriminated in the first control state, in a case where the rotational speed of the rotating electric machine (80) is equal to or higher than a first prescribed rotational speed prescribed in advance, the lower-stage side failure pattern (LF) is discriminated by setting the regeneration to the second control state, and in a case where the rotational speed of the rotating electric machine (80) is lower than the first prescribed rotational speed, the lower-stage side failure pattern (LF) is discriminated by setting the motoring operation lower than a second prescribed rotational speed lower than the first prescribed rotational speed to the second control state.

[0355] If the control mode is changed from the motoring operation to the regeneration, the rotational speed of the rotating electric machine (80) is reduced. In a case where the rotational speed of the rotating electric machine 80 is low, it is possible to stop the rotating electric machine (80) by the regeneration. According to the present structure, in a case where the rotational speed of the rotating electric machine 80 is lower than the first prescribed rotational speed, the motoring operation lower than the first prescribed rotational speed is performed, and the regeneration is not performed, and thus the failure site can be appropriately discriminated in a manner that the rotating electric machine (80) is not stopped.

[0356] (1-12) Here, preferably, in a case where the rotational speed of the rotating electric machine (80) is lower than a first prescribed rotational speed prescribed in advance, the rotational speed of the rotating electric machine (80) is reduced to be lower than the second prescribed rotational speed by a shutdown control that sets all of the switching elements (3) of the multiphase to the off state or a zero Newton control that controls in a manner that the output torque of the rotating electric machine (80) becomes zero.

[0357] According to this structure, in a case where the rotational speed is not regeneratable, the rotational speed of the rotating electric machine (80) can be appropriately reduced to be lower than the second prescribed rotational speed to become the second control state.

[0358] (1-13) In addition, in the first control state, the occurrence of the open-circuit failure is detected and the failure pattern (FP) is discriminated, thereafter, in the second control state, the lower-stage side failure pattern (LF) is discriminated, thereafter, the rotating electrical machine control device (1) which discriminates the failure side arm based on the discrimination result of the first control state and the discrimination result of the second control state, in the case where the occurrence of the open-circuit failure is detected in the first control state without the hybrid pulse width modulation control, by the pulse width modulation control in which a plurality of pulses different in pattern are output in the second period (T2) and a plurality of pulses different in pattern are output in one cycle of electrical angle, or by the rectangular wave control in which one pulse is output in one cycle of electrical angle, the control of the two inverters (10) of the first inverter (11) and the second inverter (12) is performed in the first control state, thereafter, the control mode of the two inverters (10) of the first inverter (11) and the second inverter (12) is changed to the hybrid pulse width modulation control, and in the second control state, the lower-stage side failure pattern (LF) is discriminated, thereafter, the failure side arm is discriminated based on the discrimination result of the first control state and the discrimination result of the second control state.

[0359] According to the experiments and simulations by the inventors, in the case where the two inverters (10) are switched controlled by the hybrid pulse width modulation control, as described above, in the case where the open-circuit failure occurs, in the first control state and the second control state, the behavior of the alternating current (Iu, Iv, Iw) is observed to be different, but when the switching control is performed by, for example, the generally known pulse width modulation control, it is found that such a difference is not observed. However, in the case where the open-circuit failure occurs, the occurrence of the open-circuit failure and whether the failure pattern (FP) is the first failure pattern (FP1) or the second failure pattern (FP2) are discriminated. According to the present structure, after these are discriminated in the first control state, the control mode of the inverter 10 is changed to the hybrid pulse width modulation control, thereby realizing the second control state. Therefore, in the first control state and the second control state, the behavior of the alternating current (Iu, Iv, Iw) is observed to be different, thereby enabling the discrimination of the failure side arm.

