JP2002027783A - Method and apparatus for stopping synchronous motor at constant position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate hunting at an area near the target stop position at the time of stopping a synchronous motor to the constant position. SOLUTION: An apparatus for realizing stop at the constant position has a three-phase motor 4, a controller having a current control loop to control this three-phase synchronous motor 4 with a current element of the orthogonal (d) and (q) axes, a rotating angle detector 5 for detecting a rotating angle θfb of the three-phase synchronous motor 4, a current calculation unit which gives a d-axis current command Id* and a q-axis current command Iq* respectively based on a torque command Tref and a rotating angle θfb. The apparatus drives the synchronous motor in order to set a positional deviation Δθ between the rotating angle θfb of the three-phase synchronous motor 4 and the target stop position θref to zero. Further, the apparatus comprises a comparison means 12 for outputting an operation signal when a position deviation Δθ is less than the preset value Δθs as a result of comparison between the positional deviation Δθand present value Δθs, and a switching means SW1 for switching a d-axis current Id to zero based on the operation signal of the comparison means 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed position stop control method and apparatus for stopping a synchronous motor at a target stop position and maintaining the stop position.

[0002]

2. Description of the Related Art The configuration of a conventional synchronous motor is shown in FIG.
3, reference numeral 1 denotes a vector calculation unit, 2 denotes a PWM generation unit, 3 denotes an inverter power unit, 4 denotes a permanent magnet synchronous motor, 5 denotes a position detector such as a pulse generator, 6 denotes a speed calculation unit, and 7 denotes a three-phase d. A -q converter, 8 is an _Id calculator, 9 is a current detector, 10 is a speed adjuster, and 11 is a position adjuster. A value obtained by subtracting the current position θ _fb detected by the position detector 5 from the position command θ _ref is input to the speed adjuster 10 via the position adjuster 11 to generate a torque command T _ref .
This value is input to an _Iq calculator (built-in to the speed regulator 10) to generate a q-axis current command _Iq . Furthermore the values entered in the I _d calculator 8 d-axis current command I _d is made.
The q-axis current command _Iq is subtracted from the q-axis current feedback _Iqfb obtained by inputting the detection value of the motor current obtained by the current detector 9 to the three-phase dq converter 7, and the vector operation unit Enter 1. On the other hand, the d-axis current command I _d is subtracted from the d-axis current feedback I _dfb and enters the vector operation unit 1. The vector operation unit 1 generates a voltage command V ^* and a phase control angle command φ ^* from the I _qfb and I _dfb , and the signal enters the PWM generation unit 2 to control the inverter power unit 3. The position control is performed by the above operation. At this time,
In order to maintain the stop position, the correction torque according to the deviation Δθ between the target stop position and the current position has been continuously generated.

[0003]

However, in the prior art, the target stop position is very close, for example, the position detector is 409.
In the case of a pulse generator of 6 pulses / 1 rotation, if the pulse falls within ± 5 pulses, as shown in FIG. 2B, an operation of returning to the target position and a repetition of an overshoot operation, a so-called hunting operation, occur. There was a problem. Therefore, an object of the present invention is to eliminate a hunting operation very close to a target stop position.

[0004]

In order to solve the above-mentioned problems, a fixed position stopping method for a synchronous motor according to the present invention comprises a three-phase synchronous motor and a current component of d-q axes orthogonal to each other. A control device having a current control loop for controlling the three-phase synchronous motor, a rotation angle detector for detecting the rotation angle θ _fb of the three-phase synchronous motor, and d set based on the torque command T _ref and the rotation angle θ _fb , respectively. Shaft current commands I _d ^* and q
A current calculation unit for giving the shaft current command I _q ^* , and the synchronous motor is driven so that the positional deviation Δθ between the rotation angle θ _fb of the three-phase synchronous motor and the target stop position θ _ref becomes zero, thereby stopping the fixed position. The method is characterized in that when the positional deviation Δθ becomes equal to or less than a predetermined value, the d-axis current is set to zero to eliminate the rotational torque of the electric motor. Further, the synchronous motor fixed-position stopping device according to the present invention comprises a three-phase synchronous motor, a control device having a current control loop for controlling the three-phase synchronous motor with current components of orthogonal dq axes, A rotation angle detector for detecting the rotation angle θ _fb of the phase synchronous motor, and a d-axis current command I _d ^* and a q-axis current command I _q ^* which are set based on the torque command T _ref and the rotation angle θ _fb , respectively ^. And a current calculation unit for providing a fixed position stop by driving the synchronous motor so that the positional deviation Δθ between the rotation angle θ _fb of the three-phase synchronous motor and the target stop position θ _ref becomes zero. comparing the preset value [Delta] [theta] _s and the deviation [Delta] [theta] the position deviation [Delta] [theta] is the set value [Delta] [theta] _s
A comparison means for outputting an operation signal in the following case, and a switching means for switching the d-axis current _Id to zero based on the operation signal of the comparison means are provided.
By the above means, the rotational torque is eliminated within the set range close to the target stop position, and the vehicle can be stably stopped without vibration. In addition, when the set torque is out of the set range due to an external force or the like, a correction torque is generated and returns to the target stop position.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention. Differs from the conventional example shown in FIG. 3, a comparator 1 for comparing the set range [Delta] [theta] _s and the position deviation [Delta] [theta]
2 in that a switch SW1 for setting the d-axis current _Id to zero when the comparator 12 operates is provided. Hereinafter, the operation of the embodiment of the present invention will be described. Position command θ _ref
Then, a value obtained by subtracting the current position θ _fb detected by the position detector 5 is input to the speed adjuster 10 via the position adjuster 11 to generate a torque command _Tref . This value is input to an _Iq calculator (built-in to the speed regulator 10) to generate a q-axis current command _Iq . Furthermore the values entered in the I _d calculator 8 d-axis current command I _d is made. The q-axis current command _Iq is subtracted from the q-axis current feedback _Iqfb obtained by inputting the detection value of the motor current obtained by the current detector 9 to the three-phase dq converter 7, and the vector operation unit Enter 1.

