Motor control device, motor control method, and motor control program

Abstract

A control device (50) is applied to a control system (10) including a polyphase alternating current rotating electric machine (20) having an n-phase (n is an integer of 5 or more) armature winding (21), and an inverter (30) connected to the armature winding. The control device (50) includes: a switch control unit that performs switching control of the inverter and inputs a phase current to the armature winding of each phase; and a determination unit that determines whether or not the phase current can be input normally for each armature winding of each phase. In the case where the determination unit determines that the phase current cannot be normally input to the armature winding of any one or more phases, and the armature winding that is determined to be able to be input normally has three or more phases, the switch control unit changes the phase of the phase current, inputs the phase current to the normal armature winding, and drives the rotating electric machine.

Description

Motor control device, motor control method, and motor control program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2022-107914, filed on July 4, 2022, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a motor control device, a motor control method, and a motor control program.

[0003] BACKGROUND ART Conventionally, there is known a control method for quickly discharging the charge stored in a smoothing capacitor while properly protecting an inverter and a three-phase AC motor when a vehicle crashes (for example, see Patent Document 1).

[0004] In the disclosure of Patent Document 1, when a collision is detected, all upper arm transistors of the inverter are turned off and all lower arm transistors are turned on. This allows the current caused by back electromotive force to be evenly distributed among the lower arm transistors and diodes. This protects the inverter and suppresses demagnetization of the magnets in the three-phase AC motor.

[0005] JP 2012-110200 A

[0006] Incidentally, even if an abnormality occurs in a switching element constituting the inverter, there is a possibility that a secondary abnormality will occur if the back electromotive force of the motor is input to a smoothing capacitor, auxiliary equipment, etc. For this reason, when an abnormality occurs in a switching element, an active short circuit (ACS) is implemented by turning on either the upper arm transistor or the lower arm transistor of the inverter, thereby flowing a short-circuit current and suppressing overvoltage.

[0007] However, in recent years, there has been a trend toward using strong magnets (magnets with large magnetic flux linkages) to meet the demand for high output in electric motors. Since the current flowing during ACS operation is proportional to the magnetic flux linkages of the magnets, electric motors using strong magnets experience a large current flow, which can cause excessive heat generation in switching elements and lead to thermal breakdowns or malfunctions. Furthermore, when ACS is implemented, braking torque is generated, which can cause the vehicle to become unable to drive.

[0008] The present disclosure has been made in consideration of the above circumstances, and has as its main object to provide a motor control device, a motor control method, and a motor control program that can suitably control the operation of a rotating electric machine in the event of an abnormality.

[0009] The motor control device that solves the above problem is a motor control device that is applied to a control system that includes a polyphase AC rotating electric machine having n-phase (n is an integer of 5 or more) armature windings and an inverter connected to the armature windings, and that includes: a switch control unit that performs switching control of the inverter to input phase currents to the armature windings of each phase; and a determination unit that determines whether the phase currents can be input normally for each armature winding of each phase, and if the determination unit determines that the phase currents cannot be input normally for any one or more armature windings, and if there are three or more armature windings that are determined to be able to be input normally, the switch control unit changes the phase of the phase currents and inputs the phase currents to the normal armature windings to drive the rotating electric machine.

[0010] As shown in the above configuration, when phase current cannot be normally input to one or more armature windings, the phase of the phase current is changed and phase current is input to three or more armature windings among the remaining phases to drive the rotating electric machine. This prevents a sudden increase in the amount of current, which can prevent the switching elements from overheating and the inverter from failing. Furthermore, because the rotating electric machine can be continuously driven, the amount of current can be controlled to gradually decrease while the rotating electric machine is stopped. This allows the operation of the rotating electric machine to be appropriately controlled in the event of an abnormality.

[0011] A motor control method that solves the above problem is a motor control method implemented by a motor control device that is applied to a control system that includes a polyphase AC rotating electric machine having n-phase (n is an integer greater than or equal to 5) armature windings and an inverter connected to the armature windings, and includes: a switch control step that performs switching control of the inverter to input phase currents to the armature windings of each phase; and a determination step that determines, for each armature winding of each phase, whether or not the phase currents can be input normally. In the switch control step, if it is determined in the determination step that the phase currents cannot be input normally to any one or more armature windings, and if there are three or more armature windings that are determined to be able to be input normally, the phase of the phase current is changed and the phase current is input to the normal armature windings, thereby driving the rotating electric machine.