[0360] (1-14)In addition, as one embodiment, a rotating electric machine control device (1) that drives and controls a rotating electric machine having a plurality of open-circuit windings (8) independent of each other via a first inverter (11) connected to one end side of the plurality of open-circuit windings (8) and converting electric power between direct current and multiphase alternating current and a second inverter (12) connected to the other end side of the plurality of open-circuit windings (8) and converting electric power between direct current and multiphase alternating current, in which an arm (3A) of one phase of alternating current is configured by a series circuit of an upper-stage side switching element (3H) and a lower-stage side switching element (3L) in each of the first inverter (11) and the second inverter (12), and the first inverter (11) and the second inverter (12) are independently controlled, in a case where an open-circuit failure in which one switching element (3) always becomes an open-circuit state occurs in one of the inverters (10), the alternating current (Iu, Iv, Iw) of the plurality of phases is accumulated and a current accumulation value (∑Iu, ∑Iv, ∑Iw) of each phase is calculated, the occurrence of the open-circuit failure is detected based on the positive and negative of each of the current accumulation values (∑Iu, ∑Iv, ∑Iw), and the position where the open-circuit failure has occurred is identified, in a case where the occurrence of the open-circuit failure is detected, which one of a first failure pattern (FP1) in which the open-circuit failure has occurred in one of the upper-stage side arm of the first inverter (11) and the lower-stage side arm of the second inverter (12) and a second failure pattern (FP2) in which the open-circuit failure has occurred in one of the lower-stage side arm of the first inverter (11) and the upper-stage side arm of the second inverter (12) is identified based on the positive and negative of each of the current accumulation values (∑Iu, ∑Iv, ∑Iw), thereafter, one of the inverters (10) in which the open-circuit failure is assumed to have occurred is assumed to be a failure inverter and is assumed to be a failure inverter, based on the identified failure pattern (FP), the switching elements (3) of the assumed failure side arm in the upper-stage side arm and the lower-stage side arm of the assumed failure inverter in which the open-circuit failure is assumed to have occurred are set to an on state, and the switching elements (3) of the non-assumed failure side arm on the other side are set to an on state, and the other inverter is subjected to switching control, thereafter, in a case where the open-circuit failure is not detected based on the positive and negative of each of the current accumulation values (∑Iu, ∑Iv, ∑Iw), it is identified that the assumed failure inverter is the failure inverter, and it is identified that the assumed failure side arm is the failure side arm, and in a case where the open-circuit failure is detected,determining that the inverter different from the assumed faulty inverter is the faulty inverter, and determining the faulty phase arm in the faulty inverter based on the fault pattern (FP).

[0361] According to this structure, in a case where the occurrence of the open-circuit fault is detected, the inverter (10) is switch-controlled as if the assumed faulty phase arm is the faulty phase arm in a manner that enables the switch control even if the assumed faulty phase arm has the open-circuit fault. In this state, if the open-circuit fault is not detected again, it is determined that the assumption is correct, and if the open-circuit fault is detected again, it is determined that the assumption is incorrect. Therefore, according to the present structure, it is possible to determine the faulty phase arm.

[0362] (1-15) Here, preferably, in the rotating electric machine control device (1), in a case where the occurrence of the open-circuit fault is detected, it is determined which one of the first fault pattern (FP1) and the second fault pattern (FP2) is, and then the rotating electric machine (80) is reduced in speed by the active short-circuit control, or the shutdown control that sets all of the switching elements (3) of the plurality of phases to the off state, or the zero Newton control that controls in a manner that the output torque of the rotating electric machine (80) becomes zero, and then the inverter (10) different from the assumed faulty inverter is switch-controlled.

[0363] In a case where the rotating electric machine (80) is driven only by the inverter (10) different from the assumed faulty inverter, the operating region of the rotating electric machine (80) is narrower than in a case where the rotating electric machine (80) is driven using two inverters (10), for example, the operating speed is also lower. According to this structure, by reducing the speed of the rotating electric machine (80) before the inverter (10) different from the assumed faulty inverter is switch-controlled, it is possible to appropriately drive the rotating electric machine (80) only by the inverter (10).

[0364] (1-16) In addition, preferably, in the rotating electric machine control device (1), in a case where an overcurrent state occurs due to the occurrence of the open-circuit fault, the overcurrent state is eliminated by reducing the speed of the rotating electric machine (80) by the shutdown control that sets all of the switching elements (3) of the plurality of phases to the off state, or the active short-circuit control that sets the upper-stage switching element (3H) of all of the arms (3A) of the plurality of phases to the on state or sets the lower-stage switching element (3L) of all of the arms (3A) of the plurality of phases to the on state, and then the faulty phase arm is determined.

