Rotating electric machine driving device and rotating electric machine driving method

Abstract

A rotary electric machine drive device (1) is provided with: a plurality of sets of power converters (3) and (4) that are provided so as to correspond to each set, convert DC power input from a DC power source (7) into phase currents, and output the phase currents to stator windings of each set; and a control unit (5) that outputs a control signal generated on the basis of the carrier waves, controls the power converters (3) and (4) of each group, and switches the phase of the carrier waves in each group when the temperature of a part of the rotating electrical machine (2) is higher than a threshold temperature.

Description

Technical Field

[0001] This disclosure relates to a rotary motor drive device and a rotary motor drive method. Background Technology

[0002] As a drive device for rotating electric machines, a multi-drive technology is known to drive a rotating electric machine by using multiple sets of power conversion devices. When a rotating electric machine is driven by PWM (Pulse Width Modulation) control, high-order harmonic currents flow through the rotating electric machine, and these high-order harmonic currents become the main cause of increased losses and vibrations in the rotating electric machine.

[0003] Furthermore, when using multiple power conversion devices, there is a control technique that causes the phases of the higher harmonic current components generated in each group to be staggered. For example, Patent Document 1 describes a drive system that applies equal but opposite AC voltages to a rotating motor with two sets of three-phase windings having an electrical angle difference of 180 degrees.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2014 / 132385 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] In the prior art described in Patent Document 1, inductance can be increased and current ripple reduced by applying alternating voltages with opposite phases to two sets of three-phase windings in a rotating motor. However, Patent Document 1 does not describe control measures to reduce losses in the rotating motor, resulting in a technical problem where increased losses in various parts of the rotating motor lead to temperature rise.

[0009] This disclosure was made to solve the above-mentioned technical problems, and its purpose is to obtain a rotary motor drive device that can reduce the losses generated in various parts of the rotary motor and suppress the temperature rise of parts that exceed the threshold temperature.

[0010] Technical solutions to solve technical problems

[0011] The rotary motor drive device disclosed herein is a rotary motor drive device for driving a rotary motor, the rotary motor including a stator having multiple sets of stator windings with three or more phases, and a rotor as a rotating body. The rotary motor drive device includes: multiple sets of power converters, each set corresponding to a specific set, which convert DC power input from a power source into phase current and output it to the stator windings of each set; and a control unit that outputs control signals generated based on carrier waves to control the power converters of each set, and switches the phase of the carrier wave in each set when the temperature of a part of the rotary motor is higher than a threshold temperature.

[0012] Invention Effects

[0013] According to this disclosure, when the temperature of a part of a rotating electric motor is higher than a threshold temperature, by switching the phase of the carrier wave in each group, it is possible to reduce the losses generated in various parts of the rotating electric motor and suppress the temperature rise of the parts that exceed the threshold temperature. Attached Figure Description

[0014] Figure 1 This is a circuit diagram illustrating a structural example of the rotary motor drive device according to Embodiment 1.

[0015] Figure 2 This is a block diagram illustrating a structural example of the control unit involved in Embodiment 1.

[0016] Figure 3 This is a cross-sectional view showing the cross-section of a permanent magnet synchronous rotating motor.

[0017] Figure 4 This is a cross-sectional view showing the cross-section of an induction rotary motor.

[0018] Figure 5 This is a cross-sectional view of the winding structure of group 1 and group 2 in a rotating electric motor with 2 slots per pole per phase (hereinafter referred to as per pole per phase (2)).

[0019] Figure 6 This is a cross-sectional view of the winding structure of group 1 and group 2 in a rotary electric machine with 4 slots per pole per phase (hereinafter referred to as per pole per phase (4)).

[0020] Figure 7 It is a graph showing the amplitude of the phase current relative to the phase for groups 1 and 2.

[0021] Figure 8 This is a waveform diagram representing carrier wave group 1 and carrier wave group 2.

[0022] Figure 9 It is a waveform diagram that emphasizes and represents the phase difference between carriers in group 1 and carriers in group 2 by expanding the phase range.

[0023] Figure 10 It is a graph representing the rotor loss relative to the carrier phase difference between groups 1 and 2.

[0024] Figure 11 It is a graph representing the stator loss relative to the carrier phase difference between groups 1 and 2.

[0025] Figure 12 This is a flowchart illustrating the rotary motor driving method according to Embodiment 1.

[0026] Figure 13 It is a waveform diagram representing the triangular wave carrier and the phase voltage signal wave.

[0027] Figure 14 It is a graph representing the amplitude of the higher harmonic voltage relative to the DC voltage in the first component of the carrier wave as a function of the modulation rate.

[0028] Figure 15 It is a graph representing the amplitude of the higher harmonic voltage relative to the DC voltage in the second component of the carrier wave, as a function of the modulation rate.

[0029] Figure 16 It is a graph showing the higher harmonic components of the carrier wave that appear in groups 1 and 2 for frequency and rotation speed.

[0030] Figure 17A and Figure 17B This is a block diagram illustrating the hardware structure that implements the functions of the control unit of the rotary electric motor drive device according to Embodiment 1. Detailed Implementation

[0031] Implementation method 1.

[0032] Figure 1 This is a circuit diagram illustrating a structural example of the rotary electric motor drive device 1 according to Embodiment 1. Figure 1 In this configuration, the rotary motor drive unit 1 drives the rotary motor 2, and it comprises a power converter 3, a power converter 4, and a control unit 5. The DC bus 3a is switched on and off via a power switch 6a, and the DC bus 3b is switched on and off via a power switch 6b. The power converters 3 and 4 are connected to a DC power supply 7 via the DC buses 3a and 3b, respectively, receiving drive power from the DC power supply 7 and outputting regenerative power to the DC power supply 7. Additionally, the power converters 3 and 4 are connected to the rotary motor 2 via an AC bus 2a, outputting drive power to the rotary motor 2 and receiving regenerative power from the rotary motor 2.

[0033] The rotary motor 2 is a rotary motor comprising: a stator having multiple sets of stator windings with three or more phases, and a rotor as a rotating body. The rotary motor 2 includes: a rotation angle sensor 21 for detecting the rotation angle of the rotor, and a temperature detection unit 22 for detecting the temperature of the stator and the temperature of the rotor. For example, the rotary motor 2 is a multi-phase rotary motor comprising three-phase stator windings driven by two systems, one set and two sets.

[0034] The power converter 3 is a set of power converters including a set of capacitors 31, a set of power conversion circuits 32, and a rotating motor current detection unit 33. "Set 1" indicates the first set. The capacitor 31 is a smoothing capacitor connected between DC bus 3a and DC bus 3b on the power input side of the power conversion circuit 32. The power conversion circuit 32 includes switching elements 321 to 326, and performs DC-AC power conversion through the switching operation of the switching elements 321 to 326. The rotating motor current detection unit 33 detects the current flowing through the rotating motor 2 on the AC bus 2a.

[0035] One power conversion circuit 32 is an inverter circuit composed of switching elements 321, 322, 323, 324, 325, and 326 connected in a full-bridge configuration. In the power conversion circuit 32, switching elements 321 and 322 are connected in series, switching elements 323 and 324 are connected in series, and switching elements 325 and 326 are connected in series. The series-connected switching elements 321 and 322, 323 and 324, and 325 and 326 are connected in parallel with respect to the DC power supply 7.

[0036] At the connection point of the series-connected switching elements 321 and 322, one set of U-phase input terminals of the rotating electric machine 2 is connected. At the connection point of the series-connected switching elements 323 and 324, one set of V-phase input terminals of the rotating electric machine 2 is connected. At the connection point of the series-connected switching elements 325 and 326, one set of W-phase input terminals of the rotating electric machine 2 is connected. Here, the switching elements 321, 323, and 325 connected to the DC bus 3a are referred to as the upper-side switching elements, and the switching elements 322, 324, and 326 connected to the DC bus 3b are referred to as the lower-side switching elements.

[0037] Switching elements 321-326, for example, use... Figure 1The MOSFET (Metal Oxide Semiconductor Field Effect Transistor) shown is an example. In addition to MOSFETs, IGBTs (Insulated Gate Bipolar Transistors) and other transistors can also be used.

[0038] For each MOSFET that serves as a switching element 321 to 326, a freewheeling diode (FWD) is connected in parallel in the positive direction from the negative side to the positive side of the DC power supply 7, i.e., from the lower section side to the upper section side.

[0039] The two-group power converter 4 comprises two sets of capacitors 41, two sets of power conversion circuits 42, and a rotating motor current detection unit 43. "Two sets" indicates the second set. The two sets of capacitors 41 are smoothing capacitors connected between DC bus 3a and DC bus 3b on the power input side of the two-group power conversion circuits 42. The two-group power conversion circuits 42 include switching elements 421 to 426, which perform DC-AC power conversion through the switching operation of the switching elements 421 to 426. The rotating motor current detection unit 43 detects the current flowing through the AC bus 2a of the rotating motor 2.

