JP2010142013A - Device and method for controlling ac motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of torque ripple when the control mode of a motor is switched from the voltage control mode to the current control mode. <P>SOLUTION: If the magnet torque is dominant to the output torque of a motor 2 when the control mode of the motor 2 is switched from the voltage control mode to the current control mode, an interference voltage corrector 15 calculates the q-axis interference voltage correction value Δv<SB>q_dcpl</SB><SP>*</SP>based on the difference Δi<SB>d</SB>between the d-axis current detection value i<SB>d</SB>before switching the control mode and the d-axis current command value i<SB>d</SB><SP>*</SP>after switching, and a current controller 5 corrects the q-axis interference voltage command value v<SB>q_dcpl</SB><SP>*</SP>output from a command value generation unit 3 by using the q-axis interference voltage correction value Δv<SB>q_dcpl</SB><SP>*</SP>. Consequently, the occurrence of torque ripple can be prevented when the control mode of the motor 2 is switched from the voltage control mode to the current control mode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device and a control method for an AC motor having a current control mode and a voltage control mode.

2. Description of the Related Art Conventionally, a control device that switches an AC motor control mode between a current control mode and a voltage control mode is known (see Patent Document 1). When the AC motor is controlled by the voltage control mode, this control device switches the control mode to the current control mode when at least one of the phase and amplitude of the current supplied to the AC motor reaches a predetermined determination threshold. . On the other hand, when the AC motor is controlled in the current control mode, the control device switches the control mode to the voltage control mode when the amplitude of the voltage applied to the AC motor becomes equal to or greater than a predetermined determination threshold value.
JP 2002-223590 A

  When the control mode is switched to the current control mode, the determination threshold may be the current command value in the current control mode so that the current detection value before switching (actual current value) and the current command value after switching are continuously connected. desirable. Similarly, when the control mode is switched to the voltage control mode, the determination threshold in the voltage control mode is set so that the voltage amplitude detection value (actual amplitude value) before switching and the voltage amplitude command value after switching are continuously connected. The voltage amplitude command value is desirable. However, when each determination threshold is set in this way, in an ideal state where the magnet temperature of the AC motor does not change, the AC motor operating point (output torque and rotation speed) and voltage control mode corresponding to the switching condition for switching to the current control mode Since the operating point of the AC motor corresponding to the switching condition to switch to is almost the same, there is a possibility that chattering with frequent switching operations may occur.

  Therefore, the conventional control device sets a value obtained by adding a predetermined hysteresis current value to the current command value as a determination threshold when switching the control mode to the current control mode, so that the switching condition of the current control mode and the voltage control mode The switching conditions are different. However, when a value obtained by adding a predetermined hysteresis current value to the current command value is used as the determination threshold, the interference voltage command value and voltage in the current control mode with respect to the change from the current detection value before switching to the current command value after switching. The ratio of the voltage command value in the control mode is not an appropriate value. Therefore, according to the conventional control device, when the control mode is switched to the current control mode, torque pulsation occurs due to a large change in the current supplied to the AC motor before and after the control mode switching.

  The present invention has been made in view of the above problems, and an object of the present invention is to control an AC motor capable of suppressing the occurrence of torque pulsation when the control mode of the AC motor is switched from the voltage control mode to the current control mode. And providing a control method.

  In the control apparatus and control method for an AC motor according to the present invention, when the control mode of the AC motor is switched from the voltage control mode to the current control mode, the interference voltage command value is corrected based on the actual current value of the AC motor before switching. .

  According to the control device and the control method for an AC motor according to the present invention, the interference voltage command value in the current control mode and the voltage command in the voltage control mode with respect to the change from the actual current value before switching to the current command value after switching. Since the ratio of the values is an appropriate value, it is possible to suppress the occurrence of torque pulsation when the control mode of the AC motor is switched from the voltage control mode to the current control mode.

  Hereinafter, with reference to the drawings, a configuration of a control device for an AC motor according to first to fourth embodiments of the present invention will be described.

[First Embodiment]
First, with reference to FIG. 1 thru | or FIG. 9, the structure of the control apparatus of the alternating current motor used as the 1st Embodiment of this invention is demonstrated.

[Configuration of control device]
As shown in FIG. 1, the control device 1 according to the first embodiment of the present invention controls the operation of a motor 2 that drives a vehicle, and controls the amplitude and phase of a voltage applied to the motor 2. There are two control modes: a voltage control mode and a current control mode for controlling the current supplied to the motor 2. In the present embodiment, the control device 1 includes a command value generation unit 3, a command value generation unit 4, a current controller 5, a voltage controller 6, a control switch 7, a dq axis → UVW phase converter 8, and a PWM converter 9. , Inverter (INV.) 10, current sensors 11 a and 11 b, position detector 12, rotation speed calculator 13, UVW phase → dq axis converter 14, interference voltage corrector 15, and torque deviation (ΔT) corrector 16. Prepare.

The command value generation unit 3 includes a torque command value T ^* , a mechanical angular velocity ω of the motor 2, a voltage V _dc of the DC power source 17, a dq axis current command value i _d ^* , i _q ^*, and a dq axis interference voltage in the current control mode. A table indicating a correspondence relationship between the command values v _{d_dcpl} ^* and v _{q_dcpl} ^* ; The command value generation unit 3 includes a dq-axis current command value i _d ^* , i corresponding to the torque command value T ^* , the mechanical angular velocity ω of the motor 2 output from the rotational speed calculator 13, and the voltage V _dc of the DC power supply 17. _{The q} ^* and dq axis interference voltage command values v _{d_dcpl} ^* and v _{q_dcpl} ^* are retrieved from the table, and the retrieved dq axis current command values i _d ^* and i _q ^* and the dq axis interference voltage command values v _{d_dcpl} ^* and v _{q_dcpl} ^{* Is} output. As described above, the command value generation unit 3 controls the dq-axis current command values i _d ^* and i _q ^* and the dq-axis interference voltage command values v _{d_dcpl} ^* and v _{q_dcpl} ^* by an open loop method.

Corresponding command value generation unit 4, the torque command value T ^*, mechanical angular speed of the motor 2 omega, and the voltage amplitude command value v _a ^* and the voltage phase command value alpha ^* in the voltage V _dc and the voltage control mode of the DC power source 17 It has a table showing the relationship. Command value generation unit 4, the torque command value T ^*, mechanical angular speed of the motor 2 to be output from the rotation speed calculator 13 omega, and the voltage amplitude command value v _a ^* and voltage phase corresponding to the voltage V _dc of the DC power supply 17 The command value α ^* is retrieved from the table, and the retrieved voltage amplitude command value v _a ^* and voltage phase command value α ^* are output. In this way, the command value generation unit 4 controls the voltage amplitude command value v _a ^* and the voltage phase command value α ^* by an open loop method.

