JP2001346391A - AC servo motor control device and AC servo motor control method - Google Patents

Abstract

(57) Abstract: An AC servomotor control device and an AC servomotor control method that achieve high-speed response and high positional accuracy of an AC servomotor, and that prevent hunting and improve response characteristics before stopping. To get An AC servomotor driving device includes a switch switching signal generating section that outputs a switch switching signal when a current phase angle switching means has a position deviation becoming zero for the first time after the operation starts, and a current phase angle switching means outputs a force. 9 for the current phase angle of rate = 1
It is configured to switch to output a current phase angle with a power factor of 0 plus 0, and drive-control the AC servomotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC servo motor control device and an AC servo motor control method for controlling the driving of an AC servo motor by an AC power supply formed based on a command value.

[0002]

2. Description of the Related Art In an AC servomotor control device for performing feedback control of an AC servomotor, it is important that positioning control for the AC servomotor be performed with high response speed and high accuracy. In order to obtain such an AC servomotor control device, it was necessary to enhance the frequency characteristics in feedback control. In the conventional AC servomotor control device, the feedback gain is increased to improve the frequency characteristics of the feedback control. Hereinafter, a specific conventional AC servomotor control device will be described with reference to FIG. FIG. 5 is a block diagram showing an example of the configuration of a conventional AC servomotor control device.

[0003] As shown in FIG.
An encoder 102 is attached to an output unit directly connected to one mover. The encoder 102 outputs a pulse signal and an origin signal corresponding to the displacement of the mover of the AC servomotor 101 to the position / speed detector 103. The position / speed detector 103 calculates a current phase angle θe from the origin position, the current position θm, the speed ω, and the power factor = 1, based on the pulse signal output from the encoder 102 and the origin signal. The current position θm is output to an input terminal of the position controller 104, and the speed ω is output to an input terminal of the speed controller 105. The position controller 104 compares the position command θmd given from the outside of the apparatus with the current position θm calculated by the position / speed detector 103. Position controller 10
4 outputs a signal obtained by multiplying the position deviation amount Δθ of the position deviation by a predetermined position gain to the speed controller 105 when there is a position deviation between the position command θmd and the current position θm as the motor speed command ωd. .

In the speed controller 105, the position controller 1
The motor speed command ωd input from the controller 04 and the speed ω calculated by the position / speed detector 103 are compared. When there is a deviation between the motor speed command ωd and the speed ω, the speed controller 105 converts a signal obtained by multiplying the deviation amount by a predetermined speed gain into a DC current command (torque command) iq as a three-phase AC coordinate converter. Output to 106. Three-phase AC coordinate converter 1
06, a DC current command (torque command) iq;
Current phase angle θe output from trigonometric function value generator 107
U-phase current command iud and V-phase current command ivd are calculated by the following equations (1) and (2).

Uid = −√ (2/3) × iq × sin θe (1) ivd = −√ (2/3) × iq × sin (θe−2 / 3π) (2)

The three-phase AC coordinate converter 106 outputs a U-phase current command uid to the U-phase current controller 108a and outputs a V-phase current command ivd to the V-phase current controller 108b. U-phase current controller 108a detects U-phase motor current iu
If there is a deviation between the current and the U-phase current command iud, a signal obtained by multiplying the deviation by a predetermined current gain is output to the PWM inverter 109 as the U-phase motor voltage command Vu. On the other hand, when there is a difference between the detected V-phase motor current iv and the V-phase current command ivd, the V-phase current controller 108b outputs a signal obtained by multiplying the difference by a predetermined current gain. It is output to the PWM inverter 109 as Vv.

[0007] The W-phase motor voltage command Vw is Vw =-
It is calculated from the formula of Vu-Vv. In the PWM inverter 109, voltages according to the U-phase motor voltage command Vu, V-phase motor voltage command Vv, and W-phase motor voltage command Vw formed as described above are applied to each phase of the bridge circuit constituting the PWM inverter 109. Is done. When a voltage is applied to each phase of the bridge circuit, a current flows through the stator winding of the AC servomotor 101, and the mover of the AC servomotor 101 moves by a predetermined amount. AC servo motor 1
01 is a position command θmd given from outside the device.
And the speed ω becomes zero, the outputs of the position controller 104 and the speed controller 105 become zero. At this time, the DC current command (torque command) iq becomes zero, and AC
The servo motor 101 stops, and the positioning operation is completed.