[0040] The two power conversion circuits 42 are inverter circuits formed by connecting switching elements 421, 422, 423, 424, 425, and 426 in a full-bridge configuration. In the two power conversion circuits 42, switching elements 421 and 422 are connected in series, switching elements 423 and 424 are connected in series, and switching elements 425 and 426 are connected in series. The series-connected switching elements 421 and 422, 423 and 424, and 425 and 426 are connected in parallel with respect to the DC power supply 7.

[0041] At the connection point of the series-connected switching elements 421 and 422, two sets of U-phase input terminals of the rotating motor 2 are connected. At the connection point of the series-connected switching elements 423 and 424, two sets of V-phase input terminals of the rotating motor 2 are connected. At the connection point of the series-connected switching elements 425 and 426, two sets of W-phase input terminals of the rotating motor 2 are connected. Here, the switching elements 421, 423, and 425 connected to the DC bus 3a are referred to as the upper-side switching elements, and the switching elements 422, 424, and 426 connected to the DC bus 3b are referred to as the lower-side switching elements.

[0042] Switching elements 421-426, for example, use... Figure 1 The MOSFET shown is an example. In addition to MOSFETs, IGBTs and other similar devices can also be used.

[0043] For each MOSFET that serves as a switching element 421 to 426, a freewheeling diode (FWD) is connected in parallel in the positive direction from the negative side to the positive side of the DC power supply 7, i.e., from the lower section side to the upper section side.

[0044] The same type of semiconductor switching element can be used in both power converter 3 and power converter 4, but different elements can also be used.

[0045] For example, when using the same type of semiconductor switching elements, the switching elements of power converter 3 and power converter 4 can be MOSFETs or IGBTs. Alternatively, when using different types of semiconductor switching elements, the switching elements of power converter 3 can be MOSFETs, and the switching elements of power converter 4 can be IGBTs.

[0046] In addition, the switching operation of the switching elements of the power converter 3 and the power converter 4 is controlled by the control unit 5.

[0047] The rotating motor current detection unit 33 detects the current flowing through the AC bus 2a, converts the current into voltage, and outputs the rotating motor current information to the control unit 5. Figure 1 In the example, the current is detected by a shunt resistor, which is used as the current detection unit 33 of the rotating electric machine. Alternatively, the current detection unit 33 of the rotating electric machine can also be implemented using a current sensor that employs a magnetic sensor such as a Hall element.

[0048] Power switch 6a controls the power exchange between DC power supply 7 and one set of power converters 3, and power switch 6b controls the power exchange between DC power supply 7 and two sets of power converters 4. Power switches 6a and 6b are suppressed to an open-circuit state by the upper-level system when the voltage of DC power supply 7 becomes above a set value during regenerative operation of the rotating motor 2, when the voltage of DC power supply 7 becomes below a set value due to power consumption, or when the current flowing through DC power supply 7 becomes above a set value.

[0049] In addition, power switches 6a and 6b can be configured to be controlled by control unit 5.

[0050] The rotation angle sensor 21 detects the rotation angle of the rotor of the rotary electric motor 2 using a rotary transformer, encoder, or magnetic sensor. The information indicating the rotation angle of the rotor detected by the rotation angle sensor 21 is output to the control unit 5.

[0051] The temperature detection unit 22 detects the temperature of the stator and the rotor of the rotary motor 2. Information indicating the temperature of each part of the rotary motor 2 detected by the temperature detection unit 22 is output to the control unit 5. Alternatively, a temperature detection unit 22 that detects the temperature of each part of the rotary motor 2 using different methods can be used. For example, the temperature detection unit 22 can be a thermistor or a thermocouple.

[0052] Figure 1 The rotary electric motor drive unit 1 shown includes one set of power converters 3 and two sets of power converters 4, but is not limited to this. That is, the rotary electric motor drive unit 1 can be not only one or two sets of systems, but can also have more than three sets of systems. For example, the rotary electric motor drive unit 1 has more than three sets of smoothing capacitors, power conversion circuits, rotary electric motor current detection units, and switching elements of the power conversion circuits.

[0053] The control unit 5 outputs a control signal generated based on a carrier wave to control a group of power converters 3 and 4. When the temperature of a part of the rotating motor 2 is higher than a threshold temperature, the phase of the carrier wave in each group is switched.

[0054] Figure 2 This is a block diagram illustrating a structural example of control unit 5. Figure 2 In the middle, the control unit 5 includes a current command generation 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 generation unit 55, and a PWM signal generation unit 56.

[0055] The current command generation unit 51 is based on the torque command Trq. Generate a set of d-axis current command values ​​Id1 And one set of q-axis current command values ​​Iq1 , and 2 sets of d-axis current command values ​​Id2 And two sets of q-axis current command values ​​Iq2 Here, the d-axis represents the direction of magnetic flux generation by the rotor (permanent magnet) of the rotary electric machine 2, and the q-axis is an axis electrically orthogonal to the d-axis. Torque command Trq This refers to control information specifying the rotor torque of the rotating electric motor 2. This information is generated, for example, by a host system controlling the rotating electric motor drive device 1, and the current command generation unit 51 obtains it from the host system. One set of d-axis current command values ​​Id1 This refers to the current command value along the d-axis of group 1, and the current command value Iq1 along the q-axis of group 1. This is the q-axis current command value for group 1. Group 2 is the d-axis current command value Id2. These are two sets of current command values ​​along the d-axis and two sets of current command values ​​along the q-axis, Iq2. These are the current command values ​​in the q-axis direction for groups 2.

[0056] Alternatively, the current command generation unit 51 may include multiple current command maps for torque commands created using prior measured or simulated results. In this case, as a torque command Trq... Upon retrieving the mapping result, the current command generation unit 51 generates a set of d-axis current command values ​​Id1. And one set of q-axis current command values ​​Iq1 , and 2 sets of d-axis current command values ​​Id2 And two sets of q-axis current command values ​​Iq2 .

[0057] The three-phase to two-phase conversion unit 52 receives one set of U-phase current Iu1, one set of V-phase current Iv1, and one set of W-phase current Iw1 from the rotating motor current detection unit 33, and two sets of U-phase current Iu2, two sets of V-phase current Iv2, and two sets of W-phase current Iw2 from the rotating motor current detection unit 43. It also receives the electrical angle θe from the rotation angle sensor 21. The one set of U-phase current Iu1 is the current value flowing through the first set of U-phase stator windings; the one set of V-phase current Iv1 is the current value flowing through the first set of V-phase stator windings; and the one set of W-phase current Iw1 is the current value flowing through the first set of W-phase stator windings. The two sets of U-phase current Iu2 are the current values ​​flowing through the second set of U-phase stator windings; the two sets of V-phase current Iv2 are the current values ​​flowing through the second set of V-phase stator windings; and the two sets of W-phase current Iw2 are the current values ​​flowing through the second set of W-phase stator windings. The electrical angle θe is the rotation angle of the rotor of the rotating motor 2.

[0058] The three-phase to two-phase conversion unit 52 performs three-phase to two-phase coordinate transformation based on one set of U-phase current Iu1, one set of V-phase current Iv1, one set of W-phase current Iw1, two sets of U-phase current Iu2, two sets of V-phase current Iv2, two sets of W-phase current Iw2, and the electrical angle θe. This transforms the one set of U-phase current Iu1, one set of V-phase current Iv1, and one set of W-phase current Iw1 into one set of d-axis current detection values ​​Id1 and one set of q-axis current detection values ​​Iq1, and transforms the two sets of U-phase current Iu2, two sets of V-phase current Iv2, and two sets of W-phase current Iw2 into two sets of d-axis current detection values ​​Id2 and two sets of q-axis current detection values ​​Iq2. The d-axis current command value Id1 is the current command value in the d-axis direction of the unit, and the q-axis current command value Iq1 is the current command value in the q-axis direction of the unit. The two sets of d-axis current command values ​​Id2 are the current command values ​​in the d-axis direction of the two sets, and the two sets of q-axis current command values ​​Iq2 are the current command values ​​in the q-axis direction of the two sets.

[0059] A set of d-axis current command values ​​Id1 is input from the current command generation unit 51 to the current control unit 53. And one set of q-axis current command values ​​Iq1 , and 2 sets of d-axis current command values ​​Id2 And two sets of q-axis current command values ​​Iq2 In addition, the three-phase two-phase conversion unit 52 inputs one set of d-axis current command value Id1 and one set of q-axis current command value Iq1, and two sets of d-axis current command values ​​Id2 and two sets of q-axis current command values ​​Iq2 to the current control unit 53.

