JP3633270B2 - Motor control device and motor control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor control device and a control method, and more particularly to switching between sine wave control and rectangular wave control according to the state of a motor.
[0002]
[Prior art]
Conventionally, electric vehicles have attracted attention from the viewpoint of low pollution. A typical electric vehicle includes a battery, an inverter and a motor. An inverter is a kind of power converter, and converts power obtained from a battery into power supplied to a motor by switching operations of a plurality of semiconductor elements. The motor is driven by this supplied electric power, and the driving force of the vehicle is generated. The motor control device controls the output of the motor in accordance with the driver's accelerator operation, and controls the motor by sending a switching signal instructing a switching operation to the inverter. Hereinafter, a signal that controls the conversion operation of the power conversion device, such as the switching signal, is referred to as a conversion control signal.
[0003]
In motor control, sine wave control is widely performed in general. The sine wave control is control for making the voltage waveform of the power supplied to the motor a sine wave. The sine wave control is realized by, for example, vector control and PWM control. In FIG. 1 (a), a solid line sine wave signal is compared with a dotted PWM carrier to generate a switching signal. When the inverter performs power conversion according to this switching signal, the output voltage waveform to the motor is substantially a sine wave. In FIG. 1, only a single-phase voltage waveform is shown, but actually there are a plurality of voltage waveforms corresponding to the motor configuration (hereinafter the same). Such sine wave control is widely used because high motor efficiency can be obtained.
[0004]
[Problems to be solved by the invention]
FIG. 2 shows the operating range of the motor, where the horizontal axis is the rotational speed and the vertical axis is the torque. Theoretically, the motor can be used in a region surrounded by a dotted line. However, the back electromotive force of the motor is high in the high rotation and high torque regions indicated by hatching. In this region, the counter electromotive voltage rises rapidly due to disturbance factors and tends to exceed the battery voltage. In the sine wave control, it is not easy to deal with such a back electromotive voltage. Therefore, in the conventional motor control, only the area surrounded by the solid line, that is, the area excluding the shaded part is used.
[0005]
However, an increase in the output of the motor is required, and it is desired to use the motor even in a high rotation and high torque region. In order to meet such a demand, it is conceivable to use rectangular wave control.
[0006]
The rectangular wave control is a well-known control different from the sine wave control, and uses a rectangular wave as shown in FIG. The peak value (voltage value) of the rectangular wave is constant. A switching signal to the inverter is generated so that the voltage waveform of the power supplied to the motor becomes this rectangular wave.
[0007]
According to the rectangular wave control, the motor can be easily controlled even in a high rotation and high torque region where sine wave control is difficult. Therefore, it is considered that a motor having both high efficiency and high output can be realized by normally performing highly efficient sine wave control and performing rectangular wave control in a high rotation and high torque region.
[0008]
However, when switching between the sine wave control mode and the rectangular wave control mode, there arises a problem of torque fluctuation during mode switching as described below. As an example, consider a case where mode switching is performed at point x2 in the process of changing the operating state from point x1 to point x3 in FIG. At point x2, switching from sine wave control to rectangular wave control that generates equivalent torque should be performed. FIG. 3 shows voltage command values before the triangular wave comparison. In FIG. 3A, a sine wave a and a rectangular wave c generate the same torque, and the two waveforms have different phases.
[0009]
In actual mode switching, first, the sine wave a is switched to a rectangular wave b having the same phase. This is because the phase of the supply voltage to the motor cannot be changed instantaneously. Then, phase adjustment is performed under the rectangular wave control mode, and the rectangular wave b is changed to the rectangular wave c after switching.
[0010]
However, when such a switching process is performed, torque fluctuation occurs at the time of switching. This is because, in the sine wave a and the rectangular wave b having the same phase, the rectangular wave b generates a larger torque.