[0012] This prevents a sudden increase in the amount of current, which can prevent the switching elements from overheating and the inverter from failing. Furthermore, because the rotating electric machine can be continuously driven, the amount of current can be controlled to gradually decrease while the rotating electric machine is stopped. Therefore, the operation of the rotating electric machine can be suitably controlled in the event of an abnormality.

[0013] A motor control program that solves the above problem is a motor control program executed by a motor control device that is applied to a control system that includes a polyphase AC rotating electric machine having n-phase (n is an integer greater than or equal to 5) armature windings and an inverter connected to the armature windings, the program comprising: a switch control step that performs switching control of the inverter to input phase currents to the armature windings of each phase; and a determination step that determines whether the phase currents can be input normally for each armature winding of each phase. In the switch control step, if it is determined in the determination step that the phase currents cannot be input normally for any one or more armature windings, and if there are three or more armature windings that are determined to be able to be input normally, the phase of the phase current is changed and the phase current is input to the normal armature windings, thereby driving the rotating electric machine.

[0014] This prevents a sudden increase in the amount of current, which can prevent the switching elements from overheating and the inverter from failing. Furthermore, because the rotating electric machine can be continuously driven, the amount of current can be controlled to gradually decrease while the rotating electric machine is stopped. Therefore, the operation of the rotating electric machine can be suitably controlled in the event of an abnormality.

[0015] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a configuration diagram of a control system, Fig. 2 is a block diagram showing current feedback control processing, Fig. 3 is a flowchart showing switch control processing, Fig. 4 is a diagram showing PWM control, Fig. 5(a) is a diagram showing current waveforms of phase currents in normal operation, Fig. 5(b) is a diagram showing current waveforms of phase currents in abnormal operation, Fig. 6 is a diagram showing a rotating magnetic field, Fig. 7 is a diagram showing phase currents and torque in abnormal operation, and Fig. 8 is a diagram showing current waveforms of phase currents in another example.

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A motor control device according to an embodiment of the present disclosure will now be described with reference to the accompanying drawings. In the present embodiment, a control system including the motor control device is mounted on a vehicle such as an electric vehicle.

[0017] As shown in Fig. 1, the control system 10 includes a rotating electric machine 20. The rotating electric machine 20 is a polyphase AC synchronous motor having five-phase armature windings, and includes stator windings 21 as star-connected armature windings for each phase. In this embodiment, the phases are U, V, W, X, and Y. The stator windings 21 for each phase are arranged with an electrical angle offset of 72°. The rotating electric machine 20 of this embodiment is a permanent magnet synchronous motor having permanent magnets as field poles in a rotor 22 as a rotor.

[0018] The rotating electric machine 20 is an in-vehicle main motor, and its rotor 22 is capable of transmitting power to drive wheels of the vehicle (not shown). Torque generated by the rotating electric machine 20 functioning as an electric motor is transmitted from the rotor 22 to the drive wheels, thereby driving the drive wheels to rotate. The rotating electric machine 20 may be an in-wheel motor integrally provided with a wheel of the vehicle, or may be a so-called on-board motor provided on the body of the vehicle.

[0019] The control system 10 includes an inverter 30, a capacitor 31, and a storage battery 12 serving as a DC power source. The inverter 30 includes five phases of series-connected upper-arm switches Sp and lower-arm switches Sn. In this embodiment, each switch Sp, Sn is a voltage-controlled semiconductor switching element, specifically an IGBT. Therefore, the high-potential terminal of each switch Sp, Sn is the collector, and the low-potential terminal is the emitter. Freewheel diodes Dp, Dn are connected in antiparallel to each switch Sp, Sn.

[0020] In each phase, the emitter of the upper arm switch Sp and the collector of the lower arm switch Sn are connected to a first end of the stator winding 21. Second ends of the stator windings 21 of each phase are connected to each other at a neutral point. In this embodiment, the stator windings 21 of each phase are set to have the same number of turns.

