JP2021145516A - Control apparatus of ac motor - Google Patents

Abstract

To provide a control apparatus of an AC motor, correcting a d-axis voltage command value and a q-axis voltage command value, generated by a PI control by a non-interference control by using the d-axis voltage command value and the q-axis voltage command value, output from a low-pass filter, capable of reducing a man hour required for adjusting a cut-off frequency of the low-pass filter.SOLUTION: A cut-off frequency ωcd is adjusted so that a first difference of a d-axis current command value Id** and a d-axis current Id, output from a low-pass filter 151 becomes a first threshold value or less, and a cut-off frequency ωcq is adjusted so that a second difference of a q-axis current command value Iq** and a q-axis current Iq, output from a low pass filter 152 becomes a second threshold value or less.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for an AC motor.

As a control device for an AC motor, the d-axis voltage command value and q-axis voltage command value generated by PI control (Proportional Integral) are used, and the d-axis current command value and q-axis current command value output from the low-pass filter are used. Some are corrected by non-interference control. According to this control device, the low-pass filter can suppress high-frequency components included in the d-axis current command value and the q-axis current command value, and the response speed [rad / s] in the low-pass filter can be changed to the response speed in PI control. The current responsiveness can be improved by bringing them closer. Patent Document 1 is a related technique.

By the way, it is necessary to adjust the cutoff frequency of the low-pass filter in order to bring the response speed of the low-pass filter close to the response speed of the PI control.

Therefore, in the above control device, when the cutoff frequency is adjusted by experiment or simulation, there is a concern that the adjustment requires a relatively large number of man-hours.

Japanese Unexamined Patent Publication No. 2004-072856

An object according to one aspect of the present invention is to use the d-axis current command value and the q-axis current command value output from the low-pass filter to reduce the d-axis voltage command value and the q-axis voltage command value generated by PI control. This is to reduce the number of steps required to adjust the cutoff frequency of the low-pass filter in the control device of the AC motor that corrects by interference control.

The control device for an AC electric motor, which is one embodiment of the present invention, has an inverter circuit for driving the AC electric motor based on a comparison result between a carrier and a voltage command value, and converts the current flowing through the AC electric motor into a d-axis current and a q-axis current. Then, the d-axis voltage command value is calculated so that the difference between the d-axis current and the d-axis current command value becomes small by PI control, and the q-axis so that the difference between the q-axis current and the q-axis current command value becomes small. It is provided with a control circuit that calculates a voltage command value and converts the corrected d-axis voltage command value and the corrected q-axis voltage command value into a voltage command value.

The control circuit includes a first low-pass filter into which a d-axis current command value is input, a second low-pass filter in which a q-axis current command value is input, and a d-axis current command value output from the first low-pass filter. The first adjustment unit that adjusts the cutoff frequency of the first low-pass filter so that the first difference between the current and the d-axis current is equal to or less than the first threshold, and the q-axis output from the second low-pass filter. A second adjusting unit that adjusts the cutoff frequency of the second low-pass filter so that the second difference between the current command value and the q-axis current is equal to or less than the second threshold, and the q-axis current becomes the d-axis current. The d-axis voltage command value corresponding to the fluctuation of the d-axis current command value output from the first low-pass filter due to interference is output as the first correction value, and the d-axis current interferes with the q-axis current. The non-interference control unit that outputs the q-axis voltage command value corresponding to the fluctuation of the q-axis current command value output from the second low-pass filter as the second correction value, and the d-axis voltage command value before correction. After correcting the first addition unit that outputs the addition value with the second correction value as the corrected d-axis voltage command value, and the addition value of the q-axis voltage command value before correction and the first correction value. It includes a second adder that outputs as a q-axis voltage command value.

As a result, in the first and second adjustment units, the response speed of the first and second low-pass filters can be brought close to the response speed of the PI control, so that the cutoff frequencies of the first and second low-pass filters can be adjusted. The man-hours required for adjustment can be reduced.

Further, the first threshold value may be the minimum value of the first difference, and the second threshold value may be the minimum value of the second difference.

As a result, the current responsiveness is further improved as compared with the case where the first threshold value is set to a value larger than the minimum value of the first difference and the second threshold value is set to a value larger than the minimum value of the second difference. Can be done.

Further, the first and second adjusting units may be configured to repeatedly adjust the cutoff frequencies of the first and second low-pass filters while the AC motor is being driven.