[0008]

In the conventional method of controlling an AC servomotor, the frequency characteristics of feedback control have been enhanced in order to perform positioning at high speed and with high accuracy. For this reason, it is necessary to increase the feedback gain. However, even if the feedback loop is configured by an analog circuit or a digital circuit, there is a feedback delay time. As a result, according to the conventional control method of the AC servomotor, there is an oscillation frequency due to a dead time element, and if the feedback gain is increased too much, a phenomenon called hunting (periodic fluctuation) occurs. As described above, when the positioning control for stopping the AC servomotor at the predetermined position is performed by the feedback control method, the response characteristic depends on the feedback characteristic, and therefore, there is a limit in improving the response characteristic, and the hunting due to the increase in the feedback gain. And other problems.

As a control device for solving such a problem, for example, there is an AC servomotor control device disclosed in Japanese Patent Application Laid-Open No. 7-123767. This AC servo motor control device is configured to be able to control the electrical phase angle between the magnetic pole position of the stator and the magnetic pole position of the mover, which is generated by operating the mover by energizing the stator winding. ing.
In this conventional AC servomotor control device, when performing position control, the electric phase angle is set to zero when the position deviation is at or near zero, and at other times, the electric phase angle is set to 90 degrees. It is a control method.

However, according to this control method, even if the position deviation once becomes zero or a value near zero, if the position deviation becomes large due to overshoot and deviates from the vicinity of zero, the electric phase angle is reduced. The control is switched again to the feedback control set to 90 degrees. Therefore, in this control method,
During the feedback control after the switching of the electrical phase angle of 90 degrees, the response characteristic depends on the feedback characteristic, so that the response characteristic is deteriorated. Further, after the AC servomotor is stopped, it is necessary to supply a continuous current to the stator winding in order to hold the AC servomotor at the stop position, and there has been a problem that the AC servomotor generates heat due to the continuous current.

The present invention solves the above-mentioned problems in the conventional AC servomotor control device, and can achieve high-speed response and high positional accuracy, prevent occurrence of hunting, and reduce the time when the AC servomotor is stopped. Servo motor control device and A capable of suppressing heat generation in A
It is an object to obtain a C servomotor control method.

[0012]

In order to achieve the above object, an AC servomotor control device according to the present invention detects a displacement amount, a speed and a current phase angle of a motor, and outputs a position signal, a speed signal and a first signal. A position / speed detector that forms a current phase angle signal, and a position controller that receives a position deviation between the position signal of the position / speed detector and the position command signal of the motor, and outputs a motor speed command signal. A speed controller that receives a speed deviation between a speed signal of the position / speed detector and a motor speed command signal of the position controller, and outputs a DC current command signal; and a first speed controller of the position / speed detector. Switching between a current phase angle signal and a second current phase angle signal having a power factor = 0 obtained by adding 90 degrees to the first current phase angle signal;
A current phase angle switching means for outputting a second current phase angle signal when the position deviation becomes zero for the first time after the start of operation of the motor; and a first phase signal output from the current phase angle switching means.
A triangular function value generator for converting a current phase angle signal or a second current phase angle signal into a trigonometric function value signal; and a DC current command signal output from the speed controller, the trigonometric function value generator -Phase AC coordinate converter to which the trigonometric function value signal output from the controller is input, and current control for controlling the armature current of each phase by the current command value signal of each phase output from the three-phase AC coordinate converter And a PWM inverter that modulates the pulse width to drive the motor. According to the AC servo motor control device of the present invention configured as described above, the current phase angle is held at the current phase angle of the power factor = 0 when the position deviation becomes zero for the first time. The response characteristic at the time of stopping does not depend on the feedback characteristic, and the motor can be stopped at a desired position by the electric attraction force of the mover and the stator of the motor.