[0021] The collector of the upper arm switch Sp of each phase is connected to the positive terminal of the storage battery 12 by a positive side bus Lp. The emitter of the lower arm switch Sn of each phase is connected to the negative terminal of the storage battery 12 by a negative side bus Ln. The positive side bus Lp and the negative side bus Ln are connected by a capacitor 31. The capacitor 31 may be built into the inverter 30 or may be provided externally to the inverter 30.

[0022] Further, an electric current interrupter 40 that interrupts current to the electric paths L1 to L5 of each phase in the event of an abnormality is provided on each of the electric paths L1 to L5 of each phase that connect the first end of the stator winding 21 of each phase to the inverter 30. As the electric current interrupter 40, for example, a pyro-fuse that interrupts the electric paths L1 to L5 by explosion, or a switch such as a relay, is assumed.

[0023] The storage battery 12 is, for example, a battery pack, and the terminal voltage of the storage battery 12 is, for example, several hundred V. The storage battery 12 is, for example, a secondary battery such as a lithium ion battery or a nickel-metal hydride battery.

[0024] The control system 10 includes a current sensor 32, a voltage sensor 33, a rotation angle sensor 34, and a control device 50 as a motor control device. The current sensor 32 detects the current flowing through the stator windings 21 of each phase. The voltage sensor 33 detects the terminal voltage of the capacitor 31 as a power supply voltage Vdc. The rotation angle sensor 34 is, for example, a resolver, and detects the rotation angle (specifically, the electrical angle θ) of the rotor 22. The detection values ​​of the sensors 32 to 34 are input to the control device 50.

[0025] The control device 50 is primarily composed of a microcomputer 50a, which includes a CPU, ROM, RAM, etc. The functions provided by the microcomputer 50a can be provided by software stored in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination of these. For example, if the microcomputer 50a is provided by a hardware electronic circuit, the function can be provided by a digital circuit including multiple logic circuits or an analog circuit. For example, the microcomputer 50a executes a program stored in a non-transitory tangible storage medium that serves as its own storage unit. By executing the program, a method corresponding to the program is performed and a function corresponding to the program is realized. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated, for example, via a network such as the Internet.

[0026] The control device 50 receives a torque command value (required torque) from a higher-level control device (such as a higher-level ECU) (not shown). The control device 50 controls the switching of the switches Sp and Sn constituting the inverter 30 so as to control the torque of the rotating electric machine 20 to the received torque command value. In each phase, the upper arm switch Sp and the lower arm switch Sn are alternately turned on with a dead time therebetween.

[0027] Next, an example of torque control of the rotating electric machine 20 executed by the control device 50 will be described with reference to Fig. 2. In the example shown in Fig. 2, current feedback control is performed as the torque control, controlling the phase currents of the U, V, W, X, and Y phases. Fig. 2 is a block diagram showing the current feedback control process. Note that torque feedback control may be performed instead of the current feedback control.

[0028] 2, a current command value setting unit 51 uses a torque-dq map to set a d-axis current command value and a q-axis current command value based on a torque command value (powering torque command value or power generation torque command value) for the rotary electric machine 20 and an electrical angular velocity ω obtained by differentiating the electrical angle θ with respect to time. Note that the power generation torque command value is a regenerative torque command value when the rotary electric machine 20 is used as a power source for a vehicle, for example.

[0029] The dq conversion unit 52 converts the current detection values ​​(five phase currents) detected by the current sensors 32 provided for each phase into d-axis current and q-axis current, which are components of an orthogonal two-dimensional rotating coordinate system with the field direction as the d-axis.

[0030] The d-axis current feedback control unit 53 calculates a d-axis command voltage as a manipulated variable for feedback-controlling the d-axis current to the d-axis current command value. The q-axis current feedback control unit 54 calculates a q-axis command voltage as a manipulated variable for feedback-controlling the q-axis current to the q-axis current command value. Each of these feedback control units 53 and 54 calculates a command voltage using a PI feedback method based on the deviation of the d-axis current and the q-axis current from the current command value.