The current controller 5 includes the dq-axis current command values i _d ^* and i _q ^* and the dq-axis interference voltage command values v _{d_dcpl} ^* and v _{q_dcpl} ^* output from the command value generation unit 3 and the UVW phase → dq axis converter 14. The dq-axis voltage command value v is obtained by performing a general current vector control calculation including current deviation proportional integration (PI) amplification and non-interference control using the dq-axis current detection values i _d and i _q output from _d1 ^* and _vq1 ^* are generated and output (details will be described later). “Non-interference control” performs current control by separating the current supplied to the motor 2 into a q-axis current component orthogonal to the secondary magnetic flux of the motor 2 and a d-axis current component parallel to the secondary magnetic flux. In the current vector control, the d-axis current component and the q-axis current component are converted into the other current component as the q-axis voltage and the d-axis voltage by the action of the current, the inductance of the q-axis and the d-axis, and the mechanical rotation speed of the motor 2, respectively. This means control that cancels the influence of interference, and specifically means control that corrects the voltage command value using the interference voltage command value.

The voltage controller 6 uses the following formula 1 to _{calculate the} dq-axis voltage command values v _d2 ^* and v _q2 ^* from the voltage amplitude command value v _a ^* and the voltage phase command value α ^* output from the command value generation unit 4 ^. Is calculated and output.

When the control mode of the motor 2 is the current control mode, the control switch 7 converts the dq axis voltage command values v _d1 ^* and v _q1 ^* output from the current controller 5 into the dq axis voltage command value v in the current control mode. _d ^*, _v and output as ^{q *,} if the control mode of the motor 2 is a voltage control mode, * voltage controller dq-axis voltage command value output from the 6 _{v ^d2,} the _{v q2} ^* in the voltage control mode Output as dq-axis voltage command values v _d ^* and v _q ^* . The dq axis → UVW phase converter 8 uses the following formula 2 to calculate the dq axis voltage command values v _d1 ^* , v _q1 ^* output from the control switch 7 and the motor 2 detected by the position detector 12. The voltage command values v _u ^* , v _v ^* , v _w ^* of the three phases U, V, and W are calculated and output from the electrical angle θ of the rotor.

The PWM converter 9 includes an inverter 10 corresponding to the three-phase voltage command values v _u ^* , v _v ^* , v _w ^* output from the dq axis → UVW phase converter 8. Drive signals D _uu ^* , D _ul ^* , D _vu ^* , D _vl ^* , D _wu ^* , and D _wl ^* are generated and output. The drive signals D _uu ^* and D _ul ^* indicate signals for the upper and lower switching elements corresponding to the U phase, respectively, and the drive signals D _vu ^* and D _vl ^* respectively indicate the upper and lower switching elements corresponding to the V phase. The drive signals D _wu ^* and D _wl ^* indicate signals for the upper and lower switching elements corresponding to the W phase, respectively.

The inverter 10 turns on / off the corresponding switching element according to the drive signals D _uu ^* , D _ul ^* , D _vu ^* , D _vl ^* , D _wu ^* , and D _wl ^* output from the PWM converter 8. The voltage V _{dc of the} power source 17 is converted into a three-phase AC voltage v _u , v _v , v _w and output to the motor 2. Current sensors 11a, 11b, and outputs the UVW phase → dq axis converter 14 detects a current value _i u, _{i v} of U-phase and V-phase. When the current sensor is attached to only two phases as in the present embodiment, the current value of the remaining one phase that is not detected (in this embodiment, the W phase) can be calculated from Equation 3 below.

The position detector 12 detects the electrical angle θ of the rotor of the motor 2 and outputs it to the dq axis → UVW phase converter 8, the rotational speed calculator 13, and the UVW phase → dq axis converter 14. The rotational speed calculator 13 calculates the mechanical angular velocity ω of the motor 2 from the amount of change over time of the electrical angle θ of the rotor of the motor 2 to generate a command value generator 3, a command value generator 4, an interference voltage corrector 15, and Output to the torque deviation corrector 16. UVW phase → dq axis converter 14 motor 2 detected by the current sensor 11a, current _i u of U-phase and V-phase detected by 11b, _{i v} and the position detector 12 using Equation 4 below Dq-axis current detection values i _d and i _q are calculated from the electrical angle θ of the rotor.

When the magnet torque is dominant with respect to the output torque of the motor 2, the interference voltage corrector 15 determines the difference between the detected d-axis current value i _d before switching the control mode and the d-axis current command value i _d ^* after switching. calculating a q-axis interference voltage correction value _Δv q_dcpl ^* by substituting .delta.i _d a ^(* ₌ i ^d _-i d) in equation 5 below. In Equation 6, the parameter ω represents the mechanical angular velocity of the motor 2, and the parameter Ld represents the d-axis inductance. “Magnet torque is dominant with respect to the motor output” means that the integrated intensity of the torque waveform of the magnet torque is greater than the integrated intensity of the torque waveform of the reluctance torque.

When the magnet torque is dominant with respect to the output torque of the motor 2, the torque deviation corrector 16 is the difference between the q-axis current detection value i _q before switching the control mode and the q-axis current command value i _q ^* after switching. By substituting Δi _q (= i _q −i _q ^* ) into the following formula 6, the difference between the output torque of the motor 2 and the torque target value is calculated and output as a torque deviation ΔT. Note in Equation 6, the parameter ω denotes the mechanical angular speed of the motor 2, the parameter phi _a shows a magnetic flux density of the motor 2. This torque deviation ΔT is input to the command value generation units 3 and 4 as a torque command value T ^* by adding to the torque target value T ₀ ^* .

[Configuration of current controller]
As shown in FIG. 2, the current controller 5 includes a PI control unit 20 and a non-interference control unit 21. PI control unit 20, d-axis current detection value _{i d} and the d-axis current command value _i ^{d *} of the difference ^{_{Δi d (= i d -i d}} *) and q-axis current detection value _{i q} and q-axis current command value i _q ^* of the difference ^{_{Δi q (= i q -i q}} *) proportional integral (PI) calculation amplification dq-axis voltage command value by _v ^d1 _*, calculates the _{v q1} ^*. The non-interference control unit 21 _adds the q-axis interference voltage correction value Δv _{q_dcpl} ^* output from the interference voltage corrector 15 to the q-axis interference voltage command value v _{q_dcpl} ^* output from the command value generation unit 3. after correcting axial interference voltage command value _{v q_dcpl} ^*, dq-axis interference voltage command value _{v d_dcpl} ^*, _{v q_dcpl} ^* to the corresponding dq-axis interference voltage value _{v d_dcpl,} dq-axis interferometer by an open loop method of reading _{v Q_dcpl} from the table The voltages v _{d_dcpl} and v _{q_dcpl} are calculated. The non-interference control unit 21 then adds a value _obtained by adding the dq-axis interference voltage values v _{d_dcpl} and v _{q_dcpl} to the dq-axis voltage command values v _d1 ^* and v _q1 ^* calculated by the PI control unit 20. Output as _d1 ^* , v _q1 ^* .