[0060] The current control unit 53 calculates a set of d-axis current command values ​​Id1. Calculate the d-axis current deviation between the d-axis current detection value Id1 and the q-axis current command value Iq1. Calculate the 1 set of q-axis current deviations from the 1 set of q-axis current detection values ​​Iq1, and calculate the 2 sets of d-axis current command values ​​Id2. Calculate the two sets of d-axis current deviations between the two sets of d-axis current detection values ​​Id2 and the two sets of q-axis current command values ​​Iq2. The two sets of q-axis current deviations are between the two sets of q-axis current detection values ​​Iq2. The current control unit 53 calculates one set of d-axis voltage command value Vd1 by performing proportional and integral control calculations on the current deviations of each set. And one set of q-axis voltage command values ​​Vq1 , and 2 sets of d-axis voltage command values ​​Vd2 And two sets of q-axis voltage command values ​​Vq2 .

[0061] The two-phase to three-phase conversion unit 54 is based on a set of d-axis voltage command values ​​Vd1. and 1 set of q-axis voltage command values ​​Vq1 Calculate the three-phase voltage command value Vu1 in the stationary coordinate system. Vv1 and Vw1 Based on two sets of d-axis voltage command values ​​Vd2 and 2 sets of q-axis voltage command values ​​Vq2 Calculate the two sets of three-phase voltage command values ​​Vu2 in the stationary coordinate system. Vv2 and Vw2 .

[0062] The three-phase voltage command values ​​for each group calculated by the two-phase to three-phase conversion unit 54 are output to the PWM signal generation unit 56. Group 1 U-phase voltage command value Vu1 It consists of one set of U-phase voltage command values ​​and one set of V-phase voltage command values, Vv1. It consists of one set of voltage command values ​​for phase V and one set of voltage command values ​​for phase W, Vw1. This is the voltage command value for phase W (set 1). It also includes the voltage command values ​​for phase U (set 2) (Vu2). These are two sets of U-phase voltage command values ​​and two sets of V-phase voltage command values ​​Vv2. These are two sets of V-phase voltage command values ​​and two sets of W-phase voltage command values, Vw2. These are the voltage command values ​​for the two W-phase groups.

[0063] The carrier generation unit 55 takes into account the stator temperature Tst, the rotor temperature Trt, one set of carrier frequencies fc1, and two sets of carrier frequencies fc2. Based on the relationship between the stator temperature Tst and the rotor temperature Trt and their respective threshold temperatures, it generates one set of triangular wave carriers e1 and two sets of triangular wave carriers e2. The stator temperature is the temperature of the stator windings. Furthermore, the temperature of the stator windings can be calculated using a thermistor, which is used as the temperature detection unit 22.

[0064] In addition, the temperature of the stator winding can be calculated by the temperature detection unit 22. In addition to thermistors, thermocouples can also be used, and the calculation can also be based on the losses of the thermal circuit and the rotating motor 2.

[0065] When the rotary motor 2 is a permanent magnet rotary motor, the temperature of the rotor is the temperature of the permanent magnet; when the rotary motor 2 is an induction rotary motor, it is the temperature of the rotor rod or end ring.

[0066] The temperature of the permanent magnet can be calculated using the induced voltage obtained from the rotary motor 2. When the temperature of the permanent magnet changes, the magnetic force of the permanent magnet changes, and therefore the induced voltage of the rotary motor 2 also changes. Therefore, by pre-identifying the correspondence between the temperature of the permanent magnet and the induced voltage, the temperature of the permanent magnet can be calculated using the induced voltage of the rotary motor 2.

[0067] When calculating the temperature of the permanent magnet, rotor rod, or end ring, a thermocouple can be used as the temperature sensing unit 22. When installing the thermocouple on the rotor, a slip ring can be used. Without using a slip ring, the rotor temperature can be calculated by releasing and acquiring the signal from the thermocouple as an electromagnetic wave signal. Alternatively, the rotor temperature can also be calculated from the losses in the thermal circuit and the rotating motor 2.

[0068] The carrier frequency is the frequency of the electrical angle 1 cycle of the triangular wave carrier.

[0069] For example, the carrier frequency of group 1 is the frequency of one electrical angle period of group 1 triangular wave carrier e1, and the carrier frequency of group 2 is the frequency of one electrical angle period of group 2 triangular wave carrier e2. The carrier generation unit 55 calculates the phase difference between group 1 triangular wave carrier e1 and group 2 triangular wave carrier e2 based on the relationship between stator temperature Tst and a predetermined stator temperature threshold, and the relationship between rotor temperature Trt and a rotor temperature threshold. Then, based on the calculated phase difference between group 1 triangular wave carrier e1 and group 2 triangular wave carrier e2, the carrier frequency fc1 of group 1, and the carrier frequency fc2 of group 2, the carrier generation unit 55 outputs group 1 triangular wave carrier e1 and group 2 triangular wave carrier e2.

[0070] Additionally, the carrier generation unit 55 may have a triangular wave carrier phase difference map, in which the phase difference of the triangular wave carrier is recorded corresponding to the stator temperature and the rotor temperature. In this case, the carrier generation unit 55 determines each group of triangular wave carriers by retrieving the triangular wave carrier phase difference map using the stator temperature and the rotor temperature.

[0071] The PWM signal generation unit 56 is based on a set of three-phase voltage command values ​​Vu1 generated by the two-phase to three-phase conversion unit 54. Vv1 and Vw1 2 sets of three-phase voltage command values ​​Vu2 Vv2 and Vw2 The system calculates the on / off control signals for each switching element of the power conversion circuit 32 and the power conversion circuit 42, based on the triangular wave carrier e1 and two triangular wave carrier e2 generated by the carrier generation unit 55, and the DC bus voltage Vpn.

[0072] The PWM signal generation unit 56 compares the three-phase voltage command value with the triangular wave carrier wave using a comparator, determines the on / off state of the switching element based on the comparison result, and generates on / off control signals for performing switching operations according to the determined on / off state. The on / off control signals include UH1, UL1, VH1, VL1, WH1, and WL1, which are output to the first power conversion circuit 32 as one set of on / off control signals, and UH2, UL2, VH2, VL2, WH2, and WL2, which are output to the second power conversion circuit 42 as two sets of on / off control signals.

[0073] The control unit 5 causes the switching elements 321 to 326 to switch on and off by sending on / off control signals UH1, UL1, VH1, VL1, WH1 and WL1 to the first power conversion circuit 32, and causes the switching elements 421 to 426 to switch on and off by sending on / off control signals UH2, UL2, VH2, VL2, WH2 and WL2 to the second power conversion circuit 42.

[0074] The control unit 5 converts the DC power input from the DC power supply 7 into AC power by controlling the switching operation of each switching element in each power conversion circuit, and supplies the converted AC power to the rotary motor 2. Furthermore, the control unit 5 charges the DC power supply 7 with regenerative power generated by the rotary motor 2 in regenerative mode by controlling the switching operation of each switching element in each power conversion circuit.

[0075] Figure 3 This is a cross-sectional view showing the section of a permanent magnet synchronous rotary motor, illustrating the cross-section obtained by cutting the motor in a plane perpendicular to the axial direction. In the rotary motor drive unit 1, the rotary motor 2 can also be a permanent magnet synchronous rotary motor. A permanent magnet synchronous rotary motor, as shown... Figure 3 As shown, the stator 201 has windings 202, and the rotor 211 has permanent magnets 212. Figure 3 In the case of a permanent magnet synchronous rotating motor, the permanent magnet synchronous rotating motor is a distributed winding with 6 poles and 36 slots per phase (2).

[0076] In addition, there are 2 slots per pole per phase (2). The stator 201 winding is composed of multiple sets of windings. In addition, other sets of windings can be formed in the same slot. The permanent magnets 212 of the rotor 211 are arranged in a V-shape across two layers. By arranging the permanent magnets in two layers, the distance between the permanent magnets 212 on the inner diameter side of the rotor 211 and the stator windings is increased. As a result, the influence of high-order harmonic flux caused by the carrier wave of the stator windings can be reduced. In addition, the eddy currents relative to the high-order harmonic flux are smaller, and the eddy current losses can be reduced.

[0077] Figure 4 This is a cross-sectional view showing the induction rotary motor, illustrating the cross-section obtained by cutting the induction rotary motor in a plane perpendicular to the axial direction. In the rotary motor drive unit 1, the rotary motor 2 can also be an induction rotary motor. An induction rotary motor, such as... Figure 4 As shown, the stator 201 has windings 202, and the rotor 211 has rotor rods 213. The rotor rods 213 are short-circuited at both ends in the axial direction via end rings. In the induction rotating motor, the rotating magnetic field generated by the stator windings links with the rotor 211, thereby inducing current to flow through the rotor rods 213, generating torque and causing rotation. Besides being circular, the rotor rods 213 can also be elliptical, or a double-cage shape with two rotor rod slots in the radial direction. In the double-cage shape, since the distance between the rotor rods 213 on the inner diameter side of the rotor 211 and the stator windings is increased, the influence of high-order harmonic flux caused by the carrier waves of the stator windings can be mitigated.

