Motor control device, electric vehicle, and motor control method

Abstract

The present application provides a motor control device, which includes a first inverter circuit and a second inverter circuit for controlling a redundant system of a motor, and a control unit for controlling the first inverter circuit and the second inverter circuit. The first inverter circuit converts direct current into alternating current according to a PWM signal generated by using a first carrier signal. The second inverter circuit converts direct current into alternating current according to a PWM signal generated by using a second carrier signal. The control unit moves the phase of the first carrier signal and the second carrier signal respectively based on the pulsation of electromagnetic force caused by the magnetic circuit of the motor.

Description

Technical Field

[0001] This invention relates to motor control devices, electric vehicles, and motor control methods. Background Technology

[0002] In motor control devices, it is known that a control device is provided for a multiphase AC motor consisting of two sets of multiphase windings, equipped with two inverters corresponding to the two sets of windings to control the energization of each winding group.

[0003] Patent Document 1 describes a device comprising two inverter systems and a control unit. The two inverter systems are electrically independently configured corresponding to two groups of multiphase windings and output AC voltage to the two groups of multiphase windings. The two groups of multiphase windings form the stator of a multiphase AC motor, causing the rotor to generate a rotating magnetic field. The control unit controls the phase difference of the AC voltage applied to the two groups of multiphase windings. The control unit sets a control range for the phase difference that includes a reference phase difference that can reduce harmonic components of a specific order. The phase difference is changed within the control range according to the required characteristics of the multiphase AC motor or in a way that causes fluctuations in the energization of the multiphase AC motor.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-213407 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The device described in Patent Document 1 above cannot adequately suppress the vibrations and noise generated in the motor.

[0009] Technical means to solve the problem

[0010] The motor control device of the present invention is a motor control device comprising a first inverter circuit and a second inverter circuit with a redundant system for controlling a motor, and a control unit for controlling the first inverter circuit and the second inverter circuit. The first inverter circuit converts direct current to alternating current based on a PWM signal generated using a first carrier signal, and the second inverter circuit converts direct current to alternating current based on a PWM signal generated using a second carrier signal. The control unit moves the phases of the first carrier signal and the second carrier signal respectively based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor.

[0011] The motor control method of the present invention is a motor control method in a motor control device. The motor control device includes a first inverter circuit and a second inverter circuit for controlling a redundant system of a motor, and a control unit for controlling the first inverter circuit and the second inverter circuit. The first inverter circuit converts direct current into alternating current based on a PWM signal generated using a first carrier signal, and the second inverter circuit converts direct current into alternating current based on a PWM signal generated using a second carrier signal. The control unit moves the phases of the first carrier signal and the second carrier signal respectively based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor.

[0012] The effects of the invention

[0013] According to the present invention, vibrations and noise generated in the motor can be suppressed. Attached Figure Description

[0014] Figure 1 This is an overall configuration diagram of a motor drive system equipped with a motor control device.

[0015] Figure 2 (A)(B)(C)(D) are graphs showing torque pulsation without using this embodiment.

[0016] Figure 3 (A)(B)(C)(D) are graphs representing torque pulsation when this embodiment is used.

[0017] Figure 4 (A) and (B) are diagrams representing motor pulsation.

[0018] Figure 5 (A) and (B) are diagrams representing the circumferential carrier phase diagram.

[0019] Figure 6 (A) and (B) are diagrams representing radial carrier phase diagrams.

[0020] Figure 7 A graph showing the relationship between the motor's rotational speed and the excitation frequency.

[0021] Figure 8 (A) and (B) are diagrams representing the frequency of the voltage command and the carrier frequency fc.

[0022] Figure 9 This is a flowchart illustrating the processing of the control unit in a motor control device.

[0023] Figure 10 (A)(B)(C)(D) are graphs representing torque pulsation when this embodiment is used.

[0024] Figure 11 (A)(B)(C)(D) are diagrams representing the rotational order of the pulsation when this embodiment is used.

[0025] Figure 12 (A)(B)(C)(D) are diagrams representing the pulsation when this embodiment is used.

[0026] Figure 13 This is a configuration diagram of the electric vehicle system in this embodiment. Detailed Implementation

[0027] Figure 1 This is an overall configuration diagram of a motor drive system equipped with a motor control device 200.

[0028] like Figure 1 As shown, the motor drive system includes a DC power supply 100, a motor control device 200, and a motor 300. The motor control device 200 converts the DC power supplied from the DC power supply 100 into AC power to drive the motor 300. The DC power supply 100 is mainly a secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery.

[0029] The motor control device 200 includes a first inverter circuit 201, a second inverter circuit 202, a smoothing capacitor 203, a first current sensor 204, a second current sensor 205, a magnetic pole position sensor 206, a magnetic pole position detector 207, a control unit 208, and a PWM signal drive circuit 209.

[0030] The first inverter circuit 201 has upper and lower switching elements corresponding to the U-phase, V-phase, and W-phase, respectively. The switching elements consist of IGBT 221 and diodes 222, and the upper and lower arms are packaged together to form a power module 223. The switching elements can also be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The first inverter circuit 201 uses three power modules 223 to form a three-phase bridge circuit, switching the energization of each winding of the first system winding group 301 of the motor 300. The power module 223 can also be a single package containing a total of six switching elements (upper and lower arms) for the three phases.

[0031] The second inverter circuit 202 is configured as an inverter that provides a redundant system of DC power supply 100 and smoothing capacitor 203 in parallel with the first inverter circuit 201. The configuration of the second inverter circuit 202 is the same as that of the first inverter circuit 201, so its description is omitted. The second inverter circuit 202 uses power modules to form a three-phase bridge circuit, switching the energization of each winding of the second system winding group 302 of the motor 300.

[0032] A smoothing capacitor 203 suppresses and smooths the voltage ripples input from the DC power supply 100 to the first inverter circuit 201 and the second inverter circuit 202. In the following description, the first inverter circuit 201 and the second inverter circuit 202 will sometimes be collectively referred to as inverter circuits 201 and 202. Furthermore, a voltage detector 101 detects the DC voltage value of the DC power supply 100 and outputs its detected value to the control unit 208.

[0033] A first current sensor 204 is installed between the output line of the first inverter circuit 201 and the motor 300. A second current sensor 205 is installed between the output line of the second inverter circuit 202 and the motor 300. The first current sensor 204 detects the three-phase AC currents Iu1, Iv1, and Iw1 (U-phase AC current Iu1, V-phase AC current Iv1, and W-phase AC current Iw1) of the first system flowing in the motor 300. The second current sensor 205 detects the three-phase AC currents Iu2, Iv2, and Iw2 (U-phase AC current Iu2, V-phase AC current Iv2, and W-phase AC current Iw2) of the second system flowing in the motor 300.

[0034] For example, a Hall current sensor or similar device can be used to construct the first current sensor 204 and the second current sensor 205. The detection results of the three-phase AC currents Iu1, Iv1, Iw1, Iu2, Iv2, and Iw2 of the two systems by the first current sensor 204 and the second current sensor 205 are input to the control unit 208 for the generation of gate signals by the control unit 208. In addition, an example is shown in which the first current sensor 204 and the second current sensor 205 in a dual three-phase motor-inverter are each composed of three current sensors in the first system and the second system. However, it is also possible to set two current sensors in each system, and the AC current of the remaining phase can be calculated using the fact that the sum of the three-phase AC currents Iu, Iv, and Iw is zero. In addition, the pulsed DC current flowing from the DC power supply 100 into the inverter circuits 201 and 202 can also be detected using a shunt resistor or similar device inserted between the smoothing capacitor 203 and the inverter circuits 201 and 202. Subsequently, based on the DC current and the three-phase AC voltages Vu1, Vv1, Vw1, Vu2, Vv2, Vw2 of the two systems applied from the inverter circuits 201 and 202 to the motor 300, the three-phase AC currents Iu1, Iv1, Iw1, Iu2, Iv2, Iw2 of the two systems are calculated.

