Rotating electric machine control device

Abstract

Two inverters (10) respectively provided at both ends of the open-circuit winding (8) are appropriately controlled. The rotating electric machine control device (1) executes an object control in which one of the first inverter (11) and the second inverter (12) is controlled by rectangular wave control and the other inverter (10) is controlled by special pulse width modulation control which is one of pulse width modulation controls. The special pulse width modulation control is a control mode which becomes a switching pattern (Su2+) based on a difference between a switching pattern of the pulse width modulation control in a case where the open-circuit winding (8) generates a target voltage and a switching pattern (Su1+) of the rectangular wave control.

Description

TECHNICAL FIELD

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

[0002] In the IEEE paper "Dual Inverter-Fed Traction Drive with DC Sources Power Balancing Based on Synchronized PWM" by V. Oleschuk et al. published in 2007, a control device is disclosed that drives and controls a rotating electric machine by switching controlling one inverter for each of both ends of three-phase open-circuit windings of a three-phase alternating-current type rotating electric machine. On the other hand, there is a known method of, for example, switching controlling one inverter to drive and control a rotating electric machine on the other end side of a Y-type winding to which one end side of each of three-phase windings is connected. In a system using open-circuit windings and two inverters, compared with a system using a Y-type winding and one inverter, if the voltage of direct current is the same, the line voltage of alternating current voltage of the winding can be made higher, and thus the rotating electric machine can be made to operate at a higher output.

[0003] In the introduction of the paper by V. Oleschuk et al., it is described that by making the phases of carrier signals that generate pulses for switching controlling two inverters different, the size of the ripple of the current flowing in the winding can be reduced. V. Oleschuk et al. also point out that by generating the pulses in a synchronous manner rather than in an asynchronous manner using carrier signals, in applications of medium / high output, more appropriate control can also be performed. However, in either of the asynchronous manner and the synchronous manner, two inverters are always switching controlled in the same control manner.

[0004] PRIOR ART DOCUMENTS

[0005] NON-PATENT DOCUMENTS

[0006] Non-Patent Document 1: V. Oleschuk, R. Bojoi, G. Griva, F. Profumo, "Dual Inverter-Fed Traction Drive with DC Sources Power Balancing Based on Synchronized PWM", Conference Paper / June 2007, 1-4244-0743-5 / 07, IEEE, p. 260-265. SUMMARY

[0007] Preferably, the manner of switching control is determined in accordance with various factors (operating conditions) such as the torque, rotational speed, voltage at the DC side, and the like, required of the rotary electric machine, so that operation can be performed with higher system efficiency. The technology of V. Oleschuk et al. is excellent, but there is room for improvement in appropriately controlling the two inverters respectively provided at both ends of the open-winding.

[0008] In view of the above, it is desirable to provide a technology that appropriately controls the two inverters respectively provided at both ends of the open-winding.

[0009] In view of the above, as one mode, a rotary electric machine control device of the present application drives controls a rotary electric machine having a plurality of phases of open-winding independent of each other, by a first inverter connected to one end side of the plurality of phases of open-winding, which converts electric power between DC and multi-phase AC, and a second inverter connected to the other end side of the plurality of phases of open-winding, which converts electric power between DC and multi-phase AC, the first inverter and the second inverter are respectively controllable in a plurality of control modes different in switching pattern, and are controllable in the control modes independent of each other, the control modes including pulse width modulation control that outputs a plurality of pulses different in pattern in one cycle of electric angle, and rectangular wave control that outputs one pulse in one cycle of electric angle, the rotary electric machine control device performs control of one of the first inverter and the second inverter by the rectangular wave control, and control of the other of the inverters as an object by special pulse width modulation control that is one of the pulse width modulation control, the special pulse width modulation control being the control mode that becomes a switching pattern based on a difference between a switching pattern of the pulse width modulation control in a case where the open-winding generates a target voltage and a switching pattern of the rectangular wave control.

[0010] According to the structure, by performing rectangular wave control on one of the two inverters, the number of switching operations of the one inverter can be reduced, thereby reducing switching loss. In addition, the other inverter on the side on which rectangular wave control is not performed is controlled by special pulse width modulation control. In the special pulse width modulation control, the other inverter is controlled by a switching pattern based on the difference between the switching pattern of pulse width modulation control in a case where the open circuit winding generates a target voltage and the switching pattern of rectangular wave control. Therefore, even if one inverter is controlled by rectangular wave control, the rotary electric machine can be smoothly driven in cooperation with the pulse width modulation control of the other inverter. In general, in a relatively high rotation operation region in which rectangular wave control is applied, system loss can be reduced, and the rotary electric machine can be smoothly controlled. That is, according to the structure, the two inverters each provided at both ends of the open circuit winding can be appropriately controlled.

[0011] Other features and advantages of the rotary electric machine control device will become apparent from the following description of the embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF DRAWINGS

[0012] Fig. 1 is a schematic block diagram of an example of a rotary electric machine drive system.

[0013] Fig. 2 is a simplified partial block diagram of a rotary electric machine control device.

[0014] Fig. 3 is a vector diagram of a rotary electric machine drive system using two inverters.

[0015] Fig. 4 is a schematic voltage vector diagram of a rotary electric machine in a quadrature vector space.

[0016] Fig. 5 is a diagram showing an example of a control region of a rotary electric machine.

[0017] Fig. 6 is a diagram showing an example of a control region of a rotary electric machine.

[0018] Fig. 7 is a diagram showing an example of a control region of a rotary electric machine.

[0019] Fig. 8 is a waveform diagram showing an example of a voltage command and a switching control signal of special pulse width modulation control (special continuous pulse width modulation control).

[0020] Fig. 9 is a waveform diagram showing an example of a voltage command and a switching control signal of special discontinuous pulse width modulation control.

[0021] Fig. 10is an explanatory diagram showing a voltage command operation principle (result) of special continuous pulse width modulation control.

[0022] Fig. 11 is an explanatory diagram showing a voltage command operation principle (pass 1) of special continuous pulse width modulation control.

[0023] Fig. 12 is an explanatory diagram showing a voltage command operation principle (pass 2) of special continuous pulse width modulation control.

[0024] Fig. 13 is an explanatory diagram showing a voltage command operation principle (pass 3) of special continuous pulse width modulation control.

[0025] Fig. 14 is an explanatory diagram showing a voltage command operation principle (result) of special discontinuous pulse width modulation control.

[0026] Fig. 15 is an explanatory diagram showing a voltage command operation principle (pass 1) of special discontinuous pulse width modulation control.

[0027] Fig. 16 is an explanatory diagram showing a voltage command operation principle (pass 2) of special discontinuous pulse width modulation control.

[0028] Fig. 17 is an explanatory diagram showing a voltage command operation principle (pass 3) of special discontinuous pulse width modulation control.

[0029] Fig. 18 is a flowchart showing an example of a voltage command operation sequence of special pulse width modulation control.

[0030] Fig. 19 is a flowchart showing another example of a voltage command operation sequence of special pulse width modulation control.

[0031] Fig. 20 is a waveform diagram of 3-phase currents and dq-axis currents when a rectangular wave control and a general continuous pulse width modulation control (CPWM) are combined in a first high speed region.

[0032] Fig. 21 is a waveform diagram of 3-phase currents and actual modulation rates when a rectangular wave control and a continuous pulse width modulation control (CPWM) are combined in a first high speed region.

[0033] Fig. 22 is a waveform diagram of 3-phase currents and dq-axis currents when a rectangular wave control and a general pulse width modulation control (CPWM, DPWM) are combined in a first high speed region and a second high speed region.

[0034] Fig. 23 is a waveform chart of 3-phase current and actual modulation rate when the rectangular wave control and the usual pulse width modulation control (CPWM, DPWM) are combined in the first high speed region and the second high speed region.

[0035] Fig. 24 is a waveform chart of 3-phase current and dq-axis current when the rectangular wave control and the special continuous pulse width modulation control (SP-CPWM) are combined in the first high speed region.

[0036] Fig. 25 is a waveform chart of 3-phase current and actual modulation rate when the rectangular wave control and the special continuous pulse width modulation control (SP-CPWM) are combined in the first high speed region.

[0037] Fig. 26 is a waveform chart of 3-phase current and dq-axis current when the rectangular wave control and the special pulse width modulation control (SP-CPWM, SP-DPWM) are combined in the first high speed region and the second high speed region.

[0038] Fig. 27 is a waveform chart of 3-phase current and actual modulation rate when the rectangular wave control and the special pulse width modulation control (SP-CPWM, SP-DPWM) are combined in the first high speed region and the second high speed region.

[0039] Fig. 28 is a waveform chart of 3-phase current and dq-axis current when the carrier frequency is increased and the rectangular wave control and the special pulse width modulation control (SP-CPWM, SP-DPWM) are combined in the first high speed region and the second high speed region.

[0040] Fig. 29 is a waveform chart of 3-phase current and actual modulation rate when the carrier frequency is increased and the rectangular wave control and the special pulse width modulation control (SP-CPWM, SP-DPWM) are combined in the first high speed region and the second high speed region.

[0041] Fig. 30 is a waveform chart showing an example of voltage command and switching control signal in the ultra high speed region.

[0042] Fig. 31 is a waveform chart showing an example of voltage command and switching control signal in the low speed region (first low speed region).

[0043] Fig. 32 is a waveform chart showing an example of voltage command and switching control signal in the second low speed region.

[0044] Fig. 33 is a waveform chart showing another example of the voltage command and the switching control signal in the intermediate speed region.

[0045] Fig. 34 is a waveform chart showing an example of the voltage command and the switching control signal in the mixed pulse width modulation control.

[0046] Fig. 35 is a waveform chart showing another example of the voltage command and the switching control signal in the mixed pulse width modulation control.

[0047] Fig. 36 is a schematic block diagram showing another example of the rotating electric machine drive system.

[0048] Fig. 37 is a schematic block diagram showing another example of the rotating electric machine drive system.

[0049] Fig. 38 is a chart showing an example of the control region of the rotating electric machine in the single inverter system. DETAILED DESCRIPTION

[0050] Hereinafter, an embodiment of a rotating electric machine control device that drives controls a rotating electric machine having mutually independent multi-phase open-circuit windings by two inverters will be described based on the drawings. Fig. 1 is a schematic block diagram of a rotating electric machine drive system including a rotating electric machine control device 1 (MG-CTRL). The rotating electric machine 80 is, for example, a driving power source of a wheel in a vehicle such as an electric automobile or a hybrid automobile. The rotating electric machine 80 is an open-circuit winding type rotating electric machine having mutually independent multi-phase (three phases in this embodiment) stator coils 8 (open-circuit windings). One inverter 10 is connected to each end of the stator coils 8, and each inverter 10 is independently controlled to convert electric power between direct current and multi-phase (three phases in this case) alternating current. That is, a first inverter 11 (INV1) is connected to one end side of the stator coils 8, and a second inverter 12 (INV2) is connected to the other end side of the stator coils 8. Hereinafter, in a case where it is not necessary to distinguish the first inverter 11 and the second inverter 12, they will be simply referred to as inverters 10.

[0051] The inverter 10 has a plurality of switching elements 3. The switching element 3 uses an IGBT (Insulated Gate Bipolar Transistor) or a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor). In the present embodiment, the switching element 3 is an IGBT. The switching element 3 is connected to a direct current power supply 2, and is controlled to convert direct current into alternating current. Fig. 1The first switch element 31 using a Si-IGBT as the first inverter 11 and the second switch element 32 using a SiC-MOSFET (Silicon Carbide-Metal Oxide Semiconductor FET) as the second inverter 12 are exemplified. The first switch element 31 can be a Si-MOSFET other than a Si-IGBT. In addition, the second switch element 32 can be a SiC-SIT (SiC-Static Induction Transistor), a GaN-MOSFET (Gallium Nitride-MOSFET), or the like other than a SiC-MOSFET. That is, in the present embodiment, it is preferable that the second switch element 32 constituting the second inverter 12 be a switch element having relatively small switching loss when transitioning between the off state and the on state, as compared with the first switch element 31 constituting the first inverter 11.

[0052] Generally, since SiC semiconductors and GaN semiconductors are high in price as compared with Si semiconductors, in the present embodiment, a mode using a SiC semiconductor in the switch element 3 constituting one of the two inverters 10 is exemplified. However, in the case where the price of SiC semiconductors and GaN semiconductors decreases due to the effects of mass production or the like, as shown in FIG. 6, both of the inverters 10 can be constituted by SiC semiconductors (for example, SiC-MOSFETs). In addition, according to the required specifications such as the magnitude of the allowable switching loss, as shown in FIG. 7, both of the inverters 10 can be constituted by Si semiconductors (for example, Si-IGBTs). Fig. 36 Fig. 37 In addition, according to the required specifications such as the magnitude of the allowable switching loss, as shown in FIG. 7, both of the inverters 10 can be constituted by Si semiconductors (for example, Si-IGBTs).

[0053] In the two inverters 10, the arms 3A of the AC 1 phase are respectively constituted by series circuits of the upper-stage side switch elements 3H and the lower-stage side switch elements 3L. In each switch element 3, a free-wheeling diode 35 is connected in parallel in the direction from the negative electrode FG toward the positive electrode P (the direction from the lower-stage side toward the upper-stage side) as the positive direction. In addition, in the present embodiment, the two inverters 10 are connected to the respective independent direct-current power supplies 6. That is, the negative electrode FG, that is, the first floating ground FG1 of the first inverter 11 and the negative electrode FG, that is, the second floating ground FG2 of the second inverter 12 are independent of each other. In addition, the direct-current support capacitors 4 (smoothing capacitors) for smoothing the direct-current voltage are respectively provided between the inverters 10 and the direct-current power supplies 6.

[0054] ​Specifically, the first inverter 11, consisting of a series circuit of a first upper-side switching element 31H and a first lower-side switching element 31L, is connected to the DC side of a first DC support capacitor 41 (first smoothing capacitor) and is also connected to the first DC power supply 61. Its AC side is connected to one end of the multi-phase stator coil 8, thus converting power between DC and multi-phase AC. The second inverter 12, consisting of a series circuit of a second upper-side switching element 32H and a second lower-side switching element 32L, is connected to the DC side of a second DC support capacitor 42 (second smoothing capacitor) and is also connected to the second DC power supply 62. Its AC side is connected to the other end of the multi-phase stator coil 8, thus converting power between DC and multi-phase AC.