[0011]
Referring to FIG. 3B, as indicated by the phase-torque line (solid line) in the figure, the motor torque of the rectangular wave control is determined by the phase of the rectangular wave. This is because the wave height of the rectangular wave is constant. It is assumed that the mode is switched when the sine wave control is performed in the state of the point a. As described above, since the phase of the power supplied to the motor cannot be changed instantaneously, the operating state first moves from point a to point b. Then, the state of the motor changes along the phase-torque line by phase adjustment of the rectangular wave. When the operating state reaches point c, a torque equivalent to that before switching is obtained. In the above switching process, torque fluctuation corresponding to the torque difference between point a and point b occurs.
[0012]
The same applies to switching from rectangular wave control to sine wave control. In FIG. 3B, first, the phase of the rectangular wave moves from the starting point c to the point b by phase adjustment in the rectangular wave control mode. Then, after the operating state reaches point b, switching from rectangular wave control to sine wave control is performed. In this switching process, torque fluctuation corresponding to the torque difference between point b and point a occurs.
[0013]
As described above, when mode switching between sine wave control and rectangular wave control is performed, torque fluctuation occurs in the switching process. This torque fluctuation affects the vehicle behavior and is transmitted to the driver with a sense of incongruity. Therefore, it is desired to prevent the occurrence of such torque fluctuation.
[0014]
The present invention has been made in view of the above problems, and an object thereof is to provide a motor control device and a control method capable of smoothly switching between sine wave control and rectangular wave control with little torque fluctuation. .
[0015]
[Means for Solving the Problems]
The present invention provides a motor control device that controls a motor by sending a conversion control signal to a power converter that converts power obtained from a power source into power supplied to the motor. A sine wave control unit for generating a conversion control signal for generating a square wave, a rectangular wave control unit for generating a conversion control signal for converting the voltage waveform to a rectangular wave, and a sine wave control according to at least one of the motor rotation speed and the motor torque A mode switching unit that switches between a mode and a rectangular wave control mode, and a sine wave before switching from a sine wave before switching to a rectangular wave after switching, or before switchingSquare waveAfter switching fromsine waveAnd a switching intermediate control unit that generates a conversion control signal that continuously changes the voltage waveform toward the output, and the switching intermediate control unit is a sine wave having an infinite or sufficiently large amplitude of the rectangular wave The voltage waveform before switching is made closer to the voltage waveform after switching by simultaneous and continuous changes in the phase and amplitude of the sine voltage waveform.
[0016]
Preferably, the sine wave control unit generates a conversion control signal by performing PWM processing based on the sine wave signal, and the switching intermediate control unit is a modified sine wave having an intermediate phase and amplitude of the voltage waveform before and after switching. A conversion control signal is generated by performing PWM processing based on the signal.
[0017]
As described above, the square wave can be regarded as a sine wave having an infinite or sufficiently large amplitude. Accordingly, the voltage waveform before switching and the voltage waveform after switching are regarded as two sine waves having different phases and amplitudes. Therefore, the voltage waveform before switching is brought closer to the voltage waveform after switching by simultaneous and continuous changes in the phase and amplitude of the sine voltage waveform. In switching from a sine wave to a rectangular wave, the phase of the sine wave before switching is continuously brought close to the phase of the rectangular wave after switching, and at the same time, the amplitude of the sine wave before switching is infinite or sufficiently large. To be continuously approaching. In switching from the rectangular wave to the sine wave, the reverse process is performed. As described above, unlike the conventional method in which the phase adjustment of the rectangular wave is performed during the switching, the present invention changes the phase and amplitude of the sine wave simultaneously and continuously during the switching, so that a large torque is generated during the switching. Without fluctuation, the voltage waveform before switching shifts to the voltage waveform after switching.When this motor control device is applied to a vehicle motor mounted on a vehicle,Smooth mode switching with little influence on the vehicle behavior is possible, and it is possible to prevent the driver from feeling uncomfortable.
[0018]
The present invention may be applied to both switching from sine wave control to rectangular wave control and vice versa. Moreover, you may apply only to either one of switching.