[0035] A magnetic pole position sensor 206 for detecting the magnetic position θ is mounted on the motor 300. Regarding the magnetic pole position sensor 206, a rotary transformer consisting of an iron core and windings is preferred, but sensors using magnetoresistive elements or Hall elements, such as GMR sensors, can also be used.

[0036] The signal from the magnetic pole position sensor 206 is input to the magnetic pole position detector 207. The magnetic pole position detector 207 calculates the magnetic pole position θ based on the input signal. Alternatively, the magnetic pole position detector 207 may infer the magnetic position θ using the three-phase AC currents Iu1, Iv1, Iw1, Iu2, Iv2, Iw2 flowing to the two systems of the motor 300, or the three-phase AC voltages Vu1, Vv1, Vw1, Vu2, Vv2, Vw2 applied to the two systems of the motor 300 from the inverter circuits 201, 202.

[0037] The current values ​​from the first current sensor 204 and the second current sensor 205, and the magnetic position θ from the magnetic pole position detector 207 are input to the control unit 208. Furthermore, a torque command value T* corresponding to the target torque from a host controller (not shown) or similar source is input to the control unit 208. The magnetic position θ is utilized in the phase control of the alternating current, which is performed by the control unit 208 generating a gate signal based on the phase of the induced voltage of the motor 300. The control unit 208 performs PWM control based on this input information, thereby generating a PWM signal for driving the motor 300 and outputting it to the PWM signal drive circuit 209.

[0038] The PWM signal driving circuit 209 generates gate signals for controlling the switching elements of the first inverter circuit 201 and the second inverter circuit 202 based on the PWM signal input from the control unit 208, and outputs them to the inverter circuits 201 and 202.

[0039] Inverter circuits 201 and 202 control the switching elements according to the gate signals input from the PWM signal drive circuit 209, thereby converting the DC power supplied from the DC power supply 100 into AC power and outputting it to the motor 300. The smoothing capacitor 203 smooths the DC power supplied from the DC power supply 100 to the inverter circuits 201 and 202.

[0040] Motor 300 is a synchronous motor driven by alternating current supplied from inverter circuits 201 and 202, and has a stator and a rotor. The stator of motor 300 has two systems of three-phase windings: a first system winding group 301 and a second system winding group 302. Alternating current is input from the first inverter circuit 201 to the first system winding group 301, conducting three-phase alternating currents Iu1, Iv1, and Iw1 in each winding constituting the first system winding group 301, generating armature flux in each winding.

[0041] Similarly, alternating current is input from the second inverter circuit 202 to the second system winding group 302, conducting three-phase alternating currents Iu2, Iv2, and Iw2 in the windings constituting the second system winding group 302, generating armature magnetic flux in each winding. The combined magnetic flux of the armature magnetic flux generated in each winding of these two systems generates attractive and repulsive forces with the magnetic flux of the permanent magnets arranged in the rotor, thereby generating torque in the rotor and driving the rotor to rotate.

[0042] Figure 1 In the diagram, one control unit 208 and one PWM signal drive circuit 209 are shown, but each inverter circuit 201 and 202 may also have a PWM signal drive circuit and a control unit 208. Furthermore, each inverter circuit 201 and 202 may also have a PWM signal drive circuit 209 and a control unit 208 respectively.

[0043] The control unit 208 receives a torque command value T* from a higher-level controller (not shown) and calculates the current phase of the current that should be energized in the inverter circuits 201 and 202 of the first and second systems, respectively, based on the torque command value T*. Further, the control unit 208 calculates a voltage command value such that the current energized in the inverter circuits 201 and 202 of the first and second systems changes to the desired current phase, generates a PWM signal based on the three-phase current command values ​​of the first and second systems, and outputs it to the PWM signal drive circuit 209. The PWM signal drive circuit 209 generates a gate signal based on the received PWM signal and drives the switching elements of the inverter circuits 201 and 202.

[0044] Furthermore, a storage unit 218 storing various spectra is connected to the control unit 208. The control unit 208 moves the phase of the PWM carrier signal used in generating the PWM signals that control the operation of the first inverter circuit 201 and the second inverter circuit 202, based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300, as detailed later. At this time, processing is performed with reference to the spectra pre-stored in the storage unit 218. The control unit 208 is, for example, a microcomputer. Alternatively, the storage unit 218 may be located inside the control unit 208.

[0045] Regarding the driving of motor 300, ideally it would be driven by sinusoidal current. However, for motor 300 that operates at variable speed, the frequency of the current flowing from inverter circuits 201 and 202 to motor 300 must be controlled according to the speed of motor 300. Therefore, motor 300 that operates at variable speed is mostly driven by inverter circuits 201 and 202.

[0046] The PWM control performed by the control unit 208 is classified into two methods based on the difference in the control mode of the frequency (carrier frequency) of the PWM carrier signal used in the generation of the PWM signal. Specifically, there is asynchronous PWM control with a fixed carrier frequency independent of the frequency of the current flowing to the motor 300, and synchronous PWM control in which the carrier frequency is controlled as an integer multiple of the frequency of the current flowing to the motor 300. When using asynchronous PWM control to drive the motor 300 at high speed, the current waveform flowing to the motor 300 will not be a three-phase symmetrical waveform, resulting in electromagnetic force pulsation in the motor 300. When using synchronous PWM control, the current waveform flowing to the motor 300 becomes a three-phase symmetrical waveform, so compared with asynchronous PWM control, a reduction in electromagnetic force pulsation in the motor 300 can be expected.

[0047] The pulsation of the electromagnetic force generated by motor 300 is due to the change in electromagnetic force generated in the rotor caused by the current flowing through inverter circuits 201 and 202 to motor 300. The pulsation of the electromagnetic force generated by motor 300 can be broadly divided into a circumferential pulsation component, namely torque pulsation, and a radial pulsation component, namely electromagnetic excitation force. The main factors contributing to the pulsation of the electromagnetic force in motor 300 are the changes in electromagnetic force resulting from the shape of the motor's magnetic circuit, which consists of the stator core, stator coils, rotor core, and rotor magnets, and the changes in electromagnetic force resulting from harmonics in the current flowing from inverter circuits 201 and 202 to the coils of motor 300, controlled by inverter circuits 201 and 202.

[0048] High-speed motors 300 typically employ magnetic field weakening control, so even with the same torque, the magnitude and phase of the electromagnetic force pulsations caused by the magnetic circuit differ. Furthermore, the magnitude of magnetic field weakening also depends on the DC voltage of the DC power supply 100. The primary reason for the harmonic components in the current flowing from inverter circuits 201 and 202 to the coils of motor 300 is that the control of inverter circuits 201 and 202 is achieved through PWM control, where the voltage is applied using a PWM signal rather than a sine wave. The pulse amplitude of this PWM signal depends on the DC voltage.

[0049] Here, in a motor drive system that drives a motor 300 with two independent systems of windings equipped with neutral points 303 and 304 in the stator by connecting two inverter circuits 201 and 202, the pulsation of electromagnetic force is determined by three factors: the pulsation of electromagnetic force caused by the magnetic circuit of the motor 300 with two systems of windings, the pulsation of electromagnetic force caused by the control of the first inverter circuit 201, and the pulsation of electromagnetic force caused by the control of the second inverter circuit 202.