[0055] 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. That is, the rated voltage "E1" of the first DC power supply 61 and the rated voltage "E2" of the second DC power supply 62 are the same, and are simply referred to as the rated voltage "E" without distinction. Therefore, the voltage (DC link voltage) "Vdc1" on the DC side of the first inverter 11 and the voltage (DC link voltage) "Vdc2" on the DC side of the second inverter 12 are also the same voltage. In addition, the first DC support capacitor 41 and the second DC support capacitor 42 are also capacitors with the same rated capacitance. The rated voltage of the DC power supply 6 is approximately 48 volts to 400 volts. The DC power supply 6 is composed, for example, of a secondary battery (rechargeable battery) such as a nickel-metal hydride battery or a lithium-ion battery, and a double-layer capacitor. The rotary motor 80 can function as a motor or a generator. The rotary motor 80 converts the power from the DC power supply 6 into power (power operation) via the inverter 10. Alternatively, the rotary motor 80 can convert the rotational driving force transmitted from the wheels, etc., into electricity, and charge (regenerate) the DC power supply 6 via the inverter 10.

[0056] like Fig. 1 As shown, inverter 10 is controlled by rotating motor control device 1. Rotating motor control device 1 can control each of the first inverter 11 and the second inverter 12 in independent control methods (details of the control methods will be described later). Rotating motor control device 1 is constructed with logic circuits such as those from a microcomputer as its core component. For example, rotating motor control device 1 performs current feedback control using vector control based on the target torque (torque command) of rotating motor 80 provided by other control devices such as vehicle control devices (not shown), and controls rotating motor 80 via inverter 10.

[0057] The actual currents flowing in the stator coils 8 of the respective phases of the rotary electric machine 80 are detected by the current sensors 15, and the magnetic pole positions of the rotor of the rotary electric machine 80 at each time are detected by the resolver or the like rotary sensor 13. The rotary electric machine control device 1 performs current feedback control using the detection results of the current sensors 15 and the rotary sensor 13. The rotary electric machine control device 1 is configured to have various functional sections for performing current feedback control, each of which is realized by cooperation of hardware and software (programs) of a microcomputer or the like.

[0058] Fig. 2 The block diagram simply shows the functional sections of a part of the rotary electric machine control device 1. In the vector control method, the actual currents (U-phase current Iu, V-phase current Iv, W-phase current Iw) flowing in the rotary electric machine 80 are coordinate-converted into vector components (d-axis current Id, q-axis current Iq) of the d-axis and the q-axis which are the direction of the magnetic field (magnetic flux) generated by the permanent magnet provided to the rotor of the rotary electric machine 80 and the direction orthogonal to the d-axis (the direction that leads the direction of the magnetic field by electric angle by π / 2), and feedback control is performed. The rotary electric machine control device 1 performs coordinate conversion by the 3-phase 2-phase coordinate conversion section 55 based on the detection results (θ: magnetic pole position, electric angle) of the rotary sensor 13.

[0059] The current feedback control section 5 (FB) performs feedback control of the rotary electric machine 80 based on the deviation between the current command (d-axis current command Id*, q-axis current command Iq*) based on the torque command of the rotary electric machine 80 and the actual current (d-axis current Id, q-axis current Iq) in the dq-axis orthogonal vector coordinate system, and calculates the voltage command (d-axis voltage command Vd*, q-axis voltage command Vq*). The rotary electric machine 80 is driven by the two inverters 10, the first inverter 11 and the second inverter 12. Therefore, the d-axis voltage command Vd* and the q-axis voltage command Vq* are respectively divided into the first d-axis voltage command Vd1* and the first q-axis voltage command Vq1* for the first inverter 11, and the second d-axis voltage command Vd2* and the second q-axis voltage command Vq2* for the second inverter 12 in the distribution section 53 (DIV). As described above, in the present embodiment, the DC link voltage "Vdcl" of the first inverter 11 and the DC link voltage "Vdc2" of the second inverter 12 are the same voltage (Vc1 = Vdc2). Therefore, the divided voltage commands are also "Vd1* = Vd2*" and "Vq1* = Vq2*".

[0060] 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 has two voltage control units 7, each of which has a three-phase voltage command processing unit 73 and a modulation unit 74 (MOD). Specifically, the rotating electric machine control device 1 has: a first voltage control unit 71 that generates switching control signals (Su1, Sv1, Sw1) for the U-phase, V-phase, and W-phase of the first inverter 11; and a second voltage control unit 72 that generates switching control signals (Su2, Sv2, Sw2) for the U-phase, V-phase, and W-phase of the second inverter 12. Further details will be provided in [reference needed]. Fig. 9-10 The following will be described later, but the voltage commands (Vu1**, Vv1**, Vw**) of the first inverter 11 and the voltage commands (Vu2**, Vv2**, Vw2**) of the second inverter 12 are phase-differentiated by "π". Therefore, the value obtained by subtracting "π" from the detection result (θ) of the rotation sensor 13 is input to the second voltage control unit 72.

[0061] like Fig. 2 As shown, the second voltage control unit 72, in addition to having a three-phase voltage command calculation unit 73 and a modulation unit 74 connected in the same way as the first voltage control unit 71, also has another three-phase voltage command calculation unit 73 (a three-phase voltage command calculation unit 73B for special modulation), a modulation unit (a modulation unit 75 for special modulation), and a selection unit 76. In the second voltage control unit 72, the selection unit 76 selects the normally modulated switch control signal generated by the modulation unit 74 and the specially modulated switch control signal generated by the modulation unit 75, and outputs them as the switch control signals (Su2, Sv2, Sw2) of the second inverter 12. This special modulation is a special pulse width modulation, which will be described later and referred to again later. Fig. 8-19 Detailed description follows. Furthermore, the control module is not limited to this structure. For example, a normally modulated 3-phase voltage command and a specially modulated 3-phase voltage command generated by the special modulation unit 75 can be selected in the selection unit, and a shared modulation unit can generate switching control signals (Su2, Sv2, Sw2) for the second inverter 12 based on the selected voltage command.

[0062] Furthermore, as described later, the modulation method includes synchronous modulation that is synchronized with the rotation of the rotating motor 80 and asynchronous modulation that is independent of the rotation of the rotating motor 80. Generally, the module for generating the switch control signal based on synchronous modulation (in the case of software, the generation process) is different from the module for generating the switch control signal based on asynchronous modulation. The voltage control unit 7 described above generates the switch control signal based on a voltage command and a carrier wave that is asynchronous with the rotation of the rotating motor 80. However, in this embodiment, for the sake of simplicity, the case where the voltage control unit 7 also generates a switch control signal based on synchronous modulation (for example, the switch control signal in the case of rectangular wave control described later) will be described.

[0063] Furthermore, as described above, each arm 3A of the inverter 10 is composed of a series circuit of an upper-side switching element 3H and a lower-side switching element 3L. Fig. 2 Although there is no distinction, the switching control signals for each phase are output as two types of signals: upper-level switching control signals and lower-level switching control signals. For example, the first U-phase switching control signal Su1, which controls the switching of the U-phase of the first inverter 11, is output as two signals: the first U-phase upper-level switching control signal Su1+ with a "+" appended to the end and the first U-phase lower-level switching control signal Su1- with a "-" appended to the end. Furthermore, if the upper-level switching element 3H and the lower-level switching element 3L constituting each arm 3A are simultaneously turned on, then arm 3A becomes short-circuited. To prevent this, a dead time is provided so that both the upper-level and lower-level switching control signals for each arm 3A become inactive. This dead time is also added to the voltage control unit 7.

[0064] like Fig. 1 As 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 drive circuit 2 (DRV) and are individually switched. The high-voltage system circuit (the system connected to the DC power supply 6) used by the inverter 10 to drive the rotating motor 80 and the low-voltage system circuit (the system with an operating voltage of about 3.3 volts to 5 volts) of the rotating motor control device 1, which uses a microcomputer or the like as its core, have significantly different operating voltages (power supply voltages of the circuit). The drive circuit 2 relays the drive capability (e.g., the ability to operate subsequent circuits by adjusting voltage amplitude and output current) of the drive signal (switching control signal) for each switching element 3. The first drive circuit 21 relays the switching control signal to the first inverter 11, and the second drive circuit 22 relays the switching control signal to the second inverter 12.

[0065] The rotating electric machine control device 1 can execute, as a manner of switching the switching elements 3 that constitute the first inverter 11 and the second inverter 12 (a manner of voltage waveform control), both of pulse width modulation (PWM) control that outputs a plurality of pulses of different patterns in one cycle of electrical angle and rectangular wave control (1-pulse control (1-Pulse)) that outputs one pulse in one cycle of electrical angle. That is, the rotating electric machine control device 1 can execute the pulse width modulation control and the rectangular wave control as the control manner of the first inverter 11 and the second inverter 12. In addition, as described above, the rotating electric machine control device 1 can control each of the first inverter 11 and the second inverter 12 in a mutually independent control manner.

[0066] In addition, the pulse width modulation has a manner of sinusoidal pulse width modulation (SPWM), continuous pulse width modulation (CPWM) such as space vector pulse width modulation (SVPWM), discontinuous pulse width modulation (DPWM), and the like. Therefore, in the pulse width modulation control that the rotating electric machine control device 1 can execute, the control manner includes continuous pulse width modulation control and discontinuous pulse width modulation control.

[0067] The continuous pulse width modulation is a modulation manner in which the pulse width modulation is continuously executed for all of the arms 3A of the multiphase, and the discontinuous pulse width modulation is a modulation manner in which the pulse width modulation is executed for a part of the arms 3A of the multiphase, including a period in which the switching element is fixed to the on state or the off state. Specifically, in the discontinuous pulse width modulation, for example, the signal level of the switching control signal of the inverter corresponding to one phase in the 3-phase alternating current power is sequentially fixed, and the signal level of the switching control signal corresponding to the other 2 phases is varied. In the continuous pulse width modulation, all of the phases are modulated without fixing the switching control signal corresponding to a certain phase as described above. These modulation manners are determined in accordance with an operation condition of the rotating electric machine 80, such as a rotational speed, a torque, and the like, and a modulation rate (a ratio of an effective value of a line voltage of the 3-phase alternating current with respect to a direct current voltage) required to satisfy the operation condition.

[0068] In the pulse width modulation, a pulse is generated on the basis of a size relationship between an amplitude of an alternating current waveform as a voltage command and an amplitude of a waveform of a triangular wave (including a sawtooth wave)-like carrier (CA) (refer to, for example, Japanese Patent Application Publication No. 2002- 339593). Fig. 7 There is also a case where a PWM waveform is directly generated by digital operation without comparison with the carrier, but in this case, the amplitude of the alternating current waveform as a command value and the amplitude of the imaginary carrier waveform also have a correlation relationship.

[0069] In the pulse width modulation based on digital operation, the carrier is determined in accordance with a control period of the rotating electric machine control device 1, for example, an operation period of a microcomputer, an operation period of an electronic circuit, or the like. That is, even in the case where multiphase alternating-current electric power is used for driving the alternating-current rotating electric machine 80, the carrier has a period (an asynchronous period) that is not bound by the rotational speed, the rotational angle (the electric angle) of the rotating electric machine 80. Therefore, the carrier and each pulse generated based on the carrier are not synchronized with the rotation of the rotating electric machine 80. Therefore, there is a case where the modulation method such as the sinusoidal wave pulse width modulation, the space vector pulse width modulation is called asynchronous modulation. In contrast to this, the modulation method in which a pulse is generated in synchronization with the rotation of the rotating electric machine 80 is called synchronous modulation. For example, in the rectangular wave control (rectangular wave modulation), since one pulse is output in one period of the electric angle of the rotating electric machine 80, the rectangular wave modulation is synchronous modulation.

[0070] However, as an index indicating the conversion rate from the direct-current voltage to the alternating-current voltage, there is a modulation rate indicating the proportion of the effective value of the line voltage of the multiphase alternating-current voltage with respect to the direct-current voltage. Generally, the maximum modulation rate of the sinusoidal wave pulse width modulation is about 0.61 (≈0.612), and the maximum modulation rate of the space vector pulse width modulation control is about 0.71 (≈0.707). The modulation method having a modulation rate exceeding about 0.71 is called "overmodulation pulse width modulation" as a modulation method that increases the modulation rate more than usual. The maximum modulation rate of the "overmodulation pulse width modulation" is about 0.78. This modulation rate 0.78 is a physically (mathematically) limit value in the electric power conversion from direct-current to alternating-current. In the overmodulation pulse width modulation, when the modulation rate reaches 0.78, it becomes the rectangular wave modulation (1-pulse modulation) that outputs one pulse in one period of the electric angle. In the rectangular wave modulation, the modulation rate is fixed to the physical limit value, that is, about 0.78.

[0071] The overmodulation pulse width modulation with a modulation ratio of less than 0.78 can also be implemented using the principle of either of the synchronous modulation method and the asynchronous modulation method. A representative modulation method of the overmodulation pulse width modulation is discontinuous pulse width modulation. The discontinuous pulse width modulation can also be implemented using the principle of either of the synchronous modulation method and the asynchronous modulation method. For example, in the case of using the synchronous modulation method, one pulse is output in one cycle of an electrical angle in rectangular wave modulation, but a plurality of pulses is output in one cycle of an electrical angle in discontinuous pulse width modulation. If there are a plurality of pulses in one cycle of an electrical angle, the effective period of the pulses is reduced accordingly, and thus the modulation ratio is reduced. Therefore, it is not limited to the modulation ratio of approximately 0.78, and any modulation ratio of less than 0.78 can also be implemented by the synchronous modulation method. For example, a plurality of pulse modulations (Multi-Pulses) such as 9-pulse modulation (9-Pulses) that outputs 9 pulses in one cycle of an electrical angle, 5-pulse modulation (5-Pulses) that outputs 5 pulses, and the like can also be used.

[0072] In addition, the rotating electric machine control device 1 can execute shutdown control (SDN), active short-circuit control (ASC) as a fail-safe control in a case where the inverter 10, the rotating electric machine 80 are detected to be abnormal. The shutdown control is control that changes the switching control signal to the switching element 3 constituting the entire inverter 10 to an inactive state to make the inverter 10 into a disconnection state. The active short-circuit control is control that changes either the upper side switching element 3H of the entire arm 3A of the multiphase and the lower side switching element 3L of the entire arm 3A of the multiphase to an on state, and changes the other to an off state. In addition, a case where the upper side switching element 3H of the entire arm 3A of the multiphase is changed to an on state and the lower side switching element 3L of the entire arm 3A of the multiphase is changed to an off state is referred to as upper side active short-circuit control. In addition, a case where the lower side switching element 3L of the entire arm 3A of the multiphase is changed to an on state and the upper side switching element 3H of the entire arm 3A of the multiphase is changed to an off state is referred to as lower side active short-circuit control.