[0078] Figure 5This is a cross-sectional view showing the winding structure of Group 1 and Group 2 in each pole and phase (2). The slot spacing of the stator winding in each pole and phase (2) is an electrical angle θ = 180 / (3×2) = 30 degrees. The windings of Group 1 are U1, V1 and W1, and the windings of Group 2 are U2, V2 and W2. The windings of Group 1 and Group 2 are as follows: Figure 5 As shown, the winding is performed with an offset electrical angle θ = 30 degrees. By arranging multiple sets of windings within a single pole, higher harmonics can be canceled out between the sets, resulting in low loss and low vibration. Furthermore, by employing a multi-set structure, redundancy is achieved even in the event of a failure in any system.

[0079] in addition, Figure 5 The cross-section corresponding to pole 1 is shown. In each group, the direction above the U-phase winding is the positive direction, the direction above the V-phase winding is the positive direction, and the direction below the W-phase winding is the positive direction.

[0080] Figure 6 This is a cross-sectional view showing the winding structure of Group 1 and Group 2 in each pole and phase (4). The slot spacing of the stator winding in each pole and phase (4) is an electrical angle θ = 180 / (3×4) = 15 degrees. The windings of Group 1 are U1, V1 and W1, and the windings of Group 2 are U2, V2 and W2. The windings of Group 1 and Group 2 are as follows: Figure 6 As shown, the offset is equivalent to an electrical angle θ = 30 degrees for winding, which is equivalent to two slots.

[0081] Furthermore, in each pole and phase (4), there are 4 slots per pole and phase. In each pole and phase (4), with up to 4 groups of 4 systems, the windings of each group are wound with an electrical angle θ = 15 degrees equivalent to 1 slot. In the rotary motor drive device 1, as the number of systems increases, the carrier phase difference between each group can be more precisely staggered, and the higher harmonic flux can be reduced more precisely, thereby achieving the effects of low loss and low vibration.

[0082] Figure 7 This is a graph showing the amplitude of the phase currents relative to the phase in groups 1 and 2. Figure 7 In the diagram, I1 represents the relationship between the phase current of group 1 and the corresponding electrical angle, and I2 represents the relationship between the phase current of group 2 and the corresponding electrical angle. The control unit 5 controls the phase currents output from the power conversion circuits of each group to have equal amplitudes. Furthermore, the phase difference Δ12 between the phase currents of group 1 and group 2 is controlled to an electrical angle of 30 degrees. By controlling the phase difference of the energized current to be equal to the spatial phase difference (winding spacing) of groups 1 and 2, the control unit 5 can cancel out the higher harmonic components of groups 1 and 2.

[0083] For a rotary motor 2 with windings of groups 1 and 2 wound at an electrical angle of 30 degrees, the control unit 5 controls the current amplitudes of groups 1 and 2 to be equal, and controls the current phase difference between groups 1 and 2 to be an electrical angle of 30 degrees. As a result, the rotary motor drive unit 1 can eliminate torque pulsations and electromagnetic excitation forces of the component 6f (6 times the fundamental frequency f), achieving low vibration.

[0084] Furthermore, since an electrical angle of 30 degrees is equivalent to an electrical angle of 180 degrees in the 6f component, the torque ripples in the 6f component generated in system 1 are phase-reversed with those generated in system 2. Therefore, the torque ripples in the 6f component can be eliminated. Similarly, since the magnetic flux is also canceled out, the eddy currents caused by higher harmonic magnetic flux are reduced, resulting in lower losses.

[0085] Figure 8 This is a waveform diagram representing carrier waves in group 1 and group 2. In Figure 8 In this diagram, triangular wave A is a set of one triangular wave carriers, and triangular wave B is a set of two triangular wave carriers. The control unit 5 generates triangular waves based on the carrier frequencies of each set. For example, in the case of synchronization control where the carrier frequency is an integer multiple of the fundamental frequency f, the control unit 5 generates one set of triangular wave carriers as triangular wave A and two sets of triangular wave carriers as triangular wave B. For example, in one electrical angle cycle, triangular waves A and B have nine synchronization pulses spanning nine cycles.

[0086] Furthermore, the control unit 5 can also perform asynchronous control so that the carrier frequency is not an integer multiple of the fundamental frequency f. Even in the case of asynchronous control, the control unit 5 performs control based on the stator temperature and rotor temperature to switch the carrier phase difference ΔAB of each group.

[0087] Figure 9 It is a waveform diagram that emphasizes and represents the phase difference between carrier groups 1 and 2 by expanding the phase range. Figure 8 A magnified representation of the waveform. Figure 9 In the diagram, triangular wave A is a triangular wave carrier wave of group 1, and triangular wave B is a triangular wave carrier wave of group 2. The control unit 5 can perform either synchronous control or asynchronous control to control the phase difference ΔAB between groups 1 and 2. Figure 9 The carrier phase difference ΔAB between groups 1 and 2 represents the phase after conversion to one cycle of the rotating motor 2. Furthermore, since it is a synchronous 9-pulse system, the electrical angle θ = 360 / 9 = 40 degrees is one cycle of the carrier. The phase difference ΔAB between each group of carriers is used as the angle after conversion to one cycle of the carrier to control the system.

[0088] When the control unit 5 performs control so that the phase difference ΔAB between the carrier waves of groups 1 and 2 is 360 degrees, it deflects the electrical angle θ = 40 degrees in one cycle of the rotating motor 2.

[0089] In addition, the rectangular wave voltage calculated based on the comparison between the three-phase voltage command value and the triangular wave carrier contains higher harmonics other than the fundamental wave.

[0090] The higher harmonic components caused by the carrier wave appear as sideband waves that are integer multiples of the carrier frequency fc.

[0091] Relative to the fundamental frequency f, the typical frequency components of the higher harmonics contained in the rectangular wave voltage waveform are fc±2f and 2fc±f.

[0092] Since these higher harmonic components caused by the carrier wave appear in each group, the control unit 5 cancels the magnetic flux of the higher harmonics caused by the carrier wave by changing the phase difference of the carrier wave in each group.

[0093] Given a spatial phase difference of 30 degrees between windings 1 and 2, and a temporal phase difference of 30 degrees between the currents flowing through windings 1 and 2, a phase difference of 30 + 2 × 30 = 90 degrees exists in the sideband wave caused by the first carrier wave, based on the spatial and temporal phase differences. The sideband wave caused by the first carrier wave, when added to and subtracted from the second fundamental wave, has the second fundamental wave out of phase with respect to the fundamental wave. Therefore, relative to the spatial phase, it becomes an additive expression.

[0094] Because there is a 90-degree phase difference between the spatial and temporal phase differences, setting the phase difference between groups 1 and 2 of carriers to (90 + 180 × n) degrees can cancel out the higher-order harmonic magnetic flux caused by the first carrier in groups 1 and 2. Here, n is an integer.

[0095] On the other hand, when the spatial phase difference between windings 1 and 2 is 30 degrees and the temporal phase difference between the currents of windings 1 and 2 is 30 degrees, in the sideband wave caused by the second carrier wave, there is a phase difference of 30-30=0 degrees based on the spatial phase difference and the temporal phase difference.

[0096] In the sideband wave caused by two carrier waves, the fundamental wave is added or subtracted, and the fundamental wave is in positive phase. Therefore, relative to the spatial phase, it becomes the expression after subtraction. Since there is a 0-degree phase difference between the spatial phase difference and the time phase difference, when the phase difference between the first and second carrier waves is set to (180×n) degrees, the higher harmonic magnetic flux caused by the two carrier waves of the first and second groups can be canceled.

[0097] Because the rotor is positioned with a gap separating it from the stator, the influence of higher frequency components is reduced. Therefore, while the higher harmonic flux caused by the second carrier wave decays, the higher harmonic flux caused by the first carrier wave dominates. On the other hand, since the stator is located near the windings that generate the flux, the higher harmonic flux caused by the second carrier wave dominates.

[0098] Figure 10 This is a graph representing the rotor loss relative to the carrier phase difference between groups 1 and 2. For example... Figure 10 As shown, rotor losses are minimized when n is set to an integer and the phase difference between carrier waves 1 and 2 is (90 + 180 × n) degrees. Rotor losses are losses generated in the rotor core, in the permanent magnets of a permanent magnet synchronous rotating motor, or in the rotor rod of an induction rotating motor. Setting the phase difference between carrier waves 1 and 2 to (90 + 180 × n) degrees suppresses the rise in rotor temperature.

[0099] For example, when the rotary motor 2 is a permanent magnet synchronous rotary motor, the temperature rise of the permanent magnet can be suppressed, demagnetization can be prevented, and thus torque reduction can be prevented. Furthermore, when the rotary motor 2 is an induction rotary motor, the temperature rise of the rotor rod can also be suppressed, preventing damage caused by the temperature rise of the rotor rod and increased rotor rod losses due to increased resistance.

[0100] Figure 11 This is a graph representing the stator loss relative to the carrier phase difference between groups 1 and 2. For example... Figure 11 As shown, stator loss becomes minimal when n is set to an integer and the phase difference between carrier groups 1 and 2 is (180 × n) degrees. Stator loss represents the loss generated in the stator core.

