Rotary electric machine drive device and rotary electric machine driving method

Abstract

To provide a rotary electric machine drive device which reduces loss generated in each part of a rotary electric machine and can suppress a temperature rise of a part which exceeds a threshold temperature.SOLUTION: A rotary electric machine drive device (1) includes: power converters (3) and (4) of a plurality of groups, which are provided in accordance with respective groups, convert DC power inputted from a DC power supply (7) into phase current and output current to stator windings of the respective groups; and a control part (5) which outputs a control signal generated based on a carrier wave, controls the power converters (3) and (4) of the respective groups and switches a phase of the carrier wave in the respective groups when a partial temperature of a rotary electric machine (2) is higher than a threshold temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a rotating electric machine drive device and a rotating electric machine drive method. [Background technology]

[0002] A commonly known rotating electric machine drive technology is a multiple drive technology in which a single rotating electric machine is driven by multiple groups of power conversion devices. When a rotating electric machine is driven by PWM (Pulse Width Modulation) control, harmonic currents flow through the rotating electric machine, and the harmonic currents are a factor that increases loss and vibration of the rotating electric machine.

[0003] In addition, there is a control technique for shifting the phase of harmonic current components generated in each group when using multiple groups of power conversion devices. For example, Patent Document 1 describes a drive system that applies AC voltages of equal magnitude and opposite phase to a rotating electric machine having two sets of three-phase windings that are out of phase with each other by an electrical angle of 180 degrees. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2014 / 132385 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional technology described in Patent Document 1 is capable of increasing inductance and reducing current ripple by applying phase-inverted AC voltages to a rotating electric machine with two sets of three-phase windings. However, Patent Document 1 does not describe control for reducing loss in the rotating electric machine, and there is a problem that loss increases in each part of the rotating electric machine, causing a rise in temperature.

[0006] The present disclosure is devised to solve the above-mentioned problems, and aims to provide a rotating electric machine drive device that can reduce losses generated in each part of a rotating electric machine and suppress temperature increases in parts that exceed a threshold temperature. [Means for solving the problem]

[0007] The rotating electric machine drive device according to the present disclosure is a rotating electric machine drive device that drives a rotating electric machine having a stator having multiple groups of stator windings of three or more phases, and a rotor which is a rotating body, and includes multiple groups of power converters provided corresponding to each group, which convert DC power input from a power source into a phase current and output it to the stator windings of each group, and a control unit that outputs a control signal generated based on a carrier wave to control the power converter of each group, and switches the phase of the carrier wave in each group when the temperature of a portion of the rotating electric machine is higher than a threshold temperature. Effect of the Invention

[0008] According to the present disclosure, when the temperature of a part of a rotating electric machine is higher than a threshold temperature, the phase of the carrier wave in each group can be switched to reduce losses occurring in each part of the rotating electric machine and suppress the temperature rise in parts that exceed the threshold temperature. [Brief description of the drawings]

[0009] [Figure 1] 1 is a circuit diagram showing a configuration example of a rotary electric machine drive device according to a first embodiment. [Diagram 2] 4 is a block diagram showing an example of the configuration of a control unit according to the first embodiment. FIG. [Diagram 3] FIG. 2 is a cross-sectional view showing a cross section of a permanent magnet synchronous rotating electric machine. [Figure 4] FIG. 2 is a cross-sectional view showing a cross section of an induction rotating electric machine. [Diagram 5] FIG. 1 is a cross-sectional view showing the first and second groups of winding configurations in a rotating electric machine having two slots per pole per phase (hereinafter, referred to as per pole per phase (2)). [Figure 6]FIG. 1 is a cross-sectional view showing the first and second groups of winding configurations in a rotating electric machine having four slots per phase per pole (hereinafter, referred to as (4) per pole per phase). [Figure 7] 11 is a graph showing the amplitude versus phase of the first and second groups of phase currents. [Figure 8] FIG. 2 is a waveform diagram showing a first group of carrier waves and a second group of carrier waves. [Figure 9] FIG. 11 is a waveform diagram emphasizing the phase difference between the first and second carrier waves by expanding the phase range. [Figure 10] 13 is a graph showing rotor loss versus carrier phase difference between first and second groups. [Figure 11] 13 is a graph showing stator loss versus carrier phase difference between first and second groups. [Figure 12] 4 is a flowchart showing a rotary electric machine driving method according to the first embodiment. [Figure 13] FIG. 2 is a waveform diagram showing a triangular wave carrier wave and a phase voltage signal wave. [Figure 14] 1 is a graph showing harmonic voltage amplitude with respect to DC voltage in a carrier first-order component versus modulation factor. [Figure 15] 1 is a graph showing harmonic voltage amplitude with respect to DC voltage in a carrier secondary component with respect to modulation rate. [Figure 16] 1 is a graph showing carrier harmonic components appearing in groups 1 and 2 versus frequency and rotation speed. [Figure 17] 17A and 17B are block diagrams showing a hardware configuration for realizing the functions of a control unit included in the rotary electric machine drive device according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Embodiment 1 FIG. 1 is a circuit diagram showing a configuration example of a rotating electric machine drive device 1 according to a first embodiment. In FIG. 1, the rotating electric machine drive device 1 is a device that drives a rotating electric machine 2, and is configured to include a first group power converter 3, a second group power converter 4, and a control unit 5. A DC bus 3a is opened and closed by a power switch 6a, and a DC bus 3b is opened and closed by a power switch 6b. The first group power converter 3 and the second group power converter 4 are connected to a DC power source 7 via the DC bus 3a and the DC bus 3b, and input driving power from the DC power source 7 and output regenerative power to the DC power source 7. In addition, the first group power converter 3 and the second group power converter 4 are connected to the rotating electric machine 2 via an AC bus 2a, and output driving power to the rotating electric machine 2 and input regenerative power from the rotating electric machine 2.

[0011] The rotating electric machine 2 is a rotating electric machine including a stator having multiple groups of stator windings of three or more phases, and a rotor which is a rotating body. The rotating electric machine 2 includes a rotation angle sensor 21 which detects the rotation angle of the rotor, and a temperature detection unit 22 which detects the temperature of the stator and the temperature of the rotor. For example, the rotating electric machine 2 is a multiple rotating electric machine including three-phase stator windings driven by two systems, group 1 and group 2.

[0012] The first group power converter 3 is a first group power converter including a first group capacitor 31, a first group power conversion circuit 32, and a rotating electric machine current detection unit 33. The first group refers to the first group. The first group capacitor 31 is a smoothing capacitor connected between the DC bus 3a and the DC bus 3b on the power input side of the first group power conversion circuit 32. The first group power conversion circuit 32 is a circuit including switching elements 321-326, and performs DC-AC power conversion by the switching operation of the switching elements 321-326. The rotating electric machine current detection unit 33 detects the current of the rotating electric machine 2 flowing through the AC bus 2a.

[0013] The one-group power conversion circuit 32 is an inverter circuit in which a switching element 321, a switching element 322, a switching element 323, a switching element 324, a switching element 325, and a switching element 326 are fully bridge-connected. In the one-group power conversion circuit 32, the switching element 321 and the switching element 322 are connected in series, the switching element 323 and the switching element 324 are connected in series, and the switching element 325 and the switching element 326 are connected in series. The switching elements 321 and 322 connected in series, the switching elements 323 and 324 connected in series, and the switching elements 325 and 326 connected in series are connected in parallel to the DC power source 7.

[0014] A group of U-phase input terminals of the rotating electric machine 2 is connected to a connection point between the switching elements 321 and 322 connected in series. A group of V-phase input terminals of the rotating electric machine 2 is connected to a connection point between the switching elements 323 and 324 connected in series. A group of W-phase input terminals of the rotating electric machine 2 is connected to a connection point between the switching elements 325 and 326 connected in series. Here, the switching elements 321, 323, and 325 connected to the DC bus 3a are called upper-stage switching elements, and the switching elements 322, 324, and 326 connected to the DC bus 3b are called lower-stage switching elements.

[0015] For example, metal oxide semiconductor field effect transistors (MOSFETs) as shown in Fig. 1 are used for the switching elements 321 to 326. In addition to MOSFETs, insulated gate bipolar transistors (IGBTs) and the like may also be used. A freewheel diode (FWD) is provided in parallel with each of the MOSFETs that are the switching elements 321 to 326, with the forward direction being the direction from the negative side to the positive side of the DC power supply 7, that is, the direction from the lower stage to the upper stage.

[0016] The two-group power converter 4 is a two-group power converter including a two-group capacitor 41, a two-group power conversion circuit 42, and a rotating electric machine current detection unit 43. The two-group refers to the second group. The two-group capacitor 41 is a smoothing capacitor connected between the DC bus 3a and the DC bus 3b on the power input side of the two-group power conversion circuit 42. The two-group power conversion circuit 42 is a circuit including switching elements 421-426, and performs DC-AC power conversion by the switching operation of the switching elements 421-426. The rotating electric machine current detection unit 43 detects the current of the rotating electric machine 2 flowing through the AC bus 2a.