In the AC servo motor control method according to the present invention, the position / speed detector detects the displacement, speed and current phase angle of the motor, and forms a position signal, a speed signal and a first current phase angle signal. A step of inputting a position deviation between the position signal of the position / speed detector and the position command signal of the motor to a position controller, and outputting a motor speed command signal to a speed controller; A speed deviation between the speed signal of the motor and the motor speed command signal of the position controller, and outputting a DC current command signal to a three-phase AC coordinate converter; 9 in the first current phase signal of the detector and the first current phase angle signal.
A second current phase angle signal having a power factor of 0 plus 0 is switched and output, and the second current phase angle signal is output when the position deviation becomes zero for the first time after the operation of the motor starts. Converting a first current phase angle signal or a second current phase angle signal output from the current phase angle switching means into a trigonometric function value signal by a trigonometric function value generator; A DC current command signal output from the speed controller and a trigonometric function value signal output from the trigonometric function value generator, and controlling the armature current of each phase; Driving the motor by modulating the width. According to the AC servomotor control method of the present invention having the above-described steps, the current phase angle is maintained at the current phase angle of power factor = 0 when the position deviation becomes zero for the first time. The motor stops at a desired position by the attraction force of the mover and the stator of the motor. As a result, according to the present invention, an AC servomotor control method having high-speed response and high position accuracy can be obtained.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an AC servomotor control device and an AC servomotor control method according to the present invention will be described below with reference to the accompanying drawings. << Example 1 >>

FIG. 1 is a block diagram showing an AC servomotor control device according to a first embodiment of the present invention. In FIG. 1, an encoder 2 is attached to an output unit directly connected to a mover of an AC servomotor 1.
The encoder 2 outputs a pulse signal and an origin signal corresponding to the displacement of the mover of the AC servomotor 1 to the position / speed detector 3. The position / speed detector 3 calculates the current position θm from the origin position, the velocity ω, and the current phase angle θe at which the power factor = 1, based on the pulse signal output from the encoder 2 and the origin signal. The position / speed detector 3 outputs the calculated current position θm to the speed reducer connected to the input terminal of the position controller 4, and outputs the calculated speed ω to the speed reducer connected to the input terminal of the speed controller 5. Output to

In the speed reducer connected to the input terminal of the position controller 4, a position command θmd given from outside the device and the current position θm calculated by the position / speed detector 3 are subtracted. When there is a position deviation between the position command θmd and the current position θm, the position controller 4 sets a signal obtained by multiplying the position deviation amount Δθ of the position deviation by a predetermined position gain as the motor speed command ωd. Output to In the speed reducer connected to the input terminal of the speed controller 5, the motor speed command ωd input from the position controller 4 and the speed ω calculated by the position / speed detector 3 are subtracted.
When there is a deviation between the motor speed command ωd and the speed ω, the speed controller 5 converts a signal obtained by multiplying the difference by a predetermined speed gain into a DC current command (torque command) iq as a three-phase AC coordinate converter. Output to 6.

As shown in FIG. 1, in the AC servomotor control device of the first embodiment, a current phase angle switching means 10 is provided. The current phase angle switching means 10 includes a changeover switch 11, a switch switching signal generator 12, and a current phase angle storage 13. The switch switching signal generating unit 12 is configured to output a switch switching signal S to the switch 11 and the current phase angle storage unit 13 when the positional deviation amount Δθ becomes zero for the first time after the AC servomotor 1 starts operating. I have. The current phase angle storage unit 13 outputs the power factor = 1 output from the position / speed detector 3 based on the switch switching signal S output from the switch switching signal generation unit 12.
Is stored.

The changeover switch 11 performs a changeover operation in accordance with a switch changeover signal S output from the switch changeover signal generating section 12. The switching operation of the changeover switch 11 causes the current phase angle θe output from the position / speed detector 3 at the power factor = 1 or the current phase angle θe0 stored in the current phase angle storage unit 13 to be 90 degrees (π / 2). Radians)
Any of the 0 current phase angles θe1 is output to the trigonometric function value generator 7 as the current phase angle θep. The switch switching signal generator 12 outputs a switch switching signal S when the position deviation amount Δθ becomes zero for the first time after the AC servomotor 1 starts operating. Therefore, the trigonometric function value generator 7
For the first time after the servomotor 1 starts operating, the position deviation amount Δθ
Until is zero, the current phase angle θe of the power factor = 1 output from the position / speed detector 3 is input. After the positional deviation Δθ becomes zero, the current phase angle θep input to the trigonometric function value generator 7 is 90 degrees (π / 2) equal to the current phase angle θe stored in the current phase angle storage unit 13. (Radian) is added, and the current phase angle θe1 of the power factor = 0 is obtained.

