Rotary motor control system

Abstract

This invention relates to a rotary electric motor control system. The control unit (1) determines, based on the voltage (Vdc) across the smoothing capacitor (4) and the current (Ib) flowing in the DC power supply (6), that the contactor (9) is in the open state and the rotational speed is above a speed threshold (ωth). It then controls both inverters (10) by closing control. After setting both contactors (9) to the open state and the rotational speed to less than the speed threshold (ωth), it controls the inverter (10) on the fault side by active short-circuit control, driving the inverter (10) on the normal side using the discharge torque (TQ1) of the smoothing capacitor (4). After the abnormal voltage state is cleared, it controls the normal contactor (9) to the closed state and drives the rotary electric motor (80) through one inverter (10).

Description

Technical Field

[0001] This invention relates to a rotating motor control system that drives and controls a rotating motor with open-circuit windings using two inverters. Background Technology

[0002] A rotary motor control system is known to drive and control a rotary motor by switching inverters located at both ends of a three-phase open-circuit winding of a three-phase AC rotary motor. Japanese Patent Application Publication No. 2014-192950 discloses an example of such a rotary motor control system. A smoothing capacitor for smoothing the DC voltage is connected to the DC side of each inverter. Furthermore, each inverter is connected to a different DC power supply. This document discloses a technique that allows the rotary motor to continue driving even if a switching element of the inverter driving such a three-phase open-circuit winding fails. Thus, if a switching element of either of the two inverters fails, all or all of the upper-side switching elements or all of the lower-side switching elements of the inverter containing the faulty switching element are turned on, and all of the switching elements on the other side are turned off, neutralizing the inverter and driving the rotary motor through the other inverter that is not faulty.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-192950

[0004] Faults in such rotating electric machine control systems are not limited to the switching elements in the inverter. For example, in rotating electric machine control systems, relays or contactors are often installed between the DC power supply connected to each inverter and the inverter, as well as the smoothing capacitor, to disconnect and connect the electrical connections between them. When the rotating electric machine is rotating, if a contactor malfunctions and becomes disconnected, the power supply from the DC power supply to the inverter is often cut off, or the back electromotive force of the rotating electric machine cannot be regenerated into DC power, causing the voltage across the terminals of the smoothing capacitor to rise. However, the aforementioned literature does not mention anything related to contactor faults. Summary of the Invention

[0005] In view of the above, it is desirable to provide a technique for identifying the faulty contactor and driving the rotating motor when one of the contactors installed between two inverters respectively located at both ends of the open winding and their respective connected DC power supplies fails.

[0006] In view of the above, a rotating motor control system for driving and controlling a rotating motor having independent multiphase open-circuit windings includes: a first inverter connected to one end of the open-circuit windings; a second inverter connected to the other end of the open-circuit windings; a first DC power supply connected to the first inverter; a second DC power supply connected to the second inverter; a first smoothing capacitor connected in parallel with the first DC power supply; a second smoothing capacitor connected in parallel with the second DC power supply; a first contactor for disconnecting and connecting the electrical connection between the first inverter and the first smoothing capacitor and the first DC power supply; and a second contactor for disconnecting and connecting the electrical connection between the second inverter and the second smoothing capacitor and the second DC power supply.The system includes a control unit that controls each of the first and second contactors and can independently control each of the first and second inverters. Each phase arm of the first and second inverters is composed of a series circuit of upper-side and lower-side switching elements. The control unit can perform active short-circuit control by setting all upper-side switching elements to the off state and all lower-side switching elements to the on state, or by setting all upper-side switching elements to the on state and all lower-side switching elements to the off state, and by setting all switching elements of multiple phases to the off state. The control unit controls the first inverter and the second inverter by using a shutdown control. This control uses a first upper limit voltage set to a value greater than the voltage fluctuation range of the first DC power supply, a first lower limit voltage set to a value smaller than the voltage fluctuation range of the first DC power supply, a second upper limit voltage set to a value greater than the voltage fluctuation range of the second DC power supply, and a second lower limit voltage set to a value smaller than the voltage fluctuation range of the second DC power supply. The control unit operates when the voltage across the first smoothing capacitor is higher than the first upper limit voltage or lower than the first lower limit voltage, and the current flowing in the first DC power supply is below a predetermined first lower limit current. If the first contactor is determined to be in the open state, and the voltage across the second smoothing capacitor is higher than the second upper limit voltage or lower than the second lower limit voltage, and the current flowing in the second DC power supply is below the predetermined second lower limit current, then the second contactor is determined to be in the open state. Of the first and second contactors, the one determined to be in the open state is designated as the faulty contactor, and the other is designated as the normal contactor. When the rotational speed of the rotating motor is above a predetermined speed threshold, both the first and second inverters are controlled by a shut-off control, and the upper... Both the first and second contactors are set to the open state. After the rotational speed of the rotating motor falls below the speed threshold, the inverter connected to the faulty contactor (i.e., the fault-side inverter) is controlled by the active short-circuit control to keep the normal contactor in the open state. The normal-side inverter is driven by the discharge torque of the smoothing capacitor connected to it. After the voltage rise across the normal-side smoothing capacitor is released, the normal contactor is closed, and the rotating motor is driven and controlled by the normal-side inverter.

[0007] According to this structure, when the rotating motor is in regenerative operation, a contactor fault can be detected by the current of the DC power supply that is not flowing due to the contactor being in the open state, and the voltage across the smoothing capacitor that rises due to the regenerative current. Furthermore, when the rotating motor is in power operation, a contactor fault can be detected by the current of the DC power supply that is not flowing due to the contactor being in the open state, and the voltage across the smoothing capacitor that drops to drive the rotating motor through discharge. Moreover, according to this structure, after controlling both inverters by a shutdown control, one inverter connected to the faulty contactor is short-circuited by an active short-circuit control, and the rotating motor is driven by the other inverter. At this time, if the rotational speed of the rotating motor is above a speed threshold, the non-faulty contactor is also controlled to be in the open state. Thus, the back electromotive force from the rotating motor can be absorbed by the two smoothing capacitors, and the rise in the voltage across the smoothing capacitor connected to the faulty contactor can be suppressed. In this case, although the voltage across the normal-side smoothing capacitor connected to the normal-side inverter also rises, the normal-side inverter is driven by the discharge torque, thereby discharging the normal-side smoothing capacitor. If the rise in voltage across the normal-side smoothing capacitor is eliminated, the rotating motor is driven and controlled by the normal-side inverter. Thus, according to this structure, if one of the contactors between the two inverters located at both ends of the open-circuit winding and their respective connected DC power supplies fails, the faulty contactor can be identified and the rotating motor can be driven and controlled.

[0008] Further features and advantages of the rotating electric motor control system will become clear from the following description of illustrative and non-limiting embodiments illustrated with reference to the accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a schematic block diagram of a rotary motor drive system.

[0010] Figure 2 This is a simplified partial block diagram of a rotary electric motor control device.

[0011] Figure 3 It is a schematic voltage vector diagram of a rotating electric motor in an orthogonal vector space.

[0012] Figure 4 This is a diagram showing an example of the control area of ​​a rotating electric machine.

[0013] Figure 5 This is a waveform diagram representing an example of a voltage command and switching control signal in hybrid continuous pulse width modulation (half-cycle continuous pulse).

[0014] Figure 6This is a waveform diagram representing an example of a voltage command and a switching control signal in a hybrid discontinuous pulse width modulation (half-cycle discontinuous pulse).

[0015] Figure 7 These are waveform diagrams representing other examples of voltage commands and switching control signals in hybrid continuous pulse width modulation (half-cycle continuous pulse).

[0016] Figure 8 This is a waveform diagram representing other examples of voltage commands and switching control signals for hybrid discontinuous pulse width modulation (half-cycle discontinuous pulse).

[0017] Figure 9 This is a waveform diagram representing an example of a voltage command and switching control signal with continuous pulse width modulation.

[0018] Figure 10 This is a waveform diagram representing an example of a voltage command and switching control signal with discontinuous pulse width modulation.

[0019] Figure 11 This is a flowchart illustrating an example of open-circuit fault detection and fail-safe control for a contactor.

[0020] Figure 12 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during high rotational speed / regeneration (an example of a normal contactor remaining closed).

[0021] Figure 13 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during high rotational speed / regeneration (an example where the normal contactor is also set to the open state).

[0022] Figure 14 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during high-speed / powered operation (an example of a normal contactor remaining closed).

[0023] Figure 15 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control for a contactor operating at high rotational speed / power (an example where the normal contactor is also set to the open state).

[0024] Figure 16 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during rotational speed / regeneration (an example of a normal contactor remaining in the closed state).

[0025] Figure 17This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during rotational speed / regeneration (an example where the normal contactor is also set to the open state).

[0026] Figure 18 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during medium-speed / power operation (an example of a normal contactor remaining in the closed state).

[0027] Figure 19 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during medium-speed / power operation (an example where the normal contactor is also set to the open state).

[0028] Figure 20 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during low rotational speed / regeneration (an example of a normal contactor remaining closed).

[0029] Figure 21 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during low rotational speed / regeneration (an example where the normal contactor is also set to the open state).

[0030] Figure 22 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control of a contactor during low-speed / powered operation (an example of a normal contactor remaining closed).

[0031] Figure 23 This is a timing diagram illustrating an example of open-circuit fault detection and fail-safe control for a contactor operating at low rotational speed / power (an example where the normal contactor is also set to the open state). Detailed Implementation

[0032] The following describes an embodiment of a rotary motor control device that uses two inverters to drive and control a rotary motor having independent multiphase open-circuit windings. Figure 1This is a schematic block diagram of a rotary motor control system 100 including a rotary motor control device 1 (MG-CTRL). The rotary motor 80 is, for example, a motor that serves as the driving force source for the wheels in vehicles such as electric vehicles and hybrid vehicles. The rotary motor 80 is an open-winding type rotary motor having independent multi-phase (three-phase in this embodiment) stator coils 8 (open-circuit windings). An inverter 10, which is independently controlled and converts power between DC and multi-phase (here, three-phase) AC, is connected to each end of the stator coil 8. That is, a first inverter 11 (INV1) is connected to one end of the stator coil 8, and a second inverter 12 (INV2) is connected to the other end of the stator coil 8. Hereinafter, without distinguishing between the first inverter 11 and the second inverter 12, it will be simply referred to as inverter 10.