[0050] Figure 2This example illustrates the circumferential component, or torque pulsation, of the electromagnetic force pulsation of the motor 300 without employing this embodiment. Figure 2 (A) is a diagram representing the torque acting on the shaft of motor 300. Figure 2 (B) is a diagram representing the circumferential component of the electromagnetic force pulsation caused by the magnetic circuit of motor 300. Figure 2 (C) is a diagram representing the circumferential component of the electromagnetic force pulsation generated in the motor due to the control of the first inverter circuit 201. Figure 2 (D) is a graph representing the circumferential component of the electromagnetic force pulsation generated in the motor due to the control of the second inverter circuit 202. The horizontal axis represents electrical angle, and the vertical axis represents torque. Furthermore, Figure 2 (B) Figure 2 (C) and Figure 2 (D) shows the circumferential component of the electromagnetic force pulsation caused by various factors in motor 300, namely torque pulsation.

[0051] because Figure 2 The circumferential component of the electromagnetic force pulsation caused by the magnetic circuit of motor 300 shown in (B). Figure 2 The circumferential component of the electromagnetic force pulsation caused by the control of the first inverter circuit 201 shown in (C), and Figure 2 The addition of the circumferential component of the electromagnetic force pulsation caused by the control of the second inverter circuit 202 shown in (D), such as Figure 2 As shown in (A), torque pulsation occurs on the shaft of motor 300. This torque pulsation results in vibration and noise in motor 300.

[0052] Figure 3 This is a diagram illustrating the circumferential component, or torque pulsation, of the electromagnetic force pulsation of the motor 300 when this embodiment is used. Figure 3 (A) is a diagram showing the torque of the shaft of motor 300. Figure 3 (B) is a diagram representing the circumferential component of the electromagnetic force pulsation caused by the magnetic circuit of motor 300. Figure 3 (C) is a diagram representing the circumferential component of the electromagnetic force pulsation caused by the control of the first inverter circuit 201. Figure 3 (D) is a graph representing the circumferential component of the electromagnetic force pulsation caused by the control of the second inverter circuit 202. The horizontal axis represents electrical angle, and the vertical axis represents torque. Furthermore, with Figure 2 Same, Figure 3 (B) Figure 3 (C) and Figure 3 The (D) also shows the circumferential component of the electromagnetic force pulsation caused by various factors in the motor 300, namely the torque pulsation.

[0053] In this embodiment, the phase of the electromagnetic force pulsations of the three factors is adjusted by control as described later, thereby reducing the torque pulsations ultimately generated by the motor 300. The controllable factors among these three electromagnetic force pulsations are the electromagnetic force pulsations caused by the control of the first inverter circuit 201 and the electromagnetic force pulsations caused by the control of the second inverter circuit 202. The control unit 208 adjusts the phase θ of the electromagnetic force pulsations caused by the control of the first inverter circuit 201 based on the electromagnetic force pulsations caused by the magnetic circuit of the motor 300. I1 Furthermore, the phase θ of the electromagnetic force pulsation caused by the control of the second inverter circuit 202. I2 The phase θ of the electromagnetic force pulsation caused by the control of the first inverter circuit 201. I1 The adjustment refers to adjusting the phase (carrier phase θ) of the PWM carrier signal used in generating the PWM signal to control the first inverter circuit 201. C1 The phase θ of the electromagnetic force pulsation caused by the control of the second inverter circuit 202 is determined. I2 The adjustment refers to adjusting the phase (carrier phase θ) of the PWM carrier signal used in generating the PWM signal to control the second inverter circuit 202. C2 (to be carried out)

[0054] like Figure 3 As shown in (C), for example, the pulsation of electromagnetic force caused by the control of the first inverter circuit 201 is relative to... Figure 3 The motor 300 shown in (B) moves, for example, by 20 degrees due to the pulsation of electromagnetic force caused by the magnetic circuit. Further, for example, Figure 3 The electromagnetic force pulsation caused by the control of the second inverter circuit 202 shown in (D) is relative to Figure 3 The motor 300 shown in (B) moves, for example, by 40 degrees due to the pulsation of electromagnetic force caused by the magnetic circuit of the motor 300. Thus, as... Figure 3 As shown in (A), it is possible to suppress the pulsation generated in the shaft torque of motor 300, thereby suppressing the vibration and noise of motor 300.

[0055] Furthermore, the above text discusses adjusting the carrier phase θ separately. C1、 θ C2 The phase θ of the circumferential component in the electromagnetic force pulsation caused by adjusting the control of the first inverter circuit 201 I1 The phase θ of the circumferential component in the electromagnetic force pulsation caused by the control of the second inverter circuit 202 I2 The reduction of the circumferential component of the electromagnetic force pulsation generated in the motor 300, i.e., torque pulsation, was explained. Here, the same control can also be applied to the radial component of the electromagnetic force pulsation generated in the motor 300, i.e., the electromagnetic excitation force. That is, the carrier phase θ can be adjusted separately. C1、 θC2 By adjusting the phase of the radial component of the electromagnetic force pulsation caused by the control of the first inverter circuit 201 and the phase of the radial component of the electromagnetic force pulsation caused by the control of the second inverter circuit 202, the radial component of the electromagnetic force pulsation generated in the motor 300, i.e., the electromagnetic excitation force, is reduced.

[0056] Figure 4 (A) Figure 4 (B) is a diagram representing the motor pulsation. Figure 4 (A) is a pulsation diagram of the electromagnetic force used in the circumferential component of motor 300. Figure 4 (B) is a pulsation diagram of the electromagnetic force used for the radial component of motor 300. All of these are pre-stored in the storage unit 218.

[0057] like Figure 4 As shown in (A), the electromagnetic force pulsation diagram for the circumferential component of motor 300 is the phase θ of the electromagnetic force pulsation caused by the magnetic circuit of motor 300, expressed as the current command values ​​Id and Iq when controlling motor 300. Tr The resulting graph is a correlation graph. This graph is set to correspond to the DC voltages Vdc1, Vdc2, and Vdc3 of the DC power supply 100. Furthermore, for ease of explanation, Figure 4 The diagram in (A) is an example of a motor pulsation diagram for setting the circumferential component for three DC voltages Vdc1, Vdc2, and Vdc3. However, any motor pulsation diagram for setting the circumferential component for multiple DC voltages is acceptable, and it can be more than three.

[0058] like Figure 4 As shown in (B), the pulsation diagram of the electromagnetic force used for the radial component of motor 300 is the phase θ of the pulsation caused by the magnetic circuit of motor 300, which is the current command values ​​Id and Iq when controlling motor 300. Tr The resulting graph is a correlation graph. This graph is set to correspond to the DC voltages Vdc1, Vdc2, and Vdc3 of the DC power supply 100. Furthermore, for ease of explanation, Figure 4 The diagram in (B) is an example of a motor pulsation diagram for setting the radial component for three DC voltages Vdc1, Vdc2, and Vdc3. However, any motor pulsation diagram for setting the radial component for multiple DC voltages is acceptable, and it can be more than three.