[0365] According to the experiments and simulations by the inventor, it is confirmed that the instantaneous value of the three-phase alternating current sometimes becomes a very large value in a case where, for example, the open circuit failure occurs at an operating point where the output torque of the rotating electric machine (80) is large and the rotational speed is also high. In this case, the overcurrent state is detected, and generally the control of the inverter (10) is limited. Therefore, in this case, it is preferable to discriminate the failure side arm after the overcurrent state is eliminated.

[0366] (1-17) Further, preferably, in the rotating electric machine control device (1), the inverter (10) in which the open circuit failure has occurred among the first inverter (11) and the second inverter (12) is set as a failure inverter, the inverter (10) different from the failure inverter is set as a normal inverter, the side opposite to the failure side arm among the upper stage side arm and the lower stage side arm of the failure inverter is set as a non-failure side arm, the active short-circuit control of setting all of the switching elements (3) of the failure side arm of the failure inverter to the off state and setting all of the switching elements (3) of the non-failure side arm to the on state is performed, and the single-inverter drive control of driving the rotating electric machine (80) via the normal inverter is performed.

[0367] In a case where the inverter (10) is connected to both ends of the open circuit winding (8), if the failure inverter is short-circuited by the active short-circuit control, the multiphase open circuit winding (8) is short-circuited in the failure inverter. That is, the failure inverter becomes a neutral point, and the open circuit winding (8) is Y-connected. The failure side arm in which the switching element (3) in which the open circuit failure has occurred is included among the upper stage side arm and the lower stage side arm of the failure inverter becomes the off state and is subjected to the active short-circuit control, and thus the switching element (3) in which the open circuit failure has occurred is equivalent to a state in which the open circuit failure has not occurred. Therefore, the rotating electric machine control device 1 can appropriately perform the drive control of the rotating electric machine 80 having the open circuit winding 8 which is Y-connected via the normal inverter

[0368] (1-18) Here, preferably, in the rotating electric machine control device (1), the single-inverter drive control is performed by the pulse width modulation control of outputting a plurality of pulses different in pattern in one cycle of an electric angle.

[0369] In the hybrid pulse width modulation control, the switching control signal becomes the non-active state during the second period (T2), and the system loss can be reduced. By making the periods different from each other in the first inverter (11) and the second inverter (12) the second periods (T2), it is possible to realize a state in which switching is continuously performed by a plurality of pulses as a whole. However, in the single inverter drive control, since only one inverter (10) is switched, the AC waveform is distorted in the hybrid pulse width modulation control. Therefore, the single inverter drive control is preferably performed by pulse width modulation control that outputs a plurality of pulses having different patterns in one cycle of an electrical angle.

[0370] (2-1) In addition, as one embodiment, a rotating electric machine control device (1) that drives and controls a rotating electric machine (80) having a plurality of open-circuit windings (8) that are independent of each other via a first inverter (11) and a second inverter (12), in which the first inverter (11) is connected to one end side of the plurality of open-circuit windings (8), converts electric power between direct current and multiphase alternating current, the second inverter (12) is connected to the other end side of the plurality of open-circuit windings (8), converts electric power between direct current and multiphase alternating current, in the first inverter (11) and the second inverter (12), an arm (3A) of one phase of alternating current is configured by a series circuit of an upper side switching element (3H) and a lower side switching element (3L), the first inverter (11) and the second inverter (12) can be controlled independently of each other, in one inverter (10) of the first inverter (11) and the second inverter (12), in the case where a short-circuit fault of one switching element (3) occurs, the inverter (10) in which the short-circuit fault occurs is set as a fault inverter, the multiphase alternating currents (Iu, Iv, Iw) are respectively accumulated and the current accumulation values (∑Iu, ∑Iv, ∑Iw) of each phase are calculated, and which one of the upper side arm and the lower side arm of the fault inverter in which the short-circuit fault occurs is determined based on the positive and negative of each of the current accumulation values (∑Iu, ∑Iv, ∑Iw).