[0033] The inverter 10 is configured with multiple switching elements 3. The switching elements 3 utilize IGBTs (Insulated Gate Bipolar Transistors) and power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). Figure 1 The example shown illustrates a configuration where an IGBT is used as the switching element 3. In this embodiment, the first inverter 11 and the second inverter 12 are inverters 10 with the same circuit structure using the same type of switching element 3.

[0034] In the two inverters 10, an arm 3A of one phase of AC circuit is formed by a series circuit of the upper-side switching element 3H and the lower-side switching element 3L, respectively. A freewheeling diode 35 is connected in parallel to each switching element 3, with the direction from the negative terminal FG to the positive terminal P (from the lower side to the upper side) as the positive direction. In addition, in the multi-phase arm 3A, the side containing the upper-side switching element 3H is called the upper-side arm, and the side containing the lower-side switching element 3L is called the lower-side arm.

[0035] In this embodiment, the two inverters 10 are each connected to an independent DC power supply 6. That is, the negative terminal FG of the first inverter 11, i.e., the first floating ground FG1, and the negative terminal FG of the second inverter 12, i.e., the second floating ground FG2, are independent of each other. Furthermore, a DC link capacitor (smoothing capacitor 4) is provided between the inverters 10 and the DC power supply 6 to smooth the DC voltage. Additionally, a discharge resistor 40 is connected in parallel with the smoothing capacitor 4 between the positive and negative terminals of the DC side of the inverter 10.

[0036] Specifically, a first inverter 11, consisting of a series circuit of a first upper-side switching element 31H and a first lower-side switching element 31L, forms an AC one-phase arm 3A. A first smoothing capacitor 41 is connected to the DC side, which is also connected to a first DC power supply 61. The AC side is connected to one end of the multi-phase stator coil 8, and it converts power between DC and multi-phase AC. A second inverter 12, consisting of a series circuit of a second upper-side switching element 32H and a second lower-side switching element 32L, forms an AC one-phase arm 3A. A second smoothing capacitor 42 is connected to the DC side, which is also connected to a second DC power supply 62. The AC side is connected to the other end of the multi-phase stator coil 8, and it converts power between DC and multi-phase AC.

[0037] 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 smoothing capacitor 41 and the second smoothing capacitor 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 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 (regenerates) the DC power supply 6 via the inverter 10.

[0038] like Figure 1 As shown, inverter 10 is controlled by rotating electric machine control unit 1 (control unit). Rotating electric machine control unit 1 can control each of the first inverter 11 and the second inverter 12 independently (details of the control methods will be described later). Rotating electric machine control unit 1 is constructed with logic circuits such as microcomputers as its core components. For example, rotating electric machine control unit 1 performs current feedback control using vector control method based on the target torque (torque command) of rotating electric machine 80 provided by other control devices such as vehicle control devices (not shown), and controls rotating electric machine 80 via inverter 10.

[0039] A contactor 9 is provided between the DC power supply 6, the inverter 10, and the smoothing capacitor 4 to disconnect and connect the electrical connection between them. Specifically, a first contactor 91 is provided between the first inverter 11 and the first smoothing capacitor 41, and the first DC power supply 61; a second contactor 92 is provided between the second inverter 12 and the second smoothing capacitor 42, and the second DC power supply 62. The contactors 9 are controlled by the vehicle control device and rotary motor control device 1 (not shown) described above, and electrically connect them in the closed state (CLOSE) and disconnect them in the open state (OPEN). The contactor 9 is, for example, a relay.

[0040] The actual current flowing in each phase stator coil 8 of the rotating electric machine 80 is detected by current sensor 15, and the magnetic pole position of the rotor of the rotating electric machine 80 at each moment is detected by rotation sensor 13 such as a resolver. The rotating electric machine control device 1 uses the detection results of current sensor 15 and rotation sensor 13 to perform current feedback control. The rotating electric machine control device 1 is configured to have various functional units for current feedback control, and each functional unit is implemented through the cooperation of hardware such as a microcomputer and software (program). In addition, the DC side voltage of each inverter 10, i.e., the DC link voltage Vdc, is detected by a voltage sensor (not shown) and can be obtained by the rotating electric machine control device 1. The rotating electric machine control device 1 obtains the DC side voltage of the first inverter 11, i.e., the first DC link voltage Vdc1, and the DC side voltage of the second inverter 12, i.e., the second DC link voltage Vdc2.

[0041] Figure 2 The block diagram simply illustrates a portion of the functional units of the rotating electric machine control device 1. In the vector control method, the coordinates of the actual currents flowing into the rotating electric machine 80 (U-phase current Iu, V-phase current Iv, W-phase current Iw) are converted into vector components (d-axis current Id, q-axis current Iq) representing the direction of the magnetic field (magnetic flux) generated by the permanent magnets arranged in the rotor of the rotating electric machine 80, and the direction orthogonal to the d-axis (a direction that leads the direction of the magnetic field by π / 2 electrical angle) representing the direction of the magnetic field, and feedback control is performed. The rotating electric machine control device 1 performs coordinate transformation based on the detection results (θ: magnetic pole position, electrical angle) of the rotation sensor 13 via the three-phase two-phase coordinate transformation unit 55.

[0042] The current feedback control unit 5 (FB) performs feedback control on the rotating motor 80 in the dq-axis orthogonal vector coordinate system 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 rotating motor 80 and the actual current (d-axis current Id, q-axis current Iq), and calculates the voltage command (d-axis voltage command Vd*, q-axis voltage command Vq*). The rotating motor 80 is driven by 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 allocated in the allocation unit 53 (DIV) as 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.

[0043] As described above, the rotating electric machine control device 1 can control each of the first inverter 11 and the second inverter 12 independently, and includes two voltage control units 7, each equipped with a three-phase voltage command arithmetic unit 73 and a modulation unit 74 (MOD). Specifically, the rotating electric machine control device 1 includes a first voltage control unit 71 that generates the switching control signals (Su1, Sv1, Sw1) for each of the U-phase, V-phase, and W-phase of the first inverter 11, and a second voltage control unit 72 that generates the switching control signals (Su2, Sv2, Sw2) for each of the U-phase, V-phase, and W-phase of the second inverter 12. Although details will be described later, the voltage commands (Vu1**, Vv1**, Vw1**) of the first inverter 11 and the voltage commands (Vu2**, Vv2**, Vw2**) of the second inverter 12 are phase-differentiated by "π". Therefore, the second voltage control unit 72 inputs the value obtained by subtracting "π" from the detection result (θ) of the rotation sensor 13.

[0044] Furthermore, as described later, the modulation methods include synchronous modulation, which is synchronized with the rotation of the rotating motor 80, and asynchronous modulation, which is independent of the rotation of the rotating motor 80. Typically, the generation block for synchronously modulated switch control signals (in the case of software, a generation process) differs from the generation block for asynchronously modulated switch control signals. The voltage control unit 7 generates switch control signals based on voltage commands and a carrier wave that is asynchronous with the rotation of the rotating motor 80. However, in this embodiment, for the sake of simplicity, the case where synchronously modulated switch control signals (e.g., the switch control signals in the case of rectangular wave control described later) are also generated by the voltage control unit 7 will be described.

[0045] Furthermore, each arm 3A of the inverter 10, as described above, is composed of a series circuit of an upper-side switching element 3H and a lower-side switching element 3L. Figure 2 Although there is no difference, the switching control signals for each phase are output as two types: upper-phase switching control signals and lower-phase 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-phase switching control signal Su1+ with a "+" appended to the end, and the first U-phase lower-phase switching control signal Su1- with a "-" appended to the end. Furthermore, if the upper-phase switching element 3H and the lower-phase switching element 3L constituting each arm 3A are simultaneously in the on state, then that arm 3A becomes short-circuited. To prevent this, a pause time is provided when both the upper-phase and lower-phase switching control signals for each arm 3A are inactive. This pause time is also added to the voltage control unit 7.

[0046] like Figure 1As shown, the control terminals (gate terminals in the case of IGBTs and FETs) of each switching element 3 constituting the inverter 10 are connected to the rotating motor control device 1 via the driver circuit 2 (DRV) and are independently controlled for switching. The operating voltages (power supply voltages) of the high-voltage circuit (connected to the DC power supply 6) used by the inverter 10 to drive the rotating motor 80 and the low-voltage circuit (operating voltage of approximately 3.3V to 5V) of the rotating motor control device 1, which is based on a microcomputer, differ significantly. The driver circuit 2 enhances and relays the driving capability (e.g., voltage amplitude, output current, and the ability to operate subsequent circuits) of the drive signals (switching control signals) for each switching element 3. The first driver circuit 21 relays the switching control signals to the first inverter 11, and the second driver circuit 22 relays the switching control signals to the second inverter 12.

[0047] The rotating electric machine control device 1, as a switching mode (voltage waveform control mode) of the switching element 3 constituting the first inverter 11 and the second inverter 12, can perform, for example, pulse width modulation (PWM) control, which outputs multiple pulses with different modes in one cycle of the electrical angle, and rectangular wave control, which outputs one pulse in one cycle of the electrical angle (one-pulse control). That is, the rotating electric machine control device 1, as a control method for the first inverter 11 and the second inverter 12, can perform pulse width modulation control and rectangular wave control. Furthermore, as described above, the rotating electric machine control device 1 can control each of the first inverter 11 and the second inverter 12 in an independent control mode.

[0048] Furthermore, pulse width modulation (PWM) includes various methods such as sinusoidal PWM (SPWM), space vector PWM (SVPWM), continuous PWM (CPWM), and discontinuous PWM (DPWM). Therefore, as a control method, the PWM control that the rotating electric machine control device 1 can execute includes both continuous PWM control and discontinuous PWM.

[0049] Continuous pulse width modulation (PWM) is a modulation method that continuously modulates the pulse width of all arms 3A of the multiphase system. Discontinuous pulse width modulation (PWM) is a modulation method that modulates the pulse width of a portion of arms 3A of the multiphase system, including periods during which switching elements are fixed in an on or off state. Specifically, in discontinuous PWM, for example, the signal level of the switching control signal corresponding to one of the three-phase AC inverters is fixed sequentially, while the signal levels of the corresponding switching control signals are varied. In continuous PWM, the switching control signal is not fixed to any one corresponding switch, but all phases are modulated. The modulation method described above is determined based on the operating conditions of the rotating motor 80, such as rotational speed and torque, and the modulation rate (the ratio of the effective value of the line-to-line voltage of the three-phase AC to the DC voltage) required to meet these operating conditions.