As a result, even if the response speed in PI control changes due to deterioration of the AC motor while the AC motor is being driven, the response speed of the first and second low-pass filters changes according to the changing response speed. Therefore, the current responsiveness can be maintained.

According to the present invention, the d-axis voltage command value and the q-axis voltage command value generated by PI control are corrected by non-interference control using the d-axis current command value and the q-axis current command value output from the low-pass filter. It is possible to reduce the number of steps required to adjust the cutoff frequency of the low-pass filter in the control device of the AC motor.

It is a figure which shows the control device of the AC motor of an embodiment. It is a figure which shows the correction value output part.

Hereinafter, embodiments will be described in detail based on the drawings.

FIG. 1 is a diagram showing a control device for an AC motor according to an embodiment.

The control device 1 shown in FIG. 1 is, for example, a control device for driving an AC motor M (permanent magnet synchronous motor, etc.) mounted on a vehicle (electric forklift, plug-in hybrid vehicle, etc.), and is an inverter circuit 2. And a control circuit 3. It is assumed that the AC motor M includes an electric angle detecting unit Sp (resolver or the like) that detects the phase θ (electrical angle) of the rotor and outputs the detected phase θ to the control circuit 3.

The inverter circuit 2 converts the DC power supplied from the power supply P into AC power to drive the AC motor M, and drives the AC motor M, and is a capacitor C and switching elements SW1 to SW6 (IGBT (Insulated Gate Bipolar Transistor) or the like). And current sensors Si1 and Si2. That is, one end of the capacitor C is connected to the positive electrode terminal of the power supply P and each collector terminal of the switching elements SW1, SW3, SW5, and the other end of the capacitor C is the negative electrode terminal of the power supply P and each of the switching elements SW2, SW4, SW6. It is connected to the emitter terminal. The connection point between the emitter terminal of the switching element SW1 and the collector terminal of the switching element SW2 is connected to the U-phase input terminal of the AC motor M via the current sensor Si1. The connection point between the emitter terminal of the switching element SW3 and the collector terminal of the switching element SW4 is connected to the V-phase input terminal of the AC motor M via the current sensor Si2. The connection point between the emitter terminal of the switching element SW5 and the collector terminal of the switching element SW6 is connected to the input terminal of the W phase of the AC motor M.

The capacitor C smoothes the voltage output from the power supply P to the inverter circuit 2.

The switching element SW1 is turned on when the pulse width modulation signal S1 output from the control circuit 3 is at a high level, and is turned off when the pulse width modulation signal S1 is at a low level. The switching element SW2 is turned on when the pulse width modulation signal S2 output from the control circuit 3 is at a high level, and is turned off when the pulse width modulation signal S2 is at a low level. The switching element SW3 is turned on when the pulse width modulation signal S3 output from the control circuit 3 is at a high level, and is turned off when the pulse width modulation signal S3 is at a low level. The switching element SW4 is turned on when the pulse width modulation signal S4 output from the control circuit 3 is at a high level, and is turned off when the pulse width modulation signal S4 is at a low level. The switching element SW5 is turned on when the pulse width modulation signal S5 output from the control circuit 3 is at a high level, and is turned off when the pulse width modulation signal S5 is at a low level. The switching element SW6 is turned on when the pulse width modulation signal S6 output from the control circuit 3 is at a high level, and is turned off when the pulse width modulation signal S6 is at a low level. The carrier wave is a triangular wave, a sawtooth wave (sawtooth wave), an inverse sawtooth wave, or the like.

When the switching elements Sw1 to SW6 are turned on and off, respectively, the DC voltage output from the power supply P is converted into AC voltages Vu, Vv, and Vw whose phases differ by 120 degrees from each other. Then, the AC voltage Vu is applied to the U-phase input terminal of the AC electric motor M, the AC voltage Vv is applied to the V-phase input terminal of the AC electric motor M, and the AC voltage Vw is applied to the W-phase input terminal of the AC electric motor M. When applied, alternating currents Iu, Iv, and Iw whose phases differ from each other by 120 degrees flow through the alternating current motor M, and the rotor of the alternating current motor M rotates.

The current sensor Si1 is composed of a Hall element, a shunt resistor, and the like, and detects the alternating current Iu flowing in the U phase of the AC motor M and outputs it to the control circuit 3. Further, the current sensor Si2 is composed of a Hall element, a shunt resistor, and the like, and detects the AC current Iv flowing in the V phase of the AC motor M and outputs the AC current Iv to the control circuit 3.