[0031] The five-phase conversion unit 55 converts the d-axis and q-axis command voltages into U-, V-, W-, X-, and Y-phase command voltages. The above-mentioned units 51 to 55 are feedback control units that perform feedback control of fundamental wave currents based on dq conversion theory, and the U-, V-, W-, X-, and Y-phase command voltages are feedback control values. In this embodiment, the U-, V-, W-, X-, and Y-phase command voltages have sinusoidal waveforms with a phase shift of 72° in electrical angle. The above-mentioned units 51 to 55 are implemented by the control device 50 executing a program.

[0032] The signal generating unit 56 performs switch control processing to generate drive signals GU for the upper and lower arm switches Sp, Sn of each phase through five-phase modulation based on the command voltages for the U, V, W, X, and Y phases and the power supply voltage Vdc. The switch control processing will now be described in detail with reference to FIG. 3. While the following description may use the U phase as an example, the same applies to the other phases. The switch control processing is performed by the control device 50 functioning as the signal generating unit 56. In other words, the control device 50 executes a predetermined program to realize the function of the signal generating unit 56.

[0033] The control device 50 determines whether a phase current (or a phase voltage) can be normally input for each stator winding 21 of each phase (step S100). The determination in step S100 may be performed using a known method. For example, the control device 50 may input a phase current value for each phase from the current sensor 32 and determine whether the current value for each phase is within a normal range to determine whether the phase current can be normally input. Alternatively, the control device 50 may determine whether a phase current can be normally input by detecting an ON failure or an OFF failure of each switch Sp, Sn of the inverter 30. Alternatively, the control device 50 may determine whether a phase current can be normally input by detecting the temperature of each switch Sp, Sn and determining whether the temperature is within a normal range. Step S100 corresponds to a determination step, and by performing step S100, the control device 50 functions as a determination unit.

[0034] If the determination result in step S100 is positive (if normal input is possible), the control device 50 performs normal switch control shown in steps S101 and S102. That is, the control device 50 calculates a normalized command voltage for each phase based on the command voltage for each phase and the power supply voltage Vdc (step S101). The control device 50 then generates the normalized command voltage for each phase as a modulation signal S1, and performs PWM control based on the modulation signal S1 and the carrier signal Sig (step S102).

[0035] That is, as shown in FIG. 4 , the control device 50 calculates the PWM signal for each phase based on a magnitude comparison between the modulation signal S1 (=normalized command voltage) and the carrier signal Sig. Note that FIG. 4 shows an example for the U-phase, that is, an example of the modulation signal S1 based on the normalized command voltage Vu for the U-phase. The control device 50 generates the drive signal GU for the upper and lower arm switches Sp and Sn of each phase based on the PWM signal for each phase and a logically inverted signal of the PWM signal for each phase. That is, the control device 50 generates the drive signal GUH for the upper arm switch Sp of each phase and the drive signal GUL for the lower arm switch Sn of each phase. Note that FIG. 4 shows the transition of the carrier signal Sig and the like over a period of 180 electrical degrees.

[0036] The control device 50 outputs the generated drive signals GU for each phase to the gates of the upper and lower arm switches Sp and Sn for each phase via drivers. In this manner, PWM control is performed as switching control of the inverter 30, and a PWM voltage waveform (output waveform) is input to the stator windings 21. As a result, a phase voltage is input to the stator windings 21 for each phase, causing a phase current to flow.

[0037] The control period of the control device 50 is sufficiently shorter than the period of the carrier signal Sig. The carrier signal Sig in this embodiment is a carrier wave, and is a triangular wave signal whose rising speed and falling speed are equal.

[0038] However, there are cases where a phase current cannot be normally input to the stator winding 21 of one of the five phases of the stator windings 21. For example, an ON failure or OFF failure may occur in a switching element of the inverter 30, which may prevent a phase current from being normally input to the stator winding 21 of the phase connected to the failed switching element. In addition, there is also a possibility that an abnormality such as a break occurs in the stator winding 21 of one of the phases, preventing a phase current from being normally input.

[0039] In the past, in this case, in order to prevent secondary abnormalities caused by the back electromotive force being input to the smoothing capacitor or auxiliary equipment, it was common practice to short-circuit either the upper or lower arm switch Sp, Sn of the inverter 30 to suppress the overvoltage.