[0073] 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 multi-phase 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 method of controlling an open-winding type rotating electric machine 80 by two inverters 10 and the method of controlling a Y-connected rotating electric machine 80 by one inverter 10 (the inverter 10 on the side without active short-circuit control). Therefore, in this embodiment, it is not limited to failure protection control, and active short-circuit control is also included as a control method that can be selected in normal control. That is, the rotating electric machine control device 1 can also perform active short-circuit control as a control method for the first inverter 11 and the second inverter 12.

[0074] However, when vector control is applied to an inverter 10, eight space vectors can be defined based on the state of the three-phase arm 3A. Specifically, eight space vectors (2...) can be defined by combining the two signal levels of the three phases of the switching control signal of the upper-side switching element 3H. 3 =8). Furthermore, the signal levels of the three-phase switching control signals of the lower-level switching element 3L are complementary to the switching control signals of the upper-level switching element 3H. Therefore, a space vector can be defined using the signal level of either the upper-level or lower-level switching control signal.

[0075] If we set the high level of each switch control signal to "1" and the low level to "0", and use (UVW) to represent the signal levels of the switch control signals for phases U, V, and W, then the space vectors are (000), (001), (010), (011), (100), (101), (110), and (111). Furthermore, among these eight space vectors, (000) and (111) are called zero vectors or empty vectors because the line voltage becomes zero and no voltage is applied to the rotating motor 80, and they represent the same coordinate in the dq-axis vector coordinate system. In contrast, the other six space vectors are called dynamic vectors, and each represents a different coordinate in the dq-axis vector coordinate system.

[0076] like Fig. 1 As shown, when vector control is applied to two inverters 10, 64 space vectors (2^64) can be defined by the signal level of any one of the switch control signals on the upper and lower sides. (3·2) =2 6= 64). Of these, 10 are null vectors. If (U1V1W1 - U2V2W2) is used to represent the signal levels of the U phase (U1 phase), V phase (V1 phase), and W phase (W1 phase) of the first inverter 11 and the signal levels of the U phase (U2 phase), V phase (V2 phase), and W phase (W2 phase) of the second inverter 12, then (000-000), (001-001), (010-010), (011-011), (100-100), (101-101), (110-110), (111-111), (000-111), and (111-000) are the 10 null vectors in which the line voltage becomes zero. The remaining 54 are dynamic vectors having effective magnitudes from the origin (coordinates of the null vectors) to 18 different coordinates in the dq-axis vector coordinate system.

[0077] In Fig. 3 , the coordinates of the null vectors and the coordinates of the dynamic vectors of the 18 positions are plotted. Z0 indicates the coordinates of the null vectors in the dq-axis vector coordinate system (10 vectors are the same coordinates). Z1 to Z6 indicate the coordinates of the dynamic vectors substantially realized by one inverter 10 in the dq-axis vector coordinate system. Z7 to Z18 indicate the coordinates corresponding to the dynamic vectors realized by two inverters 10 in the dq-axis vector coordinate system.

[0078] Z1 includes (000-011), (100-000), (100-111), (111-011), Z2 includes (000-001), (110-000), (110-111), (111-001), Z3 includes (000-101), (010-000), (010-111), (111-101), Z4 includes (000-100), (011-000), (011-111), (111-100), Z5 includes (000-110), (001-000), (001-111), (111-110), and Z6 includes (000-010), (101-000), (101-111), (111-010). These 24 space vectors are combinations of space vectors of one inverter 10 being null vectors and space vectors of the other inverter 10 being dynamic vectors.

[0079] In addition, Zl: (101-001), (110-010), Z2: (010-011), (100-101), Z3: (011-001), (110-100), Z4: (001-101), (010-110), Z5: (011-010), (101-100), Z6: (001-011), (100-110) are also the coordinates of Zl to Z6, respectively. However, they are a combination of one of the space vectors which is not a null vector for one inverter 10 and both of the space vectors which are dynamic vectors for the other inverter 10.

[0080] Z7: (100-001), (110-011), Z8: (010-001), (110-101), Z9: (010-100), (011-101), Z10: (001-100), (011-110), Zl l: (001-010), (101-110), Z12: (100-010), (101-011), correspond to 12 space vectors. In addition, Z13: (100-011), Z14: (110-001), Z15: (010-101), Z16: (011-100), Z17: (001-110), Z18: (101-010), correspond to 6 space vectors.

[0081] Fig. 4 A vector diagram of one of the operation points in the dq-axis vector coordinate system of the rotating electric machine 80 is illustrated. In the figure, "Vl" is a first voltage vector indicating a voltage based on the first inverter 11, and "V2" is a second voltage vector indicating a voltage based on the second inverter 12. The voltage appearing on the open winding, i.e., the stator coil 8, by the two inverters 10 corresponds to the difference "Vl-V2" of the first voltage vector Vl and the second voltage vector V2. "Va" in the figure indicates the resultant voltage vector appearing on the stator coil 8. In addition, "Ia" indicates the current flowing in the stator coil 8 of the rotating electric machine 80. As shown in the figure, if the first inverter 11 and the second inverter 12 are controlled so that the directions of the vectors of the first voltage vector Vl and the second voltage vector V2 differ by 180 degrees, the resultant voltage vector Va is a vector obtained by adding the magnitude of the second voltage vector V2 to the direction of the first voltage vector Vl. Fig. 4

[0082] ​As in the present embodiment, in the case where the rotary electric machine 80 having the mutually independent multiphase open-circuit windings is driven controlled by the two inverters 10, generally, the two inverters 10 are subjected to the switching control in the same control mode. However, it is preferable that the mode of the switching control is determined in accordance with various factors (operation conditions) such as the torque, the rotational speed, the voltage of the DC side, and the like required for the rotary electric machine 80 so as to be able to operate with higher system efficiency. Therefore, the rotary electric machine control device 1 has a control mode in which the first inverter 11 and the second inverter 12 are controlled in different control modes in accordance with the operation region (control region R) of the rotary electric machine 80. It can be confirmed through experiments, simulations, and the like by the inventor that, by having the control mode in which the first inverter 11 and the second inverter 12 are controlled in different control modes in accordance with the operation conditions of the rotary electric machine 80, it is possible to make the system efficiency higher.

[0083] In the present embodiment, the rotary electric machine control device 1 has a control mode in which the object control is executed in which one inverter 10 (here, the first inverter 11) among the first inverter 11 and the second inverter 12 is controlled by the rectangular wave control, and the other inverter 10 (here, the second inverter 12) is controlled by the special pulse width modulation control (SP-PWM) which is one of the pulse width modulation controls. Here, the special pulse width modulation control is a control mode which becomes a switching pattern that is the difference between the switching pattern based on the pulse width modulation control in the case where the stator coil 8 generates the target voltage and the switching pattern of the rectangular wave control. As for the detailed contents, it will be described later with reference to Fig. 8-19 and the like.

[0084] As described above, in the present embodiment, the second switching element 32 which constitutes the second inverter 12 is a switching element in which the switching loss is relatively small at the time of transition between the off state and the on state, as compared with the first switching element 31 which constitutes the first inverter 11. In the case where the first inverter 11 is controlled by the rectangular wave control, the number of switching is reduced as compared with the second inverter 12 which is controlled by the special pulse width modulation control. That is, by causing the second inverter 12 in which the switching loss is relatively small to perform more switching, it is possible to suppress the loss of the entire system in the high-speed region VRH in which high output is required.

[0085] Of course, the control mode also has modes other than the mode of the object control. Each control mode is set in correspondence with the control region R (refer to Fig. 5 and the like) of the rotary electric machine 80. As shown in Fig. 5 In the present embodiment, as the control region R of the rotary electric machine 80, there are set the low-speed region VRL and the high-speed region VRH in which the rotational speed of the rotary electric machine 80 is higher than the low-speed region VRL at the same torque T. The object control is executed in the high-speed region VRH.

[0086] In addition, as shown in Fig. 5 In addition, as shown in

[0087] As described above, in the pulse width modulation control, as the control mode, there are included: continuous pulse width modulation control (CPWM) that performs pulse width modulation continuously to all of the arms 3A of the multiphase; and discontinuous pulse width modulation control (DPWM) that performs pulse width modulation to a part of the arms 3A of the multiphase, including a period in which the switching element 3 is fixed to the on state or the off state. In addition, as described above, the special pulse width modulation control (SP-PWM) is a control mode that becomes a switching pattern that is a difference between a switching pattern of the pulse width modulation control based on the stator coil 8 generating the target voltage and a switching pattern of the rectangular wave control. In the first target control, the continuous pulse width modulation is used as the pulse width modulation control, and in the second target control, the discontinuous pulse width modulation is used as the pulse width modulation control.

[0088] That is, the rotary electric machine control device 1, in the first high speed region VRH1, as the target control, performs the first target control that controls one of the inverters 10 (here, the first inverter 11) by the rectangular wave control and controls the other inverter 10 (here, the second inverter 12) by the special pulse width modulation control (SP-PWM) based on the continuous pulse width modulation control (CPWM), that is, the special continuous pulse width modulation control (SP-CPWM). In addition, the rotary electric machine control device 1, in the second high speed region VRH2, as the target control, performs the second target control that controls one of the inverters 10 (here, the first inverter 11) by the rectangular wave control and controls the other inverter 10 (here, the second inverter 12) by the special pulse width modulation control (SP-PWM) based on the discontinuous pulse width modulation control (DPWM), that is, the special discontinuous pulse width modulation (SP-DPWM).

[0089] The maximum modulation rate of discontinuous pulse width modulation (PWM) control is greater than that of continuous pulse width modulation (PWM). The second high-speed region VRH2 is the control region R where the rotational speed of the rotary motor 80 is higher than that of the first high-speed region VRH1 at the same torque T. From the viewpoint of system efficiency, it is preferable to modulate at a higher modulation rate in the second high-speed region VRH2 than in the first high-speed region VRH1. By performing special continuous pulse width modulation (PWM) control based on PWM in the first high-speed region VRH1 and special discontinuous pulse width modulation (PWM) control based on discontinuous pulse width modulation (PWM) in the second high-speed region VRH2, the rotary motor 80 can be appropriately driven throughout the entire high-speed region VRH.

[0090] In addition, such as Fig. 6 As shown, preferably, as the control region R, an ultra-high speed region VRSH is also defined, where the rotational speed of the rotary motor is higher than that of the high-speed region VRH under the same torque T. In this ultra-high speed region VRSH, the two inverters 10, the first inverter 11 and the second inverter 12, are controlled by rectangular wave control. In the high-speed region VRH, where the rotational speed of the rotary motor is lower than that of the ultra-high speed region VRSH under the same torque T, one inverter 10 is controlled by rectangular wave control, and the other inverter 10 is controlled by special discontinuous pulse width modulation. The maximum modulation rate of the typical discontinuous pulse width modulation is approximately 0.78, the modulation rate of the rectangular wave control. Since the maximum modulation rate of the special discontinuous pulse width modulation based on discontinuous pulse width modulation is also approximately 0.78, the rotary motor 80 can be appropriately driven in both the high-speed region VRH and the ultra-high speed region VRSH.

[0091] Furthermore, in the low-speed region VRL, target low-speed region control is implemented by controlling one of the first inverter 11 and the second inverter 12 (here, the first inverter 11) through active short-circuit control and controlling the other inverter 10 (here, the second inverter 12) through pulse width modulation control. That is, the rotating motor 80 is essentially driven by only one of the two inverters 10 (e.g., the second inverter 12). Since one inverter 10 does not perform switching operations, the corresponding switching losses can be reduced, and as a result, the rotating motor 80 can be driven while suppressing the overall system losses.

[0092] As described above, in this embodiment, the second inverter 12 is configured using switching elements with relatively low switching losses compared to the first inverter 11. When active short-circuit control is applied to the first inverter 11, the switching losses of the first inverter 11, which has relatively high switching losses, are approximately zero. Furthermore, since the switching losses of the second inverter 12 are relatively low, overall system losses can be suppressed in the low-speed region (VRL).

[0093] In addition, such as Fig. 7 As shown, the low-speed region VRL can also be divided, with a first low-speed region VRL1 and a second low-speed region VRL2 where the rotational speed of the rotary motor 80 is higher than that of the first low-speed region under the same torque T. Furthermore, the object low-speed control performed in the low-speed region VRL can have two types of control: a first object low-speed control performed in the first low-speed region VRL1 and a second object low-speed control performed in the second low-speed region VRL2. Alternatively, if the low-speed region VRL is not divided, the object control performed throughout the entire low-speed region VRL is preferably the first object low-speed control.

[0094] In pulse width modulation (PWM) control, the control methods include: continuous PWM control, which continuously performs PWM on all arms 3A of the multiphase; and discontinuous PWM control, which performs PWM on a portion of the arms 3A of the multiphase, including periods during which the switching element 3 is fixed in an on or off state. Continuous PWM control is used in the first low-speed region VRL1, and discontinuous PWM control is used in the second low-speed region VRL2.

[0095] Specifically, in the first low-speed region VRL1, the rotating electric machine control device 1 performs first target low-speed region control by controlling one of the first inverters 11 and the second inverter 12 (here, the first inverter 11) through active short-circuit control, and by controlling the other inverter 10 (here, the second inverter 12) through continuous pulse width modulation control. Furthermore, in the second low-speed region VRK2, the rotating electric machine control device 1 performs second target low-speed region control by controlling one of the first inverters 11 and the second inverter 12 (here, the first inverter 11) through active short-circuit control, and by controlling the other inverter 10 (here, the second inverter 12) through discontinuous pulse width modulation control.

[0096] The maximum modulation rate of the discontinuous pulse width modulation control is greater than the maximum modulation rate of the continuous pulse width modulation control. The second low speed region VRL2 is a control region R in which the rotational speed of the motor 80 is higher than the first low speed region VRL1 at the same torque T, and from the viewpoint of system efficiency, it is preferable to modulate at a higher modulation rate in the second low speed region VRL2 than in the first low speed region VRL1. By executing the first target low speed region control using the continuous pulse width modulation control in the first low speed region VRL1 and executing the second target low speed region control using the discontinuous pulse width modulation in the second low speed region VRL2, it is possible to appropriately drive the motor 80 in the entire low speed region VRL.

[0097] In addition, when modulating in the low speed region VRL, depending on the frequency of the carrier wave CA (refer to Fig. 31 , Fig. 32 , etc.), noise in the audible frequency band can sometimes be generated. In the low speed region VRL, the sound generated along with vehicle travel (travel sound such as the contact sound of the tires with the road surface) is also small, and thus in the case where the noise output from the inverter 10 is noise in the audible frequency band, there is a possibility that the user will easily hear the noise. Here, by making the frequency of the carrier wave CA higher, it is possible to make the frequency of the noise outside the audible frequency band. Since the second inverter 12 is configured using switching elements that have a relatively small switching loss compared to the first inverter 11, even if the frequency of the carrier wave CA is made higher, an increase in the switching loss can be suppressed.