[0050] In pulse width modulation (PWM), pulses are generated based on the relationship between the amplitude of the AC waveform (which serves as a voltage command) and the amplitude of the triangular (including sawtooth) wave-shaped carrier wave (CA). (See reference...) Figures 5-10 Sometimes, PWM waveforms are generated directly through digital calculations, independent of carrier comparison. Even in this case, the amplitude of the AC waveform, which serves as the command value, is correlated with the amplitude of the hypothetical carrier waveform.

[0051] In pulse width modulation (PWM) for digital operations, the carrier wave is determined, for example, by the computational cycle of the microcomputer, the operating cycle of the electronic circuit, and the control cycle of the rotating motor control device 1. That is, even when multiphase AC power is used to drive the AC rotating motor 80, the carrier wave has a period (asynchronous period) that is not limited by the rotational speed or rotational angle (electrical angle) of the rotating motor 80. Therefore, neither the carrier wave nor the pulses generated based on the carrier wave are synchronized with the rotation of the rotating motor 80. Thus, modulation methods such as sinusoidal pulse width modulation and space vector pulse width modulation are sometimes called asynchronous modulation. In contrast, modulation methods that generate pulses synchronously with the rotation of the rotating motor 80 are called synchronous modulation. For example, in rectangular wave control (rectangular wave modulation), one pulse is output per electrical angle cycle of the rotating motor 80, so rectangular wave modulation is synchronous modulation.

[0052] As mentioned above, as an indicator of the conversion rate from DC to AC voltage, there exists a modulation rate, which represents the ratio of the effective value of the line-to-line voltage of multiphase AC voltage to the DC voltage. Generally, the maximum modulation rate of sinusoidal pulse width modulation (PWM) is approximately 0.61 (≈0.612), and the maximum modulation rate of space vector pulse width modulation (SVM) control is approximately 0.71 (≈0.707). Modulation methods with modulation rates exceeding approximately 0.71 are called "overmodulation pulse width modulation" (OBM), as the modulation rate is higher than usual. The maximum modulation rate of "overmodulation pulse width modulation" is approximately 0.78. This 0.78 is the physical (mathematical) limit value for the DC-to-AC power conversion. In overmodulation pulse width modulation, if the modulation rate reaches 0.78, it becomes rectangular wave modulation (one-pulse modulation) that outputs one pulse in one cycle of the electrical angle. In rectangular wave modulation, the modulation rate is fixed at approximately 0.78, which is the physical limit value. Furthermore, the modulation rate values ​​illustrated here are physical (mathematical) values ​​without considering dwell time.

[0053] Overmodulation pulse width modulation (PWM) with a modulation rate less than 0.78 can be achieved using either synchronous or asynchronous modulation principles. A representative modulation method for overmodulation PWM is discontinuous pulse width modulation (PWM). PWM can be implemented using either synchronous or asynchronous modulation principles. For example, in synchronous modulation, one pulse is output within one cycle of an electrical angle in rectangular wave modulation, while in discontinuous PWM, multiple pulses are output within one cycle of an electrical angle. If multiple pulses exist within one cycle of an electrical angle, the effective period of the pulses is correspondingly reduced, thus lowering the modulation rate. Therefore, it is not limited to a fixed modulation rate of approximately 0.78; any modulation rate less than 0.78 can be achieved using synchronous modulation. For example, within one cycle of an electrical angle, it is possible to set it to output nine pulses (9-Pulses) or five pulses (5-Pulses), etc., for multi-pulse modulation.

[0054] Furthermore, the rotating electric machine control device 1, as a fail-safe control in case of an anomaly detected in the inverter 10 or the rotating electric machine 80, can execute shutdown control (SDN) and active short-circuit control (ASC). Shutdown control disables the switching control signals for all switching elements 3 constituting the inverter 10, thus shutting down the inverter 10. Active short-circuit control enables either the upper-side switching element 3H of all multi-phase arms 3A or the lower-side switching element 3L of all multi-phase arms 3A to be on, while shutting down the other side. Additionally, the case where the upper-side switching element 3H of all multi-phase arms 3A is on while the lower-side switching element 3L of all multi-phase arms 3A is off is called upper-side active short-circuit control (ASC-H). In addition, the situation in which the lower-side switching element 3L of all arms 3A of the multiphase is turned on while the upper-side switching element 3H of all arms 3A of the multiphase is turned off is called lower-side active short-circuit control (ASC-L).

[0055] As in this embodiment, when inverters 10 are connected to both ends of the stator coil 8, if one inverter 10 is short-circuited by active short-circuit control, the multiphase stator coil 8 is short-circuited in that one inverter 10. That is, that one inverter 10 becomes the neutral point, and the stator coil 8 is Y-connected. Therefore, the rotating electric machine control device 1 can realize the configuration of a rotating electric machine 80 with open winding controlled by two inverters 10, and the configuration of a rotating electric machine 80 with Y-connection controlled by one inverter 10 (the one without active short-circuit control).

[0056] Furthermore, when the back electromotive force caused by the rotation of the rotary motor 80 is large, even if all switching elements 3 are controlled to the off state by the shutdown control, the freewheeling diode 35 connected in parallel with the switching elements 3 will still be turned on. As a result, there is a possibility that the inverter 10, which is under shutdown control, will be short-circuited, thus achieving a Y-shaped connection in the rotary motor 80.

[0057] Figure 3 An example is shown: a vector diagram of an operating point in the dq-axis vector coordinate system of the rotating electric machine 80. In the diagram, "V1" represents the first voltage vector representing the voltage of the first inverter 11, and "V2" represents the second voltage vector representing the voltage of the second inverter 12. The voltage appearing in the stator coil 8, which is an open-circuit winding, via the two inverters 10 is equivalent to the difference "V1-V2" between the first voltage vector V1 and the second voltage vector V2. "Va" in the diagram shows the resultant voltage vector appearing in the stator coil 8. Additionally, "Ia" represents the current flowing in the stator coil 8 of the rotating electric machine 80. Figure 3As shown, if the first inverter 11 and the second inverter 12 are controlled with the orientations of the first voltage vector V1 and the second voltage vector V2 differing by 180 degrees, then the synthesized voltage vector Va becomes a vector obtained by adding the magnitude of the second voltage vector V2 to the orientation of the first voltage vector V1.

[0058] In this embodiment, multiple control regions R (refer to) are set corresponding to the operating conditions of the rotary motor 80. Figure 4 The rotating motor control device 1 controls the inverter 10 in a control mode corresponding to each control area R. Figure 4 An example is shown showing the relationship between the rotational speed and torque of a rotary electric motor 80. For example, as... Figure 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.

[0059] As described above, the rotating electric machine control device 1 controls each of the first inverter 11 and the second inverter 12 through multiple control methods with different switching modes. The control methods include pulse width modulation (PWM) control that outputs multiple pulses with different modes within one cycle of the electrical angle; and control for half a cycle (half-cycle) of the electrical angle (full cycle), i.e., the first period T1 (refer to...). Figure 5 In the second period T2 (e.g., during which multiple pulses with different output modes are generated), the output modes are adjusted. Figure 5 Hybrid pulse width modulation control (MX-PWM) continues in an inactive state in (etc.) (see Figures 5-8 (To be described later). The rotating electric motor control device 1 controls the inverters of both the first inverter 11 and the second inverter 12 through hybrid pulse width modulation control in the first speed region VR1 and the second speed region VR2.

[0060] 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). While details will be described later, in hybrid continuous pulse width modulation control, control continues in an inactive state during the second period T2, and pulse width modulation is performed continuously on all arms 3A of the multiphase system during the first period T1 (see reference). Figure 5 , Figure 7(And will be described later.) Similarly, although details will be described later, in the hybrid discontinuous pulse width modulation control, control is performed in a manner that continues the ineffective state during the second period T2, and pulse width modulation is performed during the first period T1, which includes a period in which the switching element 3 of a portion of the multiphase arm 3A is fixed in the on or off state (see reference). Figure 6 , Figure 8 (To be discussed later.)

[0061] In hybrid pulse width modulation (PWM) control, the switching control signal also becomes inactive during the second period T2, thus reducing the losses of inverter 10. Furthermore, the harmonic current of the switch is reduced, and the losses (iron losses) of the rotating motor 80 are also reduced. In other words, by implementing hybrid pulse width modulation control, system losses can be reduced.

[0062] For example, as shown in Table 1 below, in the first speed region VR1, the rotating electric machine control device 1 controls the inverter 10 of both the first inverter 11 and the second inverter 12 using hybrid continuous pulse width modulation control (MX-CPWM), which will be described later. Furthermore, in the second speed region VR2, the rotating electric machine control device 1 controls the inverter 10 of both the first inverter 11 and the second inverter 12 using hybrid discontinuous pulse width modulation control (MX-DPWM), which will be described later. Additionally, in the third speed region VR3, the rotating electric machine control device 1 controls the inverter 10 of both the first inverter 11 and the second inverter 12 using rectangular wave control. The terms Mi_sys, Mi_inv1, and Mi_inv2 in the table will be described later.

[0063] [Table 1]

[0064] 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

[0065] The boundaries of each control region R (the boundaries of the first speed region VR1, the second speed region VR2, and the third speed region VR3) are preferably set based on at least one of the rotational speed of the rotary motor 80 corresponding to the torque of the rotary motor 80, and the ratio of the effective value of the line-to-line voltage of the multiphase AC voltage (which can be either a command value or a converted value from the output voltage) to the DC voltage.

[0066] like Figure 4 For example, the operating conditions of the rotary motor 80 are typically defined by the relationship between rotational speed and torque. The control region R can also be set based on the rotational speed as a parameter. Here, although it is possible to set the rotational speed defining the boundary of the control region R to be constant and independent of torque, it is more preferable to set the rotational speed defining the boundary of the control region R to a value that varies depending on the torque. As a result, the rotary motor 80 can be driven and controlled efficiently according to its operating conditions.

[0067] Furthermore, for example, when the rotating motor 80 requires high output (high rotational speed, high torque), in a voltage-type inverter, this requirement is achieved by increasing the DC voltage and increasing the ratio of DC voltage to AC voltage conversion. When the DC voltage is constant, this requirement can be achieved by increasing the ratio of DC voltage to AC voltage conversion. This ratio can be expressed as the ratio of the effective value of the three-phase AC current to the DC current (in the case of a voltage-type inverter, this is equivalent to the ratio of the effective value of the three-phase AC voltage to the DC voltage). As described above, there are various control methods for the inverter 10 where this ratio ranges from low to high.