[0101] By setting the phase difference between carrier waves 1 and 2 to (180×n) degrees, the rise in stator winding temperature can be suppressed. By suppressing the rise in stator winding temperature, damage to the winding insulation film can be prevented.

[0102] Next, the rotary motor driving method according to Embodiment 1 will be described.

[0103] Figure 12 This is a flowchart illustrating the rotary motor driving method according to Embodiment 1.

[0104] The control unit 5 determines whether the temperature of the rotor of the rotary electric machine 2 is higher than a threshold temperature (step ST1). If the rotor temperature is higher than the threshold temperature (step ST1: yes), the control unit 5 performs control to make the phase difference between carrier waves 1 and 2 (90 + 180 × n) degrees (step ST2). Here, n is an integer.

[0105] When the rotary motor 2 is a permanent magnet rotary motor, the rotor temperature is, for example, the temperature of the permanent magnet. When the rotary motor 2 is an induction rotary motor, the rotor temperature is the temperature of the rotor rod or end ring. When the rotary motor 2 is a permanent magnet synchronous rotary motor, the threshold temperature corresponding to the rotor is set to a temperature lower than the temperature at which the permanent magnet demagnetizes. The ease with which demagnetization occurs depends on the material of the permanent magnet. For example, permanent magnets with a large amount of rare earth elements such as dysprosium or terbium have high coercivity and are less prone to demagnetization. However, permanent magnets with a large amount of rare earth elements are more expensive and have the disadvantage of reduced remanent flux density.

[0106] The rotary motor drive unit 1 switches the phase difference of multiple carrier waves according to a threshold temperature, thereby enabling the use of a low-cost permanent magnet with high residual magnetic flux density that suppresses the addition of rare-earth elements. Furthermore, in the case where the rotary motor 2 is an induction rotary motor, the threshold temperature is set based on the designed resistance values ​​of the rotor rod and end rings.

[0107] When the temperature of both the rotor rod and end rings rises, their resistance increases. This increased resistance leads to increased rotor losses. Therefore, by setting an upper limit resistance value for the rotor rod and end rings during the design phase, the aforementioned threshold temperature of the rotor can be determined. By setting this threshold temperature based on the upper limit resistance value of the rotor rod and end rings, the increase in rotor losses can be prevented.

[0108] Alternatively, the threshold temperature can also be set based on the upper limit temperature of the bearing of the rotary motor 2. When the bearing temperature rises, the lubricant deteriorates and its lifespan is shortened, so an upper limit temperature is set. Therefore, the threshold temperature can also be set to a value lower than the upper limit temperature of the bearing.

[0109] The rotary motor drive device 1 reduces rotor loss and suppresses rotor temperature rise by controlling the rotor temperature to make the phase difference between carrier waves of group 1 and group 2 (90+180×n) degrees when the rotor temperature is higher than the threshold temperature.

[0110] If the rotor temperature is below the threshold temperature (step ST1: No), the control unit 5 determines whether the temperature of the stator of the rotating motor 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 performs control to make the phase difference between carrier waves 1 and 2 (180×n) degrees (step ST4).

[0111] Stator temperature is the temperature of the stator windings. The threshold temperature corresponding to the stator is set based on the heat resistance temperature of the electromagnetic wire. The heat resistance temperature of the electromagnetic wire is set based on the heat resistance temperature of the material used for the insulating coating. For example, the aforementioned threshold temperature of the stator is set at a temperature lower than the heat resistance temperature of the electromagnetic wire.

[0112] Stator temperature can also refer to the temperature of the stator teeth or the back of the stator core.

[0113] The temperature of the stator winding is calculated using the thermal circuit network based on the temperature of the iron core, thereby protecting the insulation coating of the stator winding from deterioration. When the stator temperature exceeds the aforementioned threshold temperature, the control unit 5 controls the carrier phase difference between groups 1 and 2 to be (180×n) degrees, thereby reducing stator losses and suppressing the rise in stator temperature.

[0114] When the stator temperature is below the threshold temperature (step ST3: No), the control unit 5 minimizes the loss (step ST5). Here, the control unit 5 controls the phase difference between carrier waves 1 and 2 to minimize the loss generated in the rotating motor 2.

[0115] For example, the control unit 5 pre-sets the phase difference between carrier waves 1 and 2, which minimizes the losses of the rotating motor 2, as a mapping for each operating point in the speed and torque characteristics. Regardless of the operating point, the control unit 5 maintains this mapping even when... Figure 12 The flowchart shown demonstrates how to switch the carrier phase difference between groups 1 and 2 while minimizing losses. Figure 12 The series of processes shown are implemented at certain time intervals.

[0116] In addition, the mapping of the carrier phase difference between groups 1 and 2, which minimizes the loss of the rotating motor 2, can be calculated by finite element analysis or by actual measurement using a real machine.

[0117] Figure 13 This is a waveform diagram representing the triangular wave carrier and the phase voltage signal wave. Figure 13 In the triangular wave, the difference between the maximum and minimum values ​​is the DC voltage Vpn. Furthermore, the amplitude of the difference between the maximum value and 0 is 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 values. The modulation rate is defined by the wave height C of the phase voltage signal wave relative to the amplitude of the triangular wave carrier. That is, modulation rate = phase voltage wave height value / (Vpn / 2).

[0118] For example, when performing synchronous control where the carrier frequency is an integer multiple of the fundamental frequency f, the control unit 5 can reduce higher harmonic components by aligning the carrier phase with the fundamental phase to 0. This reduces the losses of the rotating motor 2 and suppresses its temperature rise. On the other hand, even when performing asynchronous control where 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 based on the temperature of the rotating motor 2. This also reduces the losses of the rotating motor 2 and suppresses its temperature rise.

[0119] Figure 14 This is a graph representing the amplitude of the higher harmonic voltage relative to the DC voltage Vpn in the first component of the carrier wave as a function of the modulation rate. The higher harmonic voltage relative to the DC voltage in the first component of the carrier wave has a frequency component of fc±2f. Figure 14 The characteristics of the frequency component fc±2f, divided by the DC voltage Vpn, with respect to the modulation rate are shown. For example... Figure 14 As shown, since the DC voltage Vpn is constant, the higher the modulation rate, the more the carrier's first-order component increases. That is, the higher the modulation rate, the greater the loss caused by the carrier's first-order component.

[0120] Since the frequency of the first component of the carrier wave is lower than that of the second component, it also affects the rotor, which is located at a gap from the stator, in the rotating motor 2. Therefore, the control unit 5 controls the modulation rate to reduce the temperature rise of the rotor. To reduce the modulation rate, the phase voltage peak value C is decreased; to reduce the phase voltage peak value C, the field weakening current is increased. That is, the current amplitude and current advance angle of the phase current are increased.

[0121] Figure 15 This is a graph representing the amplitude of the higher harmonic voltage relative to the DC voltage Vpn in the second component of the carrier wave as a function of the modulation rate. The higher harmonic voltage relative to the DC voltage Vpn in the second component of the carrier wave has a frequency of 2fc±f. Figure 15 The characteristics of the frequency component 2fc±f, divided by the DC voltage Vpn, relative to the modulation rate are shown. For example... Figure 15 As shown, the second carrier component is at its maximum when the modulation rate is 0.6. The second carrier component has a significant impact on the losses generated in the stator windings or core. Therefore, the control unit 5 reduces the losses caused by the second carrier component by controlling the modulation rate, thereby suppressing the temperature rise of the stator.

[0122] like Figure 15As shown, the loss caused by the second component of the carrier changes its trend with a modulation rate of 0.6 as the boundary. Therefore, when the modulation rate is greater than 0.6, the control unit 5 can control the modulation rate to increase it. To increase the modulation rate, the phase voltage peak value C can be increased. To increase the phase voltage peak value C, the magnetic weakening current can be decreased. That is, the current amplitude and current advance angle of the phase current can be decreased.

[0123] Figure 16 This is a graph showing the higher harmonic components of the carrier wave appearing in groups 1 and 2 for the given frequency and rotational speed. Figure 16 In this configuration, the carrier frequency of group 1 is set to fc1, and the carrier frequency of group 2 is set to fc2. When the control unit 5 switches the phase difference between group 1 and group 2 according to the temperature of the rotary motor 2, if the carrier frequencies of group 1 and group 2 are made equal, the frequency components caused by the carrier will be consistent. Therefore, the higher harmonic components caused by the carrier can be canceled out.

[0124] On the other hand, even when the carrier frequencies of Group 1 and Group 2 are different, by setting the carrier frequencies of Group 1 and Group 2 to predetermined values, it is possible to cancel the higher harmonic components caused by the carrier. For example, by controlling the carrier frequencies of Group 1 and Group 2 to satisfy fc1+2f=2fc2-f, the control unit 5 can cancel the first sideband wave of the carrier of Group 1 and the second sideband wave of the carrier of Group 2, thereby reducing the loss caused by the carrier.