[0017] The two-group power conversion circuit 42 is an inverter circuit in which a switching element 421, a switching element 422, a switching element 423, a switching element 424, a switching element 425, and a switching element 426 are fully bridge-connected. In the two-group power conversion circuit 42, the switching element 421 and the switching element 422 are connected in series, the switching element 423 and the switching element 424 are connected in series, and the switching element 425 and the switching element 426 are connected in series. The switching elements 421 and 422 connected in series, the switching elements 423 and 424 connected in series, and the switching elements 425 and 426 connected in series are connected in parallel to the DC power source 7.

[0018] Two groups of U-phase input terminals of the rotating electric machine 2 are connected to a connection point between the switching elements 421 and 422 connected in series. Two groups of V-phase input terminals of the rotating electric machine 2 are connected to a connection point between the switching elements 423 and 424 connected in series. Two groups of W-phase input terminals of the rotating electric machine 2 are connected to a connection point between the switching elements 425 and 426 connected in series. Here, the switching elements 421, 423, and 425 connected to the DC bus 3a are called upper-stage switching elements, and the switching elements 422, 424, and 426 connected to the DC bus 3b are called lower-stage switching elements.

[0019] For example, MOSFETs as shown in Fig. 1 are used for the switching elements 421 to 426. Also, in addition to MOSFETs, IGBTs or the like may be used. A freewheel diode (FWD) is provided in parallel with each of the MOSFETs that are the switching elements 421 to 426, with the forward direction being the direction from the negative side to the positive side of the DC power supply 7, that is, the direction from the lower side to the upper side.

[0020] The first group power converter 3 and the second group power converter 4 may use the same type of semiconductor switching elements, or different elements may be used. For example, when the same type of semiconductor switching elements are used, the switching elements may be MOSFETs or IGBTs in the first group power converter 3 and the second group power converter 4. When different types of semiconductor switching elements are used, the switching elements of the first group power converter 3 may be MOSFETs and the switching elements of the second group power converter 4 may be IGBTs. The switching operations of the switching elements of the first group power converter 3 and the second group power converter 4 are controlled by a control unit 5.

[0021] The rotating electric machine current detection unit 33 detects the current flowing through the AC bus 2a, and outputs rotating electric machine current information obtained by converting the current into a voltage to the control unit 5. In the example of Fig. 1, the current is detected by a shunt resistor which is the rotating electric machine current detection unit 33. Note that the rotating electric machine current detection unit 33 may be realized by a current sensor using a magnetic sensor such as a Hall element.

[0022] The power switch 6a controls the exchange of power between the DC power source 7 and the first group power converter 3, and the power switch 6b controls the exchange of power between the DC power source 7 and the second group power converter 4. The power switches 6a and 6b are held open by a higher-level system when, for example, the voltage of the DC power source 7 exceeds a set value during regenerative operation of the rotating electric machine 2, when the voltage of the DC power source 7 falls below a set value due to consumption of the DC power source 7 or the like, or when the current flowing through the DC power source 7 exceeds a set value. The power switches 6a and 6b may be configured to be controlled by the control unit 5.

[0023] The rotation angle sensor 21 detects the rotation angle of a rotor included in the rotating electric machine 2 by using a resolver, an encoder, a magnetic sensor, or the like. Information indicating the rotation angle of the rotor detected by the rotation angle sensor 21 is output to the control unit 5. The temperature detection unit 22 detects the temperature of a stator and a rotor included in the rotating electric machine 2. Information indicating the temperature of each part of the rotating electric machine 2 detected by the temperature detection unit 22 is output to the control unit 5. Furthermore, a temperature detection unit 22 that detects the temperature by a different method depending on each part of the rotating electric machine 2 may be used. For example, the temperature detection unit 22 may be a thermistor or a thermocouple.

[0024] 1 shows a case where the rotating electric machine drive device 1 includes a first group power converter 3 and a second group power converter 4, but is not limited to this. That is, the rotating electric machine drive device 1 may not only include two systems, namely, a first group and a second group, but also multiple systems, namely, three or more groups. For example, the rotating electric machine drive device 1 includes multiple groups, namely, three or more groups, of smoothing capacitors, power conversion circuits, rotating electric machine current detection units, and switching elements of the power conversion circuits.

[0025] The control unit 5 outputs a control signal generated based on the carrier wave to control the first group power converter 3 and the second group power converter 4, and switches the phase of the carrier wave in each group when the temperature of a portion of the rotating motor 2 is higher than a threshold temperature. Fig. 2 is a block diagram showing an example of the configuration of the control unit 5. In Fig. 2, the control unit 5 includes a current command generating unit 51, a three-phase to two-phase conversion unit 52, a current control unit 53, a two-phase to three-phase conversion unit 54, a carrier wave generating unit 55, and a PWM signal generating unit 56.

[0026] The current command generating unit 51 generates a torque command Trq * Based on this, the 1st group d-axis current command value Id1 * and 1 group q-axis current command value Iq1 * and the second group d-axis current command value Id2 * and 2nd group q-axis current command value Iq2 * Here, the d-axis indicates the direction in which the magnetic flux of the permanent magnet, which is the rotor of the rotating electric machine 2, is generated, and the q-axis is an axis electrically perpendicular to the d-axis. * is control information for specifying the torque of the rotor included in the rotating electric machine 2, and is generated, for example, in a higher-level system that controls the rotating electric machine drive device 1, and is acquired by the current command generating unit 51 from the higher-level system. * is the current command value in the d-axis direction of the first group, and the q-axis current command value Iq1 * is the current command value in the q-axis direction of the first group. * is the current command value in the d-axis direction of the second group, and the second group q-axis current command value Iq2 * is the current command value in the q-axis direction for the two groups.

[0027] The current command generating unit 51 may have a plurality of current command maps for torque commands created using actual measurement results or simulation results. In this case, the current command generating unit 51 may generate a torque command Trq * As a result of searching the map based on * and 1 group q-axis current command value Iq1 * and the second group d-axis current command value Id2 * and 2nd group q-axis current command value Iq2 * and may be generated.

[0028] Three-phase to two-phase conversion unit 52 receives as input the first group U-phase current Iu1, the first group V-phase current Iv1, and the first group W-phase current Iw1 from rotating electric machine current detection unit 33, receives as input the second group U-phase current Iu2, the second group V-phase current Iv2, and the second group W-phase current Iw2 from rotating electric machine current detection unit 43, and receives as input the electrical angle θe from rotation angle sensor 21. The first group U-phase current Iu1 is a current value flowing through the first group U-phase stator winding, the first group V-phase current Iv1 is a current value flowing through the first group V-phase stator winding, and the first group W-phase current Iw1 is a current value flowing through the first group W-phase stator winding. The second group U-phase current Iu2 is a current value flowing through the second group U-phase stator winding, the second group V-phase current Iv2 is a current value flowing through the second group V-phase stator winding, and the second group W-phase current Iw2 is a current value flowing through the second group W-phase stator winding. The electrical angle θe is the rotation angle of the rotor provided in the rotating electric machine 2.

[0029] The three-to-two-phase conversion unit 52 performs three-to-two-phase coordinate conversion based on the 1st group U-phase current Iu1, the 1st group V-phase current Iv1, and the 1st group W-phase current Iw1, the 2nd group U-phase current Iu2, the 2nd group V-phase current Iv2, and the 2nd group W-phase current Iw2, and the electrical angle θe to convert the 1st group U-phase current Iu1, the 1st group V-phase current Iv1, and the 1st group W-phase current Iw1 into a 1st group d-axis current detection value Id1 and a 1st group q-axis current detection value Iq1, and convert the 2nd group U-phase current Iu2, the 2nd group V-phase current Iv2, and the 2nd group W-phase current Iw2 into a 2nd group d-axis current detection value Id2 and a 2nd group q-axis current detection value Iq2. The 1st group d-axis current detection value Id1 is the current detection value in the 1st group d-axis direction, and the 1st group q-axis current detection value Iq1 is the current detection value in the 1st group q-axis direction. The second group d-axis current detection value Id2 is the current detection value of the second group in the d-axis direction, and the second group q-axis current detection value Iq2 is the current detection value of the second group in the q-axis direction.

[0030] The current control unit 53 receives the first group d-axis current command value Id1 from the current command generation unit 51. * and 1 group q-axis current command value Iq1 * and the second group d-axis current command value Id2 * and 2nd group q-axis current command value Iq2 * Furthermore, the current control unit 53 receives the first group d-axis current detection value Id1, the first group q-axis current detection value Iq1, the second group d-axis current detection value Id2, and the second group q-axis current detection value Iq2 from the three-phase to two-phase conversion unit 52.