[Configuration of non-interference control unit]
As shown in FIG. 3, the non-interference control unit 21 includes low-pass filters (LPF) 22 and 23. The low-pass filter 22 removes a high frequency component from the d-axis interference voltage command value v _{d_dcpl} ^* output from the command value generation unit 3 and outputs the result. The low-pass filter 23 removes a high frequency component from the q-axis interference voltage command value v _{q_dcpl} ^* output from the command value generation unit 3 and outputs the result. The initial output value of the low-pass filter 23 is _obtained by adding the q-axis interference voltage correction value Δv _{q_dcpl} ^* to the q-axis interference voltage command value v _{q_dcpl} ^* when the control mode of the motor 2 is switched from the voltage control mode to the current control mode. Set to a value. Thereby, the output value of the low-pass filter 23 is changed from the voltage control mode to the current control mode when the motor 2 is switched from the voltage control mode to the q-axis interference voltage command value v _{q_dcpl} ^* to the q-axis. The value _obtained by adding the interference voltage correction value Δv _{q_dcpl} ^* converges to the q-axis interference voltage command value v _{q_dcpl} ^* .

[Motor control operation]
Next, the control operation of the motor 2 by the control device 1 will be described.

  FIG. 4 shows the relationship between the output characteristics of the motor 2 and the control switching points, and the vertical axis and the horizontal axis show the output torque and the mechanical rotation speed of the motor 2, respectively. The maximum efficiency region shown in the figure indicates a region in which the operation of the motor 2 is controlled by selecting the minimum current (maximum efficiency current) at which the motor 2 can output the torque target value. In general, when the mechanical rotation speed of the motor 2 increases, the induced voltage increases, so that the terminal voltage of the motor 2 reaches the maximum voltage that can be output by the inverter 10. For this reason, when the terminal voltage of the motor 2 becomes equal to or higher than a predetermined value, the motor 2 is controlled so that the terminal voltage of the motor 2 does not exceed the maximum voltage that the inverter 10 can output by increasing the current that weakens the magnetic flux. It is necessary to control the operation. Specifically, the voltage amplitude is made constant at the maximum value that can be output by the inverter 10 and the torque is set to a desired value by controlling the voltage phase. So that the terminal voltage does not exceed the maximum voltage that the inverter 10 can output. In FIG. 4, a control region in which a current that weakens this magnetic flux is supplied is referred to as a weak magnetic flux region.

  When the rotational speed of the rotor of the motor 2 is increased and the control mode of the motor 2 is switched from the current control mode to the voltage phase control mode, the boundary between the above-mentioned maximum efficiency region and the weak magnetic flux region as shown by point B in FIG. It is desirable to do it on a line. However, when the mechanical rotation speed of the motor 2 decreases and the voltage control mode is switched to the current control mode, if the same switching is performed on the same boundary line, control switching may occur frequently (chattering). Therefore, in actuality, when switching from the voltage control mode to the current control mode, switching is performed at point D shown in FIG. 4 so that hysteresis is provided at the timing of control mode switching. Hereinafter, the control mode switching process will be described in detail with reference to the flowchart shown in FIG.

[Control mode switching process]
The flowchart shown in FIG. 5 starts at the timing when the power supply of the control device 1 is switched from the off state to the on state, and the control mode switching process proceeds to step S1. This control mode switching process is repeatedly executed every predetermined control cycle.

  In step S1, the control switch 7 determines whether the current control mode is the current control mode or the voltage control mode. As a result of the determination, if the current control mode is the current control mode, the control switch 7 advances the control mode switching process to step S2. On the other hand, when the current control mode is the voltage control mode, the control switch 7 advances the control mode switching process to the process of step S5.

In the processing of step S2, the control switch 7 determines that the voltage amplitude (v _d1 ^{* 2} + v _q1 ^{* 2} ) ^1/2 calculated from the dq axis voltage command values v _d1 ^* and v _q1 ^* is the voltage amplitude command value v _a. ^* Determine whether or not it is greater than As a result of the determination, when the voltage amplitude (v _d1 ^{* 2} + v _q1 ^{* 2} ) ^1/2 is equal to or greater than the voltage amplitude command value v _a ^* , the control switch 7 changes the control mode of the motor 2 to the current as the process of step S3. After switching from the control mode to the voltage control mode, the control mode switching process proceeds to step S7. On the other hand, when the voltage amplitude (v _d1 ^{* 2} + v _q1 ^{* 2} ) ^1/2 is less than the voltage amplitude command value v _a ^* , the control switch 7 controls to maintain the control mode in the current control mode. The mode switching process proceeds to step S4.

In step S4, the control switch 7 outputs the dq axis voltage command values v _d1 ^* and v _q1 ^* output from the current controller 5 as dq axis voltage command values v _d ^* and v _q ^* . Thereby, the process of step S4 is completed and the control mode switching process returns to the process of step S1.

In the process of step S5, the control switch 7 determines whether or not the dq-axis current detection values i _d and i _q have reached the switching line L2 shown in FIG. The solid line L1 shown in FIG. 6 indicates the maximum efficiency current on the dq-axis current coordinate, and the current command value in the maximum efficiency region is controlled to be this maximum efficiency current. When switching from the voltage control mode to the current control mode, it is preferable to perform the switching on the solid line L1 indicating the maximum efficiency current. However, as described above, in order to avoid chattering, the dotted line L2 is obtained by adding hysteresis to the maximum efficiency current. Set the appropriate switching line. The control switch 7 determines whether or not the dq-axis current detection values i _d and i _q have reached the switching line L2 using the locus data of the dotted line L2 stored in advance. As a result of the determination, when the dq-axis current detection values i _d and i _q reach the switching line L2, the control switch 7 switches the control mode of the motor 2 from the voltage control mode to the current control mode as a process of step S6. Thereafter, the control mode switching process proceeds to the process of step S4. On the other hand, when the dq-axis current detection values i _d and i _q have not reached the switching line L2, the control switch 7 performs the control mode switching process in step S7 in order to maintain the control mode in the voltage control mode. Proceed to

In the process of step S7, the control switch 7 outputs the dq axis voltage command values v _d2 ^* and v _q2 ^* output from the voltage controller 6 as dq axis voltage command values v _d ^* and v _q ^* . Thereby, the process of step S7 is completed, and the control mode switching process returns to the process of step S1.