[0125] When the temperature rise of the switching elements in each power conversion circuit group differs, the control unit 5 reduces the switching losses of the highest-temperature switching element by setting different carrier frequencies for each group. Even when the carrier frequencies for each group are set to different values, the control unit 5 controls the carrier frequencies of groups 1 and 2 to satisfy fc1 + 2f = 2fc2 - f, and controls the carrier phase difference between groups 1 and 2 based on the temperature of the rotary motor 2. As a result, the rotary motor drive device 1 can selectively suppress the temperature rise of the stator and rotor.

[0126] In the case where the rotating motor 2 is a permanent magnet synchronous rotating motor, eddy currents are generated in the permanent magnet due to higher harmonic flux. 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 higher harmonic flux caused by the second component of the carrier is a 2fc ± f component, and the eddy currents generated in the permanent magnet are represented by the square of the higher harmonic flux, becoming a 4fc component. The 4fc component of the eddy currents generated in the permanent magnet is calculated as the sum of the 2fc + f and 2fc - f components. To reduce the 4fc component of the eddy currents generated in the permanent magnet, the skin depth can be considered when setting the carrier frequency.

[0127] With the carrier frequency of the power converter set to fc, the thickness of the permanent magnet in the magnetization direction set to W, and the relative permeability of the permanent magnet set to μ, r When the magnetic conductivity of the permanent magnet is set to σ and the vacuum permeability is set to μ0, in order to remove the 4fc component of the eddy current generated in the permanent magnet, the carrier frequency fc can be determined to satisfy fc>4 / (πμ). r μ0σW 2 ) relationship.

[0128] By reducing a certain component or higher of the eddy current components generated in the permanent magnet, the control unit 5 makes the losses caused by the carrier wave in the stator and rotor more clearly defined. Therefore, when switching between the carrier phase differences of group 1 and group 2, the control unit 5 can more effectively suppress the temperature rise of the parts where temperature rise is to be suppressed.

[0129] When the semiconductor switching element in the power converter is a silicon carbide (SiC) element, the carrier phase can be switched at high speed by utilizing heat dissipation. The control unit 5 can more effectively achieve the effect of suppressing the temperature rise of specific parts of the rotating motor 2 by switching the carrier phase difference of each group.

[0130] A multilevel inverter can also be used as the power converter. Even when using a multilevel inverter, the control unit 5 can suppress the temperature rise of specific parts of the rotating motor 2 by switching the carrier phase difference of each group.

[0131] Next, the hardware configuration for implementing the functions of the control unit 5 will be explained.

[0132] The current command generation unit 51, three-phase to two-phase conversion unit 52, current control unit 53, two-phase to three-phase conversion unit 54, carrier wave generation unit 55, and PWM signal generation unit 56 included in the control unit 5 are implemented by a processing circuit. That is, the control unit 5 includes components for executing... Figure 12 The processing circuits for each step ST1 to ST5 are shown. The processing circuits can be dedicated hardware or CPUs (Central Processing Units) that execute programs stored in memory.

[0133] Figure 17A This is a block diagram showing the hardware configuration that enables the functions of the control unit 5. Figure 17B This is a block diagram showing the hardware configuration of the software that executes the functions of control unit 5. Figure 17A and Figure 17BIn this interface, the input interface 100 is, for example, an interface that relays signals output from the rotation angle sensor 21, temperature detection unit 22, rotating motor current detection unit 33, and rotating motor 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 power conversion circuit 32 and the second power conversion circuit 42.

[0134] In the processing circuit Figure 17A In the case of the processing circuit 102 of the dedicated hardware shown, the processing circuit 102 corresponds, for example, to 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.

[0135] The functions of the current command generation unit 51, the three-phase two-phase conversion unit 52, the current control unit 53, the two-phase three-phase conversion unit 54, the carrier generation unit 55, and the PWM signal generation unit 56 provided by the control unit 5 can be implemented by different processing circuits, or these functions can be integrated into one processing circuit.

[0136] When the processing circuit is Figure 17B When the processor 103 is shown, the functions of the current command generation 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 generation unit 55, and the PWM signal generation unit 56 provided in the control unit 5 are implemented by software, firmware, or a combination of software and firmware. Furthermore, the software or firmware is represented as a program and stored in the memory 104.

[0137] The processor 103 implements the functions of the current command generation 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 generation unit 55, and the PWM signal generation unit 56 of the control unit 5 by reading and executing the program stored in the memory 104. For example, the control unit 5 includes the memory 104, which is used to store the results of execution when executed by the processor 103. Figure 12 The program for steps ST1 to ST5 shown. These programs cause the computer to execute the steps or methods of processing performed by the control unit 5. The memory 104 may also be a computer-readable storage medium storing programs for enabling the computer to function as the control unit 5.

[0138] The memory 104 includes, for example, non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), and EEPROM (Electrically Erasable Programmable ROM), as well as disks, floppy disks, optical disks, mini-CDs, DVDs, etc.

[0139] The functions of the current command generation unit 51, three-phase to two-phase conversion unit 52, current control unit 53, two-phase to three-phase conversion unit 54, carrier generation unit 55, and PWM signal generation unit 56 in the control unit 5 can be partially implemented by dedicated hardware, while the remainder can be implemented by software or firmware. For example, the functions of the current command generation unit 51, three-phase to two-phase conversion unit 52, current control unit 53, and two-phase to three-phase conversion unit 54 are implemented by the processing circuit 102, which is dedicated hardware, while the functions of the carrier generation unit 55 and PWM signal generation unit 56 are implemented by the processor 103 reading and executing the program stored in the memory 104. As described above, the processing circuit can implement the above functions using hardware, software, or a combination thereof.

[0140] As described above, the rotary motor drive device 1 according to Embodiment 1 drives a rotary motor 2. The rotary motor 2 includes a stator having three-phase stator windings driven by two systems (set 1 and set 2) and a rotor as a rotating body. The rotary motor drive device 1 includes: a set of power converters 3 and two sets of power converters 4, which are respectively provided corresponding to each set and convert DC power input from DC power supply 7 into phase current and output to the stator windings of each set; and a control unit 5, which outputs a control signal based on carrier wave generation to control the set of power converters 3 and 4. When the temperature of a part of the rotary motor 2 is higher than a threshold temperature, the phase of the carrier wave in each set is switched. By switching the phase of the carrier wave in each set when the temperature of a part of the rotary motor 2 is higher than the threshold temperature, the rotary motor drive device 1 can reduce the losses generated in various parts of the rotary motor 2 and suppress the temperature rise of parts exceeding the threshold temperature.

[0141] In the rotary motor drive device 1 according to Embodiment 1, the control unit 5 changes the phase difference of the carrier waves in each group when the temperature of the stator or the rotor of the rotary motor 2 is higher than a threshold temperature. As a result, the rotary motor drive device 1 can reduce losses generated in various parts of the rotary motor 2 and suppress temperature rise in parts exceeding the threshold temperature.

[0142] In the rotary motor drive device 1 according to Embodiment 1, the rotary motor 2 is a multi-phase rotary motor including three-phase stator windings driven by two systems, group 1 and group 2. When the temperature of the stator or the rotor of the rotary motor 2 exceeds a threshold temperature, the control unit 5 changes the phase difference of the carrier waves in each group. Therefore, the rotary motor drive device 1 can reduce losses generated in various parts of the rotary motor 2 and suppress temperature rise in parts exceeding the threshold temperature.

[0143] In the rotary motor drive device 1 according to Embodiment 1, when the stator temperature or the rotor temperature is below a threshold temperature, the control unit 5 sets the phase difference of the carrier waves in each group to minimize the losses of the rotary motor 2. Therefore, the rotary motor drive device 1 can reduce the losses generated in various parts of the rotary motor 2 and suppress the temperature rise of parts exceeding the threshold temperature.

[0144] In the rotary electric motor drive device 1 according to Embodiment 1, when the control unit 5 performs synchronization control to make the carrier frequency an integer multiple of the fundamental frequency, it aligns the phase of the carrier with the phase of the fundamental frequency to 0. This reduces higher harmonic components, thus the rotary electric motor drive device 1 can reduce the losses of the rotary electric motor 2 and suppress its temperature rise.

[0145] In the rotary electric motor drive device 1 according to Embodiment 1, the stator windings of set 1 and set 2 are configured with an electrical angle interval of 30 degrees. Since multiple sets of windings can be arranged within one pole, the rotary electric motor drive device 1 can cancel out high-order harmonics between the sets, thereby achieving low loss and low vibration.

[0146] In the rotary electric motor drive device 1 according to Embodiment 1, the control unit 5 controls the phase current output from the first set of power converters 3 to the first set of stator windings to have the same current amplitude as the phase current output from the second set of power converters 4 to the second set of stator windings, and controls the phase current phase difference between the first and second sets to be an electrical angle of 30 degrees. As a result, the rotary electric motor drive device 1 can reduce losses generated in various parts of the rotary electric motor 2 and suppress temperature rise in parts exceeding the threshold temperature.