[0031] The current control unit 53 outputs the first group d-axis current command value Id1 * Calculate the 1st group d-axis current deviation between the 1st group d-axis current detection value Id1 and the 1st group q-axis current command value Iq1 * Calculate the 1st group q-axis current deviation between the 1st group q-axis current detection value Iq1 and the 2nd group d-axis current command value Id2 * Calculate the 2nd group d-axis current deviation between the 2nd group d-axis current detection value Id2 and the 2nd group q-axis current command value Iq2 * The current control unit 53 calculates the second group q-axis current deviation between the second group q-axis current detection value Iq2 and the second group q-axis current detection value Iq3. The current control unit 53 performs proportional and integral control calculations on the current deviation of each group to calculate the first group d-axis voltage command value Vd1. * and 1st group q-axis voltage command value Vq1 * and the second group d-axis voltage command value Vd2* and 2nd group q-axis voltage command value Vq2 * Calculate the following:

[0032] The two-phase to three-phase conversion unit 54 converts the first group d-axis voltage command value Vd1 * and the q-axis voltage command value Vq1 * Based on this, the first group three-phase voltage command value Vu1 in the stationary coordinate system is * , Vv1 * and Vw1 * Calculate the d-axis voltage command value Vd2 for group 2. * and the 2nd group q-axis voltage command value Vq2 * Based on this, the two-group three-phase voltage command value Vu2 in the stationary coordinate system is * , Vv2 * and Vw2 * Calculate. The three-phase voltage command values ​​of each group calculated by the two-phase to three-phase conversion unit 54 are output to the PWM signal generation unit 56. * is the voltage command value of the U phase of group 1, and the V phase voltage command value of group 1 Vv1 * is the voltage command value of the V phase of group 1, and the U phase voltage command value of group 1 Vw1 * is the voltage command value of the W phase of the first group. * is the voltage command value of the U phase of the second group, and the V phase voltage command value of the second group Vv2 * is the voltage command value of the V phase of the second group, and the voltage command value of the U phase of the second group Vw2 * is the voltage command value of the W phase of the second group.

[0033] The carrier wave generating unit 55 receives the stator temperature Tst, the rotor temperature Trt, the first carrier frequency fc1, and the second carrier frequency fc2, and generates the first triangular wave carrier e1 and the second triangular wave carrier e2 based on the relationship between the stator temperature Tst and the rotor temperature Trt and the respective threshold temperatures. The stator temperature is the temperature of the stator winding. The temperature of the stator winding can be calculated using the thermistor that is the temperature detection unit 22.

[0034] Moreover, the temperature of the stator windings calculated by the temperature detector 22 may be calculated using a thermocouple instead of a thermistor, and the calculation may be made based on a thermal circuit and losses in the rotating electrical machine 2. If the rotating electric machine 2 is a permanent magnet rotating electric machine, the rotor temperature is the temperature of the permanent magnets, and if the rotating electric machine 2 is an induction rotating electric machine, it is the temperature of the rotor bars or end rings. The temperature of the permanent magnet can be calculated using the induced voltage obtained from the rotating electric machine 2. When the temperature of the permanent magnet changes, the magnetic force of the permanent magnet changes, and the induced voltage of the rotating electric machine 2 also changes. Therefore, by knowing in advance the correspondence relationship between the temperature of the permanent magnet and the induced voltage, it becomes possible to calculate the temperature of the permanent magnet using the induced voltage of the rotating electric machine 2.

[0035] To calculate the temperature of the permanent magnets, rotor bars, or end rings, a thermocouple may be used as the temperature detection unit 22, and a slip ring may be used to attach the thermocouple to the rotor. If a slip ring is not used, the rotor temperature can be calculated by emitting and acquiring the signal from the thermocouple as a radio wave signal. Alternatively, the rotor temperature can be calculated from the thermal circuit and losses in the rotating electric machine 2.

[0036] The carrier frequency is the frequency of one electrical period of the triangular carrier wave. For example, the first group carrier frequency is the frequency of the first group triangular wave carrier e1 in one electrical angle cycle, and the second group carrier frequency is the frequency of the second group triangular wave carrier e2 in one electrical angle cycle. The carrier wave generating unit 55 calculates the phase difference between the first group triangular wave carrier e1 and the second group triangular wave carrier e2 based on the magnitude relationship between the stator temperature Tst and a predetermined stator temperature threshold value, and the magnitude relationship between the rotor temperature Trt and the rotor temperature threshold value. Then, the carrier wave generating unit 55 outputs the first group triangular wave carrier e1 and the second group triangular wave carrier e2 based on the calculated phase difference between the first group triangular wave carrier e1 and the second group triangular wave carrier e2, the first group carrier frequency fc1, and the second group carrier frequency fc2.

[0037] The carrier wave generating unit 55 may have a triangular wave carrier phase difference map in which the phase difference of the triangular wave carrier is registered in association with the stator temperature and the rotor temperature. In this case, the carrier wave generating unit 55 identifies the triangular wave carrier of each group by searching the triangular wave carrier phase difference map using the stator temperature and the rotor temperature.

[0038] The PWM signal generating unit 56 converts the first group three-phase voltage command value Vu1 generated by the two-phase to three-phase conversion unit 54 into * , Vv1 * and Vw1 * and the two-group three-phase voltage command value Vu2 * , Vv2 * and Vw2 * Based on the first group triangular wave carrier wave e1 and the second group triangular wave carrier wave e2 generated by the carrier wave generating unit 55 and the DC bus voltage Vpn, an on / off control signal is calculated for each switching element provided in the first group power conversion circuit 32 and the second group power conversion circuit 42. The PWM signal generating unit 56 uses a comparator to compare the three-phase voltage command value with a triangular carrier wave, determines the on / off of the switching elements based on the comparison result, and generates on / off control signals for performing switching operation with the determined on / off. The on / off control signals include first-group on / off control signals UH1, UL1, VH1, VL1, WH1, and WL1 output to the first-group power conversion circuit 32, and second-group on / off control signals UH2, UL2, VH2, VL2, WH2, and WL2 output to the second-group power conversion circuit 42.

[0039] The control unit 5 controls the switching elements 321-326 to turn on and off using on / off control signals UH1, UL1, VH1, VL1, WH1 and WL1 to the first group power conversion circuit 32, and controls the switching elements 421-426 to turn on and off using on / off control signals UH2, UL2, VH2, VL2, WH2 and WL2 to the two group power conversion circuit 42. The control unit 5 controls the switching operation of each switching element included in the power conversion circuit of each group, thereby converting the DC power input from the DC power source 7 into AC power, and supplies the converted AC power to the rotating electric machine 2. Furthermore, the control unit 5 controls the switching operation of each switching element included in the power conversion circuit of each group, thereby charging the DC power source 7 with regenerative power generated by the rotating electric machine 2 in a regenerative state.

[0040] Fig. 3 is a cross-sectional view showing a cross section of a permanent magnet synchronous rotating electric machine, showing a cross section of the permanent magnet synchronous rotating electric machine cut along a plane perpendicular to the axial direction. In the rotating electric machine drive device 1, the rotating electric machine 2 may be a permanent magnet synchronous rotating electric machine. As shown in Fig. 3, the permanent magnet synchronous rotating electric machine has a winding 202 in a stator 201, and a permanent magnet 212 in a rotor 211. In Fig. 3, the permanent magnet synchronous rotating electric machine has 6 poles and 36 slots, and has distributed winding of every pole per phase (2).

[0041] In the case of per pole per phase (2), the number of slots per pole per phase is two. The winding of the stator 201 is composed of multiple groups of windings. Also, other groups of windings may be configured in the same slot. The permanent magnets 212 of the rotor 211 are configured to be arranged in a V-shape across two layers. By arranging the permanent magnets in two layers, the permanent magnets 212 on the inner diameter side of the rotor 211 are farther away than the stator windings. This makes it possible to reduce the influence of harmonic magnetic flux caused by the carrier of the stator winding. Also, the eddy current due to the harmonic magnetic flux is reduced, and the eddy current loss can be reduced.

[0042] FIG. 4 is a cross-sectional view showing a cross section of an induction rotating electric machine, and shows a cross section of the induction rotating electric machine cut on a plane perpendicular to the axial direction. The rotating electric machine drive device 1 may have the rotating electric machine 2 as an induction rotating electric machine. As shown in FIG. 4, the induction rotating electric machine has a winding 202 on a stator 201, and a rotor bar 213 on a rotor 211. The rotor bar 213 is short-circuited by end rings at both ends in the axial direction. In the induction rotating electric machine, the rotating magnetic field generated by the stator winding interlinks with the rotor 211, so that an induced current flows in the rotor bar 213, generating torque and causing rotation. The rotor bar 213 may be elliptical or have a double cage shape having two rotor bar slots in the radial direction other than a circular shape. In the double cage shape, the rotor bar 213 on the inner diameter side of the rotor 211 is farther away than the stator winding, so that it is possible to reduce the influence of harmonic magnetic flux caused by the carrier of the stator winding.

[0043] FIG. 5 is a cross-sectional view showing the first and second group winding configurations for each pole and each phase (2). The slot spacing of the stator winding for each pole and each phase (2) is an electrical angle θ=180 / (3×2)=30 degrees. The first group of windings are U1, V1, and W1, and the second group of windings are U2, V2, and W2. As shown in FIG. 5, the first group of windings and the second group of windings are wound with an electrical angle of θ=30 degrees shift. By arranging multiple groups of windings within one pole, it is possible to cancel out harmonics between the groups, resulting in low loss and low vibration. In addition, by configuring multiple groups, it is possible to obtain the effect of redundancy even if one of the systems fails. In addition, Figure 5 shows a cross section of one pole, and in each group, upward current flow is positive for the U-phase winding, upward current flow is positive for the V-phase winding, and downward current flow is positive for the W-phase winding.