[0059] Figure 4 (A) Figure 4 The motor pulsation diagram shown in (B) is pre-stored using experimental or design values. For example, making Figure 1 As shown, when the motor drive system operates under the condition of DC voltage Vdc1 of DC power supply 100, determine a certain current command value Id, Iq, and the phase θ of the electromagnetic force pulsation caused by the magnetic circuit of motor 300 under that condition.Tr This data is then plotted. Subsequently, the phase θ of the electromagnetic force pulsation is determined by making various changes to the current command values ​​Id and Iq. Tr And create a graph. Similarly, change the DC voltage of DC power supply 100 and create a graph. In this case, select which component—the circumferential or radial—to reduce electromagnetic force pulsation based on the speed of motor 300. For example, when the speed of motor 300 is low, create... Figure 4 The circumferential component diagram shown in (A) is used. When the motor speed is high (300 rpm), it is made... Figure 4 The radial component is shown in (B). In addition, the motor pulsation diagram also stores in advance the magnitude of the electromagnetic force pulsation (torque pulsation generated in the circumferential direction and electromagnetic excitation force generated in the radial direction) caused by the magnetic circuit of the motor 300 based on the current command values ​​id and iq, and the reference phase for the electrical angle of the motor 300.

[0060] When the control unit 208 references the graph stored in the storage unit 218, it references the graph when the motor 300 rotates at a low speed. Figure 4 The circumferential component shown in (A) is used to determine the phase θ of the electromagnetic force pulsation corresponding to the current command values ​​Id and Iq. Tr When the motor speed is high at 300 rpm, refer to Figure 4 The radial component shown in (B) is used to determine the phase θ of the electromagnetic force pulsation corresponding to the current command values ​​Id and Iq. Tr .

[0061] Figure 5 (A) Figure 5 (B) is a diagram representing the circumferential carrier phase diagram. Figure 5 (A) is the carrier phase diagram used for the first circumferential component of the first inverter circuit 201. Figure 5 (B) is the carrier phase diagram used for the second circumferential component of the second inverter circuit 202. All of them are pre-stored in the storage unit 218.

[0062] like Figure 5 As shown in (A), the carrier phase diagram used for the first circumferential component of the first inverter circuit 201 is the carrier phase θ of the circumferential component of the current command values ​​Id and Iq when controlling the motor 300, used to reduce electromagnetic force pulsations caused by the control of the first inverter circuit 201. C1 A map formed by association. For example... Figure 5 As shown in (B), the carrier phase diagram used for the second circumferential component of the second inverter circuit 202 is the carrier phase θ of the circumferential component of the current command values ​​Id and Iq when controlling the motor 300, used to reduce electromagnetic force pulsations caused by the control of the second inverter circuit 202. C2The resulting graphs are correlated. These graphs are set to correspond to the DC voltages Vdc1, Vdc2, and Vdc3 of the DC power supply 100, respectively. Furthermore, for ease of explanation, Figure 5 (A) Figure 5 The illustration in (B) shows an example of setting the carrier phase diagram for the first circumferential component and the carrier phase diagram for the second circumferential component for three DC voltages Vdc1, Vdc2, and Vdc3 respectively. However, these diagrams can be set for multiple DC voltages, or more than three.

[0063] Figure 6 (A) Figure 6 (B) is a diagram representing the radial carrier phase diagram. Figure 6 (A) is the carrier phase diagram used for the first radial component of the first inverter circuit 201. Figure 6 (B) is the carrier phase diagram used for the second radial component of the second inverter circuit 202. All of them are pre-stored in the storage unit 218.

[0064] like Figure 6 As shown in (A), the carrier phase diagram used for the first radial component of the first inverter circuit 201 is the carrier phase θ of the radial component of the control of the motor 300, which is the current command values ​​Id and Iq when controlling the motor 300, and is used to reduce the electromagnetic force pulsation caused by the control of the first inverter circuit 201. C1 A map formed by association. For example... Figure 6 As shown in (B), the carrier phase diagram used for the second radial component of the second inverter circuit 202 is the carrier phase θ of the radial component of the control of the motor 300, which is the current command values ​​Id and Iq when controlling the motor 300, and is used to reduce the electromagnetic force pulsation caused by the control of the second inverter circuit 202. C2 The resulting graphs are correlated. These graphs are set to correspond to the DC voltages Vdc1, Vdc2, and Vdc3 of the DC power supply 100, respectively. Furthermore, for ease of explanation, Figure 6 (A) Figure 6 The illustration in (B) shows an example of setting the carrier phase diagram for the first radial component and the carrier phase diagram for the second radial component for three DC voltages Vdc1, Vdc2, and Vdc3 respectively. However, these diagrams can be set for multiple DC voltages, or more than three.

[0065] in addition, Figure 5 (A) Figure 5 The circumferential carrier phase diagram of (B) and Figure 6 (A) Figure 6 The aforementioned carrier phase θ in the radial carrier phase diagram of (B) C1 θ C2 Therefore Figure 4 (A) Figure 4Phase θ in the motor pulsation diagram of (B) Tr The phase difference between the electromagnetic force pulsation caused by the magnetic circuit of motor 300 and the phase difference between the electromagnetic force pulsation caused by the control of the first inverter circuit 201 and the second inverter circuit 202 is expressed as follows: Figure 5 (A) Figure 5 The circumferential carrier phase diagram of (B) and Figure 6 (A) Figure 6 The radial carrier phase diagrams of (B) are shown respectively.

[0066] Figure 5 (A) Figure 5 The PWM carrier phase diagram of the circumferential component shown in (B) is pre-stored using experimental or design values. For example, making Figure 1 The motor drive system shown is operating under DC voltage Vdc1 of DC power supply 100. The system calculates a certain current command value Id, Iq, and the carrier phase θ of the circumferential component of the electromagnetic force pulsation caused by the control of the first inverter circuit 201 and the second inverter circuit 202 under this condition. C1 θ C2 And create a graph. Specifically, by continuously shifting the phase of the PWM carrier signal of the first inverter circuit 201, the phase at which the torque ripple of the motor 300 reaches its minimum is determined as the carrier phase θ. C1 The second inverter circuit 202 is the same. That is, simply shift the phase of the PWM carrier signal used for PWM control of inverter circuits 201 and 202 to phase θ. C1 θ C2 This means that the circumferential electromagnetic force pulsations caused by these controls can be minimized. Then, by making various changes to the current command values ​​Id and Iq, the carrier phase θ under different conditions is determined. C1 θ C2 And create a graph. The same applies below; change the DC voltage of DC power supply 100 and create a graph.

[0067] Figure 6 (A) Figure 6 The radial component PWM carrier phase diagram shown in (B) is similarly pre-stored using experimental or design values. For example, making Figure 1 The motor drive system shown is operating under DC voltage Vdc1 of DC power supply 100. The system calculates a certain current command value Id, Iq, and the carrier phase θ of the radial component of the electromagnetic force pulsation caused by the control of the first inverter circuit 201 and the second inverter circuit 202 under this condition. C1 θ C2This data is then plotted. Subsequently, the carrier phase θ is calculated under various conditions by modifying the current command values ​​Id and Iq. C1 θ C2 And create a graph. The same applies below; change the DC voltage of DC power supply 100 and create a graph.

[0068] Furthermore, at a low motor speed of 300, it is made into Figure 5 (A) Figure 5 The circumferential component diagram shown in (B) is used. When the motor speed is high (300 rpm), it is made... Figure 6 (A) Figure 6 The radial component is shown in (B).

[0069] When the control unit 208 references the graph stored in the storage unit 218, it references the graph when the motor 300 rotates at a low speed. Figure 5 (A) Figure 5 The circumferential component shown in (B) is used to determine the carrier phase θ corresponding to the current command values ​​Id and Iq. C1 θ C2 When the motor speed is high at 300 rpm, refer to Figure 6 (A) Figure 6 The radial component shown in (B) is used to determine the carrier phase θ corresponding to the current command values ​​Id and Iq. C1 θ C2 .