[Interference voltage correction processing]
Next, the flow of interference voltage correction processing according to the first embodiment of the present invention will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 7 starts at the timing when the power supply of the control device 1 is switched from the off state to the on state, and the interference voltage correction process proceeds to step S11. This interference voltage correction process is repeatedly executed every predetermined control period.

  In the process of step S11, the interference voltage corrector 15 performs control from the current control mode to the voltage control mode when the current control mode is the voltage control mode, the current control mode, or the control mode is switched from the voltage control mode to the current control mode. It is determined whether the mode is switched. As a result of the determination, when the current control mode is the voltage control mode, the interference voltage corrector 15 advances the interference voltage correction process to the process of step S12. If the current control mode is the current control mode or the control mode switching from the current control mode to the voltage control mode, the interference voltage corrector 15 ends the series of interference voltage correction processing. If the current control mode is the control mode switching from the voltage control mode to the current control mode, the interference voltage corrector 15 advances the interference voltage correction process to the process of step S13.

In the process of step S12, the interference voltage corrector 15 stores the d-axis current detection value _{i d,} which is input from the UVW → dq axis converter 14. In the case where the d-axis current detection value i _d is stored by the last interference voltage correction processing, interference voltage corrector 15, overwriting the previous d-axis current detection value i _d by this d-axis current detection value i _d To do. Thereby, the process of step S12 is completed and a series of interference voltage correction processes are completed.

In the process of step S13, the interference voltage corrector 15, d-axis current command value i _d ^* of the difference .DELTA.i _d of d-axis current detection value i _d and the switch before switching the stored control mode by the processing in step S12 ₍₌ i ^d _-i d ^*) is calculated. Thereby, the process of step S13 is completed, and the interference voltage correction process proceeds to the process of step S14.

In the process of step S14, the interference voltage corrector 15 calculates a q-axis interference voltage correction value _Δv q_dcpl ^* by substituting a difference value .DELTA.i _d calculated by the process at step S13 in equation 6 described above, calculates The q-axis interference voltage correction value Δv _{q_dcpl} ^* is output to the current controller 5. Thereby, the process of step S14 is completed, and the interference voltage correction process proceeds to the process of step S15.

In the process of step S15, the current controller 5 adds the q-axis interference voltage correction value Δv _{q_dcpl} ^* calculated by the process of step S14 to the q-axis interference voltage command value v _{q_dcpl} ^* output from the command value generation unit 3. The obtained value is set as the initial output value of the low-pass filter 23. Thereby, the process of step S15 is completed and a series of interference voltage correction processes are completed.

[Torque pulsation and torque step]
FIG. 8 shows (a) torque when the control mode of the motor 2 is switched from the voltage control mode to the current control mode in the control device 1 (present invention) and the conventional control device (prior art) according to the embodiment of the present invention. Response, (b) Torque command value, (c) q-axis current detection value, (d) d-axis current detection value, (e) q-axis voltage command value, and (f) q-axis interference voltage waveform showing time changes FIG. FIG. 9 is an enlarged waveform diagram of the time change of (e) q-axis voltage command value and (f) q-axis interference voltage shown in FIG. 8 and 9 indicate the interference voltage value before correction by the above-described interference voltage correction processing, and the point B indicates the interference voltage value after correction by the above-described interference voltage correction processing. Time T = T1 indicates the time when the control mode of the motor 2 is switched from the voltage control mode to the current control mode.

When the control mode of the motor 2 is switched from the voltage control mode to the current control mode, it is desirable to switch at a point where the current detection value before switching and the current command value after switching are continuous. However, in practice, since hysteresis is provided to prevent chattering, the control mode is switched at a point where hysteresis is applied to the current. In this case, in the prior art, there is a difference between the current detection value immediately before switching and the current command value after switching, and the current suddenly changes before and after switching, resulting in torque pulsation (see the dotted line in FIG. 8A). This torque pulsation is caused by the interference voltage value of the non-interference control in the current control mode after switching (the voltage E shown in FIG. 9) with respect to the change in the actual current value before switching and the current command value after switching. ) And the voltage value (voltage D shown in FIG. 9) of current deviation proportional integral control (D / E) is not an appropriate value. In contrast, in the present invention, as described above, when the control mode is switched, the interference voltage correction value is corrected by calculating the interference voltage correction value based on the change in the actual current value before switching and the current command value after switching. Thus, the ratio (D / E) of the interference voltage value of non-interference control and the voltage value of current deviation proportional integral control in the current control mode with respect to the change of the actual current value before switching and the current command value after switching. It was set to an appropriate value. As a result, the interference voltage v _{q_dcpl} exhibits an ideal response as shown by the solid line in FIGS. 8 (f) and 9 (f), and suppresses the torque pulsation as shown by the solid line in FIG. 8 (a). it can.

  In the current control mode, the command value generator 3 controls each command value, and in the voltage control mode, the command value generator 4 controls each command value. In the prior art, when the temperature of the motor 2 is different from the temperature of the motor 2 when the table data referred to by the command value generation units 3 and 4 is created, the torque in the current control mode is indicated by a dotted line in FIG. And a step is generated between the output torque in the voltage control mode. Although the output torque of the motor 2 is determined by the magnetic flux and the current, since the current is controlled to a desired value in the current control mode, the change in the magnetic flux due to the temperature change of the motor 2 becomes a torque error factor. On the other hand, since the current is not controlled in the voltage control mode, the magnetic flux and the current change with a change in the temperature of the motor, causing a torque error. That is, since the torque error characteristic with respect to the temperature of the motor 2 is different between the current control mode and the voltage phase control mode, a step in the output torque occurs. On the other hand, in the present invention, as described above, the change in the output torque due to the switching is calculated, and the torque after the switching as in the torque command value shown in FIG. 8B so that the output torque before and after the switching becomes constant. Since the command value is corrected, the torque step is eliminated as shown by the solid line in FIG.