[0040] However, when the rotating electric machine 20 is used as the main engine of a vehicle, a strong magnet is often used because high output is required, and in this case, there is a possibility that the short-circuit current due to the back electromotive force will be large. If the current amount becomes large, the switching element operating normally will generate excessive heat, and there is a possibility that a failure due to heat will occur. Furthermore, if a short circuit occurs in the first place, the power source will be lost, the vehicle will be stranded, and depending on the location of the abnormality, there is a possibility that an inconvenient situation (such as vehicle congestion) will occur.

[0041] Therefore, when a phase current cannot be normally input to any of the five-phase stator windings 21, the following processing is carried out. Switch control in the event of an abnormality will be described below.

[0042] 3, if the determination result in step S100 is negative (if the phase current cannot be input normally), it is determined whether there are four phases of the stator windings 21 to which phase current can be input normally (whether there is only one phase of the stator winding 21 that is abnormal) (step S201). If the determination result is negative, the switch control process ends. In this case, ACS may be performed by turning on one of the upper and lower arm switches Sp and Sn of the inverter 30 and turning off the other.

[0043] On the other hand, if the determination result in step S201 is positive, the control device 50 controls the current interruption unit 40 to interrupt the flow of current to the electrical paths L1 to L5 connected to the stator winding 21 for which it has been determined that a phase current cannot be normally input (step S202). For example, if it has been determined that a normal phase current cannot be normally input to the U-phase stator winding 21, the control device 50 controls the current interruption unit 40 provided in the electrical path L1 to interrupt the flow of current to the electrical path L1 connected to one end (the end opposite the neutral point) of the U-phase stator winding 21.

[0044] Next, the control device 50 specifies (step S203) normalized command voltages (voltage command values) for instructing the phase currents (and phase voltages) to be input to the remaining four normal stator windings 21. In step S203, the control device 50 determines the phase currents (and phase voltages) to be input to the remaining stator windings 21 so as to retard the phase of the phase current (and phase voltage) to be input to the stator winding 21 of the phase that is one electrical angle earlier than the phase determined not to be able to receive normal phase current, and to advance the phase of the phase current (and phase voltage) to be input to the stator winding 21 of the phase that is one electrical angle later than the phase determined not to be able to receive normal phase current.

[0045] For example, if the stator windings 21 are arranged in the order of U, V, W, X, and Y phases, and if the W phase fails, as shown in Figure 5(b), the phase currents to be input to the remaining stator windings 21 are determined so that the phase current of the V phase is retarded by 36° and the phase current of the X phase is advanced by 36°. Note that Figure 5(a) shows the phases of the phase currents when all phases are normal, and Figure 5(b) shows the phases of the remaining phase currents when the W phase fails. Then, the normalized command voltages of the phases are specified so that the determined phase currents (and phase voltages) are input.

[0046] That is, in step S203, a normalized command voltage (voltage command value) is set to specify the phase of the phase current to be input to the stator windings 21 of each phase that has been determined to be able to be normally input, so that the rotating magnetic field formed by the remaining four-phase stator windings 21 has a circular shape. The normalized command voltage to specify the phase of the phase current to be input to the remaining stator windings 21 of each phase may be determined, for example, by map calculation or by calculation. Note that when the normalized command voltage is determined by map calculation, a map is prepared for each phase in which an abnormality has occurred (i.e., for each combination of four normal phases).

[0047] Then, the control device 50 generates a modulation signal S1 based on the identified normalized command voltage for each phase, and, similarly to step S102, performs PWM control based on the modulation signal S1 and the carrier signal Sig (step S204). As a result, PWM control is executed as switching control of the inverter 30, and a PWM voltage waveform (output waveform) is input to the stator windings 21. As a result, the phase voltages determined in step S203 are input to the remaining four-phase stator windings 21, causing phase currents to flow.

[0048] By performing the above process, even if one of the stator windings 21 fails, the rotating magnetic field formed by the remaining four stator windings 21 can be made circular, as shown by the dashed lines in FIG. 6 . The rotating magnetic field formed in this case is weaker than the rotating magnetic field (shown by the solid lines) when phase current is input to the five-phase stator windings 21, but it is still circular. Note that FIG. 6 is a schematic illustration, and in reality, some irregularities (torque ripple) are formed. However, the torque ripple is within the allowable range in an emergency. Specifically, the torque ripple is set to be within a range of 10% or less. In other words, when the average torque is 100 Nm, the torque is set to be within a range of 95 Nm to 100 Nm.