[0068] As shown in Table 1, if the control region R is set based on the ratio (modulation rate) of the effective value of the three-phase AC power to the DC power determined according to the requirements of the rotating motor 80, then the rotating motor 80 can be driven and controlled efficiently according to its operating conditions. Furthermore, in the table, "Vi_inv1" indicates the modulation rate of the first inverter 11, "Mi_inv2" indicates the modulation rate of the second inverter 12, and "Mi_sys" indicates the overall modulation rate of the system.

[0069] As described above, Table 1 illustrates the modulation rates corresponding to each control region R. In this embodiment, the inter-terminal voltage "E1" of the first DC power supply 61 and the inter-terminal voltage "E2" of the second DC power supply 62 are the same (both are voltages "E"). If the effective value of the AC side of the first inverter 11 is set to "Va_inv1" and the effective value of the AC side of the second inverter 12 is set to "Va_inv2", then the modulation rate "Mi_inv1" of the first inverter 11 and the modulation rate "Mi_inv2" of the second inverter 12 are as shown in equations (1) and (2) below. In addition, the overall system modulation rate "Mi_sys" is as shown in equation (3) below.

[0070] Mi_inv1=Va_inv1 / E1=Va_inv1 / E···(1)

[0071] Mi_inv2=Va_inv2 / E2=Va_inv2 / E···(2)

[0072] Mi_sys=(Va_inv1+Va_inv2) / (E1+E2)

[0073] =(Va_inv1+Va_inv2) / 2E···(3)

[0074] Regarding the instantaneous value of voltage, the instantaneous vector needs to be considered. However, if only the modulation rate is considered, the overall modulation rate "Mi_sys" of the system becomes "(Mi_inv1+Mi_inv2) / 2" through equations (1) to (3). In addition, Table 1 shows the modulation rates corresponding to each control region R as nominal values. Therefore, in actual control, considering oscillations when changing the control mode in the control region R, the modulation rates corresponding to each control region R may also include overlapping ranges.

[0075] In addition, the modulation rate "a" shown in Table 1 and the modulation rate "b" shown in Table 2 (described later) are set based on the theoretical upper limit of the modulation rate in each modulation scheme, and also take into account the dwell time. For example, "a" is about 0.5 to 0.6, and "b" is about 0.25 to 0.3.

[0076] Here, refer to Figures 5-8 The waveforms of the voltage commands (Vu1**, Vu2**) for phase U and the upper-side switch control signals (Su1+, Su2+) for phase U are shown to illustrate hybrid pulse width modulation control (MX-PWM). The diagrams of the lower-side switch control signal Su2- for phase U, as well as those for phases V and W, are omitted. Figure 5 as well as Figure 7 A waveform example of hybrid continuous pulse width modulation control (MX-CPWM) is shown. Figure 6 as well as Figure 8 A waveform example of hybrid discontinuous pulse width modulation control (MX-DPWM) is shown.

[0077] exist Figure 5 as well as Figure 6 The diagram shows an example of the carrier CA (i.e., the first carrier CA1) of the first inverter 11, the carrier CA (i.e., the second carrier CA2) of the second inverter 12, the common U-phase voltage command (i.e., the common U-phase voltage command Vu**) in both the first inverter 11 and the second inverter 12, the first U-phase upper-side switch control signal Su1+, and the second U-phase upper-side switch control signal Su2+. The diagrams of 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 W-phase are omitted (the same applies to other control methods).

[0078] For example, the first carrier CA1 can vary between "0.5 < CA1 < 1", the second carrier CA2 can vary between "0 < CA2 < 0.5", and the voltage command (V**) can vary between "0 ≤ V** ≤ 1". By comparing the carrier CA (first carrier CA1 and second carrier CA2) with the voltage command (V**), the switch control signal becomes "1" when the voltage command is greater than or equal to the carrier CA, and becomes "0" when the voltage command is less than the carrier CA. The comparison logic between the carrier CA and the voltage command (V**) is the same in the following explanation.

[0079] like Figure 5 as well as Figure 6 As shown, the amplitudes of the first carrier CA1 and the second carrier CA2 are half the amplitude allowed by the voltage command (V**). In general pulse width modulation, the amplitude of carrier CA is the same as the amplitude allowed by the voltage command; the carrier CA in hybrid pulse width modulation can be called a half-carrier. By using such a half-carrier, in half a period of the electrical angle (full cycle), i.e., the first period T1 (half-cycle), because this half-carrier intersects with the voltage command (V**), multiple pulses with different output modes are output as the switching control signal. In another half period, i.e., the second period T2 (half-cycle), because the half-carrier does not intersect with the voltage command (V**), the switching control signal is output in a continuously inactive state.

[0080] In addition, in hybrid discontinuous pulse width modulation control, such as Figure 6 As shown, in the second period T2, pulses that are locally active are also output as switching control signals. This is because the modulation rate of the underlying discontinuous pulse width modulation is larger than that of continuous pulse width modulation. In the second period T2, pulses that are active are output near the amplitude center and inflection point of the voltage command (V**). Figure 6 As shown, it can also be said that in hybrid discontinuous pulse width modulation control, the inactive state continues to be output during the second period T2. Furthermore, when the second period T2 is set only as the period during which the switch control signal is inactive (a period less than 1 / 2 cycle), and the period within one cycle is set to a period other than the second period T2 (a period greater than 1 / 2 cycle), hybrid pulse width modulation can also be defined as follows. It can also be said that hybrid pulse width modulation control is performed by outputting multiple pulses with different modes during the first period T1 (more than 1 / 2 cycle of the electrical angle), and continuing the inactive state during the remainder of the second period T2 (the second period of the electrical angle).

[0081] Figure 7 as well as Figure 8 Examples of hybrid continuous pulse width modulation control and hybrid discontinuous pulse width modulation control are shown. Figure 5 as well as Figure 6 Different forms. The generated switch control signals are the same. In Figure 7 as well as Figure 8 The diagram illustrates an example of the carrier CA (i.e., first carrier CA1) of the first inverter 11, the carrier CA (i.e., second carrier CA2) of the second inverter 12, the U-phase voltage command (i.e., first U-phase voltage command Vu1**) of the first inverter 11, the U-phase voltage command (i.e., second U-phase voltage command Vu2**) of the second inverter 12, the first U-phase upper-side switch control signal Su1+, and the second U-phase upper-side switch control signal Su2+. For example, the first carrier CA1 and the second carrier CA2 can vary between "0.5 < CA1 < 1", and the voltage command (V**) can vary between "0 ≤ V** ≤ 1". The first carrier CA1 and the second carrier CA2 are 180 degrees (π) out of phase. Furthermore, the first U-phase voltage command Vu1** and the second U-phase voltage command Vu2** are also 180 degrees (π) out of phase.

[0082] like Figure 7 as well as Figure 8 As shown, the amplitudes of the first carrier CA1 and the second carrier CA2 are half the amplitudes allowed by the voltage command (V**). Therefore, Figure 7 as well as Figure 8 The carrier CA shown is also a half-carrier. By using such a half-carrier, during the first period T1 (half a cycle or more of the electrical angle), the half-carrier intersects with the voltage command (V**), resulting in multiple pulses output as a switching control signal with different modes. During the remaining period of the period, the second period T2, the switching control signal is output in a continuously inactive state because the half-carrier does not intersect with the voltage command (V**).

[0083] exist Figure 5 as well as Figure 6 The configuration illustrated is a modulation method using two half-carriers and a voltage command (V**) as a common reference, which can also be called a dual-half-carrier / single-reference method. On the other hand, in Figure 7 as well as Figure 8 The configuration illustrated is a modulation method using two half-carriers and two voltage commands (V**), which can also be called a dual half-carrier / dual reference mode.

[0084] As mentioned above Figures 5-8The hybrid pulse width modulation control generates multiple pulses based on the carrier CA (i.e., half-carriers, first carrier CA1 and second carrier CA2) of the variable region of the command value (voltage command, which in the above example is the U-phase voltage command (Vu** (Vu** = Vu1** = Vu2**), Vu1**, Vu2**)) and the command value. Furthermore, in this embodiment, two hybrid pulse width modulation control methods are illustrated: a dual half-carrier / single reference method and a dual half-carrier / dual reference method.

[0085] In dual half-carrier / single reference mode, such as reference Figure 5 as well as Figure 6 As explained, a pulse for the first inverter 11 is generated based on a first half-carrier (first carrier CA1) whose amplitude center is set on either the high-voltage side or the low-voltage side (here, the high-voltage side) compared to the half-carrier and the command value (common U-phase voltage command Vu**) and a common command value (common U-phase voltage command Vu**) shared in both the first inverter 11 and the second inverter 12. In this method, a pulse for the second inverter 12 is generated based on a second half-carrier (second carrier CA2) with the same phase as the first half-carrier (first carrier CA1) and whose amplitude center is set on either the high-voltage side or the low-voltage side (here, the low-voltage side) compared to the command value (common U-phase voltage command Vu**) and the command value (common U-phase voltage command Vu**).

[0086] In dual half-carrier / dual reference mode, such as reference Figure 7 as well as Figure 8 As explained, pulses for the first inverter 11 are generated based on a first half-carrier (first carrier CA1) whose amplitude center is set on either the high-voltage side or the low-voltage side (here, the high-voltage side) compared to the half-carrier and the command value (first U-phase voltage command Vu1**, second U-phase voltage command Vu2**), and a first command value (first U-phase voltage command Vu1**) for the first inverter 11. In this method, pulses for the second inverter 12 are generated based on a second half-carrier (second carrier CA2) whose phase is 180 degrees different from the first half-carrier (first carrier CA1) and is set on the same side as the first half-carrier (first carrier CA1) (the high-voltage side), and a second command value (second U-phase voltage command Vu2**) whose phase is 180 degrees different from the first command value (first U-phase voltage command Vu1**).

[0087] In addition, as described in Table 2 below, in the first speed region VR1 and the second speed region VR2, there are cases where the inverter 10 is controlled by pulse width modulation without hybrid pulse width modulation. Figure 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, the following parameters are provided: first U-phase voltage command Vu1**, second U-phase voltage command Vu2**, carrier CA, first U-phase upper-side switch control signal Su1+, and second U-phase upper-side switch control signal Su2+. Additionally, Figure 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 segment side switch control signal Su1+, and the second U-phase upper segment side switch control signal Su2+ are shown.

