JP6583827B2 - AC motor control method and control apparatus - Google Patents

Description

  The present invention relates to a control method and a control device for a permanent magnet field synchronous motor and an induction motor which are inverter-driven AC motors.

  In the AC motor, the rotor position angle and the motor current are detected, and torque control, speed control, and position control are performed by a control device. In this control method, the alternating current, which is a motor current, is converted into a direct current by converting the coordinates of the rotor position angle, and controlled by a field current and a torque current command value for the direct current motor (see, for example, Patent Document 1). .

  FIG. 8 is a block diagram showing an example of a control device 51 using a conventional control method for the AC motor 50.

  As shown in the figure, an AC motor 50 to be controlled is connected to a voltage-type PWM inverter 52. A current sensor 53 is provided on a power line connected from the voltage source PWM inverter 52 to the AC motor 50. A position sensor 54 for detecting the rotor position angle θ is provided in the vicinity of the rotor of the AC motor 50, and a differentiator 55 is connected to the position sensor 54. The differentiator 55 converts the rotor position angle θ acquired from the position sensor 54 into an electrical angular velocity ω.

  The control device 51 includes a three-phase → two-phase converter 61, an αβ → dq converter 62, a speed controller 63, a current controller 64, a dq → αβ converter 65, and a two-phase → three-phase converter 66. is doing.

  The three-phase → two-phase converter 61 converts the detected value of the three-phase current detected by the current sensor 53 into a detected value of the two-phase αβ-axis current and outputs the detected value to the αβ → dq converter 62. The αβ → dq converter 62 uses the rotor position angle θ to detect the detected value of the αβ axis current in the fixed coordinate system and the detected value of the dq axis current in the rotating coordinate system (including the torque component and the field component). And output to the current controller 64. The speed controller 63 calculates a torque current component command value in the dq-axis current of the rotating coordinate system using the speed command value and the electrical angular velocity ω, and outputs the command value to the current controller 64. The current controller 64 uses the detected value of the dq axis current and the command value of the dq axis current in the rotating coordinate system (including the torque component and the field component) to operate the dq axis voltage in the rotating coordinate system ( Torque component and field component are included) and output to the dq → αβ converter 65. The dq → αβ converter 65 uses the rotor position angle θ to convert the operation value of the dq axis voltage of the rotating coordinate system into the operation value of the αβ axis voltage of the fixed coordinate system, and a two-phase → three-phase converter. 66. The two-phase → three-phase converter 66 converts the operation value of the two-phase αβ-axis voltage into the operation value of the three-phase voltage and outputs it to the voltage-type PWM inverter 52.

  In the αβ → dq converter 62 in the control device 51, rotation coordinate conversion (from the αβ axis of the fixed coordinate system to the dq axis of the rotation coordinate system) is performed with respect to the motor current by the rotor position angle θ as shown in Expression (1). Coordinate conversion) is performed.

FIG. 9 shows dq-axis currents i _d and i _q by this rotational coordinate conversion.

  The following equation (2) is a motor model of the dq coordinate axes when a permanent magnet synchronous motor is used as the AC motor 50.

However,
v _d , v _q : d-axis voltage, q-axis voltage (d and q-axis components of armature voltage)
i _d , i _q : d-axis current, q-axis current (d, q-axis components of armature current)
L _d : d-axis inductance L _q : q-axis inductance R: armature winding resistance p: differential operator ω: rotor angular velocity φ _f : armature flux linkage of permanent magnet

In the control of an AC motor, a field weakening state is generally used in which the d-axis current, which is a field current, is reduced so as not to exceed the upper limit of the applied voltage that can be output by the inverter main circuit. From equation (2), i _d it can be seen to become weak magnetic field the absolute value becomes the voltage drops small when a negative q-axis voltage v _q. Conventionally, in FIG. 9, it is necessary to design so that i _d and i _q are within the second quadrant so that they are within the voltage limit. Therefore, when the AC motor 50 is controlled at a wide range of speeds, it is necessary to change the field current command value in order to avoid an induced voltage higher than the applied voltage.

Further, the following equation (3) is a motor model when the induction motor is controlled by the phase of the secondary magnetic flux φ _rd as the AC motor 50, and is substantially the same as the equation (2) of the permanent magnet synchronous motor, Control is possible with field current and torque current.