[0098] However, as exemplified in Fig. 36 and Fig. 37 , the first inverter 11 and the second inverter 12 can also be configured using the same switching elements 3. In addition, as exemplified in Fig. 1 , even in the case where the second inverter 12 is configured using switching elements that have a relatively small switching loss compared to the first inverter 11, as described above, there are cases where the frequency of the carrier wave CA of the second inverter 12 is not set to be high. In such a case, it is not limited to the manner of controlling the first inverter 11 by active short-circuit control, and it can also be the manner of controlling the second inverter 12 by active short-circuit control.

[0099] In addition, in such a case, in order not to consume due to only a large number of switching of the one inverter 10 (here, the second inverter 12) that is not controlled by active short-circuit control, in the low speed region VRL, the control manner of the first inverter 11 and the control manner of the second inverter 12 are alternately switched in accordance with a predetermined condition. By switching the control manner, it is also possible to suppress a case where the discharge amount of only one of the first direct current power supply 61 and the second direct current power supply 62 increases. Here, the predetermined condition is, for example, preferably a fixed time or the discharge amount of the direct current power supply 6.

[0100] In addition, as shown in Fig. 7 the intermediate speed region VRM in which the rotational speed of the motor 80 is higher than the low speed region VRL and lower than the high speed region VRH at the same torque T can also be set as the control region R. In the intermediate speed region VRM, both the first inverter 11 and the second inverter 12 are controlled by discontinuous pulse width modulation control.

[0101] In the above, in a case where the first low speed region VRL1, the second low speed region VRL2, the intermediate speed region VRM, the first high speed region VRH1, the second high speed region VRH2, and the super high speed region VRSH are set as the control region R, an example of the control mode applied to the first inverter 11 and the second inverter 12 is shown in Table 1 below.

[0102] [Table 1]

[0103] R INV1 INV2 VRL1 (VRL) ASC CPWM (PWM) VRL2 (VRL) ASC DPWM (PWM) VRM DPWM DPWM VRH1 (VRH) 1-Pulse SP-CPWM (SP-PWM) VRH2 (VRH) 1-Pulse SP-DPWM (SP-PWM) VRSH 1-Pulse 1-Pulse

[0104] Here, preferably, the boundary of each control region R is set in accordance with at least one of the ratio of the line voltage of the multiphase alternating voltage to the direct current voltage and the ratio of the effective value of the rotational speed of the motor 80 to the direct current voltage corresponding to the torque of the motor 80.

[0105] As Fig. 5-7 illustrated above, the operating condition of the motor 80 is often defined by the relationship between the rotational speed and the torque. Preferably, the control region R is set based on the rotational speed as one parameter. Here, although the rotational speed that defines the boundary of the control region R can be set to be constant regardless of the torque, it is more preferable to set the rotational speed that defines the boundary of the control region R to be different values according to the torque. Thereby, the motor 80 can be driven with high efficiency according to the operating condition of the motor 80.

[0106] In addition, for example, in a case where the motor 80 requires a high output (fast rotational speed, high torque), in a voltage type inverter, this requirement is achieved by making the direct current voltage higher or making the ratio of the direct current voltage to the alternating current voltage higher. In a case where the direct current voltage is constant, this requirement is achieved by making the ratio of the direct current voltage to the alternating current voltage higher. This ratio can be expressed as the ratio of the effective value of the three-phase alternating current power to the direct current power (in the case of a voltage type inverter, this is equivalent to the ratio of the effective value of the line voltage of the three-phase alternating voltage to the direct current voltage). As described above, in the control mode of the inverter 10, there are various modes in which this ratio is from low to high.

[0107] If the control region is set based on the ratio (modulation rate) of the effective value of the line voltage of the 3-phase alternating voltage with respect to the direct current voltage determined in accordance with the requirements on the rotating electric machine 80, the control rotating electric machine 80 can be driven with high efficiency according to the operating conditions of the rotating electric machine 80. Table 2 shown below corresponds to Table 1 described above, and illustrates the modulation rates corresponding to each control region R. Details will be described later, but in the table, "Mi_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 modulation rate of the entire system.

[0108] [Table 2]

[0109]

[0110] In the present embodiment, the terminal-to-terminal voltage "E1" of the first direct current power supply 61 and the terminal-to-terminal voltage "E2" of the second direct current power supply 62 are the same (both are voltage "E"). If the effective value on the alternating current side of the first inverter 11 is set as "Va_inv1" and the effective value on the alternating current side of the second inverter 12 is set as "Va_inv2", 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 the following equations (1), (2). In addition, the modulation rate "Mi_sys" of the entire system is as shown in the following equation (3).

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

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

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

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

[0115] In terms of the instantaneous value of the voltage, the instantaneous vector needs to be considered, but if only the modulation rate is simply considered, it is derived from equations (1) to (3) that the modulation rate "Mi_sys" of the entire system is "(Mi_inv1 + Mi_inv2) / 2". In addition, in Table 2, the modulation rates corresponding to each control region R are shown as rated values. Therefore, at the time of actual control, a range overlapping the modulation rates corresponding to each control region R can also be included in consideration of hunting and the like when the control mode changes in the control region R.

[0116] Further, the modulation ratio "X" is set in consideration of the theoretical upper limit value (approximately 0.707) of the modulation ratio based on continuous pulse width modulation (space vector pulse width modulation) and further in consideration of the dead time. As shown in Table 2, in the low speed region VRL (the first low speed region VRLl and the second low speed region VRL2), modulation is sometimes performed by only one inverter 10. Since continuous pulse width modulation control can be performed in the entire region of the low speed region VRL, in the low speed region VRL, the maximum modulation ratio "2X" of one inverter 10 (here, the second inverter 12) is set in consideration of the theoretical upper limit value (approximately 0.707 in space vector pulse width modulation) of the modulation ratio based on continuous pulse width modulation control and further in consideration of the dead time, for example, to approximately 0.5 to 0.6. Therefore, the modulation ratio "X" is set to a value of, for example, approximately 0.25 to 0.3. The modulation ratios "a, b, c" are appropriately set based on experiments, simulations, and the like.

[0117] Hereinafter, the control modes in the respective control regions R will be described with reference to waveforms of the voltage commands (Vu1**, Vu2**) of the U phase and the upper side switching control signals (Su1+, Su2+) of the U phase. The second U phase lower side switching control signal Su2- and the V phase and the W phase are omitted from illustration.

[0118] First, the special pulse width modulation control (SP-PWM) that is most characteristic in the present embodiment and is performed in the high speed region VRH will be described with reference to Fig. 8-19 Fig. 8 The special continuous pulse width modulation control (SP-CPWM) is shown in Fig. 9 The special discontinuous pulse width modulation control (SP-DPWM) is shown in

[0119] In Fig. 8 and Fig. 9 An example of the carrier wave CA that is common to the first inverter 11 and the second inverter 12, the voltage command of the first inverter 11, that is, the first U phase voltage command Vu1**, the voltage command of the second inverter 12, that is, the second U phase voltage command Vu2**, the first U phase upper side switching control signal Su1+, and the second U phase upper side switching control signal Su2+ is shown in the first inverter 11 and the second inverter 12. The first U phase lower side switching control signal Su1-, the second U phase lower side switching control signal Su2-, and the V phase and the W phase are omitted from illustration (the same applies to other control modes).

[0120] ​For example, the carrier CA varies between "0 < CA < 1", and the voltage command (V**) varies substantially within the range of "0 ≤ V** ≤ 1". By comparing the carrier CA and the voltage command (V**), the switch control signal becomes "1" when the voltage command is above the carrier CA, and the switch control signal becomes "0" when the voltage command is less than the carrier CA. The comparison logic of the carrier CA and the voltage command (V**) is also the same in the following description.

[0121] As described above, the special pulse width modulation control (SP-PWM) is a control mode that becomes a switching pattern that is the difference between a switching pattern based on the pulse width modulation control when the stator coil 8 generates the target voltage and a switching pattern of the rectangular wave control. Therefore, the voltage command (V**) of the special pulse width modulation control (SP-PWM) is set based on the difference between the voltage command (V**) for the pulse width modulation control when the stator coil 8 generates the target voltage and the voltage command (V**) for the rectangular wave control. For example, the voltage command (V**) of the special continuous pulse width modulation control (SP-CPWM) is set based on the difference between the voltage command (V**) for the continuous pulse width modulation control when the stator coil 8 generates the target voltage and the voltage command (V**) for the rectangular wave control. In addition, the voltage command (V**) of the special discontinuous pulse width modulation control (SP-DPWM) is set based on the difference between the voltage command (V**) for the discontinuous pulse width modulation control when the stator coil 8 generates the target voltage and the voltage command (V**) for the rectangular wave control.

[0122] Hereinafter, the principle and the sequence of operating the voltage command (V**) of the special pulse width modulation control will be described with reference to the block diagram of Fig. 2 , and Fig. 10-19 . Fig. 10-13 The principle of operating the voltage command (V**) of the special continuous pulse width modulation control is shown, Fig. 14-17 the principle of operating the voltage command (V**) of the special discontinuous pulse width modulation control is shown, Fig. 18 and Fig. 19 the sequence of operating the voltage command (V**) of the special pulse width modulation control is shown. Here, the voltage command (Vu**) of the U phase within the voltage command (V**) of the 3 phases is exemplified as a representative.

[0123] Fig. 10 The principle of operating the voltage command (V**) of the special continuous pulse width modulation control is shown, Fig. 8The voltage command (Vu2**) of the special continuous pulse width modulation control, the voltage command (Vu1**) of the rectangular wave control, and the carrier CA are illustrated. That is, the operation result of the voltage command (Vu2**) of the special continuous pulse width modulation control is shown. As described above, the carrier CA varies between "0 < CA < 1", and the voltage commands (Vu1**, Vu2**) vary in the range of "0" or more and "1" or less.

[0124] Fig. 11 The voltage command (Vu2**) of the continuous pulse width modulation control, the voltage command (Vu1**) of the rectangular wave control, and the carrier CA are illustrated. For example, as shown in Fig. 2 In the special modulation 3-phase voltage command operation section 73B of the second voltage control section 72 that operates the 3-phase voltage command of the second inverter 12, both the 3-phase voltage command (Vu1**) of the first inverter 11 and the voltage command (Vu2**) of the second inverter 12 are operated. Here, the voltage command of the rectangular wave control (1-Pulse) is operated as the 3-phase voltage command (Vu1**) of the first inverter 11, and the voltage command of the continuous pulse width modulation control (CPWM) is operated as the 3-phase voltage command (Vu2**) of the second inverter 12. As shown in Fig. 18 In the first step #1, these voltage commands are acquired as basic voltage commands (basic voltage command acquisition step). "Vu_INV1_Ref" is the basic voltage command (first basic voltage command) of the first inverter 11. "Vu_INV2_Ref" is the basic voltage command (second basic voltage command) of the second inverter 12. The first basic voltage command corresponds to the voltage command for the rectangular wave, and the second basic voltage command corresponds to the voltage command for the pulse width modulation (here, the voltage command for the continuous pulse width modulation).

[0125] Fig. 12 The voltage commands after the second step #2 and the third step #3 of Fig. 18 are shown. In the second step #2, the total voltage command "Vu_total_Ref" (system voltage command) that is output using the first inverter 11 and the second inverter 12 is operated (system voltage command operation step). As described with reference to Fig. 4 and the like, the voltage command of the first inverter 11 and the voltage command of the second inverter 12 are set to be 180 degrees out of phase. Therefore, as shown in Fig. 12 and Fig. 18 the system voltage command "Vu_total_Ref" is operated as the difference between the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref".

[0126] As shown in Fig. 12As shown, the wave height of the system voltage command "Vu_total_Ref" is larger than the variation range "0 < CA < 1" of the carrier CA, the center of which is "0". In order to make the center of the amplitude of the system voltage command "Vu_total_Ref" coincide with the center of the amplitude of the first fundamental voltage command "Vu_INV1_Ref", in the third step #3, the center of the amplitude of the first fundamental voltage command "Vu_INV1_Ref" is shifted from "0.5" which is the center of the variation range "0 < CA < 1" of the carrier CA to "0". Although the third step #3 can be called a negative shift step in a narrow sense, since it is a correction made in association with the operation of the system voltage command, it can also be included in the system voltage command operation step. In the present embodiment, the second step #2 and the third step #3 correspond to the system voltage command operation step. In addition, in the block diagram (3-phase voltage command operation section 73B for special modulation) of FIG. 7, the operation of the difference in the second step #2 is illustrated as a representative for simplicity. Fig. 2

[0127] Fig. 13 The voltage commands after the execution of the fourth step #4 of Fig. 18 are shown. In the fourth step #4, the second fundamental voltage command "Vu_INV2_Ref" is optimized for special continuous pulse width modulation (voltage command optimization step) based on the first fundamental voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref" which are calculated in the system voltage command operation step (#2, #3). As shown in Fig. 13 and Fig. 18 , the second fundamental voltage command "Vu_INV2_Ref" is calculated as the difference between the first fundamental voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref". The second fundamental voltage command "Vu_INV2_Ref" corresponds to a voltage command for special pulse width modulation (here, a voltage command for special discontinuous pulse width modulation) (which becomes a voltage command for special pulse width modulation after the fifth step #5 and the sixth step #6 described later).

[0128] The centers of the amplitudes of the first fundamental voltage command "Vu_INV1_Ref" and the second fundamental voltage command "Vu_INV2_Ref" at the time of completion of the execution of the fourth step #4 are as shown in Fig. 13 ​"0". Thus, in a fifth step #5, positive displacement processing (positive displacement step) is performed to return the amplitude center from "0" to "0.5" which is the center of the range of variation "0 < CA < 1" of the carrier CA. Next, in a sixth step #6, the first basic voltage command "Vu INV1 Ref" is set in the voltage command "Vu1**" of the first inverter 11, and the second basic voltage command "Vu INV2 Ref" is set in the voltage command "Vu2**" of the second inverter 12 (voltage command setting step). As with the third step #3 (negative displacement step), the fifth step #5 is a correction operation. Thus, as with the inclusion of the third step #3 and the second step #2 in the system voltage command operation step, the fifth step #5 and the sixth step #6 can also be included in the voltage command setting step. In the present embodiment, the fifth step #5 and the sixth step #6 correspond to the voltage command setting step.