[0019]
Another aspect of the present invention is a motor control method for controlling a motor by adjusting power supplied to the motor, wherein the voltage waveform of the power supplied to the motor is a sine wave control mode, and the voltage It includes a mode switching step that switches the rectangular wave control mode for changing the waveform to a rectangular wave according to the state of the motor. In this mode switching step, the rectangular wave is regarded as an infinite or sufficiently large sine wave. Of the phase and amplitude of the sinusoidal voltage waveformAt the same timeBy the continuous change, the voltage waveform is made to approach from a sine wave before switching to a rectangular wave after switching, or from a rectangular wave before switching to a sine wave after switching. According to this aspect, the above-described effects of the present invention can be obtained in the form of a motor control method.Further, this motor control method may be applied to control of a vehicle motor mounted on the vehicle.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments (hereinafter referred to as embodiments) of the invention will be described with reference to the drawings.
[0021]
First, the principle of mode switching according to the present embodiment will be described with reference to FIG. Here, switching processing from the sine wave control mode to the rectangular wave control mode will be described. However, the reverse mode switching process is substantially the same except that the switching direction is different.
[0022]
In FIG. 4A, a sine wave a1 is a voltage waveform before mode switching, and a rectangular wave c1 is a voltage waveform after mode switching. The sine wave a1 and the rectangular wave c1 have different phases, and both voltage waveforms generate an equivalent torque.
[0023]
In the present embodiment, it is regarded that “the rectangular wave c1 is a sine wave having an infinite or sufficiently large amplitude, and its peak value is limited by the upper voltage limit (maximum battery voltage)”. As a result, the voltage waveforms at the start and end of switching are both sine waves, and the two sine waves can be regarded as having different phases and amplitudes.
[0024]
Before starting the mode switching, the phase and amplitude of the sine wave a1 are set to the switching initial value. In addition, the phase of the rectangular wave c1 is set as the switching target phase, and an infinite amplitude is set as the switching target amplitude.
[0025]
When mode switching starts, the phase and amplitude of the voltage waveform are changed simultaneously and continuously from the initial switching value to the switching target value. That is, the phase of the sine wave is continuously changed from the initial phase to the target phase, and at the same time, the amplitude of the sine wave is continuously changed from the initial amplitude toward the infinite amplitude.
[0026]
A voltage waveform b1 in FIG. 4 is a voltage waveform in the middle of switching. This voltage waveform b1 is a sine wave having a phase and amplitude intermediate between the switching initial stage and the switching target. Since the voltage value is limited at the maximum battery voltage as in the case of the rectangular wave, a part of the waveform is flat. The voltage waveform b1 in the middle of the change generates a motor torque that is equal to or close to the sine wave a1 and the rectangular wave c1 before and after switching. Therefore, the voltage waveform can be changed from the sine wave a1 to the rectangular wave c1 without causing a large torque fluctuation.
[0027]
Referring to FIG. 4B, the point a1 is the operating state in the sine wave control mode before switching. Point c1 is the operating state in the rectangular wave control mode after switching. The points a1 and c1 have the same torque but different phases. In the conventional mode switching, first, switching from sine wave control to rectangular wave control is performed, and the operation state moves from point a1 to point b1 by this switching. Then, phase adjustment by rectangular wave control is performed, and the operating state moves from point b1 to point c1 along the phase-torque line. Conventionally, torque fluctuations caused by such a locus of the driving state occur.
[0028]
On the other hand, in the present embodiment, the rectangular wave in the state of the point c1 is regarded as a sine wave having an infinite amplitude. Then, due to the continuous change in the phase and amplitude of the voltage waveform as shown in FIG. 4A, the operating state shifts from a point a1 to a point c1 with a locus close to a straight line as shown by a dotted line. . During this time, the voltage waveform is a sine wave until just before the operating state reaches the point c1. As is clear from FIG. 4B, according to the present embodiment, it is possible to reduce torque fluctuation at the time of mode switching.
[0029]
FIG. 5 shows a drive system for an electric vehicle on which the motor control device of this embodiment is mounted. The battery 2 is connected to the motor 6 via the inverter 4. The motor 6 is a permanent magnet type three-phase AC motor. The motor 6 is connected to the wheel 10 via the reduction gear 8. A direct current is supplied from the battery 2 to the inverter 4. This direct current is converted into alternating current by the inverter 4, and the motor 6 rotates with the electric power supplied from the inverter 4. Then, the output torque of the motor 6 is transmitted to the wheel 10 via the reduction gear 8, and the vehicle travels.