[0049] 7, even if one of the stator windings 21 fails, it is possible to control the torque of the rotating electric machine 20 while suppressing the flow of overcurrent. Naturally, however, the failure of one of the stator windings 21 will result in a decrease in the output (torque) of the rotating electric machine 20, but this decrease in torque is within an allowable range in an emergency. Specifically, it is possible to output torque sufficient to move the vehicle.

[0050] The above embodiment provides the following excellent effects.

[0051] (1) When the control device 50 determines that a phase current cannot be normally input to one of the stator windings 21, but determines that four stator windings 21 are normal, it changes the phase of the phase current and inputs the phase current to the remaining four stator windings 21 to drive the rotating electric machine 20. In other words, the rotating electric machine 20 can be continuously driven, and the rotating electric machine 20 can be stopped while controlling the amount of current to gradually decrease. This prevents short-circuit current due to back electromotive force from flowing. Therefore, even in a rotating electric machine 20 using a ferromagnet, a sudden increase in the amount of current can be suppressed. This prevents excessive heat generation in the switches Sp and Sn of the inverter 30, which can cause the inverter 30 to malfunction. Furthermore, the operation of the rotating electric machine 20 can be appropriately controlled in the event of an abnormality. This prevents loss of power source and a sudden stop of the vehicle.

[0052] (2) When it is determined that a phase current cannot be normally input to any one of the stator windings 21, the control device 50 retards the phase of the phase current to be input to the stator winding 21 of the phase immediately preceding the phase determined to be unable to be normally input, among the four stator windings 21 determined to be able to be normally input, and advances the phase of the phase current to be input to the stator winding 21 of the phase immediately succeeding the phase determined to be unable to be normally input. This makes it possible to make the rotating magnetic field closer to a circular shape by simply changing the control content.

[0053] (3) A normalized command voltage (voltage command value) is set to specify the phase of the phase current to be input to the stator windings 21 of each phase that has been determined to be capable of normal input, so that the rotating magnetic field formed by the remaining four-phase stator windings 21 is circular. This makes it possible to control torque and suppress the occurrence of noise, torque ripple, and the like. Furthermore, when this normalized command voltage is determined by map calculation, it is possible to reduce the processing load on the control device 50.

[0054] (4) When the control device 50 determines that a phase current cannot be normally input to any stator winding 21, it controls the current interrupter 40 to interrupt the current flow to the electrical paths L1 to L5 connected to that stator winding 21. This reliably prevents current from flowing to the abnormal stator winding 21. For example, even if an ON failure occurs in the switches Sp and Sn, it is possible to prevent unexpected overcurrent from flowing to the stator winding 21.

[0055] Other Embodiments Hereinafter, modifications in which the control system 10 in the above embodiment is partially modified will be described.

[0056] In the above embodiment, the phase of the phase current input to the stator winding 21 of the phase immediately preceding the phase determined to be unable to be normally input is retarded, and the phase of the phase current input to the stator winding 21 of the phase immediately succeeding the phase is advanced. As another example, the phase of the phase current input to the stator winding 21 of the phase immediately preceding and two phases preceding the phase determined to be unable to be normally input may be retarded, and the phase of the phase current input to the stator winding 21 of the phase immediately succeeding the phase and two phases succeeding the phase may be advanced, so that the phases of the phase currents input to the remaining four stator windings 21 are equally spaced. In this case, the degree of advance or delay may be changed for each phase.

[0057] That is, as long as the rotating magnetic field formed by the remaining stator windings 21 can be made closer to a circular shape, the manner in which the phase is advanced or retarded may be changed arbitrarily.

[0058] In the above embodiment, the rotating electric machine 20 has five stator windings 21. However, the number of phases is not limited to five, and the rotating electric machine 20 may have stator windings 21 with an integer number of five or more phases. That is, the rotating electric machine 20 may have n-phase stator windings 21 (n is an integer number equal to or greater than five). In this case, as described above, the phase of the phase current input to the stator winding 21 of the phase immediately preceding the phase determined to be unable to be normally input may be retarded, and the phase of the phase current input to the stator winding 21 of the phase immediately following the phase determined to be unable to be normally input may be advanced. For example, in a case where the rotating electric machine has seven stator windings 21 in the order of U, V, W, X, Y, Z, and A electrical angles, if the X-phase stator winding 21 fails, the phase currents may be input so that the W-phase is retarded by 14.5° and the Y-phase is advanced by 14.5°, as shown in FIG. 8 .