[0088] When both the first inverter 11 and the second inverter 12 are switched, 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-to-line voltage is "2E" (see also...). Figure 3 (Vector diagram). Furthermore, the first DC power supply 61 and the second DC power supply 62 are independent, and the first voltage E1 of the first DC power supply 61 and the second voltage E2 of the second DC power supply 62 can also have 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. The same 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 given to both inverters 10.

[0089] However, when the inverter 10 is switched on and off, pulsating components that overlap with the fundamental frequency of the alternating current sometimes generate noise in the audio frequency band. When the two inverters 10 are controlled with pulses of different shapes, pulsations corresponding to each pulse are generated, raising concerns about increased noise in the audio frequency band. This is especially true when the rotating motor 80 rotates at low speeds, increasing the likelihood that the frequency of the pulsating components (or their sideband frequencies) will be included in the audio frequency band. Preferably, the control method of the rotating motor 80, i.e., the control method of the inverter 10, should be appropriately set according to the operating conditions to achieve both high system efficiency and reduced audible noise.

[0090] In this embodiment, the rotating electric motor control device 1 is configured to switch between a loss reduction priority mode (efficiency priority mode) and a noise reduction priority mode as the control mode for the rotating electric motor 80. In the loss reduction priority mode, the rotating electric motor control device 1 uses hybrid pulse width modulation control to control the switching of the inverter 10, as described above with reference to Table 1. In the noise reduction priority mode, the rotating electric motor control device 1 uses pulse width modulation control to control the switching of the inverter 10, as illustrated in Table 2 below.

[0091] [Table 2]

[0092] R Mi_sys INV1 Mi_inv1 INV2 Mi_inv2 VR1 M < b CPWM M < b CPWM M < b VR2-2 b≤M<0.78 DPWM b≤M<0.78 DPWM b≤M<0.78 VR3 M＝0.78 1-Pulse M＝0.78 1-Pulse M＝0.78

[0093] When the inverter 10 is switched on and off, pulsating components that sometimes overlap with the fundamental frequency of the alternating current can generate noise in the audio frequency band. This is especially true when the rotating motor 80 rotates at low speeds, increasing the likelihood that the frequency of the pulsating component (or its sideband frequencies) will be included in the audio frequency band. In hybrid pulse width modulation, such as... Figures 5-8 As shown, during the half-cycle of the electrical angle, the two inverters 10 are controlled with different pulse patterns, thus generating pulsations corresponding to each pulse, which may increase the noise in the audio 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 hitting the road surface) is also relatively low. Therefore, if the noise output from one of the driven inverters 10 is in the audio frequency band, the noise may be more easily heard by the user.

[0094] For example, it is preferable to select the noise reduction priority mode when the vehicle starts or decelerates towards a stop, considering that noise in the audio frequency band is easily heard by the user, and to select the loss reduction priority mode when the vehicle is running stably. In addition, the above modes can also be selected by the user's operation (setting switch (including input from touch panel, etc.)).

[0095] In the noise reduction priority mode, 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 first inverter 11 and the second inverter 12 are controlled by pulse width modulation control instead of hybrid pulse width modulation control. For the two inverters 10 that flow current to the stator coil 8, the phase difference of the current is approximately 180 degrees, so the phase difference of the current containing the pulsating component is also approximately 180 degrees. Therefore, at least a portion of the pulsating component can be canceled out, and noise in the audio frequency band can be reduced.

[0096] As explained above, the rotating electric machine 80, which has independent multiphase open-circuit windings, is appropriately controlled by the rotating electric machine control device 1, which can independently control each of the first inverter 11 and the second inverter 12. However, as described above, the rotating electric machine control system 100 provides contactors such as relays between the DC power supply 6 connected to each inverter 10 and the inverters 10 and the smoothing capacitor 4 for disconnecting and connecting the electrical connections between them. When the rotating electric machine 80 is rotating, if the contactor 9 becomes disconnected due to a fault or other reason (an open-circuit fault occurs), the power supply from the DC power supply 6 to the inverters 10 is often cut off, or the back electromotive force of the rotating electric machine 80 cannot be regenerated in the DC power supply 6, causing the voltage between the terminals of the smoothing capacitor 4 to rise.

[0097] As described above, the rotating motor control device 1 can independently control each of the first inverter 11 and the second inverter 12. For example, if any contactor 9 experiences an open-circuit fault, the inverter 10 connected to the faulty contactor 9 cannot be switched, and the rotating motor 80 cannot be controlled. However, as described above, by actively short-circuiting one inverter 10, which is then short-circuited and set as the neutral point of the stator coil 8, the rotating motor 80 can be driven and controlled as a rotating motor with the stator coil 8 configured as a Y-shaped junction (single inverter torque control mode). Therefore, it is preferable to identify the faulty contactor 9 and quickly quell the transient state caused by the fault, and appropriately execute the single inverter torque control mode.

[0098] In the rotating electric machine control system 100 of this embodiment, the rotating electric machine control device 1 identifies a faulty contactor 9 and appropriately performs fail-safe control based on the control state corresponding to the fault of the contactor 9. Here, fail-safe control refers to quickly quelling the transitional state caused by the open-circuit fault of the contactor 9 and appropriately performing control in a single-inverter torque control mode.

[0099] As described above, the rotary motor control system 100 for driving and controlling a rotary motor 80 having independent multi-phase open-circuit windings (stator coils 8) includes: a first inverter 11 connected to one end of the open-circuit windings; a second inverter 12 connected to the other end of the open-circuit windings; a first DC power supply 61 connected to the first inverter 11; a second DC power supply 62 connected to the second inverter 12; a first smoothing capacitor 41 connected in parallel with the first DC power supply 61; a second smoothing capacitor 42 connected in parallel with the second DC power supply 62; a first contactor 91 for disconnecting and connecting the electrical connection between the first inverter 11 and the first smoothing capacitor 41 and the first DC power supply 61; a second contactor 92 for disconnecting and connecting the electrical connection between the second inverter 12 and the second smoothing capacitor 42 and the second DC power supply 62; and a rotary motor control device 1 (control unit) for controlling each of the first contactor 91 and the second contactor 92 and being capable of independently controlling each of the first inverter 11 and the second inverter 12.

[0100] Although detailed content is referenced Figures 11-23 As will be described later, if the voltage across the first smoothing capacitor 41 (first DC link voltage Vdc1) is higher than the first upper limit voltage VrefH1 or lower than the first lower limit voltage VrefL1, and the current flowing in the first DC power supply 61 (first battery current Ib1) is below the predetermined first lower limit current Iref1, the rotary motor control device 1 determines that the first contactor 91 is in the open state. Similarly, if the voltage across the second smoothing capacitor 42 (second DC link voltage Vdc2) is higher than the second upper limit voltage VrefH2 or lower than the second lower limit voltage VrefL2, and the current flowing in the second DC power supply 62 (second battery current Ib2) is below the predetermined second lower limit current Iref2, the rotary motor control device 1 determines that the second contactor 92 is in the open state. Here, this determination process is referred to as the contactor open circuit determination process. Furthermore, among the first contactor 91 and the second contactor 92, the contactor 9 determined to be in the open state in the contactor open circuit determination process is designated as a faulty contactor, and the other contactor 9 is designated as a normal contactor.

[0101] Furthermore, the first upper limit voltage VrefH1 is set to a value larger than the voltage variation range of the first DC power supply 61. For example, if the rated voltage of the first DC power supply 61 is 300 [V] and a voltage variation of ±25% is allowed, the voltage variation range is 220 [V] to 380 [V]. Therefore, the first upper limit voltage VrefH1 is set to, for example, 400 [V]. The first lower limit voltage VrefL1 is set to a value smaller than the voltage variation range of the first DC power supply 61. According to the above example, the first lower limit voltage VrefL1 is set to a value less than 220 [V], for example, 200 [V]. Similarly, the second upper limit voltage VrefH2 is set to a value larger than the voltage variation range of the second DC power supply 62, and the second lower limit voltage VrefL2 is set to a value smaller than the voltage variation range of the second DC power supply 62. In this embodiment, the first DC power supply 61 and the second DC power supply 62 have the same rated voltage and the same specifications, and the first upper limit voltage VrefH1 and the second upper limit voltage VrefH2 are set to the same value. Furthermore, the first lower limit voltage VrefL1 and the second lower limit voltage VrefL2 are also set to the same value. In this case, the first upper limit voltage VrefH1 and the second upper limit voltage VrefH2 can be referred to simply as the upper limit voltage VrefH, and the first lower limit voltage VrefL1 and the second lower limit voltage VrefL2 can be referred to simply as the lower limit voltage VrefL. Of course, the first upper limit voltage VrefH1 and the second upper limit voltage VrefH2 can also be set to different values, and the first lower limit voltage VrefL1 and the second lower limit voltage VrefL2 can also be set to different values.

[0102] The following is for reference Figures 11-23 Specifically, this section explains the detection of open-circuit faults in contactors and their fail-safe control. Figure 11 The flowchart illustrates an example of the detection of open-circuit faults in a contactor and the sequence of fail-safe controls. Figures 12-23 The timing diagram illustrates an example of the detection of an open-circuit fault in the contactor and the action of fail-safe control. Figures 12-15 This is an example where the rotational speed of the rotary motor 80 is relatively high (e.g., above 13,000 rpm). Figures 20-23 This is an example where the rotational speed of the rotary motor 80 is relatively low (e.g., less than 5000 rpm). Figures 16-19 This is an example of a rotary motor 80 whose rotational speed is a medium rotational speed (e.g., around 9000 rpm). Figure 12 , Figure 13 , Figure 16 , Figure 17 , Figure 20 , Figure 21 This is an example of a rotary motor 80 performing a regenerative operation. Figure 14 , Figure 15 , Figure 18 , Figure 19 , Figure 22 , Figure 23 This is an example of a rotating electric motor 80 performing a powered operation. Additionally, Figure 12 , Figure 14 , Figure 16 , Figure 18 , Figure 20 , Figure 22 This is an example of a normal contactor performing fail-safe control while remaining in the closed state. Figure 13 , Figure 15 , Figure 17 , Figure 19 , Figure 21 , Figure 23 This is an example of setting a normal contactor to the open state to perform fail-safe control. Figure 11 The flowchart shown illustrates an example of performing fail-safe control by also setting a normal contactor to the open state.