Next, the switching timing of the current phase angle θep input to the trigonometric function value generator 7 will be described with reference to FIG. FIG. 2 is a timing chart showing the switching timing of the current phase angle θep input to the trigonometric function value generator 7. Since a value having various levels is set as the position command θmd, a band-shaped area indicated by oblique lines in FIG. 2 indicates a range of a certain level in which the position command θmd is set, and is indicated by surrounding the band-shaped area. The position of the intersection in the solid line indicates the time when the position command θmd switches. Changeover switch 11 in current phase angle switching means 10
Is, for example, the position command θmd (t
Position command θmd (t) from time -1) to time (t)
At the timing Ts1 at which the switch is made, the contact 1 is switched to the contact 2. Next, at the timing To1 at which the position deviation amount Δθ becomes zero, the changeover switch 11 switches from the contact 2 to the contact 1. The current phase angle θep output from the current phase angle switching means 10 is converted into a trigonometric function value in the trigonometric function value generator 7 and output to the three-phase AC coordinate converter 6.

In the three-phase AC coordinate converter 6, the DC current command (torque command) iq output from the speed controller 5 is output.
And the current phase angle θ output from the trigonometric function generator 7
U-phase current command iud and V-phase current command ivd are calculated by the following equations (3) and (4) using the trigonometric function value of ep.

Uid = −√ (2/3) × iq × sin θep (3) ivd = −√ (2/3) × iq × sin (θep−2 / 3π) (4)

The three-phase AC coordinate converter 6 outputs a U-phase current command i
ud to the U-phase current controller 8a, and outputs the V-phase current command iv
d is output to the V-phase current controller 8b. U-phase current controller 8
a, the detected U-phase motor current iu and the U-phase current command i
If there is a deviation between the current value and the Ud, a signal obtained by multiplying the deviation amount by a predetermined current gain is used as a U-phase motor voltage command Vu as PW
Output to M inverter 9.

On the other hand, if there is a deviation between the detected V-phase motor current iv and the V-phase current command ivd, the V-phase current controller 8b displays a symbol obtained by multiplying the deviation by a predetermined current gain. It outputs to the PWM inverter 9 as the motor voltage command Vv. The W-phase motor voltage command Vw is Vw = −V
It is calculated from the equation of u-Vv. PWM inverter 9
In the above, the U-phase motor voltage command Vu, the V-phase motor voltage command Vv, and the W-phase motor voltage command V
A voltage corresponding to w is applied to each phase of the bridge circuit forming the PWM inverter 9. When a voltage is applied to each phase of the bridge circuit in this manner, a current flows through the stator winding of the AC servomotor 1 and the mover of the AC servomotor 1 moves by a predetermined amount. The mover of the AC servomotor 1 reaches the position indicated by the position command θmd given from outside the device, and the speed ω becomes zero. At this time, the position controller 4 and the speed controller 5
Becomes zero, that is, the DC current command (torque command) iq becomes zero. Thereby, the AC servomotor 1
Stops, and the positioning operation is completed.

As described above, the AC servo motor control device of the first embodiment switches the current phase angle θep output from the current phase angle switching means 10 so that the AC servo motor 1 is fixed when the AC servo motor 1 is operating and when it is stopped. The current phase angle of the current flowing through the slave winding is switched, and the response characteristics at the time of stop do not depend on the feedback characteristics, and the mover of the AC servomotor 1 is electrically attracted by the mover and the stator of the AC servomotor 1. Stops at the desired position.

Embodiment 2 Hereinafter, Embodiment 2 which is one embodiment of the AC servomotor control device of the present invention will be described with reference to the accompanying drawings. FIG. 3 shows the AC of the second embodiment.
It is a block diagram showing a servo motor control device. In FIG. 2, components having the same functions and configurations as those of the AC servomotor control device of the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 3, an encoder 2 is attached to an output section of the AC servomotor 1 which is directly connected to the mover. The encoder 2 outputs a pulse signal and an origin signal corresponding to the changed position of the mover of the AC servomotor 1 to the position / speed detector 3. The position / speed detector 3 calculates the current position θm, speed ω, and power factor from the origin position based on the pulse signal output from the encoder 2 and the origin signal.
The current phase angle θe that becomes 1 is calculated. The calculated current position θm is input to a speed reducer connected to the input terminal of the position controller 4, and the calculated speed ω is input to a speed reducer connected to the input terminal of the speed controller 5. ing.