[0070] Next, refer to Figure 7 The pulsation of radial electromagnetic force (electromagnetic excitation force) caused by the magnetic circuit of motor 300 is explained.

[0071] When the motor 300 is running at high speed, the number of pulses / cycles decreases on the high-speed side, so synchronous PWM control is used in this embodiment. When using synchronous PWM control, the radial electromagnetic force pulsation caused by the magnetic circuit of the motor 300 can be overlapped with the radial electromagnetic force pulsation caused by the harmonic current caused by the control of the inverter circuits 201 and 202, regardless of the speed of the motor 300.

[0072] Figure 7 This is a graph showing the relationship between the rotational speed of motor 300 and the excitation frequency (the frequency of radial pulsation). The horizontal axis represents the rotational speed of motor 300, and the vertical axis represents the excitation frequency.

[0073] Before the speed of motor 300 reaches 12000 rpm, asynchronous PWM control is used; when the speed of motor 300 exceeds 12000 rpm, synchronous PWM control is used.

[0074] Figure 7The example shown is of a Motor 300, which is an 8-pole motor (pole number P = 8). Furthermore, in... Figure 7 In the example, under asynchronous PWM control, the carrier frequency fc = 10kHz. Under synchronous PWM control, the carrier frequency fc is adjusted by forming a PWM carrier signal of 9 pulses per cycle of the voltage command.

[0075] First, the excitation frequency caused by the magnetic circuit of motor 300 will be explained. The electrical angle (fundamental current) of rotating motor 300 is set as frequency f1 [Hz]. The relationship between the rotational speed N [rpm] of motor 300 and electrical angle frequency f1 is expressed by the following equation (1). P is the number of poles of motor 300.

[0076] f1=N / 60×P / 2[rpm]···(1)

[0077] The excitation frequency f6 of the 6th rotation (electric angle) of motor 300 is expressed by the following formula (2). The excitation frequency f12 of the 12th rotation (electric angle) of motor 300 is expressed by the following formula (3).

[0078] f6=6×f1[Hz]···(2)

[0079] f12=12×f1[Hz]···(3)

[0080] Figure 7 In the diagram, f6 represents the excitation frequency f6 at the 6th rotational order (electrical angle), and f12 represents the excitation frequency f12 at the 12th rotational order (electrical angle). For example... Figure 7 As shown, the excitation frequencies f6 and f12 increase linearly from the asynchronous PWM control region to the synchronous PWM control region. Furthermore, the carrier frequency fc is fixed in asynchronous PWM control.

[0081] Next, the excitation frequency (radial pulsation frequency) caused by the harmonic currents generated by the inverter circuits 201 and 202 will be explained. The sideband wave components of the carrier frequency fc and fc±3f1 are called the 0th order excitation frequency of the ring. Furthermore, the so-called 0th order of the ring refers to the rotational order of the radial pulsation of the motor 300. The radial component of the electromagnetic force generated by the air gap of the motor 300, and the radial component that changes time uniformly in the radial direction, is called the 0th order mode of the ring. In this embodiment, the radial pulsation of the electromagnetic force in the radial direction of the motor 300 is reduced by targeting the radial pulsation of the 0th order of the ring.

[0082] In the case of asynchronous PWM control, for example, if the speed of motor 300 is 6000rpm, then fc±3f1 becomes the following equation (4) and the following equation (5).

[0083] fc+3f1=10000+3×6000 / 60×8 / 2=11200[Hz]···(4)

[0084] fc-3f1=10000-3×6000 / 60×8 / 2=8800[Hz]···(5)

[0085] In the case of synchronous PWM control, if the PWM carrier signal is set to 9 pulses per cycle of the voltage command, then the carrier frequency fc is represented by the following equation (6). Therefore, the sideband components are respectively expressed as equations (7) and (8).

[0086] fc=9×f1[Hz]···(6)

[0087] fc+3f1=9×f1+3×f1=12×f1[Hz]···(7)

[0088] fc-3f1=9×f1-3×f1=6×f1[Hz]···(8)

[0089] like Figure 7 As shown, under synchronous PWM control, the frequencies f6 and f12 of the radial electromagnetic force pulsation caused by the magnetic circuit of motor 300 overlap with the frequencies fc+3f1 and fc-3f1 of the radial electromagnetic force pulsation caused by the control of inverter circuits 201 and 202. Thus, the radial electromagnetic force pulsation caused by the magnetic circuit of motor 300 and the radial electromagnetic force pulsation caused by the control of inverter circuits 201 and 202 become the same frequency. Therefore, by shifting the phase of the radial electromagnetic force pulsation caused by the control of inverter circuits 201 and 202 using the control described later, the electromagnetic excitation force caused by the magnetic circuit of motor 300 can be canceled.

[0090] Figure 8 A diagram showing the frequency of the voltage command and the carrier frequency fc. Figure 8 (A) shows the waveform of the first inverter circuit 201. Figure 8 (B) shows the waveform of the second inverter circuit 202. The left side of each figure shows the motor 300 at a low speed, and the right side of each figure shows the motor 300 at a high speed.

[0091] Figure 1 The control unit 208 shown is a synchronous PWM control unit, which controls the frequency of the voltage command and the carrier frequency fc. The frequency of the voltage command is the frequency f1 [Hz] of the electrical angle (fundamental current) of the rotating motor 300. Figure 8 (A) Figure 8 As shown on the left side of (B), at low speeds, the carrier frequency fc is controlled by a PWM carrier signal that forms 9 pulses per cycle at the voltage command frequency f1. Figure 8 (A) Figure 8 As shown on the right side of (B), the same applies at high speeds, controlling the carrier frequency fc by generating a PWM carrier signal that produces 9 pulses per cycle of the voltage command frequency f1. The waveform of the first inverter circuit 201 is the same as the waveform of the second inverter circuit 202. This example illustrates the generation of a PWM carrier signal that produces 9 pulses per cycle of the voltage command frequency f1, and the frequency of the PWM carrier signal only needs to be an integer multiple of the voltage command frequency. It is particularly preferred that the control is performed in a manner where this integer multiple is an odd integer multiple, and furthermore, it is preferred that the control is performed in a manner where it is an integer multiple of 3.

[0092] That is, the control unit 208 adjusts the carrier frequency fc synchronously with the frequency f1 of the voltage command of the drive motor 300, such that the frequency of the PWM carrier signal used in the PWM control of the first inverter circuit 201 and the second inverter circuit 202 is changed to an integer multiple of the frequency of the voltage command of the drive motor 300. By adjusting the carrier frequency in this way, when using synchronous PWM control, the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300 can be overlapped with the pulsation of the electromagnetic force caused by the control of the inverter circuits 201 and 202, regardless of the rotational speed of the motor 300. Thus, the two pulsations become the same frequency, so by shifting the phase of the pulsation of the electromagnetic force caused by the control of the inverter circuits 201 and 202 as described later, the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300 can be canceled out.

[0093] Figure 9 This is a flowchart illustrating the processing of the control unit 208 of the motor control device 200.

[0094] Figure 9 The flowchart shown illustrates execution at regular intervals or whenever a torque command value T* is input. Furthermore, the program shown in the flowchart can be executed using a computer equipped with a CPU, memory, etc. Hardware logic circuits can also be used to implement all or part of the processing. Furthermore, the program can be provided by pre-storing it in the storage medium of the motor control device 200. Alternatively, the program can be provided by storing it in a separate storage medium, or by recording and storing it in the storage medium of the motor control device 200 via a network line. It can also be provided in the form of a computer-readable computer program product in various forms, such as data signals (carrier waves).