[0103] In addition, Figures 12-23 In the timing diagram, contactor 9 is marked as "OPEN" when it is in the open state and "CLOSE" when it is in the closed state. The control modes of the first inverter 11 and the second inverter 12 are shown in Tables 1 and 2. Figures 1-10 As explained, the control mode that drives the inverter 10 based on torque commands and through pulse width modulation control (including rectangular wave modulation control) is labeled "torque mode". Additionally, as mentioned above, the shutdown control is labeled "SDN", and the active short-circuit control is labeled "ASC". The voltage values ​​of the first DC link voltage Vdc1 and the second DC link voltage Vdc2 are, respectively, the first normal voltage Vtyp1 and the second normal voltage Vtyp2 under normal conditions. Under rated conditions, they are the same voltage, and without distinction, they are simply referred to as the normal voltage Vtyp. As described later, the value of the DC link voltage Vdc varies due to the opening and closing of the contactor 9, etc. Figures 12-23 The DC link voltage Vdc is shown using V52, V38, V48, etc. The larger of these numbers indicates a higher voltage. Similarly, the rotational speed of the rotary motor 80 is also shown. Figures 12-23 The rotational speed is indicated by R15, R3, etc. Regarding the rotational speed, the larger number indicates a higher rotational speed. Furthermore, although details will be discussed later, MD1 represents the dual-inverter torque control mode, MD2 represents the off control mode (non-torque control mode), and MD3 represents the single-inverter torque control mode.

[0104] like Figure 11As shown, the rotary motor control device 1 first detects the voltage across the first smoothing capacitor 41 (first DC link voltage Vdc1), the voltage across the second smoothing capacitor 42 (second DC link voltage Vdc2), the current flowing in the first DC power supply 61 (first battery current Ib1), and the current flowing in the second DC power supply 62 (second battery current Ib2) (#1). These are respectively determined by... Figure 1 Voltage sensors (not shown) measure the first DC link voltage Vdc1 and the second DC link voltage Vdc2 (collectively referred to as DC link voltage Vdc), which are detected, for example, by means of a vehicle network such as CAN (Controller Area Network) obtained from the rotary motor control device 1. The first battery current Ib1 and the second battery current Ib2 are also measured by... Figure 1 The current sensor, not shown in the diagram, measures the current, and the data is detected, for example, by the rotary motor control device 1 via an in-vehicle network such as CAN. The rotary motor control device 1 detects the first DC link voltage Vdc1, the second DC link voltage Vdc2, the first battery current Ib1, and the second battery current Ib2 according to the control cycle of vector control. A long detection cycle results in low resolution, while a short detection cycle reduces the capacity of temporary storage devices such as memory and increases the computational load. Therefore, it is preferable, for example, to detect the first DC link voltage Vdc1, the second DC link voltage Vdc2, the first battery current Ib1, and the second battery current Ib2 sequentially, using the control cycle of vector control as the unit.

[0105] Next, the rotary motor control device 1 determines whether the first DC link voltage Vdc1 is higher than the first upper limit voltage VrefH1 or lower than the first lower limit voltage VrefL1, and whether the first battery current Ib1 is lower than the first lower limit current Iref1 (#2a). If this condition is met, the rotary motor control device 1 determines that the first contactor 91 has an open circuit fault, sets the first contactor 91 as a faulty contactor, and sets the other second contactor 92 as a normal contactor. In addition, the inverter 10 connected to the side of the first contactor 91, which is the faulty contactor, i.e., the first inverter 11, is set as the faulty side inverter, and the inverter 10 connected to the side of the second contactor 92, which is the normal side inverter, i.e., the second inverter 12, is set as the normal side inverter (#3a).

[0106] Similarly, the rotating motor control device 1 determines whether the second DC link voltage Vdc2 is higher than the second upper limit voltage VrefH2 or lower than the second lower limit voltage VrefL2, and whether the second battery current Ib2 is lower than the second lower limit current Iref2 (#2b). If this condition is met, the rotating motor control device 1 determines that the second contactor 92 has an open circuit fault, sets the second contactor 92 as a faulty contactor, and sets the other first contactor 91 as a normal contactor. In addition, the inverter 10 connected to the side of the second contactor 92, which is the faulty contactor, i.e., the second inverter 12, is set as the faulty side inverter, and the inverter 10 connected to the side of the first contactor 91, which is the normal side inverter, i.e., the first inverter 11, is set as the normal side inverter (#3b).

[0107] In addition, Figure 11 The illustrated flowchart shows the form where step #3b is executed in step #3a if the condition is not met, but it can also be the opposite. When referred to collectively as steps #2a and #2b, this is called step #2; when referred to collectively as steps #3a and #3b, this is called step #3. Step #2 is equivalent to the contactor open-circuit determination process described above. Furthermore, the first lower limit current Iref1 and the second lower limit current Iref2 are values ​​close to zero, set to values ​​greater than the maximum error of the current sensor measuring the battery current Ib.

[0108] Here, refer to Figures 12-23 The timing diagram. Figures 12-23 Similar to the previous configuration, initially, the first contactor 91 and the second contactor 92 are in the closed state (CLOSE), and the inverter 10 and the smoothing capacitor 4 are electrically connected to the DC power supply 6. Both the first inverter 11 (INV1) and the second inverter 12 (INV2) are controlled in torque mode (dual inverter torque control mode). The first DC link voltage Vdc1 and the second DC link voltage Vdc2 are the first normal voltage Vtyp1 and the second normal voltage Vtyp2, respectively, both being normal voltages Vtyp.

[0109] Furthermore, in the case of regenerative operation of the rotary motor 80, a negative torque is output ( Figure 12 , Figure 13 , Figure 16 , Figure 17 , Figure 20 , Figure 21 When the rotating motor 80 is in operation, it outputs a positive torque. Figure 14 , Figure 15 , Figure 18 , Figure 19 , Figure 22 , Figure 23The rotational speed increases to R15 at high rotational speeds. Figures 12-15 ), rising to R9 at medium rotational speed. Figures 16-19 ), rising to R3 at low rotational speeds. Figures 20-23 Here, in Figures 12-23 Similarly, at time t1, the second contactor 92 experienced an open circuit fault and became open.

[0110] If the second contactor 92 is in the open state, the power generated during the regenerative operation of the rotary motor 80 will not be regenerated to the second DC power supply 62, thus charging the second smoothing capacitor 42. Therefore, the voltage across the second smoothing capacitor 42, i.e., the second DC link voltage Vdc2, rises from the second normal voltage Vtyp2. Figure 12 , Figure 13 , Figure 16 , Figure 17 , Figure 20 , Figure 21 ).according to Figure 12 , Figure 16 and Figure 20 Comparison Figure 13 , Figure 17 and Figure 21 The comparison shows that the higher the rotational speed of the rotary motor 80, the greater the voltage rise. The rising second DC link voltage Vdc2 reaches the second upper limit voltage VrefH2 at time t21(t2). Although not shown in the timing diagram, the second battery current Ib2 is approximately zero due to the second contactor 92 being in the open state, satisfying the condition that the second battery current Ib2 is below the second lower limit current Iref2. If the second DC link voltage Vdc2 reaches the second upper limit voltage VrefH2, then the following condition is satisfied: Figure 11 The conditions for step #2 (#2b).

[0111] On the other hand, when the rotary motor 80 is in operation, the power supply from the second DC power supply 62 to the rotary motor 80 is interrupted, and the rotary motor 80 uses the power stored in the second smoothing capacitor 42 for operation. That is, when power is supplied from the second smoothing capacitor 42 to the rotary motor 80, the voltage across the second smoothing capacitor 42, i.e., the second DC link voltage Vdc2, drops from the second normal voltage Vtyp2. Figure 14 , Figure 15 , Figure 18 , Figure 19 , Figure 22 , Figure 23The decreasing second DC link voltage Vdc2 becomes below the second lower limit voltage VrefL2 at time t22 (t2). Although not shown in the timing diagram, the second battery current Ib2 is approximately zero due to the second contactor 92 being in the open state, satisfying the condition that the second battery current Ib2 is below the second current lower limit value. If the second DC link voltage Vdc2 becomes below the second lower limit voltage VrefL2, then the following condition is satisfied: Figure 11 The conditions for step #2 (#2b).

[0112] If satisfied Figure 11 The condition for step #2 is that if an open-circuit fault is detected in contactor 9, the rotating motor control device 1 shuts down both the first inverter 11 and the second inverter 12 (#4). That is, in... Figures 12-23 Similarly, at time t2, the operating modes of the first inverter 11 and the second inverter 12 shift from torque control mode (dual inverter torque control mode MD1) to off control mode MD2 (non-torque control mode).

[0113] Next, the rotary motor control device 1 determines whether the operating region of the rotary motor 80 is a high-rotation region (#5). Furthermore, if the operating region of the rotary motor 80 is a high-rotation region, the normal contactor, in this case, sets the first contactor 91 to the open state (#6). Figure 13 , Figure 15 , Figure 17 , Figure 19 , Figure 21 , Figure 23 ). Figure 14 , Figure 16 , Figure 18 , Figure 20 , Figure 22 An example is shown where the first contactor 91 is not in the open state. For example, Figure 20 , Figure 22 Examples are shown for low rotational speeds, and examples are shown for... Figure 11 In step #5, the case is determined not to be in the high rotation region. Although the details will be described later, even if the operating region of the rotary motor 80 is in the high rotation region, it is possible to obtain a configuration in which the normal contactor is not set to the open state (OPEN). Figure 14 , Figure 16 (Also includes a timing diagram as the intermediate rotational speed) Figure 18 , Figure 20 This example illustrates such a form. Additionally, Figure 21 , Figure 23 As a comparative example, an example is shown where the normal contactor is set to the open state even when the rotational speed of the rotary motor 80 is low.

[0114] For example, when comparing the first contactor 91 being in the open state at time t2 (time t21)... Figure 13 Even at time t2 (t22), the first contactor 91 remains in the closed state (CLOSE). Figure 12 At that time, for the second DC link voltage Vdc2, the first contactor 91 remains in the closed state. Figure 12 The "V52" contactor is now in the open state compared to the first contactor 91. Figure 13 The "V48" is high. If the first contactor 91 is in the open state, regenerative power flows in the first smoothing capacitor 41 and the second smoothing capacitor 42 to charge the two smoothing capacitors 4.