[0129] In addition, although the block diagram of Fig. 2 is simplified, the first step #1 to the sixth step #6 are performed by the special modulation 3-phase voltage command operation section 73B. The special modulation modulation section 75 generates a special pulse width modulation control (SP-PWM) switching control signal based on the special pulse width modulation control (SP-PWM) voltage command (V**). In the case where the special pulse width modulation control (SP-PWM) is selected as the control method, the special pulse width modulation control (SP-PWM) switching control signal is output via the selection section 76. In Fig. 2 , a method is exemplified in which the 3-phase voltage command operation section 73 and the modulation section 74 for general modulation, the special modulation 3-phase voltage command operation section 73B and the special modulation modulation section 75 for special pulse width modulation, and the selection section 76 which selects and outputs the switching control signal generated by each modulation section (74, 75) are included. However, as described above, it is also possible to select the 3-phase voltage command of general modulation and the 3-phase voltage command of special modulation generated by the special modulation modulation section 75 in the selection section, and generate a switching control signal based on the selected voltage command by a common modulation section.

[0130] Fig. 14 It is shown that Fig. 9The voltage command (Vu2**) of the special discontinuous pulse width modulation control, the voltage command (Vu1**) of the rectangular wave control, and the carrier CA are shown. That is, the operation result of the voltage command (Vu2**) of the special discontinuous pulse width modulation control is shown. The voltage command (Vu1**) of the rectangular wave control varies in the range of "0" or more and "1" or less in correspondence with the carrier CA varying between "0" and "1", but the voltage command (Vu2**) of the special discontinuous pulse width modulation control also varies in the range of "0" or less and "1" or more outside the range of the variation domain of the carrier CA.

[0131] Fig. 15 The voltage command (Vu2**) of the discontinuous pulse width modulation control, the voltage command (Vu1**) of the rectangular wave control, and the carrier CA are shown. As described above, in the special modulation 3-phase voltage command operation section 73B (refer to Fig. 2 ), both the 3-phase voltage command (Vu1**) of the first inverter 11 and the voltage command (Vu2**) of the second inverter 12 are operated. Here, the voltage command of the rectangular wave control (1-Pulse) is operated as the 3-phase voltage command (Vu1**) of the first inverter 11, and the voltage command of the discontinuous pulse width modulation control (DPWM) is operated as the 3-phase voltage command (Vu2**) of the second inverter 12. As described with reference to Fig. 18 , in the first step #1, the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref" are acquired (basic voltage command acquisition step). The first basic voltage command corresponds to the voltage command for the rectangular wave, and the second basic voltage command corresponds to the voltage command for the pulse width modulation (here, the voltage command for the discontinuous pulse width modulation).

[0132] Fig. 16 The voltage command after the second step #2 and the third step #3 of Fig. 18 are shown. In the second step #2, the total voltage command "Vu_total_Ref" (system voltage command) output using the first inverter 11 and the second inverter 12 is operated. As shown in Fig. 16 and Fig. 18 , the system voltage command "Vu_total_Ref" is operated as the difference between the first basic voltage command "Vu_INV1_Ref" and the second basic voltage command "Vu_INV2_Ref".

[0133] As shown in Fig. 16As shown, the wave height of the system voltage command "Vu_total_Ref" is larger than the variation range "0 < CA < 1" of the carrier CA, and the amplitude center is "0". In order to make the amplitude center of the system voltage command "Vu_total_Ref" coincide with the amplitude center of the first fundamental voltage command "Vu_INV1_Ref", in the third step #3, the amplitude center of the first fundamental voltage command "Vu_INV1_Ref" is shifted from "0.5" which is the amplitude center of the carrier CA to "0" (negative shift step). As described above, the third step #3 is a correction performed in conjunction with the operation of the system voltage command, and thus can also be included in the system voltage command operation step. In the present embodiment, the second step #2 and the third step #3 correspond to the system voltage command operation step.

[0134] Fig. 17 The voltage commands after the fourth step #4 in which Fig. 18 is executed are shown. In the fourth step #4, the second fundamental voltage command "Vu_INV2_Ref" is optimized based on the first fundamental voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref" which are calculated in the system voltage command operation step (#2, #3) (voltage command optimization step). As shown in Fig. 17 and Fig. 18 , the second fundamental voltage command "Vu_INV2_Ref" is calculated as the difference between the first fundamental voltage command "Vu_INV1_Ref" and the system voltage command "Vu_total_Ref". The second fundamental voltage command "Vu_INV2_Ref" corresponds to the voltage command for special pulse width modulation (in this case, the voltage command for special discontinuous pulse width modulation) (becomes the voltage command for special pulse width modulation after the fifth step #5 and the sixth step #6 described later.).

[0135] The amplitude centers of the first fundamental voltage command "Vu_INV1_Ref" and the second fundamental voltage command "Vu_INV2_Ref" at the time of completion of the execution of the fourth step #4 are as shown in Fig. 17The value shown is "0". Therefore, in the fifth step #5, a positive displacement process (positive displacement step) is performed to return the amplitude center from "0" to "0.5", which is the amplitude center of the carrier CA. Next, in the sixth step #6, the first basic voltage command "Vu_INV1_Ref" is set in the voltage command "Vu1**" of the first inverter 11, and the second basic voltage command "Vu_INV2_Ref" is set in the voltage command "Vu2**" of the second inverter 12 (voltage command setting step). Since the fifth step #5 and the third step #3 (negative displacement step) are both correction operations, the fifth step #5 can also be included in the voltage command setting step together with the sixth step #6, just like the system voltage command operation steps. In this embodiment, the fifth step #5 and the sixth step #6 are equivalent to the voltage command setting steps. As described above, the special modulation three-phase voltage command operation unit 73B executes the first step #1 to the sixth step #6.

[0136] Fig. 19 The flowchart illustrates the method of further executing the seventh step #7. The special modulation unit 75 executes the seventh step #7. In addition, if a normally modulated three-phase voltage command and a specially modulated three-phase voltage command generated by the special modulation unit 75 are selected in the selection unit, and a common modulation unit generates a switching control signal based on the selected voltage command, the seventh step #7 is executed in the common modulation unit.

[0137] In step 7 #7, by setting "K" to a coefficient greater than "1" and setting the carrier CA frequency "F CA (Carrier frequency) multiplied by "K" to set the carrier frequency F CA That is, making the carrier frequency F CA The higher the value, the higher the modulation resolution. "K" can be set to, for example, "2". More details on this effect will be provided later. Fig. 20-29 (especially) Fig. 26-29 This will be described in more detail. Additionally, the carrier frequency F... CA Equivalent to modulation frequency.

[0138] The above is for reference only. Fig. 10-19The special pulse width modulation control can be a control mode in which a switching pattern is generated based on a special pulse width modulation voltage command. Specifically, a voltage command that generates a switching pattern of one inverter controlled by rectangular wave control in a case where the open circuit winding, i.e., the stator coil 8, generates a target voltage is set as a rectangular wave voltage command, a voltage command that generates a switching pattern of another inverter controlled by pulse width modulation control in a case where the target voltage is generated with a phase that differs by 180 degrees from the rectangular wave voltage command is set as a pulse width modulation voltage command, a difference between the rectangular wave voltage command and the pulse width modulation voltage command is set as a voltage command of both inverters as a whole, i.e., a system voltage command, a difference between the system voltage command in a state where the amplitude center is aligned and the rectangular wave voltage command is set as a special pulse width modulation voltage command, and the special pulse width modulation control can be a control mode in which a switching pattern is generated based on the special pulse width modulation voltage command.

[0139] In addition, as described with reference to Fig. 19 In the low speed region VRL, in a case where at least one of the first inverter 11 and the second inverter 12 is controlled by pulse width modulation control, in the high speed region VRH, the special pulse width modulation control can also be performed at a higher modulation frequency than in the pulse width modulation control.

[0140] The special pulse width modulation control is performed in the high speed region VRH, as described with reference to Table 1, Table 2, and the like. In the high speed region VRH, the first inverter 11 is driven by rectangular wave control, and the second inverter 12 is driven by special pulse width modulation control. Hereinafter, advantages of a case where the second inverter 12 is driven by special pulse width modulation control in comparison with a case where the second inverter 12 is driven by ordinary pulse width modulation in a state where the first inverter 11 is driven by rectangular wave control are described. Also, as described with reference to Fig. 19 the carrier frequency F CA Advantages of making the carrier frequency F

[0141] Hereinafter, the results of the speed sweep experiment, the speed sweep simulation are described with reference to the waveform diagrams of Fig. 20-29 Fig. 20-29 The results of the speed sweep experiment, the speed sweep simulation are shown.

[0142] Fig. 20 and Fig. 21 ​The waveform chart shows the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) together with the 3-phase currents in the case where the rectangular wave control (1-Pulse) and the usual continuous pulse width modulation control (CPWM) are combined in the first high speed region VRH1. Fig. 22 and Fig. 23 The waveform chart shows the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) together with the 3-phase currents in the case where the rectangular wave control (1-Pulse) and the usual continuous pulse width modulation control (CPWM) are combined in the first high speed region VRH1 of the middle-high speed and in the case where the rectangular wave control (1-Pulse) and the usual discontinuous pulse width modulation control (DPWM) are combined in the second high speed region VRH2. That is, Fig. 20 and Fig. 21 The waveform chart shows the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) together with the 3-phase currents in the case where the rectangular wave control (1-Pulse) and the usual continuous pulse width modulation control (CPWM) are combined in the first high speed region VRH1 of the middle-high speed and in the case where the rectangular wave control (1-Pulse) and the usual discontinuous pulse width modulation control (DPWM) are combined in the second high speed region VRH2. That is, Fig. 22 and Fig. 23 The waveform chart shows the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) together with the 3-phase currents in the case where the rotational motor 80 speed rises with the passage of time, shifts from the first high speed region VRH1 to the second high speed region VRH2, and switches the control mode of the inverter 10. Fig. 26-29 Also the same). As shown in Fig. 20-23 , pulsation of the frequency "6f" of 6 times the motor electric frequency f (the electric frequency of the rotational motor 80) appears in either one of the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys).

[0143] Here, in order to improve the pulsation of the "6f", the second inverter 12 is controlled by the special continuous pulse width modulation control (SP-CPWM) in the first high speed region VRH1 and by the special discontinuous pulse width modulation control (SP-DPWM) in the second high speed region VRH2. Fig. 24-27 The waveform chart shows the case.

[0144] Fig. 24 and Fig. 25 The waveform chart corresponds to the waveform chart of Fig. 20 and Fig. 21 At the same torque and the same speed as Fig. 20 and Fig. 21 , the waveform chart shows the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) together with the 3-phase currents in the case where the rectangular wave control (1-Pulse) and the usual continuous pulse width modulation control (CPWM) are combined in the first high speed region VRH1 of the middle-high speed and in the case where the rectangular wave control (1-Pulse) and the usual discontinuous pulse width modulation control (DPWM) are combined in the second high speed region VRH2. Fig. 20 and Fig. 21 The case where the usual continuous pulse width modulation control (CPWM) is executed is exemplified, and in contrast to this, the case where the special continuous pulse width modulation control (SP-CPWM) is executed is exemplified in Fig. 24 and Fig. 25 Likewise, Fig. 26 and Fig. 27 The waveform chart corresponds to the waveform chart of Fig. 22 andFig. 23 corresponding to the waveform chart of FIG. 6, and Fig. 22 Fig. 23 at the same torque and the same rotational speed, Fig. 22 Fig. 23 the case where the special pulse width modulation control (SP-CPWM, SP-DPWM) is executed is exemplified in Fig. 24 Fig. 25

[0145] Specifically, Fig. 24 Fig. 25 the waveform chart of FIG. 6 shows the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) together with the 3-phase currents in the case where the rectangular wave control (1-Pulse) and the special continuous pulse width modulation control (SP-CPWM) are combined in the first high speed region VRH1. Fig. 26 Fig. 27 the waveform chart of FIG. 6 shows the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) together with the 3-phase currents in the case where the rectangular wave control (1-Pulse) and the special continuous pulse width modulation control (SP-CPWM) are combined in the first high speed region VRH1. Fig. 24 Fig. 25

[0146] Comparing Fig. 20-21 Fig. 24-25 it is found that either one of the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) can reduce the pulsation of the frequency "6f" which is 6 times the motor electrical frequency f, and thus can improve the pulsation. However, comparing Fig. 22-23 Fig. 26-27 it is found that in either one of the dq-axis currents (Id, Iq) and the actual modulation ratio (Mi_sys) a pulsation of the frequency "2f" which is 2 times the motor electrical frequency f newly appears. That is, in the relatively low speed side in the high speed region VRH, although the improvement of the reduction of the pulsation of "6f" is achieved by combining the rectangular wave control and the special pulse width modulation control, in the relatively high speed side in the high speed region VRH, even if the pulsation of "6f" is reduced, a new problem of generating the pulsation of "2f" occurs.

[0147] As Fig. 10 Fig. 14 ​​​​​​​​​​​As shown, the pulsation of "2f" is attributed to the abrupt changes in the voltage command (V**) of the special pulse width modulation control in phases with electrical angles of π (180 degrees) and 2π (360 degrees) (the phases of the voltage command inflection point). That is, in phases with electrical angles of π and 2π, the increase or decrease in the voltage command (V**) is much larger than in typical pulse width modulation control. Therefore, even with a carrier frequency F having sufficient resolution in typical pulse width modulation control... CA However, in special pulse width modulation control, the resolution is insufficient, and there are cases where the pulses for the switching control signal cannot be generated appropriately. Therefore, as referenced... Fig. 19 As mentioned above, increasing the carrier frequency F CA This increases the resolution of the modulation. Fig. 28-29 It shows relative to Fig. 26-27 Carrier frequency F CA Waveform diagram when set to 2x.

[0148] Fig. 28 as well as Fig. 29 waveform diagram and Fig. 26 as well as Fig. 27 Corresponding to the waveform diagram, in the context of Fig. 26 as well as Fig. 27 At the same torque and the same speed, Fig. 26 as well as Fig. 27 An example is shown where the operation is performed at the same carrier frequency F as usual. CA In the case of special pulse width modulation control (SP-CPWM, SP-DPWM) that performs modulation, in contrast, Fig. 28 as well as Fig. 29 The example illustrates execution at twice the usual carrier frequency F. CA This refers to the case of special pulse width modulation control (SP-CPWM, SP-DPWM) used for modulation. Specifically, Fig. 28 as well as Fig. 29 The waveform will be in conjunction with Fig. 26 as well as Fig. 27 The carrier frequency F in the first high-speed region VRH1 with the same speed CA Raise to Fig. 26 as well as Fig. 27 carrier frequency F CA The case of combining rectangular wave control (1-Pulse) and special continuous pulse width modulation control (SP-CPWM) at twice the speed, and the carrier frequency F in the second high-speed region VRH2. CA Raise to Fig. 26 as well as Fig. 27 carrier frequency F CAThe dq-axis currents (Id, Iq) and actual modulation rate (Mi_sys) are shown together with the 3-phase currents in the case of a combination of rectangular wave control (1-Pulse) and special discontinuous pulse width modulation control (SP-DPWM), which is twice the value of the combined rectangular wave control (1-Pulse) and special discontinuous pulse width modulation control (SP-DPWM).