[0095] exist Figure 9 In step S901, the control unit 208 receives a torque command value T* from a host controller or the like. Then, in step S902, the control unit 208 uses the received torque command value T* to generate current command values ​​Id and Iq.

[0096] Next, in step S903, the control unit 208 references... Figure 8 (A) Figure 8 As explained in (B), the adjustment is made such that the frequency of the PWM carrier signal becomes an integer multiple of the frequency of the voltage command. In this case, for example, the integer multiple is ideally adjusted to an odd integer multiple, and furthermore, it is ideally adjusted to an integer multiple of 3.

[0097] Next, in step S904, the control unit 208 selects the pulsation component to be reduced. That is, it selects the circumferential component when the rotational speed of the motor 300 is below a predetermined value, and selects the radial component when the rotational speed of the motor 300 is above the predetermined value. The rotational speed of the motor 300 is determined based on the rotational position θ from the magnetic pole position detector 207. In other words, the control unit 208 selects, based on the rotational speed of the motor 300, either the circumferential torque pulsation generated in the electromagnetic force pulsation caused by the magnetic circuit of the motor 300 or the radial electromagnetic excitation force generated in the electromagnetic force pulsation caused by the magnetic circuit of the motor 300.

[0098] Subsequently, in step S905, the control unit 208 retrieves the motor pulsation diagram stored in the storage unit 218. As already explained, the motor pulsation diagram has... Figure 4 The circumferential component shown in (A) is represented by a graph and Figure 4 The radial component spectrum shown in (B) is used. Since the pulsation component to be reduced was selected in step S904, the spectrum corresponding to the selected pulsation component is retrieved. Before the retrieval, the control unit 208 uses the voltage detector 101 to detect the DC voltage value of the DC power supply 100. That is, when the rotational speed is lower than the specified value, the spectrum is retrieved based on the current command values ​​Id and Iq. Figure 4 (A) shows the spectrum corresponding to the detected DC voltage value of the DC power supply 100 among the three circumferential components, and obtains the phase θ of the electromagnetic force pulsation caused by the magnetic circuit of the motor 300. Tr When the rotational speed is above the specified value, the system retrieves values ​​based on the current command values ​​Id and Iq. Figure 4 (B) shows the spectrum of the three radial components, corresponding to the detected DC voltage value of the DC power supply 100, to obtain the phase θ of the electromagnetic force pulsation caused by the magnetic circuit of the motor 300. Tr Generally, changes in the DC voltage of the DC power supply 100 will cause changes in the amplitude of the electromagnetic force pulsation caused by the magnetic circuit of the motor 300. In this embodiment, since the amplitude change can be accommodated by referring to the spectrum corresponding to the DC voltage value detected by the voltage detector 101 in a motor pulsation spectrum preset for multiple DC voltage values, the amplitude change can also be accommodated.

[0099] In step S906, the control unit 208 uses the phase θ retrieved in step S905 Tr To infer the phase of the pulsations caused by the magnetic circuit of motor 300. Below, refer to... Figure 10 Please provide an explanation.

[0100] Figure 10 A diagram illustrating torque pulsation when this embodiment is used. Figure 10 (A) is a graph showing the magnetic position of motor 300, with the horizontal axis representing time and the vertical axis representing electrical angle. Figure 10 (B) represents the shaft torque of motor 300. The horizontal axis represents time, and the vertical axis represents torque. Figure 10 (C) is a diagram showing the PWM carrier signal and voltage command of the first inverter circuit 201. Figure 10 (D) is a graph representing the PWM carrier signal and voltage command of the second inverter circuit 202. The horizontal axis represents time and the vertical axis represents voltage.

[0101] like Figure 10 As shown in (A), the magnetic position of motor 300 changes in a cycle of 360 electrical degrees as motor 300 rotates, with a rotation angle of 0 degrees serving as the reference position. Figure 10 As shown in (B), the electromagnetic force pulsation caused by the magnetic circuit of motor 300, which occurs in the shaft torque of motor 300, is generated in a three-phase motor 300 at a frequency of 6n times the electrical angle per cycle (n = 6, 12, 18, ...). The electromagnetic force pulsation caused by the magnetic circuit of motor 300 is determined by the current command values ​​id and iq, so the offset from the reference position of motor 300 must be confirmed.

[0102] The control unit 208 uses the detection signal from the magnetic pole position detector 207 mounted on the motor 300 and the current command value for the motor 300 to infer the phase of the pulsation caused by the magnetic circuit of the motor 300. Since the pulsation of the electromagnetic force caused by the magnetic circuit corresponding to the rotation angle of the motor 300 can be inferred, it can be used as a reference for [further actions], as described later. Figure 10 (C) Figure 10 Adjust the carrier phase θ as shown in (D). C1 and θ C2 .

[0103] return Figure 9 Explanation of the flowchart shown.

[0104] exist Figure 9 In step S907, the control unit 208 retrieves the carrier phase diagram stored in the storage unit 218. As already explained, the carrier phase diagram has... Figure 5 (A) Figure 5 The circumferential carrier phase diagram shown in (B) and Figure 6 (A) Figure 6 The radial carrier phase diagram shown in (B) is as follows.

[0105] Since the pulsation component to be reduced was selected in step S904, the spectrum corresponding to the selected pulsation component is retrieved. Before performing the search, the control unit 208 uses the voltage detector 101 to detect the DC voltage value of the DC power supply 100. That is, when the rotational speed is lower than a specified value, the spectrum is retrieved according to the current command values ​​Id and Iq respectively. Figure 5 (A) Figure 5 (B) shows the spectrum corresponding to the detected DC voltage value of the DC power supply 100 in the three circumferential components, respectively, to obtain the carrier phase θ. C1 θ C2 When the rotational speed is above the specified value, the system retrieves values ​​based on the current command values ​​Id and Iq. Figure 6 (A) Figure 6 (B) shows the spectrum corresponding to the detected DC voltage value of the DC power supply 100 in the spectrum of the three radial components, respectively, to obtain the carrier phase θ. C1 θ C2 .

[0106] Generally, changes in the DC voltage of the DC power supply 100 cause changes in the amplitude of the electromagnetic force pulsation caused by the control of the inverter circuits 201 and 202. In this embodiment, even if the amplitude of the electromagnetic force pulsation caused by the control of the inverter circuits 201 and 202 changes, the torque pulsation and electromagnetic excitation force reduction effect when superimposed with the electromagnetic force pulsation caused by the magnetic circuit of the motor 300 can be ensured by adjusting their phase. That is, the phase shift of the PWM carrier signal is adjusted according to the DC voltage values ​​applied to the first inverter circuit 201 and the second inverter circuit 202, as described later.

[0107] exist Figure 9 In step S908, the control unit 208 adjusts the phase θ of the PWM carrier signal for the first inverter circuit 201 based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300. C1 The degree of movement. Furthermore, based on the pulsation of the electromagnetic force caused by the magnetic circuit of motor 300, the phase θ of the PWM carrier signal for the second inverter circuit 202 is adjusted. C2 The degree of movement.

[0108] Subsequently, in step S909, the control unit 208 drives the first inverter circuit 201 and the second inverter circuit 202 to output AC voltage to the motor 300.

[0109] Thus, by using the combined wave of the harmonic currents flowing through the first and second inverter circuits, and taking the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300 as a reference, the phase of the PWM carrier signal is shifted. As a result, the pulsation caused by the magnetic circuit of the motor 300 can be suppressed.