As is clear from the above description, according to the control device 1 according to the first embodiment of the present invention, when the control mode of the motor 2 is switched from the voltage control mode to the current control mode, the output torque of the motor 2 is reduced. If the magnet torque is dominant, the interference voltage corrector 15, q-axis based on the d-axis current command value i _d ^* of the difference .DELTA.i _d of d-axis current detection value i _d and the switch before switching of the control mode The interference voltage correction value Δv _{q_dcpl} ^* is calculated, and the current controller 5 corrects the q-axis interference voltage command value v _{q_dcpl} ^* output from the command value generation unit 3 using the q-axis interference voltage correction value Δv _{q_dcpl} ^*. . According to such a configuration, the interference voltage value and current deviation of the non-interference control in the current control mode with respect to the change of the detected d-axis current value i _d before switching and the d-axis current command value i _d ^* after switching. Since the ratio of the voltage value of the proportional integral control becomes an appropriate value, it is possible to suppress the occurrence of torque pulsation when the control mode of the motor 2 is switched from the voltage control mode to the current control mode.

Further, according to the control device 1 according to the first embodiment of the present invention, when the torque deviation corrector 16 is dominant in the magnet torque with respect to the output torque of the motor 2, the q-axis current before the control mode is switched. Based on the difference Δi _q (= i _q −i _q ^* ) between the detected value i _q and the q-axis current command value i _q ^* after switching, the amount of change in output torque due to switching operation is calculated, and the output torque before and after switching is calculated. Since the torque command value is corrected so as to be constant, it is possible to suppress the occurrence of a torque step before and after switching the control mode of the motor 2. The torque deviation corrector 16 may correct at least one of the torque command value and the current command value.

[Second Embodiment]
Next, with reference to FIG. 10 to FIG. 12, the configuration of the AC motor control device 21 according to the second embodiment of the present invention will be described.

[Configuration of control device]
In the present embodiment, the configuration of the current controller 5, the interference voltage corrector 15, and the torque deviation corrector 16 and the flow of the interference voltage correction process are different from those in the first embodiment. Therefore, hereinafter, only the configuration of the current controller 5, the interference voltage corrector 15, and the torque deviation corrector 16 and the interference voltage correction process in this embodiment will be described.

[Configuration of interference voltage corrector]
Interference voltage corrector 15, d-axis current command value _i ^{d *} of the difference ^{_{Δi d (= i d -i d}} *) and switching of the control modes of the d-axis current detection value _{i d} and the switch before switching of the control mode By substituting the difference Δi _q (= i _q −i _q ^* ) between the previous q-axis current detection value i _q and the q-axis current command value i _q ^* after switching into the following Equation 7, the d-axis interference voltage correction value Δv _{d_dcpl} ^* and q-axis interference voltage correction value Δv _{q_dcpl} ^* are calculated. In Equation 7, the parameter ω represents the mechanical angular velocity of the motor 2, and the parameters Ld and Lq represent the d-axis and q-axis inductances, respectively.

[Configuration of current controller]
As shown in FIG. 10, the current controller 5 includes a PI control unit 20 and a non-interference control unit 24. PI control unit 20, d-axis current detection value _{i d} and the d-axis current command value _i ^{d *} of the difference ^{_{Δi d (= i d -i d}} *) and q-axis current detection value _{i q} and q-axis current command value i _q ^* of the difference ^{_{Δi q (= i q -i q}} *) dq -axis voltage command value by the proportional-integral PI calculation amplification _v ^d1 _*, calculates the _{v q1} ^*. The non-interference controller 24 outputs the d-axis interference voltage correction value Δv _{d_dcpl} ^* and the q-axis interference voltage correction value Δv _{q_dcpl} ^* output from the interference voltage corrector 15 to the d-axis interference voltage command output from the command value generation unit 3. the value _{v D_dcpl} ^* and q-axis interference voltage command value _v after correcting the d-axis interference voltage command value _{v D_dcpl} ^* and q-axis interference voltage command value _{v Q_dcpl} ^* by adding the _{q_dcpl} ^*, dq-axis interference voltage command value v _The dq axis interference voltages v _{d_dcpl} and v _{q_dcpl} are calculated by an open loop method in which the dq axis interference voltage values v _{d_dcpl} and v _{q_dcpl} corresponding to _{d_dcpl} ^* and v _{q_dcpl} ^* are read from the table. The non-interference control unit 24 then adds a value _obtained by adding the dq-axis interference voltage values v _{d_dcpl} and v _{q_dcpl} to the dq-axis voltage command values v _d1 ^* and v _q1 ^* calculated by the PI control unit 20. Output as _d1 ^* , v _q1 ^* .

[Configuration of non-interference control unit]
The non-interference control unit 24 includes low-pass filters (LPF) 25 and 26 as shown in FIG. The low-pass filter 25 removes a high frequency component from the d-axis interference voltage command value v _{d_dcpl} ^* output from the command value generation unit 3 and outputs the result. The low pass filter 26 removes a high frequency component from the q-axis interference voltage command value v _{q_dcpl} ^* output from the command value generation unit 3 and outputs the result. The initial output value of the low-pass filter 25 is _obtained by adding the d-axis interference voltage correction value Δv _{d_dcpl} ^* to the d-axis interference voltage command value v _{d_dcpl} ^* when the control mode of the motor 2 is switched from the voltage control mode to the current control mode. Set to a value. As a result, the output value of the low-pass filter 25 is changed to the d-axis interference voltage command value v _{d_dcpl} ^* as the time elapses from the time when the control mode of the motor 2 is switched from the voltage control mode to the current control mode. The value _obtained by adding the interference voltage correction value Δv _{d_dcpl} ^* converges to the d-axis interference voltage command value v _{d_dcpl} ^* . The initial output value of the low-pass filter 26 is _obtained by adding the q-axis interference voltage correction value Δv _{q_dcpl} ^* to the q-axis interference voltage command value v _{q_dcpl} ^* when the control mode of the motor 2 is switched from the voltage control mode to the current control mode. Set to a value. Thereby, the output value of the low-pass filter 26 is changed from the voltage control mode to the current control mode when the motor 2 is switched from the voltage control mode to the q-axis interference voltage command value v _{q_dcpl} ^* to the q-axis. The value _obtained by adding the interference voltage correction value Δv _{q_dcpl} ^* converges to the q-axis interference voltage command value v _{q_dcpl} ^* .

[Configuration of torque deviation corrector]
Torque deviation corrector 16, d-axis current command value _i ^{d *} of the difference ^{_{Δi d (= i d -i d}} *) and switching of the control modes of the d-axis current detection value _{i d} and the switch before switching of the control mode The torque deviation ΔT is calculated by substituting the difference Δi _q (= i _q −i _q ^* ) between the previous q-axis current detection value i _q and the q-axis current command value i _q ^* after switching into the following Equation 8. Output. Note in Equation 8, the parameter ω denotes the mechanical angular speed of the motor 2, the parameter phi _a shows a magnetic flux density of the motor 2. This torque deviation ΔT is input to the command value generation units 3 and 4 as a torque command value T ^* by adding to the torque target value T ₀ ^* .