[0149] Compare Fig. 26-27 and Fig. 28-29 It is known that either the dq axis current (Id, Iq) or the actual modulation rate (Mi_sys) can reduce the ripple of the frequency "2f", which is twice the electric motor frequency f, thereby improving the ripple. That is, it is known that in the high-speed region VRH, it is preferable to perform special pulse width modulation control by using a modulation frequency that is higher than the modulation frequency in the pulse width modulation control performed in the low-speed region VRL.

[0150] In this embodiment, special pulse width modulation control is performed on the second inverter 12. As described above, compared with the first switching element 31 constituting the first inverter 11, the second switching element 32 constituting the second inverter 12 is a component with less switching loss. Therefore, even if the carrier frequency F is... CA Increasing the switching loss can also suppress the increase in switching losses. That is, if a switching element 3 with a smaller switching loss than the switching element 3 of one of the two inverters 10 is used to construct another inverter 10, then special pulse width modulation control can be easily applied as a control method, which can suppress the increase in switching losses and easily improve the overall efficiency of the system.

[0151] Of course, the carrier frequency F under normal pulse width modulation control... CA In cases with high frequencies where special pulse width modulation control can be appropriately performed even at phase inflection points of π and 2π, it is not necessary to increase the carrier frequency F again when performing special pulse width modulation control. CA Therefore, as Fig. 1 As shown, when applying special pulse width modulation control, the switching element 3 constituting one inverter 10 does not necessarily have to be an element with lower switching losses than the switching element 3 constituting another inverter 10. For example... Fig. 36 or Fig. 37 As illustrated, this does not prevent the inverters 10 of both sides from being constructed using the same physical properties of the switching element 3.

[0152] Fig. 30The waveform chart of FIG. 6 illustrates an example of the first U-phase voltage command Vu1**, the second U-phase voltage command Vu2**, the carrier wave CA, the first U-phase upper arm switch control signal Su1+, and the second U-phase upper arm switch control signal Su2+ in the ultra-high speed region VRSH. As described above, in the ultra-high speed region VRSH, both the first inverter 11 and the second inverter 12 are controlled by the rectangular wave control. In addition, in the case where the inverter 10 is controlled by the rectangular wave control, although the carrier wave CA is not required, the carrier wave CA is also illustrated for the sake of easy comparison with other control modes.

[0153] Fig. 31 The waveform chart of FIG. 7 illustrates an example of the first U-phase voltage command Vu1** of the first inverter 11, the second U-phase voltage command Vu2** of the second inverter 12, the carrier wave CA, the first U-phase upper arm switch control signal Su1+, and the second U-phase upper arm switch control signal Su2+ in the first low speed region VRL1. In the first low speed region VRL1, the second inverter 12 is controlled by the continuous pulse width modulation control. As shown in FIG. 7, based on the carrier wave CA and the second U-phase voltage command Vu2**, the second U-phase upper arm switch control signal Su2+ is generated in a pulse shape. Fig. 31

[0154] Since the first inverter 11 is controlled by the active short control, the first U-phase voltage command Vu1** is fixed to "0", for example, and the first U-phase upper arm switch control signal Su1+ is always "0". Although not illustrated, the first U-phase lower arm switch control signal Su1- is always "1". Thereby, the upper arm switch element 3H (31H) of the U-phase arm 3A of the first inverter 11 is controlled to the off state, and the lower arm switch element 3L (31L) is controlled to the on state. The same applies to the V-phase and the W-phase, whereby the first inverter 11 is controlled by the lower arm active short control. In addition, it is also possible to not set the first U-phase voltage command Vu1** and to set the first U-phase switch control signal Su1 to a fixed value.

[0155] Fig. 32 ​The waveform chart illustrates an example of the first U-phase voltage command Vu1**, the second U-phase voltage command Vu2**, the carrier wave CA, the first U-phase upper-side switch control signal Su1+, and the second U-phase upper-side switch control signal Su2+ in the second low-speed region VRL2. As with the first low-speed region VRL1, in the second low-speed region VRL2, the first inverter 11 is controlled by the active short-circuit control, and thus the first U-phase voltage command Vu1** is a fixed value. In the second low-speed region VRL2, the second inverter 12 is controlled by the discontinuous pulse width modulation control. In the region where the second U-phase voltage command Vu2** becomes "0" or "1", the first U-phase upper-side switch control signal Su1+ is a fixed value, and the switching element 3 (in this case, the second switching element 32) is fixed to the on state or the off state.

[0156] Fig. 33 The waveform chart illustrates an example of the first U-phase voltage command Vu1**, the second U-phase voltage command Vu2**, the carrier wave CA, the first U-phase upper-side switch control signal Su1+, and the second U-phase upper-side switch control signal Su2+ in the intermediate-speed region VRM. As described above, in the third speed region VR3, both the first inverter 11 and the second inverter 12 are controlled by the discontinuous pulse width modulation control.

[0157] However, as shown in Table 3 described below, in the intermediate-speed region VRM, the rotary electric machine control device 1 can control both the first inverter 11 and the second inverter 12 by the mixed pulse width modulation control (MX-PWM) instead of the discontinuous pulse width modulation control. The mixed pulse width modulation control is one of the control modes of the inverter 10, which is a control mode that outputs a plurality of pulses of different patterns in 1 / 2 of the electrical angle period, i.e., the first period T1 (refer to Fig. 33 , Fig. 34 ) and continues the non-active state in the remaining 1 / 2 of the electrical angle period, i.e., the second period T2 (refer to Fig. 33 , Fig. 34 ).

[0158] [Table 3]

[0159]

[0160] In the mixed pulse width modulation control, since the switching control signal is in the non-active state in the second period T2, the loss of the inverter 10 is reduced, and the harmonic current due to the switching operation is also reduced, and the loss (iron loss) of the rotary electric machine 80 is also reduced. That is, by executing the mixed pulse width modulation control, it is possible to reduce the system loss.

[0161] In Fig. 34An example of the carrier CA of the first inverter 11, that is, the first carrier CA1, the carrier CA of the second inverter 12, that is, the second carrier CA2, the common U-phase voltage command Vu**, the first U-phase upper-side switch control signal Su1+, and the second U-phase upper-side switch control signal Su2+ is shown in FIG. 1. Here, although an example in which the voltage command of the continuous pulse width modulation (space vector pulse width modulation) as illustrated is used as the common U-phase voltage command Vu**, the voltage command of the discontinuous pulse width modulation as illustrated can be used as the common U-phase voltage command Vu**. Fig. 31 Fig. 32 Fig. 33 The voltage command of the discontinuous pulse width modulation as illustrated can be used as the common U-phase voltage command Vu**. In the case where the voltage command of the continuous pulse width modulation (CPWM) is used, the mixed pulse width modulation control (MX-PWM) can be referred to as mixed continuous pulse width modulation control (MX-CPWM), and in the case where the voltage command of the discontinuous pulse width modulation (DPWM) is used, the mixed pulse width modulation control (MX-PWM) can be referred to as mixed discontinuous pulse width modulation control (MX-DPWM). Here, the mixed continuous pulse width modulation control (MX-CPWM) is exemplarily described.

[0162] 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 (the first carrier CA1 and the second carrier VA2) with the voltage command (V**), the switch control signal becomes "1" when the voltage command is equal to or higher than the carrier CA, and the switch control signal becomes "0" when the voltage command is lower than the carrier CA.

[0163] As shown in FIG. 1, the amplitudes of the first carrier CA1 and the second carrier CA2 are half of the amplitude allowed for the voltage command (V**). In the usual pulse width modulation (refer to, for example, FIG. 2), the amplitude of the carrier CA is equal to the amplitude allowed for the voltage command, and the carrier CA in the mixed pulse width modulation can be referred to as a half carrier. By using such a half carrier, in the first period T1 of 1 / 2 of the electrical angle, different output patterns of pulses are output as the switch control signal because the half carrier crosses the voltage command (V**). In the second period T2 of the remaining 1 / 2 of the electrical angle, the switch control signal is output in a continuous non-active state because the half carrier does not cross the voltage command (V**). Fig. 34 Fig. 33

[0164] ​​​​In addition, although omitted from the illustration and the like, there are cases where, according to the waveform of the voltage command, a pulse that becomes active even in the second period T2 is output as the switching control signal. For example, in the case of a voltage command (V**) using discontinuous pulse width modulation, there are cases where, near the center of the amplitude of the voltage command (V**) (near the inflection point of the voltage command (V**)), a pulse that becomes active is output even in the second period T2. However, in addition to near the center of the amplitude of the voltage command (V**), a non-active state continues in the second period T2. In addition, if the second period T2 is set only as a period in which the switching control signal is in a non-active state (a period of less than 1 / 2 of a cycle), and a period other than the second period T2 (a period of 1 / 2 of a cycle or more) is set in one cycle, it is also possible to define hybrid pulse width modulation as follows. Hybrid pulse width modulation control can also be controlled to output a plurality of pulses that differ in pattern in a first period T1 of 1 / 2 of an electrical angle or more, and continue a non-active state in a remaining second period T2 of 1 cycle of an electrical angle.

[0165] Fig. 35 An example of a method of hybrid pulse width modulation control (hybrid continuous pulse width modulation control) that is different from the above is illustrated. Fig. 34 The generated switching control signals are the same. An example of a first carrier CA of the first inverter 11, that is, a first carrier CA1, a carrier CA of the second inverter 12, that is, a second carrier CA2, a U-phase voltage command of the first inverter 11, that is, a first U-phase voltage command Vu1**, a U-phase voltage command of the second inverter 12, that is, a second U-phase voltage command Vu2**, a first U-phase upper side switching control signal Su1+, and a second U-phase upper side switching control signal Su2+ is shown in Fig. 35 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 phases of the first carrier CA1 and the second carrier CA2 differ by 180 degrees (π). In addition, the phases of the first U-phase voltage command Vu1** and the second U-phase voltage command Vu2** also differ by 180 degrees (π).

[0166] As shown in Fig. 35 The amplitudes of the first carrier CA1 and the second carrier CA2 are half of the amplitudes allowed by the voltage command (V**). Therefore, Fig. 35The carrier wave CA in the illustrated manner is also a half carrier wave. By using such a half carrier wave, in the first period Tl of 1 / 2 cycle (or more) of an electrical angle, since such a half carrier wave crosses the voltage command (V**), a plurality of pulses of different patterns are output as the switching control signal. In the second period T2 of the remaining period in one cycle, since the half carrier wave does not cross the voltage command (V**), the switching control signal is output in a continuous non-active state.

[0167] Fig. 34 The illustrated manner is a manner of modulation using two half carrier waves and the voltage command (V**) as one common reference, and can be referred to as a double half carrier / single reference manner. On the other hand, Fig. 35 The illustrated manner is a manner of modulation using two half carrier waves and two voltage commands (V**), and can be referred to as a double half carrier / double reference manner.

[0168] As Fig. 8-9 , Fig. 30 , Fig. 33-35 illustrated, in a case where both the first inverter 11 and the second inverter 12 are subjected to switching control, the first U-phase voltage command Vu1** and the second U-phase voltage command Vu2** are substantially different in phase by 180 degrees. For example, the maximum amplitude of the U-phase voltage is "(4 / 3)E", and the maximum amplitude of the line voltage is "2E" (also refer to the vector diagram of FIG. 6 and FIG. 7). In addition, the first DC power supply 61 and the second DC power supply 62 are independent of each other, and the first DC voltage E1 of the first DC power supply 61 and the second DC voltage E2 of the second DC power supply 62 can also be different values. For example, the maximum amplitude of the U-phase voltage is accurately "(2 / 3)E1) + (2 / 3)E2", but in order to facilitate understanding, in the present specification, it is set to "E1 = E2 = E". Fig. 3 and Fig. 4 the vector diagram). In addition, the first DC power supply 61 and the second DC power supply 62 are independent of each other, and the first DC voltage E1 of the first DC power supply 61 and the second DC voltage E2 of the second DC power supply 62 can also be different values. For example, the maximum amplitude of the U-phase voltage is accurately "(2 / 3)E1) + (2 / 3)E2", but in order to facilitate understanding, in the present specification, it is set to "E1 = E2 = E".

[0169] As described above, in a region where the modulation rate and the rotational speed are relatively low and the electric power is relatively low, that is, a low speed region VRL, all of the electric power is supplied from one inverter 10. At this time, the voltage command (V**) is provided to one inverter 10 to perform active short-circuit control, and a normal voltage command (V**) is provided to the other inverter 10. In a region where the modulation rate and the rotational speed are higher than the low speed region VRL and the electric power is higher than the low speed region VRL, that is, an intermediate speed region VRM, a high speed region VRH, and a super high speed region VRSH, equal electric power is supplied from both inverters 10. At this time, the same voltage command (V**) is provided to both inverters 10, which are different in phase by 180 degrees (π).

[0170] However, in a case where the inverter 10 is subjected to switching control, there is a case where a pulsation component overlapping with a fundamental wave of the alternating current generates a noise in an audible frequency band. In a case where two inverters 10 are controlled in different control modes, respectively, pulsations corresponding to the respective control modes are generated, and thus a noise in the audible frequency band can increase. Especially in a case where the rotational speed of the rotating electric machine 80 is low, the frequency of the pulsation component (or a sideband frequency thereof) is highly likely to be included in the audible frequency band. The control mode of the rotating electric machine 80, that is, the control mode of the inverter 10 is preferably appropriately set in accordance with an operation condition so as to be able to achieve both of an operation at a high system efficiency and a reduction in an audible noise.

[0171] For example, the rotating electric machine control device 1 is able to switch a loss reduction priority mode and a noise reduction priority mode as the control mode of the rotating electric machine 80. For example, the rotating electric machine control device 1 controls both of the first inverter 11 and the second inverter 12 in the noise reduction priority mode in the low speed region VRL by pulse width modulation. In addition, the rotating electric machine control device 1 can control both of the first inverter 11 and the second inverter 12 in the noise reduction priority mode by continuous pulse width modulation control in the first low speed region VRL1 and by discontinuous pulse width modulation control in the second low speed region VRL2.

[0172] In the loss reduction priority mode, since only one inverter 10 is driven in the low speed region VRL in which the rotational speed of the rotating electric machine 80 is relatively low, a noise in a different frequency band is not generated in the two inverters 10. However, since the output of the driven one inverter 10 becomes large, the energy of the noise becomes high. In addition, in the low speed region VRL, a sound (a running sound such as a contact sound of a tire with a road surface) accompanying running of the vehicle is also small, and thus in a case where the noise output from the driven one inverter 10 is a noise in the audible frequency band, there is a possibility that the user easily hears the noise.