In the position controller 4, when there is a position deviation between the position command θmd given from outside the apparatus and the current position θm of the position / speed detector 3, the position deviation Δ
The signal obtained by multiplying θ by a predetermined position gain is used as the motor speed command ωd
Output as Further, in the speed controller 5, when there is a deviation between the motor speed command ωd and the speed ω, a signal obtained by multiplying the difference by a predetermined speed gain is used as a DC current command (torque command) iq. (Torque command) switching means 14. As shown in FIG.
In the servo motor control device, a current phase angle switching means 10 having the same configuration as that of the first embodiment is provided.
As shown in the figure, the current phase angle switching means 10 of the second embodiment
Includes a changeover switch 11, a switch changeover signal generation unit 12, and a current phase angle storage unit 13.

The switch switching signal generator 12 generates a switch switching signal S when the position deviation Δθ becomes zero for the first time after the operation of the AC servomotor 1 starts. The current phase angle storage unit 13 stores the current phase angle θe at the power factor = 1 when the switch switching signal S from the switch switching signal generation unit 12 is input. The changeover switch 11 receives the current phase angle θe detected by the position / speed detector 3 and the current phase stored in the current phase angle storage 13 when the switch switching signal S of the switch switching signal generator 12 is input. Power factor = 0 obtained by adding 90 degrees (π / 2 radians) to angle θe0
Between the current phase angle θe1 and the current phase angle θe1. The current phase angle θe or the current phase angle θe1 from the changeover switch 11 is output to the trigonometric function value generator 7.

As shown in FIG. 3, the AC servomotor control device of the second embodiment is provided with a DC current command (torque command) switching means 14. DC current command switching means 14
Means that the position deviation Δθ becomes zero for the first time after the operation of the AC servomotor 1 is started, that is, the current phase angle switching means 1
When the switch switching signal S is input from the switch switching signal generator 12 of 0, the switch 15 in the DC current command switching means 14 switches between the contact 1 and the contact 2. The motor-converted torque value (DC current value) iq0 of the mechanism driven by the AC servomotor 1 in a steady load state is input to the contact 1 of the changeover switch 15. A motor speed command i of the speed controller 5 is provided at the contact 2 of the changeover switch 15.
q has been entered.

Next, a specific example of the motor-converted torque value (DC current value) iq0 input to the contact 1 of the changeover switch 15 will be described. For example, when a ball screw (radius RB, reduction ratio r) is directly connected to an AC servomotor 1 (rotary motor having a rated current I0 and a rated torque T0), and a load of mass M is attached to the ball screw to operate vertically. Consider the mechanism. In this case, when the gravitational acceleration is g, the motor-converted torque value (DC current value) iq0 of the mechanism connected to the AC servomotor 1 is calculated by the following equation (5).

Iq0 = {− (Mg × RB) / (T0 × r)} × I0 (5)

Therefore, the current phase angle θep input to the trigonometric function value generator 7 until the position deviation amount Δθ becomes zero for the first time after the operation of the AC servomotor 1 is started is equal to the current phase angle from the position / speed detector 3. The angle θe. Also, a DC current command (torque command) input to the three-phase AC coordinate converter 6
iqp is the DC current command iq of the speed controller 5. On the other hand, after the position deviation amount Δθ becomes zero, the current phase angle θep input to the trigonometric function value generator 7 becomes the current phase angle θe0 stored in the current phase angle storage unit 90 by 90 degrees (π / 2).
(Radian) is added, and the current phase angle θe1 of the power factor = 0 is obtained. The DC current command (torque command) iqp input to the three-phase AC coordinate converter 6 is a motor-converted torque value (DC current value) iq0.

Using the DC current command (torque command) iqp and the trigonometric function value of the current phase angle θep output from the trigonometric function value generator 7 in the three-phase AC coordinate converter 6, the following equation (6) is obtained. The U-phase current command uid and the V-phase current command ivd are calculated by equation (7).

Uid = −√ (2/3) × iq × sin θep (6) ivd = −√ (2/3) × iq × sin (θep−2 / 3π) (7)

Next, the switching timing of the current phase angle θep input to the trigonometric function value generator 7 and the DC current command (torque command) iqp input to the three-phase AC coordinate converter 6 will be described with reference to FIG. explain. FIG. 4 shows the changeover switch 1
6 is a timing chart showing the switching timing of a current phase angle θep by 1 and a DC current command (torque command) iqp by a changeover switch 15. Current phase angle switching means 1
0 and the changeover switch 15 of the DC current command (torque command) changeover means 14 are, for example, position commands θmd at time (t−1), respectively.
Position command θmd from (t−1) to time (t)
At the timing Ts1 for switching to (t), the contact 1
To the contact 2. Next, at the timing To1 when the positional deviation amount Δθ becomes zero, the changeover switch 11
And the changeover switch 15 are switched from the contact 2 to the contact 1, respectively.