The control circuit 3 includes a drive circuit 4, a calculation unit 5, and a storage unit 6. The storage unit 6 is composed of a RAM (Random Access Memory), a ROM (Read Only Memory), or the like.

The drive circuit 4 is composed of an IC (Integrated Circuit) or the like, and outputs a U-phase voltage command value Vu *, a V-phase voltage command value Vv *, a W-phase voltage command value Vw *, and a carrier, which are output from the calculation unit 5. The comparison is performed, and the pulse width modulation signals S1 to S6 according to the comparison result are output to the respective gate terminals of the switching elements SW1 to SW6.

For example, when the U-phase voltage command value Vu * is equal to or higher than the carrier, the drive circuit 4 outputs a high-level pulse width modulation signal S1 and a low-level pulse width modulation signal S2 to output a U-phase voltage command value. When Vu * is smaller than the carrier, the low level pulse width modulation signal S1 is output and the high level pulse width modulation signal S2 is output. Further, when the V-phase voltage command value Vv * is equal to or higher than the carrier, the drive circuit 4 outputs a high-level pulse width modulation signal S3 and a low-level pulse width modulation signal S4 to output a V-phase voltage command value. When Vv * is smaller than the carrier, the low level pulse width modulation signal S3 is output and the high level pulse width modulation signal S4 is output. Further, when the W-phase voltage command value Vw * is equal to or higher than the carrier, the drive circuit 4 outputs a high-level pulse width modulation signal S5 and a low-level pulse width modulation signal S6 to output a W-phase voltage command value. When Vw * is smaller than the carrier, the low-level pulse width modulation signal S5 is output and the high-level pulse width modulation signal S6 is output.

The calculation unit 5 is composed of a microcomputer or the like, and includes a rotation number calculation unit 7, a subtraction unit 8, a torque control unit 9, a torque / current command value conversion unit 10, a coordinate conversion unit 11, and a subtraction unit 12. , A subtraction unit 13, a current control unit 14, a correction value output unit 15, an addition unit 16, an addition unit 17, and a coordinate conversion unit 18. For example, by executing a program stored in the storage unit 6, the microcomputer executes a rotation number calculation unit 7, a subtraction unit 8, a torque control unit 9, a torque / current command value conversion unit 10, a coordinate conversion unit 11, and a subtraction. A unit 12, a subtraction unit 13, a current control unit 14, a correction value output unit 15, an addition unit 16, an addition unit 17, and a coordinate conversion unit 18 are realized.

The rotation speed calculation unit 7 calculates the rotation speed ω of the AC motor M using the phase θ detected by the electric angle detection unit Sp. For example, the rotation speed calculation unit 7 obtains the rotation speed ω by dividing the phase θ by a predetermined time T (such as the operation clock of the calculation unit 5).

The subtraction unit 8 calculates the difference Δω between the rotation speed command value ω * input from the outside and the rotation speed ω output from the rotation speed calculation unit 7.

The torque control unit 9 obtains the torque command value T * by using the difference Δω output from the subtraction unit 8. For example, the torque control unit 9 refers to the information stored in the storage unit 6 in which the rotation speed ω of the AC motor M and the torque of the AC motor M are associated with each other, and the rotation corresponding to the difference Δω. The torque corresponding to the number ω is obtained as the torque command value T *.

The torque / current command value conversion unit 10 converts the torque command value T * output from the torque control unit 9 into the d-axis current command value Id * and the q-axis current command value Iq *. For example, in the torque / current command value conversion unit 10, the torque of the AC motor M and the d-axis current command value Id * and the q-axis current command value Iq * stored in the storage unit 6 are associated with each other. With reference to the information, the d-axis current command value Id * and the q-axis current command value Iq * corresponding to the torque corresponding to the torque command value T * are obtained.

The coordinate conversion unit 11 uses the alternating current Iu detected by the current sensor Si1 and the alternating current Iv detected by the current sensor Si2 to obtain the alternating current Iw flowing in the W phase of the AC electric motor M. The current detected by the current sensors Si1 and Si2 is not limited to the combination of the alternating currents Iu and Iv, and may be a combination of the alternating currents Iv and Iw or a combination of the alternating currents Iu and Iw. When the alternating currents Iv and Iw are detected by the current sensors Si1 and Si2, the coordinate conversion unit 11 obtains the alternating current Iu using the alternating currents Iv and Iw. When the alternating currents Iu and Iw are detected by the current sensors Si1 and Si2, the coordinate conversion unit 11 obtains the alternating current Iv using the alternating currents Iu and Iw.