[0147] The rotary electric motor drive device 1 according to Embodiment 1 consists of a power converter 3 that outputs phase current to a set of stator windings 1 and a power converter 4 that outputs phase current to a set of stator windings 2. The control unit 5 controls the output to ensure that the carrier frequencies of the first and second sets are equal. Therefore, the rotary electric motor drive device 1 can reduce losses generated in various parts of the rotary electric motor 2 and suppress temperature rise in parts exceeding the threshold temperature.

[0148] In the rotary electric motor drive device 1 according to Embodiment 1, when the rotor temperature is higher than a threshold temperature and n is an integer, the control unit 5 performs control to make the phase difference between the carrier waves of group 1 and group 2 (90 + 180 × n) degrees. As a result, the rotary electric motor drive device 1 can suppress the rise in rotor temperature.

[0149] In the rotary electric motor drive device 1 according to Embodiment 1, when the rotor temperature is higher than a threshold temperature, the control unit 5 increases the current amplitude and current advance angle of the phase current output from the first set of power converters 3 to the first set of stator windings and the phase current output from the second set of power converters 4 to the second set of stator windings. As a result, the rotary electric motor drive device 1 can suppress the rise in rotor temperature.

[0150] In the rotary electric motor drive device 1 according to Embodiment 1, when the stator temperature is higher than a threshold temperature and n is an integer, the control unit 5 performs control to make the phase difference between the carrier waves of group 1 and group 2 (180×n) degrees. As a result, the rotary electric motor drive device 1 can suppress the rise in stator temperature.

[0151] In the rotary electric motor drive device 1 according to Embodiment 1, when the stator temperature is higher than a threshold temperature and the modulation rate is greater than a threshold, the control unit 5 reduces the current amplitude and current advance angle of the phase currents output from the power converters 3 and 4 in groups 1 and 2. As a result, the rotary electric motor drive device 1 can suppress the rise in stator temperature.

[0152] In the rotary motor drive device 1 according to Embodiment 1, the threshold value relative to the modulation rate is 0.6. By controlling the modulation rate using this threshold value, the rotary motor drive device 1 reduces the loss caused by the second component of the carrier wave, thereby suppressing the temperature rise of the stator.

[0153] The rotary electric motor drive device 1 according to Embodiment 1 consists of a single power converter 3 that outputs phase current to a single set of stator windings and a double power converter 4 that outputs phase current to a second set of stator windings. The control unit 5, when setting the fundamental frequency of the rotary electric motor 2 to f, the carrier frequency of the single power converter 3 to fc1, and the carrier frequency of the double power converter 4 to fc2, controls the carrier frequencies of the single and double power converters to satisfy the relationship shown in fc1 + 2f = 2fc2. Therefore, the rotary electric motor drive device 1 can selectively suppress the temperature rise of the stator.

[0154] In the rotary motor drive device 1 according to Embodiment 1, the rotary motor 2 has a permanent magnet as a rotor. The control unit 5 sets the carrier frequency to fc (Hz), the thickness of the permanent magnet in the magnetization direction to W (m), and the relative permeability of the permanent magnet to μ. rWith the conductivity of the permanent magnet set to σ (S / m) and the permeability of the vacuum set to μ0, control one set of power converters 3 and two sets of power converters 4 so that the carrier frequency satisfies fc > 4 / (πμ r μ0σW 2 The relationship is shown in the diagram.

[0155] The rotary electric motor drive unit 1 reduces a portion of the eddy current components generated in the permanent magnet that exceeds a certain threshold, thereby making the losses caused by carrier waves in the stator and rotor more pronounced. Therefore, by switching the carrier phase difference between sets 1 and 2, it is possible to more effectively suppress temperature rise in the areas where temperature increase is desired.

[0156] In the rotary electric motor drive device 1 according to Embodiment 1, one set of power converters 3 and two sets of power converters 4 have an inverter circuit formed by connecting six semiconductor switching elements using silicon carbide in a full-bridge configuration. The rotary electric motor drive device 1 can more effectively suppress the temperature rise of specific parts of the rotary electric motor 2 by controlling the inverter circuit and switching the carrier phase difference of each set.

[0157] In the rotary motor drive method according to Embodiment 1, when the rotor temperature is higher than the threshold temperature and n is an integer, the control unit 5 performs control to make the phase difference between carrier waves of group 1 and group 2 (90 + 180 × n) degrees; when the stator temperature is higher than the threshold temperature and n is an integer, it performs control to make the phase difference between carrier waves of group 1 and group 2 (180 × n) degrees; and when the stator temperature is lower than the threshold temperature and the rotor temperature is lower than the threshold temperature, it sets the phase difference of the carrier waves in each group to minimize the losses of the rotary motor 2. Therefore, by executing the above method by the control unit 5, a rotary motor drive device 1 can be realized that reduces the losses generated in various parts of the rotary motor 2 and suppresses the temperature rise of parts exceeding the threshold temperature.

[0158] The various methods disclosed herein are summarized and recorded below as appendices.

[0159] (Appendix 1) A rotary motor drive device, The rotary motor drive device drives a rotary motor, which includes a stator with multiple sets of stator windings having three or more phases, and a rotor as a rotating body. The rotary motor drive device includes: Multiple sets of power converters, each corresponding to a specific group, convert DC power from the power input into phase current and output it to the stator windings of each group; and The control unit outputs a control signal generated based on a carrier wave to control the power converters in each group, and switches the phase of the carrier wave in each group when the temperature of a part of the rotating motor is higher than a threshold temperature.

[0160] (Note 2) The rotary motor drive device as described in Note 1, When the temperature of the stator of the rotating electric motor is higher than the threshold temperature, or when the temperature of the rotor is higher than the threshold temperature, the control unit changes the phase difference of the carrier waves in each group.

[0161] (Note 3) The rotary motor drive device as described in Note 1, The rotary motor is a multi-phase rotary motor comprising three-phase stator windings driven by two systems, group 1 and group 2. When the temperature of the stator of the rotating electric motor is higher than the threshold temperature, or when the temperature of the rotor is higher than the threshold temperature, the control unit changes the phase difference of the carrier waves in each group.

[0162] (Note 4) The rotary motor drive device as described in Note 3, 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 sets the phase difference of the carrier waves in each group to minimize the loss of the rotating motor.

[0163] (Note 5) The rotary electric motor drive device as described in any of Notes 2 to 4, When the carrier frequency of the carrier wave is an integer multiple of the fundamental frequency (i.e., synchronous control), the control unit aligns the phase of the carrier wave with the phase of the fundamental frequency to 0.

[0164] (Note 6) The rotary motor drive device as described in Note 3, The stator windings of groups 1 and 2 are configured with an electrical angle interval of 30 degrees.

[0165] (Note 7) The rotary motor drive device as described in Note 6, The control unit controls the phase current output from the power converter of group 1 to the stator winding of group 1 to have the same current amplitude as the phase current output from the power converter of group 2 to the stator winding of group 2, and controls the phase current phase difference between group 1 and group 2 to be an electrical angle of 30 degrees.

[0166] (Note 8) The rotary motor drive device as described in Note 3, The power converter is a power converter of group 1 that outputs phase current to group 1 of the stator windings, and a power converter of group 2 that outputs phase current to group 2 of the stator windings. The control unit performs control to ensure that the carrier frequencies of groups 1 and 2 are equal.

[0167] (Note 9) The rotary motor drive device as described in Note 8, When the temperature of the rotor is higher than the threshold temperature and n is an integer, the control unit performs control so that the phase difference between the carrier waves of group 1 and group 2 is (90 + 180 × n) degrees.

[0168] (Note 10) The rotary motor drive device as described in Note 9, When the rotor temperature is higher than the threshold temperature, the control unit increases the current amplitude and current advance angle of the phase current output from the power converter of group 1 to the stator winding of group 1 and the phase current output from the power converter of group 2 to the stator winding of group 2.

[0169] (Note 11) The rotary motor drive device as described in Note 8, When the temperature of the stator is higher than the threshold temperature and n is an integer, the control unit performs control to make the phase difference between the carriers of group 1 and group 2 (180×n) degrees.

[0170] (Note 12) The rotary motor drive device as described in Note 11, When the temperature of the stator is higher than the threshold temperature and the modulation rate is greater than the threshold, the control unit reduces the current amplitude and current advance angle of the phase current output from the power converter in groups 1 and 2.

[0171] (Note 13) The rotary motor drive device as described in Note 12, The threshold relative to the modulation rate is 0.6.

[0172] (Note 14) The rotary motor drive device as described in Note 3, The power conversion circuit comprises a power converter of group 1 that outputs phase current to group 1 of the stator windings, and a power converter of group 2 that outputs phase current to group 2 of the stator windings. When the fundamental frequency of the rotating motor is set to f, the carrier frequency of the power converter of group 1 is set to fc1, and the carrier frequency of the power converter of group 2 is set to fc2, the control unit controls the carrier frequencies of group 1 and group 2 to satisfy the relationship shown in fc1+2f=2fc2.