[0030]
The motor ECU 12 is a device that controls the torque of the motor 6 by sending switching signals (Su, Sv, Sw) to the inverter 4. The inverter 4 includes a plurality of semiconductor elements, and power conversion is performed by a switching operation of the semiconductor elements. The switching signal is a signal for causing the semiconductor element to perform a necessary switching operation, that is, a signal for causing the inverter 4 to perform necessary power conversion. In the present embodiment, this switching signal corresponds to the conversion control signal of the present invention.
[0031]
The motor current (Iu, Iv, Iw) detected by the current sensor 14 is input to the motor ECU 12. The motor current is a current supplied from the inverter 4 to the motor 6. The rotation angle sensor 16 detects the rotor angle of the motor 6 (θ: the rotation angle (position) of the rotor with respect to the stator) and sends it to the motor ECU 12. The motor speed is obtained from the rotor angle signal. Further, a signal indicating the accelerator operation amount is input from the accelerator 18 to the motor ECU 12.
[0032]
In the motor ECU 12, the torque determination unit 20 determines the torque to be output by the motor 6 based on the accelerator operation amount and the motor rotation speed (vehicle speed), and obtains a torque command T * corresponding to this output torque. Torque command T * is used by sine wave control unit 22 and rectangular wave control unit 24 to generate a switching signal to inverter 4. In the present embodiment, as shown in FIG. 6, the sine wave control mode and the rectangular wave control mode are switched according to the motor rotation speed N and the motor torque T.
[0033]
In the sine wave control mode, the sine wave control unit 22 generates a switching signal. The sine wave control unit 22 includes a well-known vector control unit 26 and a PWM control unit 28, and generates a switching signal that is pulse width modulated by vector control and PWM control. Since this process is widely used for control of electric vehicles and is well known, detailed description thereof is omitted. Schematically, a d-axis current command Id * and a q-axis current command Iq * on the dq-axis coordinates are obtained from the torque command T *. On the other hand, an excitation current Id and a torque current Iq are obtained from the motor currents Iu, Iv, Iw. Based on these command values and current values, voltage commands Vd and Vq are obtained, and further, coordinate conversion of the voltage commands Vd and Vq is performed. FIG. 1A shows the voltage signal at this stage. The voltage signal after coordinate conversion is compared with a PWM carrier wave having a predetermined shape, and switching signals Su, Sv, Sw subjected to pulse width modulation are generated. When the inverter 4 performs power conversion according to the switching signal, the voltage waveform of the motor current corresponds to a sine wave. Then, the torque determined by the torque determination unit 20 is output by the motor 6.
[0034]
On the other hand, in the rectangular wave control mode, the rectangular wave control unit 24 generates a switching signal. In the rectangular wave control, the wave height of the rectangular wave is constant, and the cycle is determined by the motor rotation speed (vehicle speed). Therefore, the phase of the rectangular wave is a control target, and the torque is determined by this phase. The reference for the phase of the rectangular wave is the rotor angle θ. In the rectangular wave control, the excitation current Id and the torque current Iq are obtained from the motor currents Iu, Iv, Iw. Then, the current torque T of the motor is obtained from these currents Id and Iq. This torque T is compared with the torque command T * to determine the phase of the rectangular wave. The phase of the rectangular wave is added to the rotor angle θ, and switching signals Su, Sv, Sw are generated based on the addition result. When the inverter 4 performs power conversion in accordance with the switching signal, the voltage waveform of the motor current corresponds to a rectangular wave. Then, the torque determined by the torque determination unit 20 is output by the motor 6.