Further, the coordinate conversion unit 11 uses the phase θ detected by the electric angle detection unit Sp to convert the alternating currents Iu, Iv, and Iw into the d-axis current Id (current component for generating a field weakening) and the q-axis. Converts to current Iq (current component for generating torque). For example, the coordinate conversion unit 11 converts the alternating currents Iu, Iv, and Iw into the d-axis current Id and the q-axis current Iq by using the transformation matrix C1 shown in the following equation 1.

Further, when the inverter circuit 2 is further provided with a current sensor Si3 for detecting the AC current Iw flowing in the W phase of the AC electric motor M in addition to the current sensors Si1 and Si2, the coordinate conversion unit 11 uses the electric angle detection unit Sp. The detected phase θ may be used to convert the alternating currents Iu, Iv, and Iw detected by the current sensors Si1 to Si3 into the d-axis current Id and the q-axis current Iq.

The subtraction unit 12 calculates the difference ΔId between the d-axis current command value Id * output from the torque / current command value conversion unit 10 and the d-axis current Id output from the coordinate conversion unit 11.

The subtraction unit 13 calculates the difference ΔIq between the q-axis current command value Iq * output from the torque / current command value conversion unit 10 and the q-axis current Iq output from the coordinate conversion unit 11.

The current control unit 14 calculates the d-axis voltage command value Vd * and the q-axis voltage command value Vq * by PI control using the difference ΔId output from the subtraction unit 12 and the difference ΔIq output from the subtraction unit 13. For example, the current control unit 14 calculates the d-axis voltage command value Vd * using the following formula 2 and calculates the q-axis voltage command value Vq * using the following formula 3. Kp is a constant of the proportional term of PI control, Ki is a constant of the integration term of PI control, Lq is the q-axis inductance of the coil constituting the AC motor M, and Ld is d of the coil constituting the AC motor M. The shaft inductance is defined, ω is the rotation speed of the rotor of the AC motor M, and Ke is the induced voltage constant.

d-axis voltage command value Vd * = Kp × difference ΔId + Ki × ∫ (difference ΔId) −ωLqIq ・ ・ ・ Equation 2

q-axis voltage command value Vq * = Kp × difference ΔIq + Ki × ∫ (difference ΔIq) + ωLdId + ωKe ・ ・ ・ Equation 3

The correction value output unit 15 has the d-axis current command value Id * and q-axis current command value Iq * output from the torque / current command value conversion unit 10 and the d-axis current Id and q-axis output from the coordinate conversion unit 11. The correction value v_dc * and the correction value v_qc * are output using the current Iq.

The addition unit 16 corrects the addition value of the d-axis voltage command value Vd * (d-axis voltage command value before correction) output from the current control unit 14 and the correction value v_qc * output from the correction value output unit 15. It is output as the later d-axis voltage command value Vd **.

The addition unit 17 corrects the addition value of the q-axis voltage command value Vq * (q-axis voltage command value before correction) output from the current control unit 14 and the correction value v_dc * output from the correction value output unit 15. It is output as the later q-axis voltage command value Vq **.

The coordinate conversion unit 18 uses the phase θ detected by the electric angle detection unit Sp to convert the d-axis voltage command value Vd ** and the q-axis voltage command value Vq ** into the U-phase voltage command values Vu * and V-phase. It is converted into a voltage command value Vv * and a W phase voltage command value Vw *. For example, the coordinate conversion unit 18 uses the transformation matrix C2 shown in the following equation 4 to convert the d-axis voltage command value Vd ** and the q-axis voltage command value Vq ** into the U-phase voltage command value Vu * and the V-phase voltage. It is converted into a command value Vv * and a W phase voltage command value Vw *.

FIG. 2 is a diagram showing a correction value output unit 15.

The correction value output unit 15 shown in FIG. 2 includes a low-pass filter 151 (first low-pass filter), a low-pass filter 152 (second low-pass filter), an adjustment unit 153 (first adjustment unit), and an adjustment unit 154. (Second adjustment unit) and non-interference control unit 155 are provided.

The low-pass filter 151 suppresses the high frequency component of the d-axis current command value Id * output from the torque / current command value conversion unit 10 and outputs the d-axis current command value Id **. It is assumed that the response speed of the low-pass filter 151 changes according to the cutoff frequency ωcd of the low-pass filter 151.