[0173] (Note 15) The rotary electric motor drive as described in any of Notes 1 to 14, The rotary electric motor has a permanent magnet as the rotor. The control unit sets the carrier frequency to fc (Hz), the thickness of the permanent magnet in the magnetization direction to W (m), and the relative permeability of the permanent magnet to μ.r With the conductivity of the permanent magnet set to σ (S / m) and the vacuum permeability set to μ0, the power converter is controlled so that the carrier frequency satisfies fc > 4 / (πμ). r μ0σW 2 The relationship is shown in the diagram.

[0174] (Note 16) The rotary electric motor drive as described in any of Notes 1 to 15, The power conversion circuit in each group has an inverter circuit with six semiconductor switching elements using silicon carbide connected in a full-bridge configuration.

[0175] (Appendix 17) A method for driving a rotary electric motor, This rotary motor driving method is based on a rotary motor driving device that drives a rotary motor. The rotary motor includes a stator with multiple sets of stator windings having three or more phases, and a rotor as a rotating body. The rotary motor driving device includes: Multiple sets of power converters, each corresponding to a specific group, convert DC power from the power input into phase current and output it to the stator windings of each group; and The control unit outputs a control signal generated based on a carrier wave to control the power converters in each group. The rotating motor drive method is characterized by... The control unit When the rotor temperature is higher than the threshold temperature and n is an integer, control is performed to ensure that the phase difference between the carrier waves of group 1 and group 2 is (90 + 180 × n) degrees. When the stator temperature is higher than the threshold temperature and n is an integer, control is performed to ensure that the phase difference between the carrier waves of group 1 and group 2 is (180×n) degrees. When the temperature of the stator is below a threshold temperature and the temperature of the rotor is below a threshold temperature, the phase difference of the carrier waves in each group is set to minimize the loss of the rotating motor.

[0176] Furthermore, it is possible to modify any constituent element of the implementation method or omit any constituent element of the implementation method.

[0177] Industrial practicality

[0178] The rotary electric motor drive device disclosed herein can be used, for example, in a power conversion device.

[0179] Label Explanation

[0180] 1 Rotary motor drive device

[0181] 2 Rotary motor

[0182] 2a AC busbar

[0183] 3 sets of power converters

[0184] DC buses 3a and 3b

[0185] 4.2 sets of power converters

[0186] 5. Control Department

[0187] 6a, 6b power switches

[0188] 7 DC power supply

[0189] 21 Rotation Angle Sensor

[0190] 22 Temperature Detection Department

[0191] 31 1 set of capacitors

[0192] 32.1 Group of power conversion circuits

[0193] 33, 43 Rotary motor current detection unit

[0194] 41 2 sets of capacitors

[0195] 42. Two sets of power conversion circuits

[0196] 51 Current Command Generation Unit

[0197] 52 Three-phase to two-phase conversion section

[0198] 53 Current Control Section

[0199] 54 Two-phase to three-phase conversion section

[0200] 55 Carrier Generation Unit

[0201] 56 PWM signal generation unit

[0202] 100 Input Interface

[0203] 101 Output Interface

[0204] 102 Processing Circuit

[0205] 103 processor

[0206] 104 Memory

[0207] 201 stator

[0208] 202 winding

[0209] 211 Rotor

[0210] 212 permanent magnet

[0211] 213 Rotor rod

[0212] Switching elements 321~326 and 421~426.

Claims

1. A rotary motor drive device, The rotary motor drive device drives a rotary motor, which includes a stator with multiple sets of stator windings having three or more phases, and a rotor as a rotating body. The rotary motor drive device is characterized by comprising: Multiple sets of power converters, each set corresponding to a specific group, convert DC power from the power input into phase current and output it to the stator winding of each group; as well as The control unit outputs a control signal generated based on a carrier wave to control the power converters in each group, and switches the phase of the carrier wave in each group when the temperature of a part of the rotating motor is higher than a threshold temperature.

2. The rotary motor drive device as described in claim 1, characterized in that, When the temperature of the stator of the rotating electric motor is higher than the threshold temperature, or when the temperature of the rotor is higher than the threshold temperature, the control unit changes the phase difference of the carrier waves in each group.

3. The rotary motor drive device as described in claim 1, characterized in that, The rotary motor is a multi-phase rotary motor comprising three-phase stator windings driven by two systems, group 1 and group 2. When the temperature of the stator of the rotating electric motor is higher than the threshold temperature, or when the temperature of the rotor is higher than the threshold temperature, the control unit changes the phase difference of the carrier waves in each group.

4. The rotary motor drive device as described in claim 3, characterized in that, 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 sets the phase difference of the carrier waves in each group to minimize the loss of the rotating motor.

5. The rotary motor drive device according to any one of claims 2 to 4, characterized in that, When the carrier frequency of the carrier wave is an integer multiple of the fundamental frequency (i.e., synchronous control), the control unit aligns the phase of the carrier wave with the phase of the fundamental frequency to 0.

6. The rotary motor drive device as described in claim 3, characterized in that, The stator windings of groups 1 and 2 are configured with an electrical angle interval of 30 degrees.

7. The rotary motor drive device as described in claim 6, characterized in that, The control unit controls the phase current output from the power converter of group 1 to the stator winding of group 1 to have the same current amplitude as the phase current output from the power converter of group 2 to the stator winding of group 2, and controls the phase current phase difference between group 1 and group 2 to be an electrical angle of 30 degrees.

8. The rotary motor drive device as described in claim 3, characterized in that, The power converter is a power converter of group 1 that outputs phase current to group 1 of the stator windings, and a power converter of group 2 that outputs phase current to group 2 of the stator windings. The control unit performs control to ensure that the carrier frequencies of groups 1 and 2 are equal.

9. The rotary motor drive device as described in claim 8, characterized in that, When the temperature of the rotor is higher than the threshold temperature and n is an integer, the control unit performs control so that the phase difference between the carrier waves of group 1 and group 2 is (90 + 180 × n) degrees.

10. The rotary motor drive device as described in claim 9, characterized in that, When the rotor temperature is higher than the threshold temperature, the control unit increases the current amplitude and current advance angle of the phase current output from the power converter of group 1 to the stator winding of group 1 and the phase current output from the power converter of group 2 to the stator winding of group 2.

11. The rotary motor drive device as described in claim 8, characterized in that, When the temperature of the stator is higher than the threshold temperature and n is an integer, the control unit performs control to make the phase difference between the carriers of group 1 and group 2 (180×n) degrees.

12. The rotary motor drive device as described in claim 11, characterized in that, When the temperature of the stator is higher than the threshold temperature and the modulation rate is greater than the threshold, the control unit reduces the current amplitude and current advance angle of the phase current output from the power converter in groups 1 and 2.

13. The rotary motor drive device as described in claim 12, characterized in that, The threshold relative to the modulation rate is 0.

6.

14. The rotary motor drive device as described in claim 3, characterized in that, The power converter is a power converter of group 1 that outputs phase current to group 1 of the stator windings, and a power converter of group 2 that outputs phase current to group 2 of the stator windings. When the fundamental frequency of the rotating motor is set to f, the carrier frequency of the power converter of group 1 is set to fc1, and the carrier frequency of the power converter of group 2 is set to fc2, the control unit controls the carrier frequencies of group 1 and group 2 to satisfy the relationship shown in fc1+2f=2fc2-f.

15. The rotary motor drive device as claimed in claim 1, characterized in that, The rotary electric motor has a permanent magnet as the rotor. The control unit sets the carrier frequency to fc (Hz), the thickness of the permanent magnet in the magnetization direction to W (m), and the relative permeability of the permanent magnet to μ. r With the conductivity of the permanent magnet set to σ (S / m) and the vacuum permeability set to μ0, the power converter is controlled so that the carrier frequency satisfies fc > 4 / (πμ). r μ0σW 2 The relationship is shown in the diagram.

16. The rotary motor drive device as claimed in claim 1, characterized in that, The power converter in each group has an inverter circuit consisting of six silicon carbide semiconductor switching elements connected in a full-bridge configuration.

17. A method for driving a rotary electric motor, This rotary motor driving method is based on a rotary motor driving device that drives a rotary motor. The rotary motor includes a stator with multiple sets of stator windings having three or more phases, and a rotor as a rotating body. The rotary motor driving device includes: Multiple sets of power converters, each set corresponding to a specific group, convert DC power from the power input into phase current and output it to the stator winding of each group; as well as The control unit outputs a control signal generated based on a carrier wave to control the power converters in each group. The control unit When the rotor temperature is higher than the threshold temperature and n is an integer, control is performed to ensure that the phase difference between the carrier waves of group 1 and group 2 is (90 + 180 × n) degrees. When the stator temperature is higher than the threshold temperature and n is an integer, control is performed to ensure that the phase difference between the carrier waves of group 1 and group 2 is (180×n) degrees. When the temperature of the stator is below a threshold temperature and the temperature of the rotor is below a threshold temperature, the phase difference of the carrier waves in each group is set to minimize the loss of the rotating motor.

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