[0173] For example, at the time of start of the vehicle or at the time of deceleration stop, the noise reduction priority mode is selected in consideration of the fact that the user easily hears a noise in the audible frequency band, and at the time of stable running in which the vehicle is stably running, the loss reduction priority mode is preferably selected. In addition, these modes can also be selected by an operation of the user (setting of a switch (including input from a touch panel and the like)).

[0174] In the noise reduction priority mode, the first inverter 11 and the second inverter 12 are controlled in the same control manner in a low speed region VRL in which the rotational speed of the rotary electric machine 80 is relatively low. In addition, the phases of the currents of the two inverters 10 that flow the currents in the stator coil 8 are made to differ by substantially 180 degrees. In the case where the two inverters 10 are controlled in the same control manner, the phases of the currents including the pulsation components differ by substantially 180 degrees. Therefore, at least a part of the pulsation components can be canceled out by each other, and the noise in the audible frequency band can be reduced.

[0175] Fig. 38 As a comparative example, an example of the control region of the rotary electric machine in a single inverter system in which the 3-phase stator coil 8 is connected through the neutral point is shown. As shown in Table 4 described below, the inverter is controlled by the continuous pulse width modulation control in the first region VR11, by the discontinuous pulse width modulation control in the second region VR13, and by the rectangular wave control in the third region VR14, for example.

[0176] [Table 4]

[0177] R Mi_sys INV1 Mi_inv VR11 M < Y, where Y > X CPWM M < Y, where Y > X VR13 Y < M < 0.78 DPWM Y < M < 0.78 VR14 M＝0.78 1-Pulse M＝0.78

[0178] Here, the modulation rate "Y" is a value larger than the modulation rate "X" exemplified in Tables 2 and 3, which is set to around 0.5 to 0.6, for example, in consideration of the theoretical upper limit value (substantially 0.707) of the modulation rate based on the continuous pulse width modulation (space vector pulse width modulation) and further the dead time.

[0179] As described above, in the present embodiment, the intermediate speed region VRM is set on the low speed side of the region corresponding to the second region VR13 and the high speed region VRH is set on the high speed side, and thus the characteristic special pulse width modulation control is executed. By the special pulse width modulation control, the loss of the inverter 10 is reduced in the operation region in which high output is required, and the harmonic current due to the switching operation is also reduced, and thus the loss (iron loss) of the rotary electric machine 80 is also reduced. That is, by executing the special pulse width modulation control, the system loss can be reduced. In addition, by setting the low speed region VRL in the region corresponding to the first region VR11, the system loss can be reduced even in the operation region in which low output is required. In addition, as described above, in the low speed region VR1, the loss reduction priority mode and the noise reduction priority mode can also be switched as appropriate. In the loss reduction priority mode, the loss of the entire system can be reduced, and in the noise reduction priority mode, the loss can be reduced and the noise can be reduced.

[0180] Hereinafter, a summary of the rotary electric machine control device (1) described above will be briefly described.

[0181] A rotating electric machine control device (1) drives and controls a rotating electric machine (80) having a plurality of mutually independent open-circuit windings (8) by a first inverter (11) connected to one end side of the plurality of open-circuit windings (8) and converting electric power between direct current and multiphase alternating current, and a second inverter (12) connected to the other end side of the plurality of open-circuit windings (8) and converting electric power between direct current and multiphase alternating current, the first inverter (11) and the second inverter (12) each being controllable by a plurality of control modes different in switching pattern, and being controllable in mutually independent control modes including pulse width modulation control outputting a plurality of pulses different in pattern in one cycle of electric angle, and rectangular wave control outputting one pulse in one cycle of electric angle, the rotating electric machine control device performing control of one inverter (10) of the first inverter (11) and the second inverter (12) by the rectangular wave control, and control of the other inverter (10) by special pulse width modulation control as one of the pulse width modulation control, the special pulse width modulation control being the control mode based on a switching pattern that is a difference between a switching pattern of the pulse width modulation control in a case where the open-circuit windings (8) generate a target voltage and a switching pattern of the rectangular wave control.

[0182] According to this structure, by performing rectangular wave control on one inverter (10) of the two inverters (10), the number of switching operations of the one inverter (10) can be reduced, and thus switching loss can be reduced. In addition, the other inverter (10) on the side on which rectangular wave control is not performed is controlled by special pulse width modulation control. In the special pulse width modulation control, the other inverter (10) is controlled by a switching pattern that is a difference between a switching pattern of pulse width modulation control in a case where the open-circuit windings (8) generate a target voltage and a switching pattern of the rectangular wave control. Thus, even if one inverter (10) is controlled by rectangular wave control, the rotating electric machine (80) can be smoothly driven in cooperation with pulse width modulation control of the other inverter. In general, in a relatively high-rotation operation region in which rectangular wave control is applied, system loss can be reduced, and the rotating electric machine (80) can be smoothly controlled. That is, according to this structure, the two inverters each provided at both ends of the open-circuit windings can be appropriately controlled.

[0183] Here, it is preferable to set a voltage command that generates a switching pattern of one of the inverters (10) controlled by the rectangular wave control to a rectangular wave voltage command in a case where the open circuit winding (8) generates a target voltage, set a voltage command that is 180 degrees out of phase with the rectangular wave voltage command and generates a switching pattern of the other of the inverters (10) controlled by the pulse width modulation control to a pulse width modulation voltage command in a case where the target voltage is generated, set a difference between the rectangular wave voltage command and the pulse width modulation voltage command to a voltage command of both of the inverters (10) as a whole, that is, a system voltage command, and set a difference between the system voltage command in a state where the center of the amplitude is made uniform and the rectangular wave voltage command to a special pulse width modulation voltage command, and the special pulse width modulation control is the control mode that generates a switching pattern based on the special pulse width modulation voltage command.

[0184] According to the present structure, in a case where the rotary electric machine (80) is smoothly driven by combining the rectangular wave control and the pulse width modulation control, it is possible to optimize the voltage command in the pulse width modulation control. According to experiments and simulations by the inventor, it is possible to confirm that, in a case where the rectangular wave control and the pulse width modulation control are simply combined, pulsation occurs in the current flowing through the open circuit winding (8) and the like. However, it is possible to confirm that, according to the special pulse width modulation control, such pulsation can be suppressed. In the special pulse width modulation control, the voltage command for generating a switching pattern is set to a difference from the rectangular wave voltage command for the rectangular wave control, based on the voltage command of the entire case where the rectangular wave control and the pulse width modulation control are combined, that is, the system voltage command. Therefore, as in the case where the rectangular wave control and the pulse width modulation control are combined, it is possible to cause the open circuit winding to generate a target voltage, and it is also possible to reduce the pulsation described above.

[0185] In addition, it is preferable that, as the control region (R) of the rotary electric machine (80), a low speed region (VRL) and a high speed region (VRH) in which the rotational speed of the rotary electric machine (80) is higher than the low speed region (VRL) at the same torque (T) are set, and the object control is executed by the rotary electric machine control device (1) in the high speed region (VRH).

[0186] Generally, in such a high speed region (VRH), the inverter (10) is controlled by a control mode of pulse width modulation using a modulation method with a high modulation rate. In the object control, since one of the two inverters (10) is subjected to the rectangular wave control, it is possible to reduce the switching loss of the one inverter (10). According to the present structure, it is possible to improve the system efficiency in the high speed region (VRH) in which a relatively high output is required for the inverter (10).

[0187] Further, preferably, in the first inverter (11) and the second inverter (12), the AC 1-phase arm (3A) is composed of a series circuit of an upper side switching element (3H) and a lower side switching element (3L), in the pulse width modulation control, as the control mode, a continuous pulse width modulation control is included, and the pulse width modulation is continuously performed on all of the arms (3A) of the multiphase; and a discontinuous pulse width modulation control is included, and the pulse width modulation is performed on a part of the arms (3A) of the multiphase, including a period in which the switching element (3) is fixed to an on state or an off state, a first high speed region (VRH1) and a second high speed region (VRH2) in which the rotational speed of the rotating electric machine (80) is higher than the first high speed region (VRH1) at the same torque (T) are set in the high speed region (VRH), in the first high speed region (VRH1), as the target control, the rotating electric machine control device (1) performs a first target control in which one of the first inverter (11) and the second inverter (12) is controlled by the rectangular wave control, and the other is controlled by the special pulse width modulation control based on the continuous pulse width modulation control, i.e., special continuous pulse width modulation, in the second high speed region (VRH2), as the target control, the rotating electric machine control device (1) performs a second target control in which one of the first inverter (11) and the second inverter (12) is controlled by the rectangular wave control, and the other is controlled by the special pulse width modulation control based on the discontinuous pulse width modulation control, i.e., special discontinuous pulse width modulation.

[0188] The maximum modulation rate of the discontinuous pulse width modulation control is greater than the maximum modulation rate of the continuous pulse width modulation control. The second high speed region (VRH2) is a control region (R) in which the rotational speed of the rotating electric machine (80) is higher than the first high speed region (VRH1) at the same torque (T), from the viewpoint of system efficiency, it is preferable to modulate at a higher modulation rate than the modulation rate of the first high speed region (VRH1) in the second high speed region (VRH2). By performing the special continuous pulse width modulation control based on the continuous pulse width modulation in the first high speed region (VRH1), and performing the special discontinuous pulse width modulation control based on the discontinuous pulse width modulation in the second high speed region (VRH2), the rotating electric machine (80) can be appropriately driven in the entire high speed region (VRH).

[0189] Further, preferably, as the control region (R) of the rotary electric machine (80), a low-speed region (VRL) and a high-speed region (VRH) in which the rotational speed of the rotary electric machine (80) is higher than in the low-speed region (VRL) at the same torque (T) are set, and the rotary electric machine control device (1) controls both the first inverter (11) and the second inverter (12) by the rectangular wave control in the high-speed region (VRH). CA ) higher than the modulation frequency (F CA ) in the pulse width modulation control.

[0190] According to the inventor's research, it was found that the voltage command in the special pulse width modulation control has a large inflection point in which the value of the voltage command sharply increases or decreases in each half cycle of the electrical angle. Also, according to the inventor's experiments and simulations, it was confirmed that a pulsation occurs in the current flowing through the open-circuit winding (8) or the like in the phase near the inflection point. This is because the modulation frequency (F CA ) does not have resolution that can cope with the value of the voltage command sharply increasing or decreasing in the phase near the inflection point. According to the present structure, the special pulse width modulation control is performed by the modulation frequency (F CA ) higher than the modulation frequency (F CA ) in the pulse width modulation control. Therefore, the modulation frequency (F CA ) can cope with the value of the voltage command sharply increasing or decreasing in the phase near the inflection point, and thus the above-described pulsation can be reduced.

[0191] Further, preferably, a super-high-speed region (VRSH) in which the rotational speed of the rotary electric machine (80) is higher than in the high-speed region (VRH) at the same torque (T) is further set, and in the super-high-speed region, the rotary electric machine control device (1) controls both the first inverter (11) and the second inverter (12) by the rectangular wave control.

[0192] In the high-speed region (VRH), one inverter (10) is controlled by the rectangular wave control, and the other inverter (10) is controlled by the special pulse width modulation. By changing the control mode of the other inverter (10) to the rectangular wave control, it is possible to smoothly change the control mode from the target control in the high-speed region (VRH) to the rectangular wave control in the super-high-speed region (VRSH). That is, according to the present structure, it is possible to appropriately drive the rotary electric machine 80 in the high-speed region VRH and the super-high-speed region VRSH.

[0193] Further, preferably, in the first inverter (11) and the second inverter (12), the AC 1-phase arm (3A) is composed of a series circuit of an upper side switching element (3H) and a lower side switching element (3L), respectively, and the control mode further includes: active short-circuit control that sets the upper side switching element (3H) of all the arms (3A) of the multiphase to an on state or sets the lower side switching element (3L) of all the arms (3A) of the multiphase to an on state, in the low speed region (VRL), the rotating electric machine control device (1) executes the object low speed region control that controls one of the first inverter (10) and the second inverter (12) by the active short-circuit control and controls the other of the inverters (10) by the pulse width modulation control.

[0194] By executing the object low speed region control, the rotating electric machine (80) is substantially driven by only one of the two inverters (10). Since one inverter (10) does not perform a switching operation, it is possible to suppress the loss of the entire system while driving the rotating electric machine (80).

[0195] Further, preferably, in the first inverter (11) and the second inverter (12), the AC 1-phase arm (3A) is composed of a series circuit of an upper side switching element (3H) and a lower side switching element (3L), in the pulse width modulation control, as the control mode, a continuous pulse width modulation control is included, and the pulse width modulation is continuously performed on all of the arms (3A) of the multiphase; and a discontinuous pulse width modulation control is included, and the pulse width modulation is performed on a part of the arms (3A) of the multiphase, including a period in which the switching element (3) is fixed to an on state or an off state, in the low speed region (VRL), a first low speed region (VRL1) and a second low speed region (VRL2) in which the rotational speed of the rotating electric machine (80) is higher than the first low speed region (VRL1) at the same torque (T) are set, in the first low speed region (VRL1), the rotating electric machine control device (1) performs a first target low speed region control as the target low speed region control, in which one of the first inverter (11) and the second inverter (12) is controlled by the active short-circuit control, and the other is controlled by the continuous pulse width modulation control, in the second low speed region (VRL2), the rotating electric machine control device (1) performs a second target low speed region control as the target low speed region control, in which one of the first inverter (11) and the second inverter (12) is controlled by the active short-circuit control, and the other is controlled by the discontinuous pulse width modulation control.

[0196] The maximum modulation rate of the discontinuous pulse width modulation control is greater than the maximum modulation rate of the continuous pulse width modulation control. The second low speed region (VRL2) is a control region (R) in which the rotational speed of the rotating electric machine (80) is higher than the first low speed region (VRL1) at the same torque (T), and from the viewpoint of system efficiency, it is preferable that the modulation be performed at a higher modulation rate than the modulation rate of the first low speed region (VRL1) in the second low speed region (VRL2). By performing the first target low speed region control using the continuous pulse width modulation control in the first low speed region (VRL1), and performing the second target low speed region control using the discontinuous pulse width modulation in the second low speed region (VRL2), the rotating electric machine (80) can be appropriately driven in the entire low speed region (VRL).

[0197] Further, preferably, the rotating electric machine control device (1) alternately switches the control mode of the first inverter (11) and the control mode of the second inverter (12) according to a predetermined condition in a case where the subject low speed region control of controlling one of the first inverter (10) and the second inverter (12) by the active short-circuit control and the other of the inverters (10) by the pulse width modulation control is executed in the low speed region (VRL).