[0044] FIG. 6 is a cross-sectional view showing the first and second group winding configurations for each pole and each phase (4). The slot spacing of the stator winding for each pole and each phase (4) is an electrical angle θ=180 / (3×4)=15 degrees. The first group of windings are U1, V1, and W1, and the second group of windings are U2, V2, and W2. As shown in FIG. 6, the first group of windings and the second group of windings are wound with an electrical angle θ of 30 degrees, which corresponds to two slots.

[0045] In the case of per pole per phase (4), the number of slots per pole per phase is four. In the case of four systems having up to four groups per pole per phase (4), the windings of each group are wound with a shift of electrical angle θ=15 degrees, which corresponds to one slot. In the rotating electric machine drive device 1, the more systems are added, the more finely the phase difference of the carrier wave between each group can be shifted, making it possible to reduce harmonic magnetic flux in a finer manner, thereby achieving the effects of lowering loss and vibration.

[0046] FIG. 7 is a graph showing the amplitude versus phase of the first and second groups of phase currents. In FIG. 7, I1 shows the relationship of the first group phase current versus the electrical angle, and I2 shows the relationship of the second group phase current versus the electrical angle. The control unit 5 controls the amplitude of the phase currents of each group output from the power conversion circuit of each group so that they are equal. Furthermore, the current phase difference Δ12 between the first group phase current and the second group phase current is controlled so that the electrical angle is 30 degrees. The control unit 5 can cancel out the harmonic components of the first and second groups by controlling the phase difference of the energizing currents so that it is equal to the spatial phase difference, which is the winding interval between the first and second groups.

[0047] The control unit 5 controls the rotating electric machine 2, in which the first and second groups of windings are wound at an interval of 30 electrical degrees, so that the current amplitudes of the first and second groups are equal, and so that the current phase difference between the first and second groups is an electrical angle of 30 degrees. This allows the rotating electric machine drive device 1 to eliminate the torque ripple and electromagnetic excitation force of 6f, which is six times the fundamental frequency f, and enables low vibration.

[0048] In addition, since an electrical angle of 30 degrees is equivalent to an electrical angle of 180 degrees for the 6f component, the torque ripple of the 6f component generated in the first group of systems and the torque ripple of the 6f component generated in the second group of systems are in a phase-inverted relationship. This makes it possible to eliminate the torque ripple of the 6f component. In addition, since the magnetic flux is also cancelled out in the same way, the eddy current caused by the harmonic magnetic flux is reduced, making it possible to reduce loss.

[0049] FIG. 8 is a waveform diagram showing a first group of carrier waves and a second group of carrier waves. In FIG. 8, triangular wave A is the first group of triangular wave carrier waves, and triangular wave B is the second group of triangular wave carrier waves. The control unit 5 generates triangular waves based on the carrier frequency of each group. For example, when performing synchronous control in which the carrier frequency is an integer multiple of the fundamental wave frequency f, the control unit 5 generates the first group of triangular wave carrier waves, which are triangular wave A, and generates the second group of triangular wave carrier waves, which are triangular wave B. For example, in one electrical angle period, there are nine periods of triangular waves A and B, resulting in nine synchronous pulses.

[0050] Furthermore, the control unit 5 may perform asynchronous control in which the carrier frequency is not an integer multiple of the fundamental wave frequency f. Even in the case of asynchronous control, the control unit 5 performs control to switch the carrier wave phase difference ΔAB of each group based on the temperature of the stator and the temperature of the rotor.

[0051] FIG. 9 is a waveform diagram emphasizing the phase difference between the first group carrier wave and the second group carrier wave by expanding the phase range, and is an enlarged view of the waveform in FIG. 8. In FIG. 9, triangular wave A is the first group triangular wave carrier wave, and triangular wave B is the second group triangular wave carrier wave. The control unit 5 may perform either synchronous control or asynchronous control to control the carrier wave phase difference ΔAB between the first group and the second group. The carrier wave phase difference ΔAB between the first group and the second group in FIG. 9 indicates the phase converted into one period of the rotating electric machine 2. In addition, since there are nine synchronous pulses, the electrical angle θ=360 / 9=40 degrees is one period of the carrier wave. The phase difference ΔAB of the carrier wave of each group is controlled as an angle converted into one period of the carrier wave.

[0052] When the control unit 5 performs control so that the carrier wave phase difference ΔAB between the first and second groups becomes 360 degrees, the electrical angle θ is shifted by 40 degrees in one period of the rotating electric machine 2. Furthermore, the square wave voltage calculated based on the comparison result between the three-phase voltage command value and the triangular wave carrier wave contains harmonics other than the fundamental wave. The harmonic components caused by the carrier appear as sidebands at integer multiples of the carrier frequency fc. For a fundamental frequency f, typical frequency components of harmonics contained in a square wave voltage waveform are fc±2f and 2fc±f.

[0053] Since these carrier-induced harmonic components appear for each group, the control unit 5 changes the carrier phase difference between each group to cancel out the magnetic flux of the carrier-induced harmonic. If the spatial phase difference between the first and second groups of windings is 30 degrees, and the time phase difference between the currents passing through the first and second groups is 30 degrees, the sideband waves caused by the primary carrier have a phase difference of 30 + 2 x 30 = 90 degrees due to the spatial phase difference and time phase difference. The sideband waves caused by the primary carrier are added or subtracted by the second fundamental wave, and the second fundamental wave is in opposite phase to the fundamental wave. For this reason, the equation for spatial phase is additive.

[0054] Since there is a phase difference of 90 degrees between the spatial phase difference and the time phase difference, when the carrier wave phase difference between the first and second groups is set to (90+180×n) degrees, it is possible to cancel out the harmonic magnetic flux caused by the primary carrier between the first and second groups. Here, n is an integer. The sideband waves caused by the primary carrier are fc±2f, and there are two types of frequency components, so the phase differences caused by the spatial phase difference and the time phase difference are also of two types, positive and negative. Therefore, by setting the carrier wave phase difference between the first and second groups to (90+180×n) degrees, it is possible to reduce losses caused by the harmonic magnetic flux caused by the primary carrier. On the other hand, if the spatial phase difference between the first and second groups of windings is 30 degrees and the time phase difference between the currents passing through the first and second groups is 30 degrees, the sideband waves caused by the secondary carrier will have a phase difference of 30-30=0 degrees due to the spatial phase difference and time phase difference.

[0055] In the sideband waves caused by the secondary carrier, the fundamental wave is added or subtracted, and the fundamental wave is in positive phase. Therefore, the equation for the spatial phase is subtracted. Since the spatial phase difference and the time phase difference result in a phase difference of 0 degrees, if the carrier phase difference between the first and second groups is set to (180×n) degrees, it is possible to cancel out the harmonic magnetic flux caused by the secondary carrier in the first and second groups. The sideband waves caused by the secondary carrier are 2fc±f, and there are two types of frequency components, but the phase difference caused by the spatial phase difference and the time phase difference is only one type, 0 degrees. However, since the harmonic magnetic flux caused by the secondary carrier changes with twice the period of the carrier phase difference, it is possible to reduce losses caused by the harmonic magnetic flux caused by the secondary carrier by setting the carrier phase difference between the first and second groups to (180×n) degrees.

[0056] Because the rotor is located across an air gap from the stator, the influence of high frequency components is small. Therefore, when the harmonic magnetic flux caused by the secondary carrier is attenuated, the harmonic magnetic flux caused by the primary carrier becomes dominant. On the other hand, because the stator is located near the winding that generates the magnetic flux, the harmonic magnetic flux caused by the secondary carrier becomes dominant.

[0057] Fig. 10 is a graph showing rotor loss versus carrier phase difference between groups 1 and 2. As shown in Fig. 10, rotor loss is minimal when the carrier phase difference between groups 1 and 2 is (90+180×n) degrees, where n is an integer. Rotor loss is loss that occurs in the rotor core, loss that occurs in the permanent magnets in a permanent magnet synchronous rotating electric machine, or loss that occurs in the rotor bars in an induction rotating electric machine. When the carrier phase difference between groups 1 and 2 is set to (90+180×n) degrees, it is possible to suppress the rise in rotor temperature. For example, if the rotating electric machine 2 is a permanent magnet synchronous rotating electric machine, it is possible to suppress the temperature rise of the permanent magnets, prevent demagnetization, and prevent torque reduction. Also, if the rotating electric machine 2 is an induction rotating electric machine, it is possible to suppress the temperature rise of the rotor bars, preventing damage to the rotor bars due to the temperature rise and increased loss of the rotor bars due to increased resistance.