[0035]
The purpose of selectively using the two control modes is to increase the motor output, as described above. In FIG. 6, in the region below the switching line m, it is preferable to control the motor in a highly efficient sine wave control mode. However, the back electromotive force of the motor is high in a high rotation and high torque region exceeding the switching line m. In this region, when the back electromotive voltage suddenly rises due to a disturbance factor such as a sudden operation of the accelerator, the back electromotive voltage exceeds the battery voltage, and torque down is likely to occur. In the sine wave control, it is not easy to deal with such a back electromotive voltage. Therefore, in the area above the switching line m, the motor is controlled in the rectangular wave control mode. In the rectangular wave control, the motor can be easily controlled even in a high rotation and high torque region where sine wave control is difficult. In this way, motor control having both high efficiency and high output is possible.
[0036]
The mode switching is performed according to an instruction from the switching instruction unit 30. As a feature of this embodiment, a mode transition period is provided at the time of mode switching. During the mode transition period, the motor is controlled by the switching intermediate control unit 32, and the voltage waveform of the motor current is deformed as shown in FIG. The Hereinafter, with reference to the flowcharts of FIG. 7 and FIG.
[0037]
FIG. 7 shows a switching process from the sine wave control mode to the rectangular wave control mode. The switching instruction unit 10 monitors the motor torque T and the motor rotational speed N, and determines whether the torque T and the rotational speed N on the switching line m in FIG. 6 are detected (S10). The determination in S10 is continued until the torque T and the rotational speed N on the line m are detected, and the sine wave control mode is continued during this time. When S10 becomes YES, the switching instruction unit 30 turns on the switching flag (S12).
[0038]
When the switching flag is turned ON, calculation processing is performed in both the sine wave control unit 22 and the rectangular wave control unit 24. The sine wave control unit 22 calculates the phase and amplitude of the current motor current voltage waveform. In the normal sine wave control mode, the phase and amplitude of the sine voltage waveform are not obtained. Here, the phase and amplitude are obtained for the following switching intermediate control. On the other hand, the rectangular wave control unit 24 calculates the phase of the rectangular wave necessary to generate a torque having the same magnitude as the current motor torque T (S14). The phase is different between a sine wave and a rectangular wave that generate equivalent torque. Therefore, the phase calculated in S14 is different from the current phase of the sine wave. In order to easily obtain these values, it is also preferable to previously create a map representing the phase and amplitude of a sine wave or rectangular wave on the switching line m in FIG.
[0039]
Next, in S16 to S20, as described with reference to FIG. 4, the voltage waveform of the motor current is transformed from the current sine wave to a rectangular wave having the phase calculated in S14. First, the phase and amplitude of the current sine wave are set to the switching initial value. Further, the phase of the rectangular wave calculated in S14 is set as the switching target phase. Furthermore, an infinite amplitude is set as the switching target amplitude. However, here, a sufficiently large amplitude that can be regarded as equivalent to infinity is set as the switching target value. That is, the target amplitude is set sufficiently large so that the sine wave having the target amplitude has substantially the same shape as the rectangular wave.
[0040]
In S16, both the amplitude and the phase are made closer to each other by a predetermined width from the switching initial value to the switching target value by the phase / amplitude adjusting unit 34 of the switching intermediate control unit 32. Then, a switching signal is generated based on the approaching amplitude and phase (S18). Here, the phase / amplitude adjusting unit 34 generates a voltage signal having the phase and amplitude obtained in S16. Then, the voltage signal is compared with a PWM carrier wave having a predetermined shape by the PWM control unit 36, thereby generating switching signals Su, Sv, Sw. It goes without saying that the PWM control unit 36 may also be used as the PWM control unit 28 of the sine wave control unit 22.
[0041]
The inverter 4 performs power conversion according to the above switching signal. As a result, the voltage waveform of the motor current is as shown in the middle part of FIG. Since the voltage value is limited at the maximum battery voltage, the voltage waveform b1 is a sine wave partially having a flat portion. This voltage waveform b1 generates a torque equivalent to or close to the sine wave a1.
[0042]
Next, the phase / amplitude adjustment unit 34 determines whether or not the current phase and amplitude obtained in S16 have reached the switching target value (S20). If S20 is NO, the process returns to S16, and further the amplitude and phase are brought closer to the switching target value. In this way, the same processing is continued until the amplitude and phase reach the switching target value.