However,
R _s : primary resistance R _r : secondary resistance L _s : primary self-inductance L _r : secondary self-inductance M: mutual inductance p: differential operator σ: leakage coefficient ω: rotor electrical angular velocity ω _m : rotor Mechanical angular velocity φ _rd : d-axis component of secondary magnetic flux

Japanese Patent Laid-Open No. 2015-231276

  FIG. 10 shows an example of torque / output characteristics with respect to the speed of the AC motor. In general, torque is limited at low speeds and output is limited at high speeds. To achieve this characteristic, the field current command must be changed as the torque decreases at speeds above the break point of the torque characteristic. There is a problem.

  Especially in applications that control torque, this problem is a major obstacle with respect to the operability of the torque command current at speeds above the break point. Specifically, there has been a problem that the torque command current changes at a speed equal to or higher than the break point, or the stability of control and the efficiency decrease. As an improvement measure, there is a method of determining a command value with an elliptical locus, but the adjustment is complicated, and the breakpoint is not particularly improved.

In order to solve the above-mentioned problem, a method for controlling an AC motor according to the present invention includes:
Using the detected value of the rotor position angle of the AC motor, by converting the detected value of the current or voltage of the AC motor from the fixed coordinate system to the rotating coordinate system, the detected value of the current or voltage of the rotating coordinate system is changed. Calculate
Using the detected value of the current or voltage of the rotating coordinate system and the command value of the current or voltage of the rotating coordinate system for the AC motor, the operation value of the current or voltage of the rotating coordinate system for the AC motor is calculated,
Using the detected value of the rotor position angle, the operation value of the current or voltage in the rotating coordinate system is transformed from the rotating coordinate system to the fixed coordinate system, thereby calculating the operation value of the current or voltage in the fixed coordinate system. And an AC motor control method for controlling the current or voltage of the AC motor thereby,
The rotor position angle used for the coordinate conversion to the rotating coordinate system and the coordinate conversion to the fixed coordinate system has a correction angle using a proportional value aω (a is a proportional coefficient) of the electric angular velocity ω of the AC motor. In addition to calculating the detection value, the command value, and the operation value in the rotational coordinate system newly defined by the correction, by adding on the axis ,
The proportionality coefficient a is set so that the correction angle is equal to or less than π / 2 [rad] when the electrical angular velocity ω of the AC motor is a maximum value.

  In the control method, as the detection value, the command value, and the operation value, either current or voltage may be used, and it is not necessary to unify either current or voltage. This is because the relationship between current and voltage in an AC motor is known, for example, as shown in the above-mentioned formulas (2) and (3), and can be appropriately converted to each other.

Although the aspect of the correction angle using the proportional value of the rotation speed of the AC motor is not particularly limited, the following aspect is exemplified.
(1) A mode in which the electric angular velocity ω of the AC motor is a proportional value aω .
(2) A mode in which the value is an n-order function value (n is an integer of 1 or more) of the proportional value aω of the electrical angular velocity ω of the AC motor.

According to this method, the rotor position angle is corrected by adding a correction angle using a proportional value aω (a is a proportional coefficient) of the electric angular velocity ω of the AC motor on the imaginary axis. There is an advantage that the motor characteristics are implicitly incorporated in the mathematical model of the control system. Therefore, unlike the conventional case, there is an effect that it is not necessary to change the field component in the command value for each motor in accordance with the break point of the control characteristic of each individual motor. The effect is considered to enable stable control and high-efficiency control including speeds above the breakpoint.

Further, the control device for an AC motor of the present invention is:
Using the detected value of the rotor position angle of the AC motor, by converting the detected value of the current or voltage of the AC motor from the fixed coordinate system to the rotating coordinate system, the detected value of the current or voltage of the rotating coordinate system is changed. Calculate
Using the detected value of the current or voltage of the rotating coordinate system and the command value of the current or voltage of the rotating coordinate system for the AC motor, the operation value of the current or voltage of the rotating coordinate system for the AC motor is calculated,
Using the detected value of the rotor position angle, the operation value of the current or voltage in the rotating coordinate system is transformed from the rotating coordinate system to the fixed coordinate system, thereby calculating the operation value of the current or voltage in the fixed coordinate system. And an AC motor control device for controlling the current or voltage of the AC motor, thereby
The rotor position angle used for the coordinate conversion to the rotating coordinate system and the coordinate conversion to the fixed coordinate system has a correction angle using a proportional value aω (a is a proportional coefficient) of the electric angular velocity ω of the AC motor. In addition to calculating the detection value, the command value, and the operation value in the rotational coordinate system newly defined by the correction, by adding on the axis ,
The proportionality coefficient a is set so that the correction angle is equal to or less than π / 2 [rad] when the electrical angular velocity ω of the AC motor is a maximum value.