[0058] Figure 11 is a graph showing the stator loss versus the carrier phase difference between groups 1 and 2. As shown in Figure 11, the stator loss is minimal when the carrier phase difference between groups 1 and 2 is (180 x n) degrees, where n is an integer. The stator loss refers to the loss that occurs in the stator core. When the carrier phase difference between groups 1 and 2 is set to (180×n) degrees, it is possible to suppress the rise in stator winding temperature. By suppressing the rise in stator winding temperature, damage to the winding insulation coating can be prevented.

[0059] Next, a method for driving a rotating electric machine according to the first embodiment will be described. FIG. 12 is a flowchart showing the rotating electric machine driving method according to the first embodiment. The control unit 5 determines whether or not the temperature of the rotor included in the rotating electric machine 2 is higher than the threshold temperature (step ST1). If the rotor temperature is higher than the threshold temperature (step ST1; YES), the control unit 5 controls the carrier phase difference between the first and second groups to be (90+180×n) degrees (step ST2), where n is an integer.

[0060] The rotor temperature is, for example, the temperature of the permanent magnet when the rotating electric machine 2 is a permanent magnet rotating electric machine, and is the temperature of the rotor bars or end rings when the rotating electric machine 2 is an induction rotating electric machine. The threshold temperature corresponding to the rotor is set to a temperature lower than the temperature at which demagnetization of the permanent magnet occurs when the rotating electric machine 2 is a permanent magnet synchronous rotating electric machine. The susceptibility of demagnetization to occur varies depending on the material of the permanent magnet. For example, permanent magnets to which a large amount of rare earth elements such as dysprosium or terbium is added have a large coercive force and are less likely to cause demagnetization. However, permanent magnets to which a large amount of rare earth elements is added have the disadvantages of being expensive and having a low residual magnetic flux density.

[0061] The rotating electric machine drive device 1 can use low-cost permanent magnets with large residual magnetic flux density and reduced addition of rare earth elements by switching the phase difference between multiple groups of carrier waves according to the threshold temperature. In addition, when the rotating electric machine 2 is an induction rotating electric machine, the threshold temperature is set by the designed resistance values ​​of the rotor bars and end rings. When the temperatures of both the rotor bars and the end rings rise, the resistance values ​​of the rotor bars and the end rings increase. As the resistance values ​​of the rotor bars and the end rings increase, rotor losses increase. Therefore, the above threshold temperature of the rotor can be set by setting the upper limit resistance values ​​of the rotor bars and the end rings at the time of design. By setting the above threshold temperature of the rotor according to the upper limit resistance values ​​of the rotor bars and the end rings, it is possible to prevent an increase in rotor losses.

[0062] The threshold temperature may be set according to the upper limit temperature of the bearings of the rotating electrical machine 2. The upper limit usage temperature is set because a rise in temperature of the bearings causes the lubricant to deteriorate and shortens the lifespan of the bearings. For this reason, the threshold temperature may be set to a value lower than the upper limit usage temperature of the bearings. When the rotor temperature is higher than the threshold temperature, the rotating electric machine drive device 1 controls the carrier phase difference between the first and second groups to be (90 + 180 × n) degrees, thereby reducing rotor loss and suppressing the rise in rotor temperature.

[0063] If the rotor temperature is equal to or lower than the threshold temperature (step ST1; NO), the control unit 5 determines whether or not the temperature of the stator included in the rotating electric machine 2 is higher than the threshold temperature (step ST3). If the stator temperature is higher than the threshold temperature (step ST3; YES), the control unit 5 controls the carrier phase difference between the first and second groups to be (180×n) degrees (step ST4). The stator temperature is the temperature of the stator winding. The threshold temperature corresponding to the stator is set according to the heat resistance temperature of the magnet wire. The heat resistance temperature of the magnet wire is set according to the heat resistance temperature of the material used for the insulating coating. For example, the threshold temperature of the stator is set to a temperature lower than the heat resistance temperature of the magnet wire.

[0064] The stator temperature may be the temperature of the stator teeth or a core such as a core back. By calculating the stator winding temperature from the core temperature using a thermal circuit network, it is possible to prevent deterioration of the insulation coating of the stator winding. When the stator temperature is higher than the threshold temperature, the control unit 5 controls the carrier phase difference between the first and second groups to be (180×n) degrees, thereby reducing stator loss and suppressing the rise in stator temperature.

[0065] If the stator temperature is equal to or lower than the threshold temperature (step ST3; NO), the control unit 5 controls the loss to be minimized (step ST5). Here, the control unit 5 controls the carrier phase difference between the first and second groups so that the loss generated in the rotating electric machine 2 is minimized. For example, the control unit 5 stores in advance, as a map, the carrier phase difference between the first group and the second group that minimizes the loss of the rotating electric machine 2 for each operating point in the rotation speed and torque characteristics. The control unit 5 can switch the carrier phase difference between the first group and the second group in any operating point state, even when the loss is minimized in the flowchart shown in Fig. 12. The series of processes shown in Fig. 12 is performed at regular time intervals. The map setting the carrier wave phase difference between the first and second groups that minimizes the loss in the rotating electric machine 2 can be calculated by finite element analysis or by actual measurement using an actual device.

[0066] FIG. 13 is a waveform diagram showing a triangular carrier wave and a phase voltage signal wave. In FIG. 13, the difference between the maximum value and the minimum value of the triangular wave is the DC voltage Vpn. Also, the difference between the maximum value and 0 of the triangular wave is the amplitude Vpn / 2. On the other hand, the phase voltage signal wave is a waveform generated by the control unit 5 based on the three-phase voltage command value. The modulation factor is defined as the peak value C of the phase voltage signal wave relative to the amplitude of the triangular carrier wave. That is, the modulation factor = phase voltage peak value / (Vpn / 2).

[0067] For example, when performing synchronous control in which the carrier frequency is an integer multiple of the fundamental frequency f, the control unit 5 can reduce harmonic components by aligning the carrier phase of the carrier and the fundamental phase to 0. This can reduce losses in the rotating electric machine 2 and suppress a rise in temperature. On the other hand, even when performing asynchronous control in which the carrier frequency is not an integer multiple of the fundamental frequency f, the control unit 5 controls the carrier phase difference of each group according to the temperature of the rotating electric machine 2. This can reduce losses in the rotating electric machine 2 and suppress a rise in temperature.

[0068] FIG. 14 is a graph showing the harmonic voltage amplitude for the DC voltage Vpn in the carrier primary component versus the modulation factor. The frequency fc±2f components appear as harmonic voltages for the DC voltage in the carrier primary component. FIG. 14 shows the characteristics of the frequency fc±2f components divided by the DC voltage Vpn versus the modulation factor. As shown in FIG. 14, since the DC voltage Vpn is constant, the larger the modulation factor, the larger the carrier primary component. In other words, the larger the modulation factor, the greater the loss caused by the carrier primary component.

[0069] Since the carrier primary component has a lower frequency than the carrier secondary component, it also affects the rotor located across the gap from the stator in the rotating electric machine 2. For this reason, the control unit 5 can suppress the temperature rise of the rotor by controlling the modulation factor to be small. In order to reduce the modulation factor, the phase voltage peak value C can be reduced, and in order to reduce the phase voltage peak value C, the weak current can be increased. In other words, the current amplitude and current advance angle of the phase current can be increased.

[0070] FIG. 15 is a graph showing the amplitude of harmonic voltages for DC voltage Vpn in the carrier secondary component versus modulation factor. As harmonic voltages for DC voltage Vpn in the carrier secondary component, frequency 2fc±f components appear. FIG. 15 shows the characteristics of the frequency 2fc±f components divided by the DC voltage Vpn versus modulation factor. As shown in FIG. 15, the carrier secondary component is maximized at a modulation factor of 0.6. The carrier secondary component has a significant effect on losses occurring in the stator winding or core. For this reason, the control unit 5 can suppress the temperature rise of the stator by controlling the modulation factor to reduce losses caused by the carrier secondary component.

[0071] 15, the loss caused by the secondary carrier changes its tendency at the border of a modulation factor of 0.6, so the control unit 5 can control the modulation factor to be larger when the modulation factor is greater than 0.6. In order to increase the modulation factor, the phase voltage peak value C can be increased, and in order to increase the phase voltage peak value C, the weak current can be reduced. In other words, the current amplitude and current advance angle of the phase current can be reduced.

[0072] Fig. 16 is a graph showing carrier harmonic components appearing in the first and second groups with respect to frequency and rotation speed. In Fig. 16, the carrier frequency of the first group is fc1, and the carrier frequency of the second group is fc2. When the control unit 5 switches the carrier phase difference between the first and second groups in response to the temperature of the rotating electric machine 2, if the carrier frequencies of the first and second groups are made equal, the frequency components caused by the carrier will match. This makes it possible to cancel out the harmonic components caused by the carrier.

[0073] On the other hand, even if the carrier frequencies of groups 1 and 2 are different, it is possible to cancel out the harmonic components caused by the carrier by setting the carrier frequency of group 1 and the carrier frequency of group 2 to predetermined values. For example, the control unit 5 can cancel out the carrier primary sideband of group 1 and the carrier secondary sideband of group 2 by controlling the carrier frequencies of groups 1 and 2 so as to satisfy fc1+2f=2fc2-f, thereby reducing the loss caused by the carrier.