[0110] Figure 3 (C) shows an example of shifting the electromagnetic force pulsation caused by the control of the first inverter circuit 201 by 20 degrees. Figure 3 (D) illustrates an example where the pulsation of the electromagnetic force caused by the control of the second inverter circuit 202 is shifted by 40 degrees. Thus, the phase θ of the pulsation of the electromagnetic force caused by the control of the first inverter circuit 201... I1 The adjustment is to adjust the carrier phase θ of the first inverter circuit 201. C1 To proceed. The phase θ of the electromagnetic force pulsation caused by the control of the second inverter circuit 202. I2 The adjustment is to adjust the carrier phase θ of the second inverter circuit 202. C2 To proceed. Therefore, as... Figure 3 As shown in (A), it is possible to suppress the torque pulsation generated in the axial direction of the motor 300 and the electromagnetic excitation force generated in the radial direction of the motor 300, thereby suppressing the vibration and noise of the motor 300.

[0111] In this embodiment, the appropriate motor is selected based on the rotational speed of the motor 300. Figure 4 (A) Figure 4 The motor pulsation diagram shown in (B) is as follows. Figure 5 (A) Figure 5 The circumferential carrier phase diagram shown in (B) Figure 6 (A) Figure 6 The radial carrier phase diagram shown in (B) illustrates this. Specifically, based on the rotational speed of the motor 300, the phase of the PWM carrier signal is shifted in a manner that reduces either the circumferential torque pulsation caused by the motor 300's magnetic circuit or the radial electromagnetic excitation force caused by the motor 300's magnetic circuit. Thus, although the rotational speed of the motor 300 affects which of the circumferential torque pulsation or the radial electromagnetic excitation force causes vibration, the pulsation of the more influential party can be reduced, thereby decreasing vibration.

[0112] In this embodiment, the DC power supply 100 is selected based on the DC voltage value detected by the voltage detector 101. Figure 4 (A) Figure 4 The motor pulsation diagram shown in (B) is as follows. Figure 5 (A) Figure 5 The circumferential carrier phase diagram shown in (B) Figure 6(A) Figure 6 The radial carrier phase diagram shown in (B) illustrates this. Specifically, the phase shift of the WM carrier signal is adjusted based on the DC voltage applied to the first inverter circuit 201 and the second inverter circuit 202. Therefore, although the amplitude of the electromagnetic force pulsation caused by the control of the first inverter circuit 201 and the second inverter circuit 202 changes due to variations in the DC voltage of the DC power supply 100, even with these amplitude changes, the reduction in torque pulsation and electromagnetic excitation force when superimposed with the electromagnetic force pulsation caused by the magnetic circuit of the motor 300 is ensured.

[0113] Next, refer to Figure 11 The rotational order of the pulsations is explained.

[0114] Figure 11 (A) is a graph showing the magnetic position of motor 300, with the horizontal axis representing time and the vertical axis representing electrical angle. Figure 11 (B) represents the torque pulsation of the shaft of motor 300. The horizontal axis represents time, and the vertical axis represents torque. Figure 11 (C) is a graph representing the sixth-order electrical angular components of torque pulsation. Figure 11 (D) is a graph representing the 12th order electrical angular components of torque pulsation, with the horizontal axis representing time and the vertical axis representing torque.

[0115] Figure 11 The torque pulsation of the motor 300 shaft shown in (B) illustrates the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300. By referring to the magnetic pole position detector 403, the electrical angle position of the rotor of the motor 300 can be confirmed. Figure 11 The electromagnetic force pulsation cut-off caused by the magnetic circuit of motor 300 shown in (B) Figure 11 If the electrical angle shown in (A) is analyzed in one cycle (360 degrees), then it becomes... Figure 11 (C) Figure 11 The shape of (D). That is, Figure 11 The waveform of (C) consists of 6 electromagnetic force pulsations within one cycle (360 degrees) of the electrical angle, and 6 pulsations occur relative to one revolution of the electrical angle, hence it is called the 6th order component of the electrical angle. Figure 11 The waveform of (D) consists of 12 electromagnetic force pulsations within one cycle (360 degrees) of the electrical angle, and 12 pulsations occur relative to one revolution of the electrical angle, hence it is called the 12th order component of the electrical angle.

[0116] Next, the control of the electromagnetic force pulsation that reduces the sixth-order component of the electrical angle will be explained.

[0117] Figure 12 A diagram illustrating the pulsation when this embodiment is used. Figure 12 (A) is a diagram showing the torque of the shaft of motor 300. Figure 12 (B) is a diagram representing the pulsation of electromagnetic force caused by the magnetic circuit of motor 300. Figure 12 (C) is a diagram representing the pulsation of electromagnetic force caused by the control of the first inverter circuit 201. Figure 12 (D) is a graph representing the pulsation of electromagnetic force caused by the control of the second inverter circuit 202. The horizontal axis represents electrical angle, and the vertical axis represents torque.

[0118] In controlling the pulsation of electromagnetic force to reduce the sixth-order component of the electrical angle, a reference is performed. Figure 9 The steps S901 to S907 and S909 described above are processed in the same way, while... Figure 9 In step S908, the following processing is performed.

[0119] like Figure 12 As shown in (C), the control unit 208 uses the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300 as a reference to adjust the phase θ of the electromagnetic force pulsation caused by the control of the first inverter circuit 201. I1 Move 30 degrees. Furthermore, as... Figure 12 As shown in (D), the control unit 208 uses the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300 as a reference to adjust the phase θ of the electromagnetic force pulsation caused by the control of the second inverter circuit 202. I2 Move 30 degrees.

[0120] Therefore, as Figure 12 As shown in (A), the 6th order electrical angle component of the pulsating torque generated in the shaft torque of motor 300 can be reduced, thereby suppressing the vibration and noise of motor 300.

[0121] Next, the control of electromagnetic force pulsation that reduces the 6th and 12th order electrical angle components will be explained.

[0122] As has already been described, Figure 3 A diagram illustrating the pulsation of the electromagnetic force of the motor 300 when using this embodiment.

[0123] In controlling the pulsation of electromagnetic force to reduce the 6th and 12th order electrical angle components, a reference is performed. Figure 9 The steps S901 to S907 and S909 described above are processed in the same way, while... Figure 9 In step S908, the following processing is performed.

[0124] like Figure 3 As shown in (C), the control unit 208 uses the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300 as a reference to adjust the phase θ of the electromagnetic force pulsation caused by the control of the first inverter circuit 201. I1 Move 20 degrees. Further, such as... Figure 3As shown in (D), the control unit 208 uses the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300 as a reference to adjust the phase θ of the electromagnetic force pulsation caused by the control of the second inverter circuit 202. I2 Move 40 degrees.

[0125] Therefore, as Figure 3 As shown in (A), the 6th and 12th order electrical angle components of the pulsating torque generated in the shaft of the motor 300 can be reduced, thereby suppressing the vibration and noise of the motor 300.

[0126] Figure 13 This is a configuration diagram of the electric vehicle system in this embodiment. Figure 13 As shown, the electric vehicle system has a power transmission system that uses the motor 300 as an electric generator, and uses the rotational driving force of the motor 300 to drive the vehicle. Furthermore, the electric vehicle system will be explained using a hybrid power system as an example.

[0127] Figure 13 In the electric vehicle 800, a front axle 801 is rotatably supported by a journal at the front, and front wheels 802 and 803 are provided at both ends of the front axle 801. A rear axle 804 is rotatably supported by a journal at the rear, and rear wheels 805 and 806 are provided at both ends of the rear axle 804.

[0128] A differential 811, which serves as a power distribution mechanism, is provided at the center of the front axle 801 to distribute the rotational driving force transmitted from the engine 810 via the transmission 812 to the left and right front axles 801.