[0371] According to experiments and simulations by the inventor, in a case where a short-circuit failure of a switching element (3) occurs in one of the two inverters (10), the three-phase current waveform becomes an asymmetric and distorted waveform. For example, the waveform of the AC current of one phase greatly deflects to the positive side, and the waveform of the AC current of one phase greatly deflects to the negative side. Furthermore, when the AC currents (Iu, Iv, Iw) are accumulated over a prescribed time, the tendency of the deflection becomes more pronounced. The direction of the deflection differs depending on the position of the switching element (3) in which the short-circuit failure occurs. Therefore, if the positive or negative of the current accumulation value (∑Iu, ∑Iv, ∑Iw) is used, it is possible to determine which of the upper side arm and the lower side arm of the faulty inverter has a short-circuit failure. By determining the failure site, it is possible to control the two inverters 10 in a manner that is not affected by the failure site, and thus it is possible to continue driving the rotating electric machine 80. In this way, according to the present structure, it is possible to determine the failure site in a case where a short-circuit failure occurs in one of the switching elements (3) of the two inverters (10) that are respectively provided at both ends of the open-circuit winding (8).

[0372] (2-2) Furthermore, preferably, in the rotating electric machine control device (1), in a case where the first inverter (11) is the faulty inverter, in a case where the current accumulation value of one phase is positive and the current accumulation values of the other phases are negative among the plurality of current accumulation values (∑Iu, ∑Iv, ∑Iw), it is determined that the short-circuit failure occurs in the upper side arm of the faulty inverter, in a case where the current accumulation value of one phase is negative and the current accumulation values of the other phases are positive among the plurality of current accumulation values (∑Iu, ∑Iv, ∑Iw), it is determined that the short-circuit failure occurs in the lower side arm of the faulty inverter, in a case where the second inverter (12) is the faulty inverter, in a case where the current accumulation value of one phase is positive and the current accumulation values of the other phases are negative among the plurality of current accumulation values (∑Iu, ∑Iv, ∑Iw), it is determined that the short-circuit failure occurs in the lower side arm of the faulty inverter, in a case where the current accumulation value of one phase is negative and the current accumulation values of the other phases are positive among the plurality of current accumulation values (∑Iu, ∑Iv, ∑Iw), it is determined that the short-circuit failure occurs in the upper side arm of the faulty inverter.

[0373] According to experiments and simulations by the inventor, it is confirmed that the AC current of the phase including the switching element (3) having a short-circuit failure deflects in a different tendency from the AC currents of the other phases. Therefore, it is possible to determine the failure site according to the deflection tendency as described above.

[0374] (2-3) In addition, preferably, in the rotating electric machine control device (1), in a case where the rotational speed of the rotating electric machine (80) is equal to or higher than a predetermined prescribed rotational speed, or in a case where the ratio of the effective value of the line voltage of the multiphase alternating current to the direct current voltage, that is, the modulation rate, is equal to or higher than a predetermined prescribed modulation rate, the shutdown control is executed in which the switching elements (3) of all of the two inverters (10) of the first inverter (11) and the second inverter (12) are brought to the off state, and during execution of the shutdown control, which one of the upper side arm and the lower side arm of the faulty inverter in which the short circuit failure has occurred is discriminated on the basis of the positive or negative of each of the current cumulative values (∑Iu, ∑Iv, ∑Iw).

[0375] In the mode in which the first inverter (11) and the second inverter (12) are connected to both ends of the open circuit winding (8), in a case where all of the switching elements (3) of the inverter (10) in which no failure has occurred are brought to the non-conducting state, a current can flow only in the direction from the negative electrode toward the positive electrode. However, when the back electromotive force (BEMF) is greater than the voltage (Vdc) of the direct current side of the inverter (10), a current flow path can also be formed on the inverter (10) in which all of the switching elements (3) are brought to the non-conducting state via the direct current power supply (6) connected to the inverter (10). Since there is a linear relationship between the back electromotive force (BEMF) and the rotational speed of the rotating electric machine (80), in a case where the rotational speed of the rotating electric machine (80) is equal to or higher than a prescribed rotational speed, the failure site can be rapidly discriminated as described above. In addition, even in a case where the modulation rate is high, there is a tendency for the output of the rotating electric machine 80 to become large and for the rotational speed to become high, and thus the failure site can be rapidly discriminated as described above.