[0043]
Here, the transition period from the switching initial value to the switching target value should be sufficiently short, and is preferably about 100 msec, for example. If the transition period is such a length, it is considered that the accelerator operation amount does not change greatly. Therefore, it is considered that the same motor torque should be generated before and after switching. In S16 described above, the phase and amplitude are brought close to the target value at every control interval. Preferably, the change width of the phase and amplitude in S16 is set so that the phase and amplitude simultaneously reach the target value.
[0044]
When the determination in S20 in FIG. 7 is YES, the switching instruction unit 30 turns off the switching flag (S22). Then, the rectangular wave control mode is set (S24). Thereafter, the rectangular wave control unit 24 performs motor control.
[0045]
FIG. 8 is a time chart showing changes in the phase and amplitude of the voltage waveform when the processing of FIG. 7 is performed. When the switching flag is turned ON, the phase and amplitude of the voltage waveform are continuously changed toward the target value at the same time. When the phase and amplitude reach the target value at the same time, the switching flag is turned off. Thereafter, rectangular wave control is performed.
[0046]
Next, the switching process from the rectangular wave control mode to the sine wave control mode will be described with reference to FIG. The switching process in FIG. 9 is substantially the same as the switching process from the sine wave to the rectangular wave described with reference to FIG. However, the direction of change in phase and amplitude at the time of switching is reversed.
[0047]
The switching instruction unit 30 monitors the motor torque T and the motor rotational speed N, and determines whether the torque T and the rotational speed N on the switching line m in FIG. 6 are detected (S30). While the determination in S32 is NO, the rectangular wave control mode continues. When S30 becomes YES, the switching instruction unit 30 turns on the switching flag (S32).
[0048]
When the switching flag is turned ON, the rectangular wave control unit 24 calculates the phase of the current rectangular wave and sends it to the switching intermediate control unit 32. The sine wave control unit 22 calculates the phase and amplitude of the sine voltage waveform necessary to generate a torque equivalent to the current motor torque T (S34). Also in this case, in order to easily obtain these values, it is preferable to previously create a map representing the phase and amplitude of the sine wave or rectangular wave on the switching line m in FIG.
[0049]
Next, the phase of the current rectangular wave is set to the switching initial value. The amplitude switching initial value is set to a sufficiently large amplitude that can be regarded as being equivalent to infinity. This amplitude value is also used in switching control from a sine wave to a rectangular wave, and is used instead of infinity. In addition, the phase and amplitude of the sine wave obtained in S34 are set as switching target values, respectively.
[0050]
In S36 to S40, the phase and the amplitude are sequentially changed from the switching initial value to the switching target value. In S36, the phase and amplitude are brought close to the target value by a predetermined width. A voltage signal corresponding to the phase and amplitude obtained in S36 is obtained, and this voltage signal is compared with the PWM carrier wave to generate a switching signal (S38). The above control is continued until the phase and amplitude reach the target values. By such control, the voltage waveform changes in the opposite direction, similar to the switching from the sine wave to the rectangular wave described above. Therefore, also in this case, the torque fluctuation during the mode transition period is small.
[0051]
When the phase / amplitude adjustment unit 34 determines that the phase and amplitude have reached the target values in S40, the switching instruction unit 30 turns off the switching flag in S42 (S42). Then, the sine wave control mode is set (S44). Thereafter, the sine wave control unit 22 performs motor control.
[0052]
The preferred embodiment of the present invention has been described above. According to this embodiment, during the mode switching, PWM sine wave control is performed while shifting the phase and amplitude simultaneously and continuously. On the other hand, conventionally, phase adjustment is performed in the rectangular wave control mode in the middle of mode switching, which causes torque fluctuations. According to this embodiment, torque fluctuation at the time of mode switching can be reduced by performing control based on a sine wave as shown in FIG. 4 during the mode transition period. As a result, smooth mode switching with little influence on the vehicle behavior is possible, and it is possible to prevent the driver from feeling uncomfortable.