[0198] By switching the control mode, it is possible to suppress the case where only one of the first inverter (11) and the second inverter (12) is consumed. Further, in a case where the first inverter (11) and the second inverter (12) are connected to the respective independent direct current power supplies (6), it is possible to suppress the case where the power consumption of only one of the direct current power supply (61) connected to the first inverter (11) and the direct current power supply (62) connected to the second inverter (12) is increased. Here, the predetermined condition preferably means, for example, a fixed time or the power consumption of the direct current power supply (6).

[0199] Further, preferably, in the first inverter (11) and the second inverter (12), the arm (3A) of the alternating current 1 phase is respectively composed of a series circuit of the upper side switching element (3H) and the lower side switching element (3L), and in the pulse width modulation control, as the control mode, the discontinuous pulse width modulation control is included which performs the pulse width modulation including a period in which the switching element (3) is fixed to the on state or the off state with respect to a part of the arms (3A) of the multiphase, and as the control region (R), an intermediate speed region (VRM) is further provided in which the rotational speed of the rotating electric machine (80) is higher than the low speed region (VRL) and lower than the high speed region (VRH) at the same torque (T), and in the intermediate speed region (VRM), the rotating electric machine control device (1) controls both of the first inverter (11) and the second inverter (12) by the discontinuous pulse width modulation control.

[0200] According to this structure, in the control region (R) between the low speed region (VRL) controlled by the low speed subject control using the active short-circuit control and the pulse width modulation control and the high speed region (VRH) controlled by the subject control using the rectangular wave control and the special pulse width modulation control, both of the inverters (10) are controlled by the discontinuous pulse width modulation control. Thereby, it is possible to smoothly drive the rotating electric machine (80) in a wide control region from the low speed region (VRL) through the intermediate speed region (VRM) to the high speed region (VRH).

[0201] Further preferably, the control mode includes a hybrid pulse width modulation control that controls to output a plurality of pulses different in pattern in 1 / 2 cycle of an electrical angle, i.e., a first period (T1), and to continue a non-active state in the remaining 1 / 2 cycle, i.e., a second period (T2), and the rotating electric machine control device (1) controls both the first inverter (11) and the second inverter (12) in the intermediate speed region (VRM) by the hybrid pulse width modulation control instead of the discontinuous pulse width modulation control.

[0202] The hybrid pulse width modulation control is a control mode that combines a period in which pulse width modulation is performed and a period in which no modulation (fixed state) is performed approximately for each half cycle within one cycle of an electrical angle. That is, since the inverter (10) does not perform a switching operation for approximately 1 / 2 of the drive time, it is possible to reduce switching loss, thereby reducing system loss.

[0203] Further preferably, a boundary of each of the control regions (R) is set in accordance with at least one of a rotational speed of the rotating electric machine (80) corresponding to a torque of the rotating electric machine (80) and a ratio of a line voltage of a multiphase alternating voltage to a direct current voltage.

[0204] An operating condition of the rotating electric machine (80) is generally defined by a relationship between a rotational speed and a torque. If the rotating electric machine control device (1) changes the control mode of controlling the first inverter (11) and the second inverter (12) based on the rotational speed as one parameter, it is possible to drive and control the rotating electric machine (80) with high efficiency in accordance with the operating condition of the rotating electric machine (80). Further, for example, in a case where the rotating electric machine (80) requires high output (fast rotational speed, high torque), in a voltage type inverter, the requirement is achieved by making the direct current voltage higher or making a ratio of the direct current voltage to alternating current voltage higher. In a case where the direct current voltage is constant, the requirement is achieved by making the ratio of the direct current voltage to alternating current voltage higher. The ratio can be expressed as a ratio of an effective value of three-phase alternating current power to direct current power (in the case of a voltage type inverter, equivalent to a ratio of an effective value of a line voltage of three-phase alternating voltage to a direct current voltage). In the control mode of controlling the inverter (10), there are various modes in which the ratio is from low to high. By changing the control mode based on a ratio of an effective value of a line voltage of a multiphase alternating voltage to a direct current voltage determined in accordance with a requirement for the rotating electric machine (80), it is possible to drive and control the rotating electric machine (80) with high efficiency in accordance with the operating condition of the rotating electric machine (80).

[0205] Further preferably, one of the inverters (10) in the first inverter (11) and the second inverter (12) is configured using a first switching element (31), and the other inverter (10) is configured using a second switching element (32) having a smaller switching loss than the first switching element (31) when transitioning between the off state and the on state, and the inverter (10) controlled by the special pulse width modulation control is configured using the second switching element (32).

[0206] The number of switching operations of the inverter (10) controlled by the rectangular wave control is smaller than that of the inverter (10) controlled by the special pulse width modulation control. According to the present configuration, the inverter (10) configured using the second switching element (32) having a relatively small switching loss is caused to perform more switching operations, and thus it is possible to suppress the loss of the entire system in the high speed region (VRH) where a high output is required.

[0207] Further preferably, in the case of the object low speed region control in which one of the first inverter (10) and the second inverter (12) is controlled by the active short-circuit control, and the other inverter (10) is controlled by the pulse width modulation control, one of the inverters (10) in the first inverter (11) and the second inverter (12) is configured using a first switching element (31), and the other inverter (10) is configured using a second switching element (32) having a smaller switching loss than the first switching element (31) when transitioning between the off state and the on state, and the inverter controlled by the pulse width modulation control is configured using the second switching element.

[0208] Further, in the low speed region VRL, the object low speed region control is performed in which one of the first inverter 11 and the second inverter 12 (here, the first inverter 11) is controlled by the active short-circuit control, and the other inverter (here, the second inverter 12) is controlled by the pulse width modulation control. That is, the rotary electric machine 80 is driven substantially only by one of the inverters 10 (for example, the second inverter 12) among the two inverters 10. Since one inverter 10 does not perform a switching operation, it is possible to suppress the loss of the entire system to drive the rotary electric machine 80.

[0209] Further preferably, the first switching element (31) is a Si-IGBT or a Si-MOSFET, and the second switching element (32) is a SiC-MOSFET or a GaN-MOSFET.

[0210] For example, since silicon carbide (SiC) has a higher insulating breakdown electric field strength than silicon (Si), in the case of constituting a high withstand voltage power device, a drift layer can be formed in a high impurity concentration and a thin film thickness. Since a large portion of the resistance component of the high withstand voltage power device becomes the resistance of the drift layer, the on-resistance per unit area of the SiC device becomes lower than that of the Si device. That is, the SiC device can reduce the switching loss compared to the Si device. The same applies to a device using gallium nitride (GaN). Therefore, in the case where the first switching element (31) is a Si device, by providing a SiC device or a GaN device as the second switching element (32), the inverter (10) can be constituted using the second switching element (32) having a relatively small switching loss compared to the first switching element (31).

[0211] Explanation of reference numerals:

[0212] 1: rotating electric machine control device, 3: switching element, 3A: arm, 3H: upper-stage side switching element, 3L: lower-stage side switching element, 8: stator coil (open winding), 10: inverter, 11: first inverter, 12: second inverter, 80: rotating electric machine, R: control region, T: torque, T1: first period, T2: second period, VRH: high speed region, VRH1: first high speed region, VRH2: second high speed region, VRL: low speed region, VRL1: first low speed region, VRL2: second low speed region, VRM: intermediate speed region, VRSH: super high speed region.

Claims

1. A rotary electric machine control device that drives controls a rotary electric machine having mutually independent multi-phase open-circuit windings by a first inverter and a second inverter, wherein the first inverter is connected to one end side of the multi-phase open-circuit windings, converts electric power between direct current and multi-phase alternating current, the second inverter is connected to the other end side of the multi-phase open-circuit windings, converts electric power between direct current and multi-phase alternating current, the first inverter and the second inverter are respectively capable of being controlled by a plurality of control modes different in switching pattern, and are capable of being controlled in mutually independent control modes, the control modes include pulse width modulation control that outputs a plurality of pulses different in pattern in one cycle of electric angle, and rectangular wave control that outputs one pulse in one cycle of electric angle, the rotary electric machine control device executes the object control that controls one inverter of the first inverter and the second inverter by the rectangular wave control, and controls the other inverter by special pulse width modulation control that is one of the pulse width modulation control, the special pulse width modulation control is the control mode that becomes a switching pattern based on a difference between a switching pattern of the pulse width modulation control in a case where the open-circuit windings generate a target voltage and a switching pattern of the rectangular wave control, a voltage command that generates a switching pattern of one inverter controlled by the rectangular wave control in a case where the open-circuit windings generate the target voltage is set as a rectangular wave voltage command, a voltage command that generates a switching pattern of the other inverter controlled by the pulse width modulation control in a case where the open-circuit windings generate the target voltage is set as a pulse width modulation voltage command, a difference between the rectangular wave voltage command and the pulse width modulation voltage command is set as a voltage command of both inverters as a whole, that is, a system voltage command, a difference between the system voltage command and the rectangular wave voltage command in a state where centers of amplitudes are made coincident is set as a special pulse width modulation voltage command, and the special pulse width modulation control is the control mode that generates a switching pattern based on the special pulse width modulation voltage command.

2. The rotary electric machine control device according to claim 1, wherein as a control region of the rotary electric machine, a low speed region and a high speed region in which a rotational speed of the rotary electric machine is higher than the low speed region at the same torque are set, and in the high speed region, the object control is executed.

3. The rotary electric machine control device according to claim 2, wherein in the first inverter and the second inverter, an arm of alternating current 1 phase is respectively constituted by a series circuit of an upper stage side switching element and a lower stage side switching element. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In the pulse width modulation control, as the control mode, there are included continuous pulse width modulation control in which pulse width modulation is continuously performed on all of the arms of the multiphase, and discontinuous pulse width modulation control in which pulse width modulation is performed on a part of the arms of the multiphase, including a period in which a switching element is fixed to an on state or an off state, In the high speed region, a first high speed region and a second high speed region in which the rotational electric machine speed is higher than the first high speed region at the same torque are set, In the first high speed region, as the target control, first target control in which one of the inverters is controlled by the rectangular wave control and the other inverter is controlled by special pulse width modulation control based on the continuous pulse width modulation control, i.e., special continuous pulse width modulation control, is executed. In the second high speed region, as the target control, second target control in which one of the inverters is controlled by the rectangular wave control and the other inverter is controlled by special pulse width modulation control based on the discontinuous pulse width modulation control, i.e., special discontinuous pulse width modulation control, is executed.

4. The rotational electric machine control device according to claim 2 or 3, wherein In the low speed region, at least one of the first inverter and the second inverter is controlled by the pulse width modulation control, In the high speed region, the special pulse width modulation control is executed at a higher modulation frequency than in the pulse width modulation control.

5. The rotary electric machine control device according to claim 2 or 3, wherein A super high speed region in which the rotational electric machine speed is higher than the high speed region at the same torque is further set, In the super high speed region, both of the first inverter and the second inverter are controlled by the rectangular wave control.

6. The rotational electric machine control device according to claim 2 or 3, wherein In the first inverter and the second inverter, an arm of AC 1 phase is composed of a series circuit of an upper side switching element and a lower side switching element, respectively, The control mode further includes active short control in which the upper side switching element of all of the arms of the multiphase is set to an on state or the lower side switching element of all of the arms of the multiphase is set to an on state, In the low speed region, target low speed region control in which one of the first inverter and the second inverter is controlled by the active short control and the other inverter is controlled by the pulse width modulation control is executed.

7. The rotational electric machine control device according to claim 6, wherein In the first inverter and the second inverter, an arm of AC 1 phase is composed of a series circuit of an upper side switching element and a lower side switching element, respectively, In the pulse width modulation control, as the control mode, there are included continuous pulse width modulation control in which pulse width modulation is continuously performed on all of the arms of the multiphase, and discontinuous pulse width modulation control in which pulse width modulation is performed on a part of the arms of the multiphase, including a period in which a switching element is fixed to an on state or an off state, In the low speed region, a first low speed region and a second low speed region in which the rotational speed of the rotary electric machine is higher than the first low speed region at the same torque are set, In the first low speed region, as the target low speed region control, first target low speed region control is performed in which one of the first inverter and the second inverter is controlled by the active short-circuit control, and the other inverter is controlled by the continuous pulse width modulation control, In the second low speed region, as the target low speed region control, second target low speed region control is performed in which one of the first inverter and the second inverter is controlled by the active short-circuit control, and the other inverter is controlled by the discontinuous pulse width modulation control.

8. The rotary electric machine control device according to claim 6, wherein In the low speed region, the control mode of the first inverter and the control mode of the second inverter are alternately switched according to a predetermined condition.

9. The rotary electric machine control device according to claim 2 or 3, wherein In the first inverter and the second inverter, an arm of an alternating current 1 phase is composed of a series circuit of an upper side switching element and a lower side switching element, In the pulse width modulation control, as the control mode, there are included discontinuous pulse width modulation control in which pulse width modulation is performed on a part of the arms of the multiphase, including a period in which a switching element is fixed to an on state or an off state, As the control region, a middle speed region in which the rotational speed of the rotary electric machine is higher than the low speed region and lower than the high speed region at the same torque is further set, In the middle speed region, both of the first inverter and the second inverter are controlled by the discontinuous pulse width modulation control.

10. The rotary electric machine control device according to claim 9, wherein The control mode includes mixed pulse width modulation control in which a plurality of pulses different in mode are output in a first period of 1 / 2 cycle of an electric angle, and a non-active state is continuously maintained in a second period of the remaining 1 / 2 cycle, In the middle speed region, both of the first inverter and the second inverter are controlled by the mixed pulse width modulation control instead of the discontinuous pulse width modulation control.

11. The rotary electric machine control device according to claim 2 or 3, wherein The boundary of each of the control regions is set in accordance with at least one of a ratio of an effective value of a line voltage of an alternating voltage to a direct voltage, and a rotational speed of the rotary electric machine corresponding to a torque of the rotary electric machine.

12. The rotary electric machine control device according to any one of claims 1 to 3, wherein one of the first inverter and the second inverter is configured using first switching elements, and the other of the first inverter and the second inverter is configured using second switching elements having a smaller switching loss than the first switching elements when transitioning between an off state and an on state, the inverter controlled by the special pulse width modulation control is configured using the second switching elements.

13. The rotary electric machine control device according to claim 6, wherein one of the first inverter and the second inverter is configured using first switching elements, and the other of the first inverter and the second inverter is configured using second switching elements having a smaller switching loss than the first switching elements when transitioning between an off state and an on state, the inverter controlled by the pulse width modulation control is configured using the second switching elements.

14. The rotary electric machine control device according to claim 12, wherein the first switching elements are Si-IGBTs or Si-MOSFETs, and the second switching elements are SiC-MOSFETs or GaN-MOSFETs.

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