[0074] When the rising temperatures of the switching elements in the power conversion circuits of each group are different, the control unit 5 sets the carrier frequency of each group to a different value, thereby reducing the switching loss of the switching element with the highest temperature. Even if the carrier frequencies of each group are set to different values, the control unit 5 controls the carrier frequencies of the first and second groups so as to satisfy fc1+2f=2fc2-f, and controls the carrier phase difference between the first and second groups according to the temperature of the rotating electric machine 2. This allows the rotating electric machine drive device 1 to selectively suppress the temperature rise of the stator and rotor.

[0075] When the rotating electric machine 2 is a permanent magnet synchronous rotating electric machine, eddy currents due to harmonic magnetic flux are generated in the permanent magnet. The eddy currents generated in the permanent magnet depend on the carrier frequency and the thickness of the permanent magnet in the magnetization direction. The harmonic magnetic flux caused by the second order of the carrier is a 2fc±f component, the eddy currents generated in the permanent magnet are expressed as the square of the harmonic magnetic flux, and the eddy currents generated in the permanent magnet are a 4fc component. The 4fc component of the eddy currents generated in the permanent magnet is calculated as the sum of the products of the 2fc+f component and the 2fc-f component. In order to reduce the 4fc component of the eddy currents generated in the permanent magnet, the carrier frequency should be set taking into account the skin depth.

[0076] The carrier frequency of the power converter is fc, the thickness of the permanent magnet in the magnetization direction is W, and the relative permeability of the permanent magnet is μ r In order to remove the 4fc component of the eddy current generated in the permanent magnet, the carrier frequency fc must be set to fc>4 / (πμ r μ0σW 2 ) can be determined so as to satisfy the relationship: The control unit 5 reduces the eddy current components generated in the permanent magnets above a certain level, thereby making the losses caused by the carriers in the stator and rotor more evident. Therefore, when the control unit 5 switches the carrier phase difference between the first and second groups, it can more effectively suppress temperature rises in locations where it is desired to suppress temperature rises.

[0077] When the semiconductor switching elements of the power converter are elements using silicon carbide (SiC), it is possible to switch the carrier phase at high speed by utilizing the heat dissipation property. The control unit 5 can more effectively suppress the temperature rise at a specific location of the rotating electric machine 2 by switching the carrier phase difference of each group. A multilevel inverter may be used for the power converter. Even when a multilevel inverter is used, the control unit 5 can suppress a temperature rise at a specific location of the rotating electric machine 2 by switching the carrier phase difference between the groups.

[0078] Next, a hardware configuration for realizing the functions of the control unit 5 will be described. The current command generating unit 51, the three-phase to two-phase converting unit 52, the current control unit 53, the two-phase to three-phase converting unit 54, the carrier wave generating unit 55 and the PWM signal generating unit 56 included in the control unit 5 are realized by processing circuits. That is, the control unit 5 includes a processing circuit for executing each process from step ST1 to step ST5 shown in Fig. 12. The processing circuit may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in a memory.

[0079] Fig. 17A is a block diagram showing a hardware configuration for realizing the functions of the control unit 5. Fig. 17B is a block diagram showing a hardware configuration for executing software for realizing the functions of the control unit 5. In Figs. 17A and 17B, the input interface 100 is an interface that relays signals output from, for example, the rotation angle sensor 21, the temperature detection unit 22, the rotating electric machine current detection unit 33, and the rotating electric machine current detection unit 43 to the control unit 5. The output interface 101 is an interface that relays on / off control signals output from the control unit 5 to the first group power conversion circuit 32 and the second group power conversion circuit 42.

[0080] When the processing circuit is the dedicated hardware processing circuit 102 shown in FIG. 17A, the processing circuit 102 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. The functions of the current command generating unit 51, the three-phase to two-phase conversion unit 52, the current control unit 53, the two-phase to three-phase conversion unit 54, the carrier wave generating unit 55 and the PWM signal generating unit 56 provided in the control unit 5 may be realized by separate processing circuits, or these functions may be realized together by a single processing circuit.

[0081] 17B, ​​the functions of the current command generating unit 51, the three-phase to two-phase converting unit 52, the current control unit 53, the two-phase to three-phase converting unit 54, the carrier wave generating unit 55, and the PWM signal generating unit 56 included in the control unit 5 are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 104.

[0082] The processor 103 reads out and executes the programs stored in the memory 104 to realize the functions of the current command generating unit 51, the three-phase to two-phase converting unit 52, the current control unit 53, the two-phase to three-phase converting unit 54, the carrier wave generating unit 55, and the PWM signal generating unit 56 included in the control unit 5. For example, the control unit 5 includes a memory 104 for storing a program that, when executed by the processor 103, results in the processing of steps ST1 to ST5 shown in FIG. 12 being executed. These programs cause a computer to execute the procedure or method of the processing performed by the control unit 5. The memory 104 may be a computer-readable storage medium in which a program for causing a computer to function as the control unit 5 is stored.

[0083] Memory 104 may be, for example, a non-volatile or volatile semiconductor memory such as a Random Access Memory (RAM), a Read Only Memory (ROM), a flash memory, an Erasable Programmable Read Only Memory (EPROM), an Electrically-EPROM (EEPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD, etc.

[0084] Some of the functions of the current command generating unit 51, the three-phase to two-phase converting unit 52, the current control unit 53, the two-phase to three-phase converting unit 54, the carrier wave generating unit 55, and the PWM signal generating unit 56 included in the control unit 5 may be realized by dedicated hardware, and the remaining functions may be realized by software or firmware. For example, the current command generating unit 51, the three-phase to two-phase converting unit 52, the current control unit 53, and the two-phase to three-phase converting unit 54 are realized by a processing circuit 102 which is dedicated hardware, and the carrier wave generating unit 55 and the PWM signal generating unit 56 are realized by the processor 103 reading and executing a program stored in the memory 104. In this way, the processing circuit can realize the above functions by hardware, software, firmware, or a combination of these.

[0085] As described above, the rotating electric machine drive device 1 according to the first embodiment drives the rotating electric machine 2 including a stator having a three-phase stator winding driven by two systems, a first group and a second group, and a rotor which is a rotating body, and includes a first group power converter 3 and a second group power converter 4 which are provided corresponding to each group and convert DC power input from a DC power source 7 into a phase current and output it to the stator winding of each group, and a control unit 5 which outputs a control signal generated based on a carrier wave to control the first group power converter 3 and the second group power converter 4, and switches the phase of the carrier wave in each group when the temperature of a part of the rotating electric machine 2 is higher than the threshold temperature. When the temperature of a part of the rotating electric machine 2 is higher than the threshold temperature, the rotating electric machine drive device 1 can reduce losses occurring in each part of the rotating electric machine 2 and suppress a temperature rise in a part that exceeds the threshold temperature by switching the phase of the carrier wave in each group.

[0086] In the rotating electric machine drive device 1 according to the first embodiment, when the temperature of the stator of the rotating electric machine 2 is higher than the threshold temperature or the temperature of the rotor is higher than the threshold temperature, the control unit 5 changes the phase difference of the carrier waves in each group. This enables the rotating electric machine drive device 1 to reduce losses occurring in each portion of the rotating electric machine 2 and suppress temperature rises in portions that exceed the threshold temperature.

[0087] In the rotating electric machine drive device 1 according to the first embodiment, the rotating electric machine 2 is a multiple rotating electric machine having three-phase stator windings driven by two systems, group 1 and group 2. When the temperature of the stator of the rotating electric machine 2 is higher than the threshold temperature or the temperature of the rotor is higher than the threshold temperature, the control unit 5 changes the phase difference of the carrier waves in each group. This enables the rotating electric machine drive device 1 to reduce losses occurring in each portion of the rotating electric machine 2 and suppress temperature rises in portions that exceed the threshold temperature.

[0088] In the rotating electric machine drive device 1 according to the first embodiment, when the temperature of the stator is lower than the threshold temperature and the temperature of the rotor is lower than the threshold temperature, the control unit 5 sets the phase difference of the carrier waves in each group so as to minimize the loss of the rotating electric machine 2. This enables the rotating electric machine drive device 1 to reduce the loss occurring in each portion of the rotating electric machine 2 and suppress the temperature rise in the portion that exceeds the threshold temperature.

[0089] In the rotating electric machine drive device 1 according to the first embodiment, in the case of synchronous control in which the carrier frequency of the carrier wave is an integer multiple of the fundamental wave frequency, the control unit 5 aligns the phase of the carrier wave and the phase of the fundamental wave to 0. This makes it possible to reduce harmonic components, so that the rotating electric machine drive device 1 can reduce losses in the rotating electric machine 2 and suppress a rise in temperature thereof.