[0053]
A modification of this embodiment will be described. In the present embodiment, the power conversion device is an inverter, but it goes without saying that power conversion devices other than the inverter are also applicable to the present invention. The motor may be a motor other than a permanent magnet type synchronous motor. Further, other control that does not use PWM control may be performed. Moreover, it is preferable to perform the control of the present invention also during regenerative braking.
[0054]
The present invention is also suitably applied to a hybrid vehicle. A hybrid vehicle is a kind of electric vehicle, and is equipped with both an electric motor and an internal combustion engine. The present invention can be suitably applied to control of the motor of this hybrid system. In addition, the present invention can be applied to control of any motor that is not for an electric vehicle.
[Brief description of the drawings]
FIG. 1 is a diagram showing a voltage waveform of a motor current by sine wave control and rectangular wave control.
FIG. 2 is a diagram showing an operation range of motor control of a conventional electric vehicle.
FIG. 3 is a diagram illustrating switching from conventional sine wave control to rectangular wave control.
FIG. 4 is a diagram illustrating a switching process from sine wave control to rectangular wave control in the embodiment of the present invention.
FIG. 5 is a diagram illustrating a configuration of a motor control device according to an embodiment of the present invention.
FIG. 6 is a diagram showing an operation region in which a sine wave control mode and a rectangular wave control mode are set.
7 is a diagram showing a switching process from a sine wave control mode to a rectangular wave control mode in the system of FIG.
8 is a time chart showing a process of changing the phase and amplitude of a voltage waveform when the processing of FIG. 7 is performed.
9 is a diagram showing a switching process from a rectangular wave control mode to a sine wave control mode in the system of FIG.
[Explanation of symbols]
2 battery, 4 inverter, 6 motor, 12 motor ECU, 14 current sensor, 16 rotation angle sensor, 20 torque determination unit, 22 sine wave control unit, 24 rectangular wave control unit, 26 vector control unit, 28, 36 PWM control unit , 30 switching instruction unit, 32 switching intermediate control unit, 34 phase / amplitude adjustment unit.

Claims (5)

In a motor control device that controls a motor by sending a conversion control signal to a power conversion unit that converts power obtained from a power source into power supplied to the motor,
A sine wave control unit that generates a conversion control signal for converting a voltage waveform of power supplied to the motor into a sine wave;
A rectangular wave control unit for generating a conversion control signal for converting the voltage waveform into a rectangular wave;
A mode switching unit that switches between the sine wave control mode and the rectangular wave control mode according to at least one of the motor rotation speed and the motor torque;
When the mode is switched, a conversion control signal that continuously changes the voltage waveform from the sine wave before switching to the rectangular wave after switching or from the rectangular wave before switching to the sine wave after switching is generated. A switching intermediate control unit,
Including
The switching intermediate control unit regards the rectangular wave as an infinite or sufficiently large sine wave, and switches the voltage waveform before switching by simultaneous and continuous changes in the phase and amplitude of the sine voltage waveform. A motor control device characterized in that the motor voltage device approaches a later voltage waveform. The apparatus of claim 1.
The sine wave control unit generates a conversion control signal by performing PWM processing based on a sine wave signal,
The switching intermediate control unit generates a conversion control signal by performing PWM processing based on a modified sine wave signal having an intermediate phase and amplitude between voltage waveforms before and after switching. The apparatus according to claim 1 or 2,
The motor is a vehicle motor mounted on a vehicle, and controls the vehicle motor. A motor control method for controlling the motor by adjusting the power supplied to the motor,
A mode switching step of switching between a sine wave control mode for changing the voltage waveform of power supplied to the motor to a sine wave and a rectangular wave control mode for changing the voltage waveform to a rectangular wave according to the state of the motor;
In this mode switching step, the rectangular wave is regarded as an infinite or sufficiently large sine wave, and the voltage waveform is changed to a sine before switching by simultaneous and continuous changes in the phase and amplitude of the sine voltage waveform. A motor control method characterized by approaching from a wave to a rectangular wave after switching or from a rectangular wave before switching to a sine wave after switching. The motor control method according to claim 4,
The motor is a vehicle motor mounted on a vehicle, and the vehicle motor is controlled.

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