The low-pass filter 152 suppresses the high frequency component of the q-axis current command value Iq * output from the torque / current command value conversion unit 10 and outputs the q-axis current command value Iq **. It is assumed that the response speed of the low-pass filter 152 changes according to the cutoff frequency ωcq of the low-pass filter 152.

The adjustment unit 153 lower-passes the d-axis current command value Id ** output from the low-pass filter 151 so that the first difference between the d-axis current Id and the d-axis current Id output from the coordinate conversion unit 11 is equal to or less than the first threshold value. The cutoff frequency ωcd of the filter 151 is adjusted. For example, the first threshold value is an arbitrary value in the range from the minimum value Idmin (such as zero) of the first difference to a predetermined value Idref larger than the minimum value Idmin. For example, the predetermined value Idref is the addition of the amount of change in the d-axis current command value Id * required to change the response speed of the d-axis current command value Id * in the current control unit 14 by 5 [%] and the minimum value Idmin. Let it be a value. When the first threshold value is set to the minimum value Idmin, the current responsiveness can be further improved as compared with the case where the first threshold value is set to a value larger than the minimum value Idmin.

For example, the adjusting unit 153 calculates the cutoff frequency ωcd so that the first difference is minimized by the weighted least squares method using the evaluation function shown in the following formula 5 and the algorithm shown in the following formula 6. Let y _i be the following equation 7 and θ ^T z _i be the following equation 8. Further, λ is a weighting coefficient, and 0 <λ ≦ 1.

y _i = d-axis current Id ・ ・ ・ Equation 7

θ ^T z _i = d-axis current command value Id ** = (1-cutoff frequency ωcd x predetermined time T) x d-axis current command value Id ** _k-1 + cutoff frequency ωcd x predetermined time T x d-axis Current command value Id * _k-1・ ・ ・ Equation 8

The adjustment unit 154 makes a low pass so that the second difference between the q-axis current command value Iq ** output from the low-pass filter 152 and the q-axis current Iq output from the coordinate conversion unit 11 is equal to or less than the second threshold value. The cutoff frequency ωcq of the filter 152 is adjusted. For example, the second threshold value is an arbitrary value in the range from the minimum value Iqmin (such as zero) of the second difference to a predetermined value Iqref larger than the minimum value Iqmin. For example, the predetermined value Iqref is the addition of the amount of change in the q-axis current command value Iq * required to change the response speed of the q-axis current command value Iq * in the current control unit 14 by 5 [%] and the minimum value Iqmin. Let it be a value. When the second threshold value is set to the minimum value Iqmin, the current responsiveness can be further improved as compared with the case where the second threshold value is set to a value larger than the minimum value Iqmin.

For example, the adjusting unit 154 calculates the cutoff frequency ωcq such that the second difference is minimized by the weighted least squares method using the evaluation function shown in the above equation 5 and the algorithm shown in the above equation 6. Let y _i be the following equation 9 and θ ^T z _i be the following equation 10.

y _i = q-axis current Iq ・ ・ ・ Equation 9

θ ^T z _i = q-axis current command value Iq ** = (1-cutoff frequency ωcq x predetermined time T) x q-axis current command value Iq ** _k-1 + cutoff frequency ωcq x predetermined time T x q-axis Current command value Iq * _k-1・ ・ ・ Equation 10

The adjustment timing of the cutoff frequencies ωcd and ωcq is not particularly limited. For example, the adjusting units 153 and 154 adjust the cutoff frequencies ωcd and ωcq at the start of driving the AC motor M. Alternatively, the adjusting units 153 and 154 repeatedly adjust the cutoff frequencies ωcd and ωcq while the AC motor M is being driven. If the cutoff frequencies ωcd and ωcq are repeatedly adjusted while the AC motor M is being driven, even if the response speed in PI control changes due to the deterioration of the AC motor M during the driving of the AC motor M, the change will occur. Since the response speeds of the low-pass filters 151 and 152 can be changed according to the response speed, the current responsiveness can be maintained.