  In the control device, either the current or the voltage may be used as the detection value, the command value, and the operation value, and it is not necessary to unify either the current or the voltage. The reason is the same as that in the method for controlling the AC motor.

  Although the aspect of the correction angle using the proportional value of the rotation speed of the AC motor is not particularly limited, it is the same as that in the AC motor control method.

  Also by this control device, the same effect as the control method can be obtained.

  According to the control method and control apparatus for an AC motor according to the present invention, there is an excellent effect that stable control and high-efficiency control including a speed equal to or higher than the break point of the control characteristic of the motor can be achieved.

It is a block diagram which shows an example of the control apparatus of the AC motor which concerns on one Embodiment which actualized this invention. It is a figure which shows the mode of a change of the cosh and sinh function of Formula (6), (7). It is a figure which shows the rotation coordinate transformation of this invention. It is a graph showing an example of the locus | trajectory of the armature current accompanying the increase in electrical angular velocity (omega). It is a graph showing an example of the locus | trajectory of the armature voltage accompanying the increase in electrical angular velocity (omega). It is a figure which shows the simulation result of the speed response at the time of torque fluctuation. It is a figure which shows the experimental result of an electrical frequency-torque characteristic. It is a block diagram which shows the control apparatus of the conventional AC motor. It is a figure which shows the conventional rotation coordinate transformation. It is a figure which shows the torque and output characteristics with respect to the speed of an AC motor.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an AC motor control method and a control device embodying the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an example of a control device 1 using the method for controlling an AC motor of the present invention.

  As shown in the figure, an AC motor 50 to be controlled is the same as the conventional example, and is connected to a voltage-type PWM inverter 52. A current sensor 53 is provided on a power line connected from the voltage source PWM inverter 52 to the AC motor 50. A position sensor 54 for detecting the rotor position angle θ is provided in the vicinity of the rotor of the AC motor 50, and a differentiator 55 is connected to the position sensor 54. The differentiator 55 converts the rotor position angle θ acquired from the position sensor 54 into an electrical angular velocity ω.

  The control device 1 includes a three-phase-to-two-phase converter 61, an arithmetic unit 11, an αβ → d′ q ′ converter 12, a speed controller 63, a current controller 14, a d′ q ′ → αβ converter 15, and A two-phase to three-phase converter 66 is included. Note that among the constituent elements of the control device 1, those given the same reference numerals as those of the control device 51 of the conventional example indicate that the constituent elements are the same.

  The three-phase → two-phase converter 61 converts the detected value of the three-phase current detected by the current sensor 53 into the detected value of the two-phase αβ-axis current and outputs the detected value to the αβ → d′ q ′ converter 12. The computing unit 11 calculates cosh aω and sinh aω using the electrical angular velocity ω. The αβ → d′ q ′ converter 12 uses the rotor position angle θ, cosh aω and sinh aω to detect the detected value of the αβ axis current in the fixed coordinate system and the d′ q ′ axis current in the rotating coordinate system. It is converted into a value (including a torque component and a field component) (details will be described later) and output to the current controller 14. The speed controller 63 calculates the command value of the torque current component in the d′ q′-axis current of the rotating coordinate system using the speed command value and the electrical angular velocity ω, and outputs the command value to the current controller 14. The current controller 14 uses the detected value of the dq-axis current and the command value (torque component) of the dq-axis current in the rotating coordinate system to calculate the operation value (torque component and field component) of the dq-axis voltage in the rotating coordinate system. And d′ q ′ → αβ converter 15. The d′ q ′ → αβ converter 15 uses the rotor position angle θ, cosh aω and sinh aω to convert the d′ q ′ axis voltage operation value of the rotating coordinate system into the αβ axis voltage operation of the fixed coordinate system. It is converted into a value and output to the 2-phase → 3-phase converter 66. The two-phase → three-phase converter 66 converts the operation value of the two-phase αβ-axis voltage into the operation value of the three-phase voltage and outputs it to the voltage-type PWM inverter 52.

  In the case of torque control, the speed controller 63 is not blocked, and the dq axis current command value (torque component) plays the same role as the torque command value.

  The αβ → d′ q ′ converter 12 performs rotation coordinate conversion (coordinate conversion from the αβ axis of the fixed coordinate system to the d′ q ′ axis of the rotation coordinate system) as shown in Expression (4).