[0376] (2-4) In addition, preferably, in the rotating electric machine control device (1), in a case where the rotational speed of the rotating electric machine (80) is less than a predetermined prescribed rotational speed, or in a case where the ratio of the effective value of the line voltage of the multiphase alternating current to the direct current voltage, that is, the modulation rate, is less than a predetermined prescribed modulation rate, torque control is performed on the first inverter (11) and the second inverter (12) on the basis of a torque command that is equal to or less than a predetermined prescribed torque (T2), and during execution of the torque control, which one of the upper side arm and the lower side arm of the faulty inverter in which the short circuit failure has occurred is discriminated on the basis of the positive or negative of each of the current cumulative values (∑Iu, ∑Iv, ∑Iw).

[0377] In the case where the first inverter 11 and the second inverter 12 are connected to both ends of the open circuit winding 8, in the case where the back electromotive force (BEMF) is smaller than the voltage (Vdc) of the direct current side of the inverter 10, in the case where all of the switching elements (3) of the inverter (10) in which no fault has occurred become non-conducting states, only the current flowing in the direction from the negative electrode to the positive electrode is possible. Therefore, if the shutdown control is performed in the case where the short circuit fault is detected, it is not possible to discriminate the fault site. According to the present configuration, by driving both inverters (10) with the specified torque (T2) of low torque at which the consumed current is relatively small, it is possible to make the current flow through the inverter (10). Therefore, in the state where the short circuit fault has occurred, it is possible to suppress the load on the inverter (10) or the open circuit winding (8) and to discriminate the fault site.

[0378] (2-5) In addition, preferably, in the rotating electric machine control device (1), the inverter (10) other than the fault inverter among the first inverter (11) and the second inverter (12) is set as a normal inverter, the side in which the short circuit fault has occurred among the upper stage side arm and the lower stage side arm of the fault inverter is set as a fault side arm, the other side is set as a non-fault side arm, the active short circuit control in which all of the switching elements (3) of the fault side arm of the fault inverter are set as conducting states and all of the switching elements (3) of the non-fault side arm are set as non-conducting states is performed, and the single inverter drive control in which the rotating electric machine (80) is driven via the normal inverter is performed.

[0379] In the case where the inverters (10) are connected to both ends of the open circuit winding (8), if the fault inverter is short-circuited by the active short circuit control, the polyphase open circuit winding (8) is short-circuited in the fault inverter. That is, the fault inverter becomes a neutral point and the open circuit winding (8) is Y-connected. The fault side arm in which the switching element (3) in which the short circuit fault has occurred is included among the upper stage side arm and the lower stage side arm of the fault inverter is short-circuited and is subjected to the active short circuit control, and therefore, the switching element (3) in which the short circuit fault has occurred is equivalent to the state in which no short circuit fault has occurred. Therefore, the rotating electric machine control device (1) can appropriately drive control the rotating electric machine (80) having the open circuit winding (8) which is Y-connected via the normal inverter.

[0380] Explanation of reference numerals:

[0381] 1: motor control device, 3: switching element, 3A: arm, 3H: upper-stage side switching element, 3L: lower-stage side switching element, 8: stator coil (open winding), 10: inverter, 11: first inverter, 12: second inverter, 80: motor, FP: failure mode, FP1: first failure mode, FP2: second failure mode, LF: lower-stage side failure mode, LF1: first lower-stage side failure mode, LF2: second lower-stage side failure mode, H1: first period, H2: second period, Iu: U-phase current (AC current), Iv: V-phase current (AC current), Iw: W-phase current (AC current), T2: second torque command (specified torque), ∑Iu: U-phase cumulative current (current cumulative value), ∑Iv: V-phase cumulative current (current cumulative value), ∑Iw: W-phase cumulative current (current cumulative value).