The current phase angle θep output from the current phase angle switching means 10 is converted into a trigonometric function value by a trigonometric function value generator 7 and output to a three-phase AC coordinate converter 6.
The three-phase AC coordinate converter 6 uses the DC current command (torque command) iq output from the speed controller 5 and the trigonometric function value of the current phase angle θep output from the trigonometric function value generator 7. , U-phase current command iud and V-phase current command i
vd is calculated by the aforementioned equations (6) and (7). Three
The phase AC coordinate converter 6 outputs the U-phase current command uid to the U-phase current controller 8a, and outputs the V-phase current command ivd to the V-phase current controller 8b. When there is a deviation between the detected U-phase motor current iu and the U-phase current command iud in the U-phase current controller 8a, a signal obtained by multiplying the deviation by a predetermined current gain is used as the U-phase motor voltage command Vu. PWM inverter 9
Output to

On the other hand, when there is a deviation between the detected V-phase motor current iv and the V-phase current command ivd, the V-phase current controller 8b outputs a signal obtained by multiplying the deviation by a predetermined current gain. It outputs to the PWM inverter 9 as the motor voltage command Vv. The W-phase motor voltage command Vw is Vw = −V
It is calculated from the equation of u-Vv. PWM inverter 9
In the above, the U-phase motor voltage command Vu, the V-phase motor voltage command Vv, and the W-phase motor voltage command V
A voltage corresponding to w is applied to each phase of the bridge circuit constituting the PWM inverter 9. When a voltage is applied to each phase of the bridge circuit in this manner, a current flows through the stator winding of the AC servomotor 1 and the mover of the AC servomotor 1 moves by a predetermined amount. The mover of the AC servo motor 1 reaches the position indicated by the position command θmd given from outside the device, and the speed ω
Becomes zero. At this time, the outputs of the position controller 4 and the speed controller 5 become zero, that is, a DC current command (torque command).
iq becomes zero. Thus, the AC servomotor 1 stops, and the positioning operation is completed.

As described above, in the AC servomotor controller of the second embodiment, the current phase angle θep input to the trigonometric function value generator 7 and the DC current command input to the three-phase AC coordinate converter 6 By switching the (torque command) iqp, the current phase angle of the current flowing through the stator winding is switched between when the AC servomotor is operating and when it is stopped. Because of such a configuration, A of Example 2
In the C servo motor control device, the response characteristic at the time of stop does not depend on the feedback characteristic, and the movable element of the AC servo motor 1 stops at a desired position by the electric attractive force of the movable element and the stator of the AC servo motor 1. . Further, the AC servomotor control device according to the second embodiment can hold the motor stopped even when a steady load such as a vertical load is applied to the AC servomotor.

[0039]

As apparent from the detailed description of the embodiments, the present invention has the following effects.
According to the present invention, the AC servomotor is configured so that the current phase angle of the current flowing through the stator winding is switched between when the AC servomotor is operating and when the AC servomotor is stopped. Instead, the mover of the AC servomotor can be stopped at a desired position by the electric attractive force of the mover and the stator of the AC servomotor. Therefore, according to the AC servo motor control device and the AC servo motor control method of the present invention, high-speed response and high positional accuracy can be realized in drive control of the AC serve motor, and hunting prevention and stop response characteristics are improved. Can be achieved.

Further, according to the present invention, even when a steady load such as a vertical load is applied to the AC servomotor, it is possible to maintain the motor stop, thereby realizing high-speed response and high positional accuracy of the motor stop control. As a result, hunting can be prevented, and the response characteristics up to the stop can be improved. Furthermore, according to the present invention, even when a steady load such as a vertical load is applied to the AC servomotor, the motor torque conversion value of the steady load can be set to the command value. Thus, the heat generation of the motor can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an AC servomotor control device according to a first embodiment which is an embodiment of the present invention.

FIG. 2 is a timing chart showing a timing of switching a current phase angle according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of an AC servo motor control device according to a second embodiment which is an embodiment of the present invention.

FIG. 4 is a timing chart showing a current phase angle and a switching timing of a DC current command (torque command) in Embodiment 2 of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional AC servomotor control device.