[0115] With the first contactor 91 in the closed state, the voltage rise of the second DC link voltage Vdc2 increases because only the second smoothing capacitor 42 is charged.

[0116] like Figure 14 as well as Figure 15 As shown, even when the rotating motor 80 is in operation, the smoothing capacitor 4 is charged by back electromotive force, so the same phenomenon is observed. Furthermore, through... Figure 12 as well as Figure 13 ,and Figure 16 as well as Figure 17 , Figure 20 as well as Figure 21 The comparison, and Figure 14 as well as Figure 15 , Figure 18 as well as Figure 19 , Figure 22 as well as Figure 23 The comparison shows that the lower the rotational speed of the rotary motor 80, the smaller the voltage rise of the second DC link voltage Vdc2.

[0117] While the above description covers the regenerative operation of the rotary motor 80, the same applies to its power operation. Those skilled in the art will refer to [the relevant documentation / reference]. Figure 14 , Figure 15 , Figure 18 , Figure 19 , Figure 22 , Figure 23 This is easy to understand, so detailed explanations are omitted. Additionally, the determination in step #5 can also be performed based on the operating range of the rotary motor 80, similar to step #7 described later, and can also be performed by comparing the rotational speed of the rotary motor 80 with the speed threshold ωth.

[0118] At time t2, both the first inverter 11 and the second inverter 12 are shut down, thereby reducing the rotational speed of the rotary motor 80 using a so-called braking torque. The rotary motor 80 is illustrated at high and medium rotational speeds. Figure 11 The case of rotational speed above the velocity threshold ωth illustrated in step #7 Figures 12-19 The timing diagram illustrates the decreasing rotational speed starting from time t3. This occurs when the rotational speed of the rotary motor 80 is at a low speed. Figures 20-23 In the timing diagram, during the determination in step #5, the rotational speed is also less than the speed threshold ωth, so even if the control mode MD2 is turned off, the rotational speed does not decrease.

[0119] The following explanation, following step #5, will first describe the control in the high-rotation region (the case of transitioning from step #5 to step #6). The rotational speed of the rotary motor 80 decreases, and at time t4, the rotational speed (at...) Figure 11 When the value of the inverter on the fault side (represented by "ω") is less than the speed threshold ωth (#7), the rotating electric machine control device 1 then controls the fault-side inverter, i.e., the second inverter 12 (#8a(#8)), through active short-circuit control. Then, the rotating electric machine control device 1 controls the normal-side inverter, i.e., the first inverter 11 (#9(#9a)), through pulse width modulation control.

[0120] like Figure 13 As shown, at time t4, the rotational speed becomes R3 (here, the speed threshold ωth > R3). From time t4 onwards, at time t5, the second inverter 12 is controlled by active short-circuit control. Moreover, from time t5 onwards, at time t6, the rotating motor control device 1 controls the normal-side inverter, i.e., the first inverter 11, by pulse width modulation control.

[0121] Here, with the normal contactor, i.e., the first contactor 91, controlled to the open state, the first smoothing capacitor 41 is also charged, and the first DC link voltage Vdc1 is higher than the first normal voltage Vtyp1. Figure 13 , Figure 15 , Figure 17 , Figure 19 、( Figure 21 ), ( Figure 23 Therefore, a discharge torque command TQ1 is applied to the normal-side inverter, i.e., the first inverter 11, and driven by pulse width modulation control, thereby discharging the first smoothing capacitor 41 (#10). This discharge torque command TQ1 is less than 1% of the maximum torque applied to the rotating motor 80, for example, a small torque of about 1 [Nm]. By driving the rotating motor 80 with a small output torque, the smoothing capacitor 4 can be discharged without placing a large load on the rotating motor 80.

[0122] Through pulse width modulation control caused by the discharge torque command TQ1, the first smoothing capacitor 41 is discharged, and at time t7, the first DC link voltage Vdc1 drops to the first normal voltage Vtyp1. The rotating motor control device 1 returns the normal contactor, i.e., the first contactor 91, to the closed state and sets the torque command to zero (#11). That is, the command for the discharge torque command TQ1 ends. Next, at time t8 after time t7, the rotating motor control device 1 begins to assign a normal torque command to the first inverter 11 and drives the rotating motor 80 (#12) through torque control mode (single inverter torque control mode MD3). In addition, since pulse width modulation control based on the discharge torque command TQ1 is executed, the control mode from time t6 onwards is equivalent to the single inverter torque control mode MD3.

[0123] If the operating region of the rotary motor 80 is not the high-rotation region, that is, when transitioning from step #5 to step #8b, such as Figure 20 as well as Figure 22 As shown, at time t5, the second inverter 12 (#8b) is controlled by active short-circuit control. Furthermore, from time t5 onwards at time t6, the rotating motor control device 1 controls the normal-side inverter, i.e., the first inverter 11 (#9 (#9b)), by pulse width modulation control.

[0124] However, in Figure 11 The flowchart illustrated above demonstrates and explains how the normal contactor is controlled to the open state based on whether the operating region of the rotary motor 80 is a high-rotation region or whether the rotational speed of the rotary motor 80 is less than the speed threshold ωth. However, as referred to above... Figure 12 Figure 13 The reason for setting the normal contactor to the open state is to suppress the rise of the voltage across the smoothing capacitor 4 connected to the faulty contactor, i.e., the DC link voltage Vdc. Therefore, as long as the rise of the DC link voltage Vdc does not exceed the withstand voltage of the smoothing capacitor 4 and the inverter 10, the normal contactor can be kept in the closed state even in high-rotation areas. That is, even in high-rotation areas, such as... Figure 13 , Figure 15 That way, the normal contactor doesn't need to be set to the open state, but... Figure 12 , Figure 14 That would keep the normal contactor in the closed state.

[0125] For example, when the rotating motor control device 1 is in a state where the rotational speed of the rotating motor 80 is the preset maximum rotational speed, and one of the first contactor 91 and the second contactor 92 is in the open state while the other is in the closed state, if the voltage across the smoothing capacitor 4 connected to the contactor 9 in the open state is below the withstand voltage of the inverter 10, and if it is determined that one of the first contactor 91 and the second contactor 92 is a faulty contactor, even if the rotational speed of the rotating motor 80 is above the predetermined speed threshold ωth, the other normal contactor may not be set to the open state and may be kept in the closed state.

[0126] When the normal contactor is switched from the closed state to the open state, the voltage across the smoothing capacitor 4 connected to the normal contactor also rises, requiring control to reduce the risen voltage. Even if the voltage across the smoothing capacitor 4 connected to the faulty contactor rises, if it does not exceed the withstand voltage of the smoothing capacitor 4 or the inverter 10 connected to the smoothing capacitor 4, the necessity to disperse the back electromotive force of the rotating motor 80 to the two smoothing capacitors 4 is low. Therefore, fail-safe control can be performed with simple control.

[0127] As described above, in the event of an open-circuit fault in either contactor 9, the rotary motor control device 1 can drive and control the rotary motor 80 using only the inverter 10 connected to the other contactor 9 that is not faulty. However, since the rotary motor 80, which is normally driven by two inverters 10, is driven by only one inverter 10, it is difficult to achieve the usual output. Therefore, the rotary motor control device 1 preferably limits the torque and rotational speed that the rotary motor 80 can output to a specified range when it is determined that one of the first contactor 91 and the second contactor 92 is in the open state. In addition, it is preferable to issue a warning to the driver of the vehicle regarding the occurrence of a contactor 9 fault.

[0128] By limiting torque and rotational speed within specified ranges, vehicle operation can continue even under constant constraints. Furthermore, a warning is issued to the driver, allowing the driver to identify vehicle malfunctions and continue driving even under constant constraints, moving the vehicle to a safe location such as the roadside, or to a repair shop or roadside service facility for rapid repairs. In other words, it enables a so-called limp home mode.

[0129] As explained above, according to this embodiment, if one of the smoothing capacitors provided in the two inverters respectively located at both ends of the open winding fails, the smoothing capacitor that has failed can also be identified.

[0130] [Implementation Summary]

[0131] The following is a brief overview of the rotary electric motor control system (100) described above.

[0132] A rotary motor control system (100) for driving and controlling a rotary motor (80) having mutually independent multiphase open-circuit windings (8) comprises, in one embodiment: a first inverter (11) connected to one end of the open-circuit windings (8); a second inverter (12) connected to the other end of the open-circuit windings (8); a first DC power supply (61) connected to the first inverter (11); a second DC power supply (62) connected to the second inverter (12); a first smoothing capacitor (41) connected in parallel with the first DC power supply (61); a second smoothing capacitor (42) connected in parallel with the second DC power supply (62); and a capacitor that connects the first inverter (11) and the first smoothing capacitor (42) in parallel. The system includes a first contactor (91) for disconnecting and connecting the container (41) to the first DC power supply (61); a second contactor (92) for disconnecting and connecting the second inverter (12) and the second smoothing capacitor (42) to the second DC power supply (62); and a control unit (1) for controlling each of the first contactor (91) and the second contactor (92) and for independently controlling each of the first inverter (11) and the second inverter (12). The arm (3A) of each AC phase of the first inverter (11) and the second inverter (12) is composed of a series circuit of an upper-side switching element (3H) and a lower-side switching element (3L). The control unit (1) can control the first inverter (11) and the second inverter (12) by setting all the upper-side switching elements (3H) to the off state and all the lower-side switching elements (3L) to the on state, or setting all the upper-side switching elements (3H) to the on state and all the lower-side switching elements (3L) to the off state, and by setting all the multi-phase switching elements (3) to the off state, respectively. It uses a first upper limit voltage (VrefH1) set to a value larger than the voltage variation range of the first DC power supply (61) and a value set to a value smaller than the voltage variation range of the first DC power supply (61). The control unit (1) determines that the first contactor (91) is in the open state when the voltage (Vdc1) across the first smoothing capacitor (41) is higher than the first upper limit voltage (VrefH1) or lower than the first lower limit voltage (VrefL1), and the current (Ib1) flowing in the first DC power supply (61) is lower than the predetermined first lower limit current (Iref1).When the voltage (Vdc2) across the second smoothing capacitor (42) is higher than the second upper limit voltage (VrefH2) or lower than the second lower limit voltage (VrefL2), and the current (Ib2) flowing in the second DC power supply (62) is below the predetermined second lower limit current (Iref2), the second contactor (92) is determined to be in the open state. Of the first contactor (91) and the second contactor (92), one contactor (9) determined to be in the open state is designated as the fault contactor, and the other contactor (9) is designated as the normal contactor. When the rotational speed of the rotary motor (80) is above the predetermined speed threshold (ωth), the first inverter (11) and the second inverter (62) are controlled by a shutdown control. 12) Both the first contactor (91) and the second contactor (92) are set to the open state. After the rotational speed of the rotary motor (80) is less than the speed threshold (ωth), the inverter (10) connected to the faulty contactor, i.e., the fault-side inverter, is controlled by the active short-circuit control. The normal contactor is kept in the open state, and the normal-side inverter is driven by the discharge torque of the smoothing capacitor (4) connected to the normal-side inverter, i.e., the normal-side smoothing capacitor. After the rise of the voltage (Vdc) across the normal-side smoothing capacitor is released, the normal contactor is controlled to the closed state, and the rotary motor (80) is driven and controlled by the normal-side inverter.