  Further, the d′ q ′ → αβ converter 15 performs the rotation coordinate reverse conversion (coordinate conversion from the d′ q ′ axis of the rotation coordinate system to the αβ axis of the fixed coordinate system) as shown in Expression (5). .

  In the equations (4) and (5), cos (θ + jaω) and sin (θ + jaω) can be expressed as the following equations (6) and (7), respectively. The αβ → d′ q ′ converter 12 and the d′ q ′ → αβ converter 15 perform coordinate conversion using these equations (6) and (7).

  FIG. 2 shows how the cosh and sinh functions of Equations (6) and (7) change.

  Cosh represents that the current amplitude changes according to the electrical angular velocity ω at aω on the horizontal axis, and sinh represents that the phase changes.

  As in the equations (4) and (5), the rotor position angle θ is corrected by adding a correction angle consisting of a proportional value of the electric angular velocity ω of the AC motor 50 on the imaginary axis. A feature of the present invention is a method of coordinate conversion using the rotor position angle (θ + jaω). In this way, by adding the electrical angular velocity ω of the AC motor 50 on the imaginary axis, the current amplitude and the second term that is the imaginary part by the first term cosh aω that is the real part of the equations (6) and (7). The phase changes by sinh aω.

Conventionally, in FIG. 9, i _d and i _q are designed to be within the ellipse of the second quadrant so that they are within the voltage limit. However, in the control method of the present invention, the coefficient a applied to the electrical angular velocity ω is designed. Will do. Since aω is a delayed phase with respect to the conventional q axis, the maximum value of the electrical angular velocity ω is designed to be a value of π / 2 [rad] or less. The design index of the correction angle is not particularly limited, but is π / 6 [rad] when the electrical angular velocity ω is 1/3 of the maximum value, and 2π / 6 [rad when the electrical angular velocity ω is 2/3 of the maximum value. ], Π / 2 [rad] at the maximum value is exemplified. This design index is within the limit of π / 2 [rad] or less at the maximum value of the electrical angular velocity ω of the AC motor 50. If the torque is emphasized, the design index is shifted in the plus direction. It is good to shift to.

FIG. 3 shows the relationship between the d′ q ′ axis obtained by this rotational coordinate conversion and the conventional dq axis. By simply setting the torque current i _{q ′} on the d′ q ′ axis, the electric current depends on the electrical angular velocity ω. in the dq axis Te, so that the torque current id and the field current i _q is set.

FIG. 4 shows an example of the locus of the armature current associated with the increase in the electrical angular velocity ω in the control method and control apparatus of the present invention, and the field weakening current increases as the electrical angular velocity ω increases. . As described above, equation (2) is a motor model of the dq coordinate axis when a permanent magnet synchronous motor is used as the AC motor 50, and the voltage locus is drawn by substituting the current of FIG. 4 into equation (2). Then, as shown in FIG. In the example of FIG. 5, it can be confirmed that the amplitude of the voltage vector is within the voltage limit circle (95 V in this example) even if the electrical angular velocity ω increases. From the above, the d-axis current, which is the field current, becomes the d′-axis current that is the rotation coordinate transformation proportional to the electrical angular velocity ω, so that the sin (aω) times the current amplitude is weakened as shown in FIG. Realized as a field. That, i _d it can be seen to become weak magnetic field the absolute value becomes the voltage drops small when a negative q-axis voltage v _q.

As described above, the expression (3) is a motor model when the induction motor is controlled as the AC motor 50 by the phase of the secondary magnetic flux φ _rd , and is almost the same as the expression (2) of the permanent magnet synchronous machine. In the above equation, control is possible with field current and torque current. Therefore, as in the case of using a permanent magnet synchronous motor, a field weakening can be realized by the present invention.

  In the new d′ q ′ axis proposed by the present invention, the field current value is automatically set according to the speed information without setting the field current value as the d-axis current value. Since the fluctuation of the field current value becomes smaller compared to the change of the electrical angular velocity ω, the response is considered to be stable.

As described above with reference to the example of the torque / output characteristics with respect to the speed of the AC motor shown in FIG. 10, in general, the low speed is the maximum torque region, and the high speed is controlled to the maximum output to prevent the voltage limit from being exceeded. Yes. The field-weakening field for the electrical angular velocity ω can be designed by equation (2), but in reality, it is a set value with a certain margin from the accuracy of the position sensor 54 and the motor model error. In particular, L _d and L _q are affected by magnetic saturation at a large current and greatly influenced by a parameter error in a high speed region. Further, the inverter 52 is current control on the dq axis, and PI control is performed on the current command, and the result is a voltage command. Therefore, if the voltage command exceeds the maximum value, it cannot be controlled to the command current. From the above, the d′ q′-axis current control of the present invention also has robustness against a certain amount of parameter fluctuation in the integral control, and can be controlled to the command dq current.