[Explanation of symbols]

 Reference Signs List 1 AC servo motor 2 Encoder 3 Position / speed detector 4 Position controller 5 Speed controller 6 3-phase AC coordinate converter 7 Trigonometric function value generator 8a U-phase current controller 8b V-phase current controller 9 PWM inverter 10 Current Phase angle switching means 11 Changeover switch 12 Switch changeover signal generator 13 Current phase angle storage

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H550 BB05 DD01 EE05 FF02 FF03 GG01 GG03 GG05 GG07 GG08 HB16 LL07 LL22 LL35 5H560 DA07 DC01 XA02 XA04 XA05 XA06 5H576 AA17 BB04 BB09 DD02 DD07 EE19 GG02 GG04 LL22 LL39 LL41 LL42

Claims (6)

[Claims] 1. A position / speed detector for detecting a displacement amount, a speed, and a current phase angle of a motor to form a position signal, a speed signal, and a first current phase angle signal, and a position signal of the position / speed detector. And a position deviation between the position command signal of the motor and the position command signal, and a position controller that outputs a motor speed command signal. The speed deviation between the speed signal of the position / speed detector and the motor speed command signal of the position controller is A speed controller that inputs and outputs a DC current command signal, a first current phase angle signal of the position / speed detector, and a second current factor of 90 obtained by adding 90 degrees to the first current phase angle signal. And the current phase angle signal can be switched, and when the position deviation becomes zero for the first time since the start of the operation of the motor, the second
Current phase angle switching means for outputting a current phase angle signal, a triangular function value for converting the first current phase angle signal or the second current phase angle signal output from the current phase angle switching means to a trigonometric function value signal A three-phase AC coordinate converter to which a DC current command signal output from the speed controller is input and a trigonometric function value signal output from the trigonometric function value generator is input; Current controller that controls the armature current of each phase by the current command value signal of each phase output from the
And a PWM inverter that modulates the pulse width to drive the motor. 2. A switch switching signal generating section for outputting a switch switching signal when a phase deviation becomes zero for the first time after the start of operation of a motor, a current factor switching unit comprising: a power factor = 1 based on the switch switching signal; And a power factor obtained by adding 90 degrees to the first current phase angle signal stored in the current phase angle storage unit according to the switch switching signal. 2. The AC servomotor control device according to claim 1, further comprising: a first changeover switch for changing over so as to output a second current phase angle signal of = 0 to the trigonometric function value generator. 3. A DC current command output from the speed controller and a motor-converted torque value signal in a steady load state of a mechanism driven by a motor are switched by a switch switching signal of the switch switching signal generator. 3. The AC servomotor control device according to claim 2, further comprising a DC current command switching unit having a second switch for outputting to the three-phase AC coordinate converter. 4. A step of detecting a displacement, a speed and a current phase angle of the motor by a position / speed detector to form a position signal, a speed signal and a first current phase angle signal. A step of receiving a position deviation between a position signal of a speed detector and a position command signal of the motor and outputting a motor speed command signal to a speed controller; a speed signal of the position / speed detector and a motor of the position controller; A step of receiving a speed deviation from a speed command signal and outputting a DC current command signal to a three-phase AC coordinate converter, wherein a current phase angle switching means includes a first current phase signal of the position / speed detector and the first current phase signal; A second current phase angle signal having a power factor of 0 obtained by adding 90 degrees to the current phase angle signal of the motor is switched and output. When the position deviation becomes zero for the first time since the start of operation of the motor, the second current Outputting a phase angle signal; Converting a first current phase angle signal or a second current phase angle signal output from the current phase angle switching means into a trigonometric function value signal by a function value generator; The DC current command signal output from the device and the trigonometric function value signal output from the trigonometric function value generator are input, the step of controlling the armature current of each phase, and the pulse width modulated by the PWM inverter. A method for controlling the AC servomotor, comprising: driving the motor. 5. When the position deviation becomes zero for the first time after the start of operation of the motor, a switch switching signal is output, and the first current phase angle signal stored in the current phase angle storage section is output by the switch switching signal. Power factor with 90 degrees added = 0
5. The method of controlling an AC servo motor according to claim 4, further comprising the step of switching the second current phase angle signal to be output to the trigonometric function value generator. 6. A three-phase control system according to claim 1, wherein a DC current command output from the speed controller and a motor-converted torque value signal in a steady load state of a mechanism driven by the motor are switched by a switch switching signal of a switch switching signal generator. 6. The AC servomotor control method according to claim 5, further comprising a step of outputting to an AC coordinate converter.