The non-interference control unit 155 sets the d-axis voltage command value Vd * corresponding to the fluctuation of the d-axis current command value Id ** output from the low-pass filter 151 due to the q-axis current Iq interfering with the d-axis current Id. The q-axis voltage command value Vq * corresponding to the fluctuation of the q-axis current command value Iq ** output from the low-pass filter 152 due to the d-axis current Id interfering with the q-axis current Iq while being output as the correction value v_dc *. Is output as a correction value v_qc *. For example, the non-interference control unit 155 sets the multiplication value of the d-axis current command value Id ** and the d-axis inductance Ld as the correction value v_dc *, and sets the multiplication value of the q-axis current command value Iq ** and the q-axis inductance Lq. Is the correction value v_qc *. Then, the d-axis voltage command value Vd * and the correction value v_dc * are added to correct the d-axis voltage command value Vd *, and the q-axis voltage command value Vq * and the correction value v_qc * are added to the q-axis. By correcting the voltage command value Vq *, the fluctuation of the d-axis current command value Id * due to the q-axis current Iq interfering with the d-axis current Id and the d-axis current Id interfere with the q-axis current Iq. The fluctuations of the q-axis current command value Iq * due to the above cancel each other out, and the current responsiveness can be improved.

The control device 1 of the embodiment is a low-pass filter so that the first difference between the d-axis current command value Id ** output from the low-pass filter 151 and the d-axis current Id, which is the actual current, is equal to or less than the first threshold value. The second difference between the adjustment unit 153 that adjusts the cutoff frequency ωcd of 151 and the q-axis current command value Iq ** output from the low-pass filter 152 and the actual q-axis current Iq is equal to or less than the second threshold value. The configuration is provided with an adjusting unit 154 that adjusts the cutoff frequency ωcq of the low-pass filter 152 so as to be. In this way, the cutoff frequencies ωcd and ωcq can be automatically adjusted by the adjusting units 153 and 154, so that the cutoff frequencies ωcd and ωcq are adjusted by experiments and simulations as in the conventional case. The man-hours required for adjusting the cutoff frequencies ωcd and ωcq can be reduced.

The present invention is not limited to the above embodiments, and various improvements and changes can be made without departing from the gist of the present invention.

1 Control device 2 Inverter circuit 3 Control circuit 4 Drive circuit 5 Calculation unit 6 Storage unit 7 Rotation speed calculation unit 8 Subtraction unit 9 Torque control unit 10 Torque / current command value conversion unit 11 Coordinate conversion unit 12 Subtraction unit 13 Subtraction unit 14 Current Control unit 15 Correction value output unit 16 Addition unit 17 Addition unit 18 Coordinate conversion unit 151, 152 Low-pass filter 153, 154 Adjustment unit 155 Non-interference control unit

Claims (3)

An inverter circuit that drives an AC motor based on the comparison result between the carrier wave and the voltage command value,
The current flowing through the AC electric motor is converted into a d-axis current and a q-axis current, and the d-axis voltage command value is calculated so that the difference between the d-axis current and the d-axis current command value becomes small by PI control, and the q. The q-axis voltage command value is calculated so that the difference between the shaft current and the q-axis current command value becomes small, and the corrected d-axis voltage command value and the corrected q-axis voltage command value are used as the voltage command values. The control circuit to convert and
With
The control circuit
The first low-pass filter into which the d-axis current command value is input and
A second low-pass filter into which the q-axis current command value is input, and
The cutoff frequency of the first low-pass filter is adjusted so that the first difference between the d-axis current command value output from the first low-pass filter and the d-axis current is equal to or less than the first threshold value. 1 adjustment part and
The cutoff frequency of the second low-pass filter is adjusted so that the second difference between the q-axis current command value output from the second low-pass filter and the q-axis current is equal to or less than the second threshold value. 2 adjustment part and
The d-axis voltage command value corresponding to the fluctuation of the d-axis current command value output from the first low-pass filter due to the q-axis current interfering with the d-axis current is output as the first correction value. The q-axis voltage command value corresponding to the fluctuation of the q-axis current command value output from the second low-pass filter due to the d-axis current interfering with the q-axis current is output as the second correction value. Interference control unit and
A first addition unit that outputs an addition value of the d-axis voltage command value before correction and the second correction value as the d-axis voltage command value after correction, and
A second adder that outputs the sum of the q-axis voltage command value before correction and the first correction value as the q-axis voltage command value after correction, and
A control device for an AC motor, which is characterized by being equipped with. The control device for an AC motor according to claim 1.
The first threshold value is the minimum value of the first difference.
A control device for an AC motor, wherein the second threshold value is the minimum value of the second difference. The control device for an AC motor according to claim 1 or 2.
The first and second adjusting units are control devices for an AC motor, which repeatedly adjust the cutoff frequencies of the first and second low-pass filters while the AC motor is being driven.

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