  Next, FIG. 6 shows simulation results of speed response at the time of torque fluctuation when the field current value as the conventional d-axis current value is set and when the control method of the present invention is applied. In this simulation, the maximum speed of the AC motor is set to 700 [Hz] (the maximum value of the electrical angular speed ω is 1400π [rad / s]), and a is set to 0.0003. Regarding the speed fluctuation and current value at the time of torque fluctuation at time 60, it can be confirmed that the control method of the present invention has a smaller difference in current value before the torque fluctuation and after the response to the torque fluctuation converges. .

  In the setting of the field current value as the d-axis current, the control method of the present invention is automatically determined to the value of −sinh aω in speed, and the fact that the set value does not vary greatly contributes to responsiveness and stability. It is thought that there is.

  Next, FIG. 7 shows the electrical frequency-torque characteristics when the conventional control device 51 and the control device 1 of the present invention are applied to a system in which an AC motor 50 and a generator are coupled via a torque meter. Experimental results are shown. In this experiment, the maximum frequency of the AC motor is set to 500 [Hz] (the maximum value of the electrical angular velocity ω is 1000π [rad / s]), and a is set to 0.00047. This system implements a torque control system for an electric vehicle or the like on a bench by controlling the torque of the AC motor 50 and controlling the speed of the generator.

  A conventional control device 51 is shown in FIG. In the conventional control method, dq conversion based on Expression (1) is performed.

  The control device 1 of the present invention is shown in FIG. In the control method of the present invention, it is included in the dq conversion including the setting of the field current as the d-axis current, that is, the expression (4).

  As shown in FIG. 7, in the AC motor 50 having the same rated output, the low frequency is the maximum torque control region, and the high frequency is the maximum output control region. In the case of the conventional control in which the torque current as the q-axis current is constant and the field current as the d-axis current is variably set in the high frequency region, the speed / torque fluctuation becomes large at the high frequency of 180 Hz and becomes the upper limit. Yes. In the control method of the present invention, stable control up to 320 Hz can be confirmed on the high frequency side, and torque control in a wide speed range can be realized. According to the experimental results of the present invention, it can be confirmed that the constant torque and constant output characteristics required for the AC motor 50 can be realized.

  As described above, the control method of the AC motor 50 of this example uses the detected value of the rotor position angle θ of the AC motor 50 to coordinate the detected current value of the AC motor 50 from the fixed coordinate system to the rotating coordinate system. By converting, the detected value of the current in the rotating coordinate system is calculated, and using the detected value of the current in the rotating coordinate system and the command value of the current in the rotating coordinate system for the AC motor 50, the AC motor 50 By calculating the operation value of the voltage of the rotating coordinate system with respect to and using the detected value of the rotor position angle θ, the coordinate value of the operation value of the voltage of the rotating coordinate system is converted from the rotating coordinate system to the fixed coordinate system, The operation value of the voltage of the fixed coordinate system is calculated, and thereby the AC motor 50 is controlled, and the rotor position angle θ used for the coordinate conversion to the rotating coordinate system and the coordinate conversion to the fixed coordinate system is used. Is the electrical angular velocity ω of the AC motor 50 The correction angle using the proportional value is corrected by being added on the imaginary axis, and the correction angle is equal to or less than π / 2 [rad] when the electrical angular velocity ω of the AC motor 50 is the maximum value. Is set to According to this method, the rotor position angle θ is corrected by adding a correction angle using a value proportional to the electrical angular frequency ω of the AC motor 50 on the imaginary axis. Have the advantage of being incorporated in the mathematical model of the control system. Therefore, unlike the conventional case, there is an effect that it is not necessary to change the field component in the command value for each motor in accordance with the break point of the control characteristic of each individual motor. The effect is considered to enable stable control and high-efficiency control including speeds above the breakpoint.

  Also by the control device 1 of this example using this control method, the same effect as the control method can be obtained.