[Interference voltage correction processing]
Next, the flow of interference voltage correction processing according to the second embodiment of the present invention will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 12 starts at the timing when the power supply of the control device 1 is switched from the off state to the on state, and the interference voltage correction process proceeds to step S21. This interference voltage correction process is repeatedly executed every predetermined control period.

  In the process of step S21, the interference voltage corrector 15 performs control from the current control mode to the voltage control mode when the current control mode is the voltage control mode, the current control mode, and the control mode is switched from the voltage control mode to the current control mode. It is determined whether the mode is switched. As a result of the determination, when the current control mode is the voltage control mode, the interference voltage corrector 15 advances the interference voltage correction process to the process of step S22. If the current control mode is the current control mode or the control mode switching from the current control mode to the voltage control mode, the interference voltage corrector 15 ends the series of interference voltage correction processing. When the current control mode is the control mode switching from the voltage control mode to the current control mode, the interference voltage corrector 15 advances the interference voltage correction process to the process of step S23.

In the process of step S22, the interference voltage corrector 15, UVW → to d-axis current detection value _{i d} and the q-axis current detection value _{i q} stored is input from the dq-axis converter 14. When the d-axis current detection value i _d and the q-axis current detection value i _q are stored in the previous interference voltage correction process, the interference voltage corrector 15 determines that the current d-axis current detection value i _d and the q-axis current are the same. The detection value i _q overwrites the previous d-axis current detection value i _d and the q-axis current detection value i _q . Thereby, the process of step S22 is completed and a series of interference voltage correction processes are completed.

In the process of step S23, the interference voltage corrector 15 stores the d-axis current detection value i _d and the q-axis current detection value i _q before switching of the control mode stored in the process of step S22 and the d-axis current command after switching. to calculate the value _i ^{d *} and the q-axis current command value _i ^{q *} of the difference ^{_{Δi d (= i d -i d}} *) and the difference ^{_{Δi q (* = i q -i}} q). Thereby, the process of step S23 is completed, and the interference voltage correction process proceeds to the process of step S24.

In the process of step S24, the interference voltage corrector 15, d-axis interference voltage correction value _Δv d_dcpl ^* and by substituting the difference value .DELTA.i _d and the difference .DELTA.i _q calculated by the processing in step S23 in Equation 7 described above The q-axis interference voltage correction value Δv _{q_dcpl} ^* is calculated, and the calculated d-axis interference voltage correction value Δv _{d_dcpl} ^* and the q-axis interference voltage correction value Δv _{q_dcpl} ^* are output to the current controller 5. Thereby, the process of step S24 is completed, and the interference voltage correction process proceeds to the process of step S25.

In the process of step S25, the current controller 5 calculates the d-axis calculated by the process of step S24 to the q-axis interference voltage command value v _{d_dcpl} ^* and the q-axis interference voltage command value v _{q_dcpl} ^* output from the command value generation unit 3. A value _obtained by adding the axis interference voltage correction value Δv _{d_dcpl} ^* and the q axis interference voltage correction value Δv _{q_dcpl} ^* is set as an initial output value of the low pass filter 25 and the low pass filter 26, respectively. Thereby, the process of step S25 is completed and a series of interference voltage correction processes are completed.

As is clear from the above description, according to the control device 21 according to the second embodiment of the present invention, when the control mode of the motor 2 is switched from the voltage control mode to the current control mode, the interference voltage corrector 15 is calculating a q-axis interference voltage correction value _Δv q_dcpl ^* based on the d-axis current command value i _d ^* of the difference .DELTA.i _d of d-axis current detection value i _d and the switch before switching of the control modes, switching of the control mode before calculating a d-axis interference voltage correction value _Δv d_dcpl ^* based on the q-axis current detection value _{i q} and q axis current command value _i ^{q *} difference .DELTA.i _q after switching. Then, the current controller 5 corrects the q-axis interference voltage command value v _{q_dcpl} ^* output from the command value generation unit 3 using the q-axis interference voltage correction value Δv _{q_dcpl} ^* , and d-axis interference voltage correction value Δv _{d_dcpl} ^*. _{Is used} to correct the d-axis interference voltage command value v _{d_dcpl} ^* output from the command value generation unit 3. According to such a configuration, changes in the d-axis current detection value i _d and the q-axis current detection value i _q before switching, and the d-axis current command value i _d ^* and the q-axis current detection value i _q ^* after switching are changed. On the other hand, since the ratio of the interference voltage value of the non-interference control and the voltage value of the current deviation proportional integration control in the current control mode becomes an appropriate value, when switching the control mode of the motor 2 from the voltage control mode to the current control mode. Generation of torque pulsation can be suppressed.

Further, according to the control device 21 according to the second embodiment of the present invention, the torque deviation corrector 16 performs the d-axis current detection value i _d and the q-axis current detection value i _q before switching the control mode, and after the switching. Using the d-axis current command value i _d ^{*, the} q-axis current command value i _q ^* , and the dq-axis inductance values Ld and Lq based on these current values, the amount of change in the output torque due to the switching operation is calculated, and the output before and after the switching Since the torque command value is corrected so that the torque becomes constant, it is possible to suppress the occurrence of a torque step before and after switching the control mode of the motor 2.

[Third Embodiment]
Next, with reference to FIG. 13, the structure of the control apparatus of the alternating current motor which becomes the 3rd Embodiment of this invention is demonstrated.

[Configuration of control device]
As shown in FIG. 13, the control device 31 according to the third embodiment of the present invention includes a command value generator 4, a current controller 5, a voltage controller 6, a control switch 7, a dq axis → UVW phase converter. 8, PWM converter 9, inverter 10, current sensors 11a and 11b, position detector 12, rotation speed calculator 13, UVW phase → dq axis converter 14, interference voltage corrector 15, torque deviation corrector 16, command value A generation unit 32, an LPF 33, and a non-interference control unit 34 are provided. The same components as those of the control device 1 according to the first embodiment are given the same reference numerals, and the description thereof is omitted below.