Claims

1. A rotating electric motor control device, comprising driving and controlling a rotating electric motor having mutually independent multiphase open-circuit windings via a first inverter and a second inverter, wherein, The first inverter is connected to one end of the multiphase open-circuit winding, converting power between DC and multiphase AC. The second inverter is connected to the other end of the multiphase open-circuit winding, converting power between DC and multiphase AC. In both the first and second inverters, the arm of one phase of the AC circuit is composed of a series circuit of upper-side switching elements and lower-side switching elements. It can control the first inverter and the second inverter independently. If an open-circuit fault occurs in one of the first and second inverters, where a switching element remains open, the AC current of each phase is accumulated, and the accumulated current value of each phase is calculated. The occurrence of the open-circuit fault is detected based on the sign of each accumulated current value, and the location of the open-circuit fault is determined. When controlling the first and second inverters using hybrid pulse width modulation (PWM) control, which outputs multiple pulses with different modes during half a cycle (the first period) of the electrical angle and remains in an inactive state during the remaining half cycle (the second period), an open-circuit fault is detected. The sign of each accumulated current value under the first control state determines whether it is a first fault mode or a second fault mode. The first fault mode is when one of the upper-level arms of the first inverter and the lower-level arms of the second inverter has experienced an open-circuit fault. The second fault mode is when one of the lower-level arms of the first inverter and the upper-level arms of the second inverter is the faulty arm. Based on the cumulative current values ​​under the second control state, which is different from the first control state, it is determined whether it is a first lower-level side fault mode or a second lower-level side fault mode. The first lower-level side fault mode is when the lower-level arm of the second inverter is the faulty arm, and the second lower-level side fault mode is when the lower-level arm of the first inverter is the faulty arm. Based on the discrimination results under the first control state and the discrimination results under the second control state, determine which of the following is the faulty arm: the upper-level arm of the first inverter, the lower-level arm of the first inverter, the upper-level arm of the second inverter, and the lower-level arm of the second inverter.

2. The rotary motor control device according to claim 1, wherein, If the fault mode is determined to be the first fault mode in the first control state and the fault mode to be the first downstream fault mode in the second control state, then the downstream arm of the second inverter is determined to be the faulty arm. If the fault mode is determined to be the first fault mode in the first control state and the lower-level fault mode is not determined to be the fault mode in the second control state, then the upper-level arm of the first inverter is determined to be the faulty arm. If the first control state determines that it is the second fault mode and the second control state determines that it is the second downstream fault mode, then the downstream arm of the first inverter is determined to be the faulty arm. If the second fault mode is determined in the first control state and the lower-level fault mode is not determined in the second control state, the upper-level arm of the second inverter is determined to be the faulty arm.

3. The rotary motor control device according to claim 1, wherein, If the cumulative current value of one phase is negative while the cumulative current values ​​of the other phases are positive, the system is identified as the first fault mode. If the cumulative current value of one phase is positive and the cumulative current value of the other phases is negative, the fault mode is determined to be the second fault mode.

4. The rotary motor control device according to claim 2, wherein, If the cumulative current value of one phase is negative while the cumulative current values ​​of the other phases are positive, the system is identified as the first fault mode. If the cumulative current value of one phase is positive and the cumulative current value of the other phases is negative, the fault mode is determined to be the second fault mode.

5. The rotary electric motor control device according to any one of claims 1 to 4, wherein, If the cumulative current value of one phase is negative while the cumulative current values ​​of the other phases are positive, it is determined to be a first downstream fault mode. If the cumulative current value of one phase is positive and the cumulative current value of the other phases is negative, it is determined to be a second lower-level fault mode.

6. The rotary electric motor control device according to any one of claims 1 to 4, wherein, The first control state is power operation where the rotational speed of the rotary motor is above a predetermined first specified speed, and the second control state is regeneration.

7. The rotary electric motor control device according to any one of claims 1 to 4, wherein, The first control state is the power operation of the rotary motor with a rotation speed above a predetermined first specified speed, and the second control state is the power operation of the rotary motor with a rotation speed below a predetermined second specified speed that is lower than the first specified speed.

8. The rotary electric motor control device according to any one of claims 1 to 4, wherein, In the first control state, the occurrence of the open-circuit fault is detected and the fault mode is determined. Then, in the second control state, the fault mode of the lower-level side is determined. Finally, based on the determination results of the first control state and the determination results of the second control state, the faulty arm is determined. When controlling the first and second inverters without using the hybrid pulse width modulation control, but instead using pulse width modulation control that outputs multiple pulses with different modes during the second period and multiple pulses with different modes during one cycle of the electrical angle, or using rectangular wave control that outputs one pulse during one cycle of the electrical angle, if an open-circuit fault is detected in the first control state... The fault mode is determined in the first control state. Subsequently, the control mode of the first inverter and the second inverter is changed to the hybrid pulse width modulation control, and the fault mode of the lower-level side is determined in the second control state. Then, the faulty side arm is determined based on the discrimination results of the first control state and the discrimination results of the second control state.