[0059] Furthermore, as described above, in order to ensure that the phases of the phase currents input to the remaining six stator windings 21 are equally spaced, the phase of the phase currents input to the stator windings 21 of the phase that is one to three phases before the phase that has been determined not to be able to be normally input may be retarded, and the phase of the phase currents input to the stator windings 21 of the phase that is one to three phases after may be advanced.

[0060] In each of the above embodiments, if two or more phases of the stator windings 21 fail but three or more phases of normal stator windings 21 remain, the phase of the phase current may be changed and input to the remaining stator windings 21 to drive the rotating electric machine 20. In this case, the phase of the phase current flowing through the stator windings 21 of each phase that has been determined to be able to be normally input may be controlled so that the rotating magnetic field formed by the stator windings 21 of the remaining phases becomes circular. For example, the phase may be controlled so that the phases of the remaining phase currents are equally spaced.

[0061] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0062] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A motor control device (50) applied to a control system (10) including a polyphase AC rotating electric machine (20) having n-phase (n is an integer of 5 or more) armature windings (21) and an inverter (30) connected to the armature windings, the motor control device comprising: a switch control unit that performs switching control of the inverter to input phase currents to the armature windings of each phase, and a determination unit that determines, for each armature winding of each phase, whether the phase current can be normally input, and when the determination unit determines that the phase current cannot be normally input to any one or more armature windings, but there are three or more armature windings that are determined to be normally input, the switch control unit changes the phase of the phase current and inputs the phase current to the normal armature windings, thereby driving the rotating electric machine. [Configuration 2] The motor control device according to Configuration 1, wherein, when the determination unit determines that the phase current cannot be normally input to any one or more of the armature windings, the switch control unit delays the phase of the phase current to be input to the armature winding of the phase that is one electrical angle earlier than the phase determined to be unable to be normally input, among the armature windings determined to be able to be normally input, and advances the phase of the phase current to be input to the armature winding of the phase that is one electrical angle later than the phase determined to be unable to be normally input. [Configuration 3] The motor control device according to Configuration 1 or 2, wherein a voltage command value specifying the phase of the phase current to be input to the armature winding of each phase determined to be able to be normally input is set so that the rotating magnetic field formed by the armature windings determined to be able to be normally input is circular. [Configuration 4] A motor control device according to any one of configurations 1 to 3, wherein a voltage command value specifying the phase of a phase current to be input to the armature winding of each phase determined to be able to be normally input is identified by referring to a map, so that the rotating magnetic field formed by the armature winding determined to be able to be normally input is circular.[Configuration 5] A motor control device according to any one of configurations 1 to 4, wherein an electrical path (L1 to L5) is provided for each phase, connecting the armature winding and the inverter, and a current interrupter (40) capable of interrupting the flow of current to the electrical path for each phase is provided, and when an armature winding is determined to be unable to normally input a phase current, the switch control unit controls the current interrupter to interrupt the flow of current to the electrical path connected to that armature winding. [Configuration 6] A motor control method implemented by a motor control device (50) applied to a control system (10) including a polyphase AC rotating electric machine (20) having n-phase (n is an integer equal to or greater than 5) armature windings (21) and an inverter (30) connected to the armature windings, the motor control method comprising: a switch control step of performing switching control of the inverter to input a phase current to the armature winding of each phase; and a determination step of determining, for each armature winding of each phase, whether or not the phase current can be normally input, wherein, in the switch control step, if it is determined in the determination step that the phase current cannot be normally input to any one or more armature windings, and if there are three or more armature windings determined to be normally input, the motor control method changes the phase of the phase current and inputs the phase current to a normal armature winding to drive the rotating electric machine.[Configuration 7] A motor control program executed by a motor control device (50) applied to a control system (10) including a polyphase AC rotating electric machine (20) having n-phase (n is an integer equal to or greater than 5) armature windings (21) and an inverter (30) connected to the armature windings, the motor control program comprising: a switch control step of performing switching control of the inverter to input a phase current to the armature winding of each phase; and a determination step of determining, for each armature winding of each phase, whether or not the phase current can be normally input, wherein, in the switch control step, if it is determined in the determination step that the phase current cannot be normally input to any one or more armature windings, and if there are three or more armature windings determined to be normally input, the motor control program changes the phase of the phase current and inputs the phase current to a normal armature winding, thereby driving the rotating electric machine.