[0090] In the rotating electric machine drive device 1 according to the first embodiment, the first and second groups of stator windings are configured with windings spaced apart by an electrical angle of 30 degrees. Since multiple groups of windings can be arranged within one pole, the rotating electric machine drive device 1 can cancel out harmonics between the groups, thereby achieving low loss and low vibration.

[0091] In the rotating electric machine drive device 1 according to the first embodiment, the control unit 5 controls the phase current output from the first group power converter 3 to the first group stator winding and the phase current output from the second group power converter 4 to the second group stator winding so that their current amplitudes are equal, and controls so that the current phase difference between the first group and the second group is an electrical angle of 30 degrees. This enables the rotating electric machine drive device 1 to reduce losses occurring in each portion of the rotating electric machine 2 and suppress temperature rises in portions that exceed a threshold temperature.

[0092] The rotating electric machine drive device 1 according to the first embodiment includes a first group power converter 3 that outputs a phase current to a first group of stator windings, and a second group power converter 4 that outputs a phase current to a second group of stator windings. A control unit 5 controls the carrier frequencies of the first group and the second group to be equal. This allows the rotating electric machine drive device 1 to reduce losses occurring in each portion of the rotating electric machine 2 and suppress temperature rises in portions that exceed a threshold temperature.

[0093] In the rotating electric machine drive device 1 according to the first embodiment, when the rotor temperature is higher than the threshold temperature and n is an integer, the control unit 5 controls the phase difference of the carrier waves between the first and second groups to be (90+180×n) degrees. This enables the rotating electric machine drive device 1 to suppress an increase in the rotor temperature.

[0094] In the rotating electric machine drive device 1 according to the first embodiment, when the rotor temperature is higher than the threshold temperature, the control unit 5 increases the current amplitude and the current advance angle of the phase current output from the first group power converter 3 to the first group of stator windings and the phase current output from the second group power converter 4 to the second group of stator windings. This enables the rotating electric machine drive device 1 to suppress an increase in the stator temperature.

[0095] In the rotating electric machine drive device 1 according to the first embodiment, when the temperature of the stator is higher than the threshold temperature and n is an integer, the control unit 5 controls the phase difference of the carrier waves between the first and second groups to be (180×n) degrees. This enables the rotating electric machine drive device 1 to suppress an increase in the stator temperature.

[0096] In the rotating electric machine drive device 1 according to the first embodiment, when the temperature of the stator is higher than the threshold temperature and the modulation factor is higher than the threshold, the control unit 5 reduces the current amplitude and the current advance angle of the phase currents output from the power converters 3 and 4 in the first and second groups. This enables the rotating electric machine drive device 1 to suppress an increase in the stator temperature.

[0097] In the rotating electric machine drive device 1 according to the first embodiment, the threshold value for the modulation factor is 0.6. The rotating electric machine drive device 1 controls the modulation factor using this threshold value to reduce losses caused by the carrier secondary component, thereby making it possible to suppress a rise in the temperature of the stator.

[0098] The rotating electric machine drive device 1 according to the first embodiment includes a first group power converter 3 that outputs a phase current to a first group of stator windings, and a second group power converter 4 that outputs a phase current to a second group of stator windings. A control unit 5 controls the carrier frequencies of the first and second groups so as to satisfy the relationship fc1+2f=2fc2-f, where f is the fundamental frequency of the rotating electric machine 2, fc1 is the carrier frequency of the carrier wave of the first group power converter 3, and fc2 is the carrier frequency of the carrier wave of the second group power converter 4. This allows the rotating electric machine drive device 1 to selectively suppress a temperature rise of the stator.

[0099] In the rotary electric machine drive device 1 according to the first embodiment, the rotary electric machine 2 has a permanent magnet as a rotor. The control unit 5 calculates the carrier frequency as fc (Hz), the thickness of the permanent magnet in the magnetization direction as W (m), and the relative permeability of the permanent magnet as μ r If the conductivity of the permanent magnet is σ(S / m) and the vacuum permeability is μ0, the carrier frequency is fc>4 / (πμ r μ0σW 2 The first group power converter 3 and the second group power converter 4 are controlled so as to satisfy the relationship shown in FIG. In the rotating electric machine drive device 1, the carrier-induced losses in the stator and rotor become clearer by reducing a specific component or more of the eddy current components generated in the permanent magnets. Therefore, when the carrier phase difference between the first and second groups is switched, the temperature rise in the places where it is desired to suppress the temperature rise can be suppressed more effectively.

[0100] In the rotating electric machine drive device 1 according to the first embodiment, the first group power converter 3 and the second group power converter 4 have an inverter circuit in which six semiconductor switching elements using silicon carbide are connected in a full bridge. The rotating electric machine drive device 1 can more effectively suppress temperature rises at specific locations of the rotating electric machine 2 by controlling this inverter circuit to switch the carrier phase difference between the groups.

[0101] In the rotating electric machine driving method according to the first embodiment, the control unit 5 controls the phase difference of the carrier waves between the first and second groups to be (90+180×n) degrees when the rotor temperature is higher than the threshold temperature and n is an integer, controls the phase difference of the carrier waves between the first and second groups to be (180×n) degrees when the stator temperature is higher than the threshold temperature and n is an integer, and sets the phase difference of the carrier waves in each group so as to minimize loss in the rotating electric machine 2 when the stator temperature is lower than the threshold temperature and the rotor temperature is lower than the threshold temperature. By the control unit 5 executing the above method, it is possible to realize a rotating electric machine driving device 1 that can reduce losses occurring in each portion of the rotating electric machine 2 and suppress temperature rises in portions that exceed the threshold temperature.

[0102] Various aspects of the present disclosure are summarized below as appendices.

[0103] (Appendix 1) A rotating electric machine drive device that drives a rotating electric machine including a stator having a plurality of groups of stator windings of three or more phases and a rotor that is a rotating body, a plurality of groups of power converters provided corresponding to the respective groups, each of which converts DC power input from a power source into a phase current and outputs the phase current to the stator winding of the respective group; a control unit that outputs a control signal generated based on a carrier wave to control the power converters of each group, and switches the phase of the carrier wave in each group when a temperature of a part of the rotating electric machine is higher than a threshold temperature. A rotating electric machine drive device comprising: (Appendix 2) The control unit changes a phase difference of the carrier waves in each group when a temperature of the stator of the rotating electric machine is higher than the threshold temperature or when a temperature of the rotor of the rotating electric machine is higher than the threshold temperature. 2. A rotating electric machine drive device according to claim 1. (Appendix 3) the rotating electric machine is a multiple rotating electric machine including the three-phase stator windings driven by two systems, a first group and a second group, The control unit changes a phase difference of the carrier waves in each group when a temperature of the stator of the rotating electric machine is higher than the threshold temperature or when a temperature of the rotor of the rotating electric machine is higher than the threshold temperature. 2. A rotating electric machine drive device according to claim 1. (Appendix 4) The control unit sets a phase difference between the carrier waves in each group so that loss in the rotating electric machine is minimized when the temperature of the stator is lower than the threshold temperature and when the temperature of the rotor is lower than the threshold temperature. 4. The rotating electric machine drive device according to claim 3. (Appendix 5) The control unit aligns the phase of the carrier wave and the phase of the fundamental wave to 0 when synchronous control is performed in which the carrier frequency of the carrier wave is an integer multiple of the fundamental wave frequency. 5. The rotating electric machine drive device according to claim 2, (Appendix 6) The first and second groups of stator windings are arranged at intervals of 30 electrical degrees. 4. The rotating electric machine drive device according to claim 3. (Appendix 7) The control unit controls so that a phase current output from the power converter of group 1 to the stator winding of group 1 and a phase current output from the power converter of group 2 to the stator winding of group 2 have equal current amplitudes, and controls so that a current phase difference between group 1 and group 2 is 30 electrical degrees. 7. The rotating electric machine drive device according to claim 6, (Appendix 8) the power converter includes a first group of the power converters that outputs a phase current to a first group of the stator windings, and a second group of the power converters that outputs a phase current to a second group of the stator windings, The control unit controls the first and second groups so that their carrier frequencies are equal. 4. The rotating electric machine drive device according to claim 3. (Appendix 9) The control unit controls the phase difference of the carrier waves between the first group and the second group to be (90+180×n) degrees when the temperature of the rotor is higher than the threshold temperature and n is an integer. 9. The rotating electric machine drive device according to claim 8, (Appendix 10) When the temperature of the rotor is higher than the threshold temperature, the control unit increases a current amplitude and a current advance angle of a phase current output from a first group of the power converters to a first group of the stator windings and a phase current output from a second group of the power converters to a second group of the stator windings. 10. The rotating electric machine drive device according to claim 9, (Appendix 11) The control unit controls the phase difference of the carrier waves between the first group and the second group to be (180×n) degrees when the temperature of the stator is higher than the threshold temperature and n is an integer. 9. The rotating electric machine drive device according to claim 8, (Appendix 12) The control unit reduces a current amplitude and a current advance angle of a phase current output from the power converter in a first group and a second group when the temperature of the stator is higher than the threshold temperature and a modulation rate is greater than a threshold. 12. The rotating electric machine drive device according to claim 11, (Appendix 13) The threshold for the modulation rate is 0.6. 13. The rotating electric machine drive device according to claim 12. (Appendix 14) the power conversion circuit includes a first group of the power converters that outputs a phase current to a first group of the stator windings, and a second group of the power converters that outputs a phase current to a second group of the stator windings, The control unit controls the carrier frequencies of the first and second groups so as to satisfy the relationship fc1+2f=2fc2-f, where f is a fundamental frequency of the rotating electric machine, fc1 is a carrier frequency of the carrier wave of the power converter of the first group, and fc2 is a carrier frequency of the carrier wave of the power converter of the second group. 4. The rotating electric machine drive device according to claim 3. (Appendix 15) the rotating electric machine has a permanent magnet as the rotor, The control unit defines a carrier frequency as fc (Hz), a thickness of the permanent magnet in the magnetization direction as W (m), and a relative permeability of the permanent magnet as μ r If the electrical conductivity of the permanent magnet is σ(S / m) and the vacuum permeability is μ0, the carrier frequency is fc>4 / (πμ r μ0σW 2 ) to control the power converter so as to satisfy the relationship shown in 15. The rotating electric machine drive device according to claim 1, (Appendix 16) The power conversion circuit has an inverter circuit in which six semiconductor switching elements using silicon carbide are connected in a full bridge configuration for each group. 16. The rotating electric machine drive device according to claim 1, (Appendix 17) The present invention drives a rotating electric machine having a stator having multiple groups of stator windings of three or more phases and a rotor which is a rotating body, a plurality of groups of power converters provided corresponding to the respective groups, each of which converts DC power input from a power source into a phase current and outputs the phase current to the stator winding of the respective group; a control unit that outputs a control signal generated based on a carrier wave to control the power converters of each group, The control unit: When the temperature of the rotor is higher than a threshold temperature and n is an integer, a phase difference between the first group and the second group of the carrier waves is controlled to be (90+180×n) degrees; When the temperature of the stator is higher than a threshold temperature and n is an integer, a phase difference between the first group and the second group of the carrier waves is controlled to be (180×n) degrees; When the temperature of the stator is lower than a threshold temperature and the temperature of the rotor is lower than a threshold temperature, a phase difference of the carrier waves in each group is set so that loss of the rotating electric machine is minimized. A method for driving a rotating electric machine comprising the steps of:

[0104] Any of the components of the embodiments may be modified or omitted. [Explanation of symbols]

[0105] 1 Rotating electric machine drive device, 2 Rotating electric machine, 2a AC bus, 3 1st group power converter, 3a, 3b DC bus, 4 2nd group power converter, 5 Control unit, 6a, 6b Power switch, 7 DC power supply, 21 Rotation angle sensor, 22 Temperature detection unit, 31 1st group capacitor, 32 1st group power conversion circuit, 33, 43 Rotating electric machine current detection unit, 41 2nd group capacitor, 42 2nd group power conversion circuit, 51 Current command generation unit, 52 Three-phase to two-phase conversion unit, 53 Current control unit, 54 Two-phase to three-phase conversion unit, 55 Carrier wave generation unit, 56 PWM signal generation unit, 100 Input interface, 101 Output interface, 102 Processing circuit, 103 Processor, 104 Memory, 201 Stator, 202 Winding, 211 Rotor, 212 Permanent magnet, 213 rotor bars, 321-326, 421-426 switching elements;

Claims

1. A rotating electric machine drive device that drives a rotating electric machine including a stator having a plurality of groups of stator windings of three or more phases and a rotor that is a rotating body, a plurality of groups of power converters provided corresponding to the respective groups, each of which converts DC power input from a power source into a phase current and outputs the phase current to the stator winding of the respective group; a control unit that outputs a control signal generated based on a carrier wave to control the power converters of each group, and switches the phase of the carrier wave in each group when a temperature of a part of the rotating electric machine is higher than a threshold temperature. A rotating electric machine drive device comprising:

2. The control unit changes a phase difference of the carrier waves in each group when a temperature of the stator of the rotating electric machine is higher than the threshold temperature or when a temperature of the rotor of the rotating electric machine is higher than the threshold temperature.

2. The rotating electric machine drive device according to claim 1.

3. the rotating electric machine is a multiple rotating electric machine including three-phase stator windings driven by two systems, a first group and a second group, The control unit changes a phase difference of the carrier waves in each group when a temperature of the stator of the rotating electric machine is higher than the threshold temperature or when a temperature of the rotor of the rotating electric machine is higher than the threshold temperature.

2. The rotating electric machine drive device according to claim 1.

4. The control unit sets a phase difference between the carrier waves in each group so that loss in the rotating electric machine is minimized when the temperature of the stator is lower than the threshold temperature and when the temperature of the rotor is lower than the threshold temperature.

4. The rotating electric machine drive device according to claim 3.

5. The control unit aligns the phase of the carrier wave and the phase of the fundamental wave to 0 in a case where the carrier frequency of the carrier wave is an integer multiple of a fundamental wave frequency.

5. The rotating electric machine drive device according to claim 2, wherein the rotating electric machine drive device is a drive device for rotating an electric machine.

6. The first and second groups of stator windings are arranged at intervals of 30 electrical degrees.

4. The rotating electric machine drive device according to claim 3.

7. The control unit controls so that a phase current output from a first group of the power converter to the first group of the stator windings and a phase current output from a second group of the power converter to the second group of the stator windings have equal current amplitudes, and controls so that a current phase difference between the first group and the second group is 30 degrees electrical angle.

7. The rotating electric machine drive device according to claim 6.

8. the power converter includes a first group of the power converters that outputs a phase current to a first group of the stator windings, and a second group of the power converters that outputs a phase current to a second group of the stator windings, The control unit controls the first and second groups so that their carrier frequencies are equal to each other.

4. The rotating electric machine drive device according to claim 3.

9. The control unit controls the phase difference of the carrier waves between the first group and the second group to be (90+180×n) degrees when the temperature of the rotor is higher than the threshold temperature and n is an integer.

9. The rotating electric machine drive device according to claim 8.

10. When the temperature of the rotor is higher than the threshold temperature, the control unit increases a current amplitude and a current advance angle of a phase current output from a first group of the power converters to a first group of the stator windings and a phase current output from a second group of the power converters to a second group of the stator windings.

10. The rotating electric machine drive device according to claim 9.

11. The control unit controls the phase difference of the carrier waves between the first group and the second group to be (180×n) degrees when the temperature of the stator is higher than the threshold temperature and n is an integer.

9. The rotating electric machine drive device according to claim 8.

12. The control unit reduces a current amplitude and a current advance angle of a phase current output from the power converter in the first group and the second group when the temperature of the stator is higher than the threshold temperature and the modulation factor is greater than a threshold. The rotating electric machine drive device according to claim 11 .

13. The threshold for the modulation ratio is 0.

6.

13. The rotating electric machine drive device according to claim 12.

14. the power converter includes a first group of the power converters that outputs a phase current to a first group of the stator windings, and a second group of the power converters that outputs a phase current to a second group of the stator windings, The control unit controls the carrier frequencies of the first and second groups so as to satisfy the relationship fc1+2f=2fc2-f, where f is a fundamental frequency of the rotating electric machine, fc1 is a carrier frequency of the carrier wave of the first group of the power converter, and fc2 is a carrier frequency of the carrier wave of the second group of the power converter.

4. The rotating electric machine drive device according to claim 3.

15. the rotating electric machine has a permanent magnet as the rotor, The control unit defines a carrier frequency as fc (Hz), a thickness of the permanent magnet in the magnetization direction as W (m), and a relative permeability of the permanent magnet as μ ｒ The electrical conductivity of the permanent magnet is σ (S / m), and the vacuum permeability is μ ０ In this case, the carrier frequency is fc>4 / (πμ ｒ μ ０ σ ２ The power converter is controlled so as to satisfy the relationship shown in 2. The rotating electric machine drive device according to claim 1.

16. The power converter has an inverter circuit in which six semiconductor switching elements using silicon carbide are connected in a full bridge configuration for each group.

2. The rotating electric machine drive device according to claim 1.

17. The present invention drives a rotating electric machine having a stator having multiple groups of stator windings of three or more phases and a rotor which is a rotating body, a plurality of groups of power converters provided corresponding to the respective groups, each of which converts DC power input from a power source into a phase current and outputs the phase current to the stator winding of the respective group; a control unit that outputs a control signal generated based on a carrier wave to control the power converters of each group, The control unit: When the temperature of the rotor is higher than a threshold temperature and n is an integer, a phase difference between the first group and the second group of the carrier waves is controlled to be (90 + 180 × n) degrees; When the temperature of the stator is higher than a threshold temperature and n is an integer, a phase difference between the first group and the second group of the carrier waves is controlled to be (180×n) degrees; When the temperature of the stator is lower than a threshold temperature and the temperature of the rotor is lower than a threshold temperature, a phase difference of the carrier waves in each group is set so that loss of the rotating electric machine is minimized. A method for driving a rotating electric machine comprising the steps of:

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