On the other hand, the d-axis current command I _d is subtracted from the d-axis current feedback I _dfb and enters the vector operation unit 1. The vector operation unit 1 generates a voltage command V ^* and a phase control angle command φ ^* from the I _qfb and I _dfb , and this signal is
To control the inverter power section 3. The position control is performed by the above operation. Here, to compare the set range [Delta] [theta] _s and the position deviation [Delta] [theta] in the comparison unit 12, to SW1 off the smaller the positional deviation. If the positional deviation is large, switch SW1 is turned on. As a result, the _Id current becomes zero when it enters a certain set range with respect to the target stop position, and the normal _Id current is set when it deviates from the set range due to external force or the like. A correction torque corresponding to the position deviation is generated. In this way, the rotational torque is lost within the set range close to the target stop position, and the vehicle can be stably stopped without vibration. This situation is shown in FIG.

[0007]

As described above, according to the present invention, when the positional deviation between the target stop position and the detected position falls below a certain set value, the d-axis current is reduced to zero and the rotational torque of the motor is reduced. By eliminating this, the synchronous motor can be stably stopped at the target stop position without hunting.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a waveform diagram showing the effect of the present invention and a conventional vibration situation.

FIG. 3 is a block diagram showing an example of a conventional control device for a synchronous motor.

[Explanation of symbols]

1: vector operation unit, 2: PWM generation unit, 3: inverter power unit, 4: permanent magnet synchronous motor, 5: position detector, 6: speed operation unit, 7: three-phase dq converter, 8: I _d
Arithmetic unit, 9: current detector, 10: speed adjuster, 11: position adjuster, 12: comparator, SW1: changeover switch

Continued on the front page F term (reference) 5H530 AA07 CC07 CC10 CC15 CD13 CD24 CD32 CE16 CE30 CF03 CF20 DD03 5H560 BB04 BB12 DA07 DB07 DC12 EB01 RR10 TT07 XA02 XA04 XA05 XA12 XA13 5H576 BB04 DD02 DD07 EE01 GG01 GG05 GG01 GG01 GG01 GG01 GG05 LL22 LL41

Claims (2)

[Claims] A three-phase synchronous motor and the three-phase synchronous motor
Is controlled by current components on the orthogonal dq axes.
A control device having a control loop and rotation of the three-phase synchronous motor
Angle θ_fbRotation angle detector that detects the
Command T_refAnd the rotation angle θ_fbIs set based on
d-axis current command I_d ^*And q-axis current command I _q ^*Give current performance
Calculation unit and the rotation angle θ of the three-phase synchronous motor._fbAnd goal stop
Position θ _refSynchronization error so that the position deviation Δθ from
In the method of driving the motivation to stop at a fixed position, when the position deviation Δθ becomes equal to or less than a certain set value, d
Zero shaft current to eliminate motor torque
Characteristic method of stopping a synchronous motor in a fixed position. 2. A three-phase synchronous motor and the three-phase synchronous motor
Is controlled by current components on the orthogonal dq axes.
A control device having a control loop and rotation of the three-phase synchronous motor
Angle θ_fbRotation angle detector that detects the
Command T_refAnd the rotation angle θ_fbIs set based on
d-axis current command I_d ^*And q-axis current command I _q ^*Give current performance
Calculation unit and the rotation angle θ of the three-phase synchronous motor._fbAnd goal stop
Position θ _refSynchronization error so that the position deviation Δθ from
An apparatus for driving a motivator to stop at a fixed position, wherein the position deviation Δθ and a preset set value Δθ_sAnd the ratio
The position deviation Δθ is the set value Δθ_sWhen
Comparison means for outputting an operation signal; and an operation signal of the comparison means.
The d-axis current I_dTo switch to zero
Switching means, and a synchronous motor
Position stop device.