[0129] Regarding the engine 810 and the motor 300, the pulley on the crankshaft of the engine 810 and the pulley on the shaft of the motor 300 are mechanically connected by a belt. Thus, the rotational driving force of the motor 300 can be transmitted to the engine 810, and vice versa. In the motor 300, three-phase alternating current controlled by a motor control device 200 with built-in inverter circuits 201 and 202 is supplied to the stator coils, thereby causing the rotor to rotate and generating a rotational driving force corresponding to the three-phase alternating current. The motor control device 200 is the device described above in this embodiment.

[0130] That is, the motor 300 is controlled by the motor control device 200 to operate as an electric motor, and on the other hand, it receives the rotational driving force of the engine 810 to make the rotor rotate, thereby inducing an electromotive force in the coil of the stator, and thus operating as a generator to generate three-phase alternating current.

[0131] The motor control device 200 is a power conversion device that converts the DC power supplied from the DC power source 100, which is a high-voltage battery, into three-phase AC power. It controls the three-phase AC current flowing to the stator coil of the motor 300 according to the operating command value, which corresponds to the magnetic position.

[0132] The three-phase alternating current generated by the motor 300 is converted into direct current by the motor control device 200 to charge the DC power supply 100. The DC power supply 100 is electrically connected to the low-voltage battery 823 via the DC-DC converter 824. The low-voltage battery 823 constitutes the low-voltage (14V) power supply for the electric vehicle 800, and is used to power the starter motor 825 for initial starting (cold start) of the engine 810, the radio, lights, etc.

[0133] Generally, the vibration and noise of the motor 300 are caused by the excitation force generated by electromagnetic force being transmitted through the motor 300 body and the structure on which it is mounted, causing various parts to shake and thus generating vibration and noise. Furthermore, when the natural modes and frequencies of the structure overlap with the excitation modes and frequencies of the excitation force, a resonance state occurs, amplifying the vibration and noise. In this embodiment, the vibration and noise of the motor 300 can be reduced, thereby reducing the vibration and noise of the electric vehicle 800 equipped with the motor 300.

[0134] Based on the implementation methods described above, the following effects are achieved.

[0135] (1) The motor control device 200 includes a first inverter circuit 201 and a second inverter circuit 202 of a redundant system for controlling the motor 300, and a control unit 208 for controlling the first inverter circuit 201 and the second inverter circuit 202. The first inverter circuit 201 converts direct current to alternating current based on a PWM signal generated using a first carrier signal, and the second inverter circuit 202 converts direct current to alternating current based on a PWM signal generated using a second carrier signal. The control unit 208 moves the phases of the first carrier signal and the second carrier signal respectively based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300. As a result, vibration and noise generated in the motor can be suppressed.

[0136] (2) The motor control method is a motor control device 200 comprising a first inverter circuit 201 and a second inverter circuit 202 with a redundant system for controlling the motor, and a control unit 208 for controlling the first inverter circuit 201 and the second inverter circuit 202. In this method, the first inverter circuit 201 converts direct current (DC) to alternating current (AC) based on a PWM signal generated using a first carrier signal, and the second inverter circuit 202 converts DC to AC based on a PWM signal generated using a second carrier signal. The control unit shifts the phases of the first carrier signal and the second carrier signal respectively, based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor 300. This suppresses vibrations and noise generated in the motor.

[0137] This invention is not limited to the above-described embodiments. Other forms conceived within the scope of the technical concept of this invention are also included within the scope of this invention, as long as they do not impair the features of this invention.

[0138] Symbol Explanation

[0139] 100…DC power supply, 101…voltage detector, 200…motor control device, 201…first inverter circuit, 202…second inverter circuit, 203…smoothing capacitor, 204…first current sensor, 205…second current sensor, 206…magnetic pole position sensor, 207…magnetic pole position detector, 208…control unit, 209…PWM signal drive circuit, 223…power module, 300…motor, 301…first system winding group, 302…second system winding group.

Claims

1. A motor control device that has a first inverter circuit and a second inverter circuit that control a redundant system of a motor, and a control section that controls the first inverter circuit and the second inverter circuit, characterized by the first inverter circuit converting direct current into alternating current based on a PWM signal generated using a first carrier signal, the second inverter circuit converting the direct current into the alternating current based on a PWM signal generated using a second carrier signal, the control section moving phases of the first carrier signal and the second carrier signal respectively based on pulsation of electromagnetic force caused by a magnetic circuit of the motor, the control section adjusting frequencies of the first carrier signal and the second carrier signal respectively to be integer multiples of a frequency of a voltage command that drives the motor.

2. The motor control device according to claim 1, characterized in that the control section moves the phases of the first carrier signal and the second carrier signal respectively in a manner that moves a phase of pulsation of electromagnetic force caused by control of the first inverter circuit and a phase of pulsation of electromagnetic force caused by control of the second inverter circuit by a prescribed value respectively based on the pulsation of electromagnetic force caused by the magnetic circuit of the motor.

3. The motor control device according to any one of claims 1 to 2, characterized in that the control section selects whether to reduce torque pulsation generated in a circumferential direction of the motor or to reduce electromagnetic excitation force generated in a radial direction of the motor based on a rotational speed of the motor, and moves the phases of the first carrier signal and the second carrier signal respectively to phases that reduce the selected torque pulsation or electromagnetic excitation force.

4. The motor control device according to any one of claims 1 to 2, characterized in that the control section moves the phases of the first carrier signal and the second carrier signal respectively based on a direct current voltage value applied to the first inverter circuit and the second inverter circuit.

5. The motor control device according to any one of claims 1 to 2, characterized in that the control section infers the pulsation of electromagnetic force caused by the magnetic circuit of the motor using a detection signal of a magnetic pole position detector mounted on the motor and a current command value transmitted to the motor.

6. The motor control device according to claim 2, characterized in that the control section moves the phases of the first carrier signal and the second carrier signal respectively in a manner that moves a phase of pulsation of electromagnetic force caused by control of the first inverter circuit by 30 degrees and moves a phase of pulsation of electromagnetic force caused by control of the second inverter circuit by 30 degrees based on the pulsation of electromagnetic force caused by the magnetic circuit of the motor.

7. The motor control device according to claim 2, characterized in that The control section shifts the phases of the first carrier signal and the second carrier signal in a manner that shifts the phase of the pulsation of the electromagnetic force caused by the control of the first inverter circuit by 20 degrees and shifts the phase of the pulsation of the electromagnetic force caused by the control of the second inverter circuit by 40 degrees, based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor.

8. An electric vehicle characterized by comprising: Equipped with: The motor control device according to any one of claims 1 to 2; and the motor driven by the motor control device.

9. A motor control method, which is a motor control method in a motor control device that has a first inverter circuit and a second inverter circuit that control a redundant system of a motor, and a control section that controls the first inverter circuit and the second inverter circuit, characterized by, converting direct current into alternating current by the first inverter circuit based on a PWM signal generated using a first carrier signal, converting the direct current into the alternating current by the second inverter circuit based on a PWM signal generated using a second carrier signal, shifting the phases of the first carrier signal and the second carrier signal by the control section based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor, adjusting the frequencies of the first carrier signal and the second carrier signal to be integer multiples of the frequency of a voltage command that drives the motor, shifting the phases of the first carrier signal and the second carrier signal in a manner that shifts the phase of the pulsation of the electromagnetic force caused by the control of the first inverter circuit and the phase of the pulsation of the electromagnetic force caused by the control of the second inverter circuit by a prescribed value, based on the pulsation of the electromagnetic force caused by the magnetic circuit of the motor.

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