The command value generation unit 32 determines the correspondence relationship between the torque command value T ^* , the mechanical angular velocity ω of the motor 2, the voltage V _dc of the DC power supply 17 and the dq axis current command values i _d ^* and i _q ^* in the current control mode. It has a table to show. The command value generation unit 32 outputs a dq axis current command value i _d ^* , i corresponding to the torque command value T ^* , the mechanical angular velocity ω of the motor 2 output from the rotational speed calculator 13, and the voltage V _dc of the DC power supply 17. _q ^* is retrieved from the table and the retrieved dq-axis current command values i _d ^* and i _q ^* are output. The LPF 33 performs dq-axis current response estimated values i _d ^* and i _q ^* by performing a filtering process corresponding to the current response on the dq-axis current command values i _d ^* and i _q ^* output from the command value generation unit 32. Generate and output. The non-interference control unit 34 calculates the dq-axis interference voltage command values v _{d_dcpl} ^* and v _{q_dcpl} ^* using the dq-axis current response estimated values i _d ^* and i _q ^* , and outputs them to the current controller 5.

As described above, the control device 31 according to the present embodiment performs the dq-axis current response estimated values i _d ^* and i _q obtained by performing the filter processing corresponding to the current response on the dq-axis current command values i _d ^* and i _q ^{*. It} is an open loop method for calculating the dq axis interference voltage command values v _{d_dcpl} ^* and v _{q_dcpl} ^* used in non-interference control using ^* , and when switching the control mode of the motor 2 from the voltage control mode to the current control mode, If the magnet torque to the output torque of the motor 2 is dominant, the current controller 5, q axis output from the non-interference controller 34 using the switch before the d-axis current detection value i _d interference voltage command value v _{Correct q_dcpl} ^* . On the other hand, when the magnet torque is not dominant with respect to the output torque of the motor 2, the current controller 5 performs the non-interference control using the d-axis current detection value i _d and the q-axis current detection value i _q before switching, respectively. The q-axis interference voltage command value v _{q_dcpl} ^* and the d-axis interference voltage command value v _{d_dcpl} ^* output from the unit 34 are corrected. According to such a configuration, the ratio of the interference voltage value of the non-interference control and the voltage value of the current deviation proportional integral control in the current control mode to the change in the current detection value before switching and the current command value after switching is Since it becomes an appropriate value, it can suppress that a torque pulsation generate | occur | produces when switching the control mode of the motor 2 from a voltage control mode to a current control mode.

[Fourth Embodiment]
Finally, with reference to FIG. 14, the structure of the control apparatus of the alternating current motor which becomes the 4th Embodiment of this invention is demonstrated.

[Configuration of control device]
As shown in FIG. 14, the control device 41 according to the fourth embodiment of the present invention includes a command value generator 3, a command value generator 4, a current controller 5, a voltage controller 6, a control switch 7, dq. Axis → UVW phase converter 8, PWM converter 9, inverter 10, current sensors 11a, 11b, position detector 12, rotational speed calculator 13, UVW phase → dq axis converter 14, interference voltage corrector 15, PI control Unit 42, power calculation unit 43, torque estimator 44, LPFs 45 a and 45 b, and offset amount calculation unit 46. The same components as those of the control device 1 according to the first embodiment are given the same reference numerals, and the description thereof is omitted below.

The PI control unit 42 proportionally integrates and amplifies the deviation between the torque estimated value T ^{^} output from the torque estimator 44 and the torque target value T ₀ ^* , and subtracts the amplified deviation from the torque target value T ₀ ^* to generate torque. Calculates and outputs command value T ^* . The power calculator 43 outputs the dq axis voltage command values v _d ^* and v _q ^* output from the control switch 7 and the dq axis current detection values i _d ^* and i _q ^* output from the UVW → dq axis converter 14 ^. Is calculated and output as the power consumption of the motor 2. The torque estimator 44 calculates and outputs the estimated torque value T ^{^} from the power consumption of the motor 2 output from the power calculator 43 and the rotational angular velocity ω of the motor 2 using the following formula 9. Although Equation 8 ignores losses such as copper loss and iron loss, the estimated torque value T ^{^} may be calculated in consideration of the loss.

Offset amount calculation section 46 operates only immediately before switching the control mode of the motor 2 from the voltage phase control mode to the current control mode, the d-axis current detection value i _d and the q-axis current detection value i _q and d-axis current command value i _d ^* and the q-axis current command value _i ^{q *} for the current deviation ^{_{Δi d0 (= i d -i d}} *), calculated .DELTA.i _q0 a ^{_{(= i q -i q *)}} . The LPFs 45a and 45b operate only when the control mode is the current control mode, and their inputs are always set to zero. The LPFs 45a and 45b output current offset amounts Δi _d and Δi _q , respectively. The output initial values of the LPFs 45a and 45b are set to current deviations Δi _d0 and Δi _q0 , respectively, immediately before the control mode is switched from the voltage control mode to the current control mode. As a result, the output values of the low-pass filters 45a and 45b change from the current deviations Δi _d0 and Δi _q0 to 0 as time elapses from the time when the control mode of the motor 2 is switched from the voltage control mode to the current control mode. Converge.

  As described above, the control device 41 according to the fourth embodiment of the present invention is related to the control mode while converging the deviation between the current detection value immediately before switching the control mode and the current command value after switching to 0 with a first order delay. Instead, the torque command value is adjusted so that the output torque matches the torque target value by power feedback (torque estimation feedback). According to such a configuration, in addition to the technical effect of the first embodiment, it is possible to obtain the technical effect that the power feedback can be performed at high speed and the current change can be accelerated. The control device 41 may converge the deviation between the current command value immediately before switching the control mode and the current command value after switching to 0 with a first-order delay. The control device 41 may adjust the current command value so that the output torque matches the torque target value.

  The switching means and the correction means according to the present invention correspond to the control switch 7. The second correction means according to the present invention corresponds to the torque deviation corrector 16. The third correction unit according to the present invention corresponds to the PI control unit 42.

The embodiment to which the invention made by the present inventors is applied has been described above, but the present invention is not limited by the description and the drawings that constitute a part of the disclosure of the present invention. For example, the present embodiment is for suppressing torque pulsation that occurs when the control mode of the motor 2 is switched from the voltage control mode to the current control mode, but the present invention is not limited to the present embodiment. The present invention can be applied to general control in which the torque changes due to a sudden change in voltage or current when the control mode is switched. Specifically, it has a first current control mode and a second current control mode controlled by different command value generation units, and can be applied when switching the control mode of the motor 2 between them. Further, the voltage controller 6 shown in FIG. 1 is set to rectangular wave voltage control, and a dq axis voltage command value v corresponding to a fundamental wave component calculated from the voltage command value α ^* and the power supply voltage V _dc using the following equations 10 and 11. _{The present} invention can also be applied when outputting _d2 ^* and _vq2 ^* .