[0133] According to this structure, when the rotating motor (80) performs a regenerative operation, the occurrence of a fault in the contactor (9) can be detected by the current (Ib) of the DC power supply that is not flowing because the contactor (9) is in the open state, and the voltage (Vdc) across the smoothing capacitor (4) that rises due to the regenerative current. Furthermore, when the rotating motor (80) performs a power operation, the occurrence of a fault in the contactor (9) can be detected by the current (Ib) of the DC power supply that is not flowing because the contactor (9) is in the open state, and the voltage (Vdc) across the smoothing capacitor (4) that drops to drive the rotating motor (80) through discharge. Moreover, according to this structure, after controlling both inverters (10) by a shutdown control, one inverter (10) connected to the side of the faulty contactor (9) is short-circuited by an active short-circuit control, and the rotating motor (80) is driven by the other inverter (10). At this time, if the rotational speed of the rotating motor (80) is above the speed threshold (ωth), the contactor (9) without fault is also controlled to be in the open state. As a result, the back electromotive force from the rotating motor (80) can be absorbed by the two smoothing capacitors (4), and the rise in the voltage (VDc) across the smoothing capacitor (4) connected to the faulty contactor can be suppressed. In this case, although the voltage (Vdc) across the normal side smoothing capacitor connected to the normal side inverter also rises, the normal side inverter is driven by the discharge torque (TQ1), thereby discharging the normal side smoothing capacitor. If the rise in the voltage (Vdc) across the normal side smoothing capacitor is eliminated, the rotating motor (80) is driven and controlled by the normal side inverter. Thus, according to this structure, if one of the contactors (9) provided between the DC power supply (6) connected to the two inverters (10) respectively located at both ends of the open winding (8) fails, the faulty contactor (9) can be identified and the rotating motor (80) can be driven and controlled.

[0134] Furthermore, preferably, when the rotational speed of the rotary motor (80) is at a preset maximum rotational speed and one of the first contactor (91) and the second contactor (92) is in an open state and the other is in a closed state, when the control unit (1) performs the closing control, if the voltage (Vdc) across the smoothing capacitor (4) connected to the open contactor (9) is below the withstand voltage of the inverter (10), and if it is determined that one of the first contactor (91) and the second contactor (92) is the faulty contactor, even if the rotational speed of the rotary motor (80) is above the predetermined speed threshold (ωth), the other normal contactor will not be set to the open state but will remain in the closed state.

[0135] When the normal contactor is switched from the closed state to the open state, the voltage (Vdc) across the smoothing capacitor (4) connected to the normal contactor also rises, requiring control to reduce the voltage increase. Even if the voltage (Vdc) across the smoothing capacitor (4) connected to the faulty contactor rises, if it does not exceed the withstand voltage of the smoothing capacitor (4) or the inverter (10) connected to the smoothing capacitor (4), there is little need to disperse the back electromotive force of the rotating motor (80) to the two smoothing capacitors (4). Therefore, fail-safe control can be performed with simple control.

[0136] In addition, preferably, the rotary motor (80) is a driving force source mounted on a vehicle and driving the wheels of the vehicle. When the control unit (1) determines that one of the first contactor (91) and the second contactor (92) is in the open state, it limits the torque and rotation speed that the rotary motor (80) can output to a specified range and issues a warning to the driver of the vehicle.

[0137] By limiting torque and rotational speed within specified ranges, vehicle operation can continue even under constant constraints. Furthermore, by issuing warnings to the driver, the driver can identify vehicle malfunctions based on these warnings, allowing the vehicle to continue operating even under constant constraints, and to be pulled to a safe location such as the roadside for parking. Alternatively, the vehicle can be driven to a repair shop or roadside service facility for rapid repairs. In other words, a so-called limp home mode is possible.

[0138] In addition, it is preferable that the discharge torque (TQ1) is less than 1% of the maximum torque.

[0139] The smoothing capacitor (4) connected to the normal-side inverter is discharged by driving the inverter (10) with a discharge torque (TQ1) output, for example, through pulse width modulation control. Since the discharge torque (TQ1) is less than 1% of the maximum torque of the rotating motor (80), it is a very small torque. By driving the rotating motor (80) with such a small torque output, the smoothing capacitor (4) can be discharged without placing a large load on the rotating motor (80).

[0140] Explanation of reference numerals in the attached figures

[0141] 1: Rotating motor control device (control unit), 3: Switching element, 3A: Arm, 3H: Upper section switching element, 3L: Lower section switching element, 4: Smoothing capacitor, 6: DC power supply, 8: Stator coil (open circuit winding), 9: Contactor, 10: Inverter, 11: First inverter, 12: Second inverter, 41: First smoothing capacitor, 42: Second smoothing capacitor, 61: First DC power supply, 62: Second DC power supply, 80: Rotating motor, 91: First contactor, 92: Second contactor 100: Rotary motor control system, Ib: Battery current, Ib1: First battery current (current flowing in the first DC power supply), Ib2: Second battery current (current flowing in the second DC power supply), Iref1: First lower limit current, Iref2: Second lower limit current, TQ1: Discharge torque command, VrefH1: First upper limit voltage, VrefH2: Second upper limit voltage, VrefL1: First lower limit voltage, VrefL2: Second lower limit voltage, ωth: Speed ​​threshold.

Claims

1. A rotating electric motor control system, which is a rotating electric motor control system for driving and controlling a rotating electric motor having mutually independent multi-phase open-circuit windings, wherein, have: The first inverter is connected to one end of the aforementioned open-circuit winding; The second inverter is connected to the other end of the aforementioned open winding. A first DC power supply is connected to the aforementioned first inverter; The second DC power supply is connected to the aforementioned second inverter; A first smoothing capacitor is connected in parallel with the aforementioned first DC power supply. The second smoothing capacitor is connected in parallel with the aforementioned second DC power supply. The first contactor disconnects and connects the electrical connection between the first inverter and the first smoothing capacitor and the first DC power supply. The second contactor disconnects and connects the electrical connection between the second inverter and the second smoothing capacitor and the second DC power supply. as well as The control unit controls each of the first contactor and the second contactor, and is capable of independently controlling each of the first inverter and the second inverter. In the aforementioned first inverter and second inverter, each AC phase arm is composed of a series circuit of upper-side switching elements and lower-side switching elements. The control unit described above can control the first inverter and the second inverter by either active short-circuit control (setting all the upper-side switching elements to the off state and all the lower-side switching elements to the on state, or setting all the upper-side switching elements to the on state and all the lower-side switching elements to the off state) or shutdown control (setting all the switching elements of the multi-phase units to the off state). The system uses a first upper limit voltage set to a value larger than the voltage variation range of the first DC power supply, a first lower limit voltage set to a value smaller than the voltage variation range of the first DC power supply, a second upper limit voltage set to a value larger than the voltage variation range of the second DC power supply, and a second lower limit voltage set to a value smaller than the voltage variation range of the second DC power supply. The aforementioned control unit If the voltage across the first smoothing capacitor is higher than the first upper limit voltage or lower than the first lower limit voltage, and the current flowing in the first DC power supply is below the predetermined first lower limit current, then the first contactor is determined to be in the open state. If the voltage across the second smoothing capacitor is higher than the second upper limit voltage or lower than the second lower limit voltage, and the current flowing in the second DC power supply is below the predetermined second lower limit current, then the second contactor is determined to be in the open state. Of the first contactor and the second contactor described above, the contactor determined to be in the open state is designated as the faulty contactor, and the other contactor is designated as the normal contactor. When the rotational speed of the aforementioned rotating motor is above a predetermined speed threshold, both the first inverter and the second inverter are controlled by a shutdown control, and both the first contactor and the second contactor are set to the open state. After the rotational speed of the aforementioned rotating motor falls below the aforementioned speed threshold, the inverter connected to the aforementioned fault contactor, i.e., the fault-side inverter, is controlled by the aforementioned active short-circuit control to keep the aforementioned normal contactor in the open state, and the inverter connected to the normal contactor, i.e., the normal-side inverter, is driven by the discharge torque of the smoothing capacitor connected to the normal-side inverter, i.e., the normal-side smoothing capacitor. After the rise in voltage across the normal-side smoothing capacitor is released, the normal contactor is controlled to be closed, and the rotating motor is driven and controlled by the normal-side inverter.

2. The rotary electric motor control system according to claim 1, wherein, When the rotational speed of the rotary motor is at a preset maximum rotational speed, and one of the first contactor and the second contactor is in the open state while the other is in the closed state, if the voltage across the smoothing capacitor connected to the open contactor is below the withstand voltage of the inverter, and if it is determined that one of the first contactor and the second contactor is the faulty contactor, the control unit will not set the other normal contactor to the open state and will keep it in the closed state even if the rotational speed of the rotary motor is above a predetermined speed threshold.

3. The rotary electric motor control system according to claim 1 or 2, wherein, The aforementioned rotary motor is a driving force source mounted on a vehicle and driving the vehicle's wheels. When the control unit determines that one of the first contactor and the second contactor is in the open state, it limits the torque and rotational speed that the rotary motor can output to a specified range and issues a warning to the driver of the vehicle.

4. The rotating electric motor control system according to any one of claims 1 to 3, wherein, The discharge torque mentioned above is less than 1% of the maximum torque.

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