In addition, this invention is not limited to the said embodiment, For example, it can also be suitably changed and embodied as follows, for example in the range which does not deviate from the meaning of invention.
(1) The correction angle mode using the proportional value of the rotation speed of the AC motor 50 is changed to a mode in which the proportional value of the rotation speed of the AC motor 50 is an n-order function value (n is an integer of 1 or more), for example. thing. For example, the correction value may be a linear function value a′ω + b ′ (a ′ and b ′ are constants).
(2) In the control method, appropriately changing which of current or voltage is used for each of the detected value, the command value, and the operation value.
(3) Instead of the arithmetic unit 11 that calculates cosh aω and sinh aω from ω, an arithmetic unit that calculates aω from ω is used, and an αβ → d′ q ′ converter 12 and d using the output of the arithmetic unit The configuration is such that coordinate conversion is performed by the 'q' → αβ converter 15.
(4) The arithmetic unit 11 for calculating cosh aω, sinh aω from ω is omitted, and the αβ → d′ q ′ converter 12 and the d′ q ′ → αβ converter 15 perform coordinate conversion using ω. Make up.

DESCRIPTION OF SYMBOLS 1 Control apparatus 11 Calculator 12 (alpha) (beta)->d'q'converter 14 Current controller 15 d'q'-(alpha) beta converter 50 AC motor 51 Control apparatus 52 Inverter 53 Current sensor 54 Position sensor 55 Differentiator 61 3 phase-> 2 Phase converter 62 αβ → dq converter 63 Speed controller 64 Current controller 65 dq → αβ conversion 66 2 phase → 3 phase converter

Claims (6)

Using the detected value of the rotor position angle of the AC motor, by converting the detected value of the current or voltage of the AC motor from the fixed coordinate system to the rotating coordinate system, the detected value of the current or voltage of the rotating coordinate system is changed. Calculate
Using the detected value of the current or voltage of the rotating coordinate system and the command value of the current or voltage of the rotating coordinate system for the AC motor, the operation value of the current or voltage of the rotating coordinate system for the AC motor is calculated,
Using the detected value of the rotor position angle, the operation value of the current or voltage in the rotating coordinate system is transformed from the rotating coordinate system to the fixed coordinate system, thereby calculating the operation value of the current or voltage in the fixed coordinate system. And an AC motor control method for controlling the current or voltage of the AC motor thereby,
The rotor position angle used for the coordinate conversion to the rotating coordinate system and the coordinate conversion to the fixed coordinate system has a correction angle using a proportional value aω (a is a proportional coefficient) of the electric angular velocity ω of the AC motor. In addition to calculating the detection value, the command value, and the operation value in the rotational coordinate system newly defined by the correction, by adding on the axis ,
The AC motor control method in which the proportionality coefficient a is set so that the correction angle is equal to or less than π / 2 [rad] when the electrical angular velocity ω of the AC motor is a maximum value. The method of controlling an AC motor according to claim 1, wherein the correction angle is a proportional value aω of an electrical angular velocity ω of the AC motor. 2. The method of controlling an AC motor according to claim 1, wherein the correction angle is an n-order function value (n is an integer of 1 or more) of a proportional value aω of an electrical angular velocity ω of the AC motor. Using the detected value of the rotor position angle of the AC motor, by converting the detected value of the current or voltage of the AC motor from the fixed coordinate system to the rotating coordinate system, the detected value of the current or voltage of the rotating coordinate system is changed. Calculate
Using the detected value of the current or voltage of the rotating coordinate system and the command value of the current or voltage of the rotating coordinate system for the AC motor, the operation value of the current or voltage of the rotating coordinate system for the AC motor is calculated,
Using the detected value of the rotor position angle, the operation value of the current or voltage in the rotating coordinate system is transformed from the rotating coordinate system to the fixed coordinate system, thereby calculating the operation value of the current or voltage in the fixed coordinate system. And an AC motor control device for controlling the current or voltage of the AC motor, thereby
The rotor position angle used for the coordinate conversion to the rotating coordinate system and the coordinate conversion to the fixed coordinate system has a correction angle using a proportional value aω (a is a proportional coefficient) of the electric angular velocity ω of the AC motor. In addition to calculating the detection value, the command value, and the operation value in the rotational coordinate system newly defined by the correction, by adding on the axis ,
The AC motor control device in which the proportionality coefficient a is set so that the correction angle is π / 2 [rad] or less when the electrical angular velocity ω of the AC motor is a maximum value. The AC motor control device according to claim 4, wherein the correction angle is a proportional value aω of an electrical angular velocity ω of the AC motor. 5. The control apparatus for an AC motor according to claim 4, wherein the correction angle is an n-order function value (n is an integer of 1 or more) of a proportional value aω of an electrical angular velocity ω of the AC motor.