  In addition to the examples shown in the embodiment, there are various ways of providing hysteresis at the control mode switching point. However, in any case, by providing hysteresis, voltage or current changes suddenly and torque changes. The present invention is applicable. As described above, other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

It is a block diagram which shows the structure of the control apparatus of the alternating current motor used as the 1st Embodiment of this invention. It is a block diagram which shows the internal structure of the current controller shown in FIG. It is a block diagram which shows the internal structure of the non-interference control part shown in FIG. It is a figure which shows the relationship between the output characteristic of a motor, and a control switching point. It is a flowchart figure which shows the flow of the control mode switching process used as the 1st Embodiment of this invention. It is a figure which shows an example of the switching line of a control mode. It is a flowchart figure which shows the flow of the interference voltage correction process used as the 1st Embodiment of this invention. (A) Torque response when the motor control mode is switched from the voltage phase control mode to the PWM current control mode in the control device (the present invention) and the conventional control device (prior art) according to the first embodiment of the present invention. , (B) Torque command value, (c) q-axis current detection value, (d) d-axis current detection value, (e) q-axis voltage command value, and (f) q-axis interference voltage waveform diagram showing time changes It is. It is an enlarged waveform diagram of the time change of (e) q-axis voltage command value and (f) q-axis interference voltage shown in FIG. It is a block diagram which shows the internal structure of the current controller in the control apparatus of the alternating current motor used as the 2nd Embodiment of this invention. It is a block diagram which shows the internal structure of the non-interference control part shown in FIG. It is a flowchart figure which shows the flow of the interference voltage correction | amendment process used as the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the control apparatus of the alternating current motor used as the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the control apparatus of the alternating current motor used as the 4th Embodiment of this invention.

Explanation of symbols

1: Control device 2: Motor (AC motor)
3, 4: Command value generator 5: Current controller 6: Voltage controller 7: Control switch 8: dq axis → UVW phase converter 9: PWM converter 10: Inverters 11a, 11b: Current sensor 12: Position detection Device 13: Revolution calculator 14: UVW phase → dq axis converter 15: Interference voltage corrector 16: Torque deviation (ΔT) corrector

Claims (10)

A first voltage is calculated by calculating a current command value and an interference voltage command value corresponding to the torque command value, performing non-interference control based on the interference voltage command value, and performing a current vector control calculation based on the current command value. A current control mode for controlling the AC motor by outputting a command value;
A voltage control mode for calculating a second voltage command value corresponding to the torque command value and controlling the AC motor based on the calculated second voltage command value;
Switching means for switching the control mode of the AC motor between the current control mode and the voltage control mode;
When the switching means switches the control mode of the AC motor from the voltage control mode to the current control mode, the switching means comprises correction means for correcting the interference voltage command value based on the actual current value of the AC motor before switching. A control device for an AC electric motor that is characterized. In the control apparatus for an AC motor according to claim 1,
When the interference voltage command value is calculated by referring to a table showing a correspondence relationship between the torque command value and the interference voltage command value, and the magnet torque is dominant with respect to the output torque of the AC motor, the correction means A control apparatus for an AC motor, wherein a q-axis side interference voltage command value is corrected based on a difference between a d-axis current value before switching the control mode and a d-axis current command value after switching. In the control apparatus for an AC motor according to claim 1,
When the interference voltage command value is calculated by referring to a table indicating a correspondence relationship between the torque command value and the interference voltage command value, the correction unit is configured to change the q-axis current value before switching the control mode and the q value after switching. The interference voltage command value on the d-axis side is corrected based on the difference between the shaft current command values, and the interference on the q-axis side based on the difference between the d-axis current value before switching the control mode and the d-axis current command value after switching. A control apparatus for an AC motor, wherein the voltage command value is corrected. In the control apparatus for an AC motor according to claim 1,
The interference voltage command value is calculated using a current response estimated value obtained by applying a filter process corresponding to a current response to the current command value, and the magnet torque is dominant over the output torque of the AC motor. In some cases, the correction unit corrects the interference voltage command value on the q-axis side based on the d-axis current value before switching the control mode. In the control apparatus for an AC motor according to claim 1,
When the interference voltage command value is calculated using a current response estimated value obtained by applying a filter process corresponding to a current response to the current command value, the correction means is configured to change the q axis before switching the control mode. A control apparatus for an AC motor that corrects a d-axis side interference voltage command value based on a current value and corrects a q-axis side interference voltage command value based on a d-axis current value before switching. In the control apparatus for an AC motor according to any one of claims 1 to 5,
Calculates the amount of change in output torque by switching the control mode of the AC motor from the voltage control mode to the current control mode, and the torque command value and current after switching so that the output torque is constant before and after switching of the control mode A control device for an AC electric motor, comprising: a second correction unit that corrects at least one of the command values. The control apparatus for an AC motor according to claim 6,
When the magnet torque is dominant with respect to the output torque of the AC motor, the second correction means outputs the output torque based on the difference between the q-axis current value before switching the control mode and the q-axis current command value after switching. A control device for an AC motor, characterized in that a change amount of the AC motor is calculated. The control apparatus for an AC motor according to claim 6,
The second correction means includes a d-axis current value and a q-axis current value before switching the control mode, a d-axis current command value and a q-axis current command value after switching, a d-axis current value and a q-axis current value. A control device for an AC motor that calculates an amount of change in output torque using d-axis and q-axis inductance values corresponding to. In the control apparatus of the alternating current motor according to any one of claims 1 to 5,
The third correction means corrects the torque command value or the current command value so that the output torque of the AC motor matches the torque target value, and the third correction means is configured such that the switching means is a control mode of the AC motor. When switching the voltage control mode from the voltage control mode to the current control mode, the deviation between the current detection value or current command value before switching and the current command value after switching is calculated, and the current command value is used as the current command value offset amount. A control apparatus for an AC motor, wherein the current command value offset is made asymptotic to 0 in addition to the value. A first voltage is calculated by calculating a current command value and an interference voltage command value corresponding to the torque command value, performing non-interference control based on the interference voltage command value, and performing a current vector control calculation based on the current command value. A current control process for controlling the AC motor by outputting a command value;
A voltage control process for calculating a second voltage command value corresponding to the torque command value and controlling the AC motor based on the calculated second voltage command value;
A switching process for switching the control mode of the AC motor between the current control process and the voltage control process;
A correction process for correcting the interference voltage command value based on an actual current value of the AC motor before switching when the control mode of the AC motor is switched from the voltage control process to the current control process by the switching process. A control method for an AC motor, which is characterized.

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