[0063] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A motor control device (50) applied to a control system (10) including a polyphase AC rotating electric machine (20) having an n-phase (n is an integer of 5 or more) armature winding (21) and an inverter (30) connected to the armature winding, a switch control unit that performs switching control of the inverter to input a phase current to the armature winding of each phase; a determination unit that determines whether or not the phase current can be normally input for each of the armature windings of each phase, When the judgment unit judges that the phase current cannot be normally input to any one or more of the armature windings, and there are three or more armature windings that have been judged to be able to be normally input, the switch control unit changes the phase of the phase current, inputs the phase current to the normal armature winding, drives the rotating electric machine, and then controls the amount of current flowing through the armature winding to be reduced, and finally performs short-circuit control to stop the rotating electric machine.

2. 2. The motor control device according to claim 1, wherein, when the determination unit determines that the phase current cannot be normally input to any one or more of the armature windings, the switch control unit retards a phase of a phase current to be input to the armature winding of a phase that is one electrical angle earlier than the phase determined to be unable to be normally input among the armature windings determined to be able to be normally input, and advances a phase of a phase current to be input to the armature winding of a phase that is one electrical angle later than the phase determined to be unable to be normally input.

3. 2. The motor control device according to claim 1, wherein a voltage command value that specifies a phase of a phase current to be input to the armature winding of each phase that is determined to be able to be normally input is set so that a rotating magnetic field formed by the armature winding that is determined to be able to be normally input is circular.

4. 2. The motor control device according to claim 1, wherein a voltage command value that specifies a phase of a phase current to be input to the armature winding of each phase that is determined to be able to be normally input is identified by referring to a map, so that a rotating magnetic field formed by the armature winding that is determined to be able to be normally input is circular.

5. For each phase, an electrical path (L1 to L5) is provided that connects the armature winding and the inverter, A current interruption unit (40) capable of interrupting the current flow through the electrical path of each phase is provided, 5. The motor control device according to claim 1, wherein, when an armature winding is determined to be unable to normally input a phase current, the switch control unit controls the current interruption unit to interrupt the current flow through the electrical path connected to the armature winding.

6. A motor control method implemented by a motor control device (50) applied to a control system (10) including a polyphase AC rotating electric machine (20) having an n-phase (n is an integer of 5 or more) armature winding (21) and an inverter (30) connected to the armature winding, a switch control step of performing switching control of the inverter to input a phase current to the armature winding of each phase; a determination step of determining whether or not the phase current can be normally input for each of the armature windings of each phase; In the switch control step, if it is determined by the determination step that the phase current cannot be normally input to any one or more of the armature windings, and if there are three or more armature windings that are determined to be able to be normally input, the phase of the phase current is changed, the phase current is input to the normal armature winding, and the rotating electric machine is driven, and then the amount of current flowing through the armature winding is controlled to be small, and finally short-circuit control is performed to stop the rotating electric machine. This is a motor control method.

7. A motor control program executed by a motor control device (50) applied to a control system (10) including a polyphase AC rotating electric machine (20) having an n-phase (n is an integer of 5 or more) armature winding (21) and an inverter (30) connected to the armature winding, a switch control step of performing switching control of the inverter to input a phase current to the armature winding of each phase; a determination step of determining whether or not the phase current can be normally input for each of the armature windings of each phase; In the switch control step, if it is determined by the determination step that the phase current cannot be normally input to any one or more of the armature windings, and there are three or more armature windings that are determined to be able to be normally input, the phase of the phase current is changed, the phase current is input to the normal armature winding, and the rotating electric machine is driven, and then the amount of current flowing through the armature winding is controlled to be small, and finally short-circuit control is performed to stop the rotating electric machine. This is a motor control program.