9. A rotating electric motor control device, comprising driving and controlling a rotating electric motor having mutually independent multiphase open-circuit windings via a first inverter and a second inverter, wherein... The first inverter is connected to one end of the multiphase open-circuit winding, converting power between DC and multiphase AC. The second inverter is connected to the other end of the multiphase open-circuit winding, converting power between DC and multiphase AC. In both the first and second inverters, the arm of one phase of the AC circuit is composed of a series circuit of upper-side switching elements and lower-side switching elements. It can control the first inverter and the second inverter independently. If an open-circuit fault occurs in one of the first and second inverters, where a switching element remains open, the AC current of each phase is accumulated, and the accumulated current value of each phase is calculated. The occurrence of the open-circuit fault is detected based on the sign of each accumulated current value, and the location of the open-circuit fault is determined. In the event that the open-circuit fault is detected, The sign of each accumulated current value determines whether it is a first fault mode or a second fault mode. The first fault mode is an open-circuit fault occurring in either the upper-level arm of the first inverter or the lower-level arm of the second inverter. The second fault mode is an open-circuit fault occurring in either the lower-level arm of the first inverter or the upper-level arm of the second inverter. Then, one of the first inverters and the second inverter is assumed to be the faulty inverter that has experienced the open-circuit fault and is used as the assumed faulty inverter. Based on the identified fault mode, all the switching elements of the faulty arm (assuming an open-circuit fault) in the upstream and downstream arms of the assumed faulty inverter are set to the ON state, while all the switching elements of the non-assumed faulty arm on the other side are set to the ON state for active short-circuit control. Furthermore, switching control is performed on inverters different from the assumed faulty inverter. Subsequently, based on the sign of each of the accumulated current values, and assuming no open-circuit fault is detected, the assumed faulty inverter is determined to be the faulty inverter, and the assumed faulty arm is determined to be the faulty arm. In the event of an open-circuit fault, the inverter that is different from the assumed faulty inverter is identified as the faulty inverter, and the faulty arm in the faulty inverter is identified based on the fault mode.

10. A rotating electric motor control device, comprising driving and controlling a rotating electric motor having mutually independent multiphase open-circuit windings via a first inverter and a second inverter, wherein, The first inverter is connected to one end of the multiphase open-circuit winding, converting power between DC and multiphase AC. The second inverter is connected to the other end of the multiphase open-circuit winding, converting power between DC and multiphase AC. In both the first and second inverters, the arm of one phase of the AC circuit is composed of a series circuit of upper-side switching elements and lower-side switching elements. It can control the first inverter and the second inverter independently. In the event of a short-circuit fault in one of the first inverters or the second inverter, where a switching element is short-circuited, The inverter that experienced the short-circuit fault is designated as the faulty inverter. The AC current of each phase is accumulated and the cumulative current value of each phase is calculated. Based on the sign of each cumulative current value, it is determined which of the upstream and downstream arms of the faulty inverter has experienced the short-circuit fault. In the case where the first inverter is the faulty inverter... If the cumulative current value of one phase is positive and the cumulative current values ​​of the other phases are negative, it is determined that a short-circuit fault has occurred on the upstream arm of the faulty inverter. If the cumulative current value of one phase is negative while the cumulative current values ​​of the other phases are positive, it is determined that a short-circuit fault has occurred in the downstream arm of the faulty inverter. In the case that the second inverter is the faulty inverter... If the cumulative current value of one phase is positive and the cumulative current values ​​of the other phases are negative, it is determined that a short-circuit fault has occurred on the downstream arm of the faulty inverter. If the cumulative current value of one phase is negative and the cumulative current value of the other phases is positive, it is determined that a short-circuit fault has occurred in the upper-level arm of the faulty inverter.

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