JP2896280B2 - Motor control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a motor, and more particularly to a control device for a motor capable of compensating for a synchronization deviation due to an increase in rotation speed.

[0002]

2. Description of the Related Art A driving device for driving a synchronous motor of this type mainly includes a position detection sensor capable of detecting the position of the synchronous motor and a phase detection device such as a pole sensor for detecting a rotational position signal of each phase of the synchronous motor. A position / speed control device that forms a current command from a sensor, a position detection signal from the position detection sensor and a position command, and a power conversion command signal from the current command and a rotational position signal of each phase from the pole sensor. And a PWM power conversion unit that performs power conversion based on a power command signal from the three-phase distribution device.

In such a driving device, the position of the rotor of the synchronous motor is detected by using a phase detection sensor such as a pole sensor, and the detected rotation position signal of each phase is taken into a three-phase distribution device, and the rotation is detected. Based on the position signal, U phase, V phase,
A power conversion command signal is formed by sine-shifting the W phase by 120 ° to form a power conversion command signal, and the PWM power conversion unit is driven by these power conversion command signals to energize each phase of the synchronous motor, thereby controlling the rotation of the synchronous motor. Controlling. Thus, the three-phase synchronous motor can be stably driven without being out of synchronization. In the torque-rotation speed characteristic, even when the rotation speed increases, the torque does not drop significantly.

[0004]

However, in the case of the above driving device, there is actually a delay due to the inductive reactance existing in the current loop, and a calculation delay in the case of software control, so that the rotational speed is reduced. However, there is a disadvantage that the synchronization gradually shifts as the pressure rises, and the rotation speed-torque characteristics deteriorate.

When positioning is performed using a three-phase synchronous motor, no special speed detection sensor is provided in addition to the position detection sensor. The reason is that speed detection sensors are generally very expensive. In this case, since the speed detection signal is obtained from the position detection signal from the position detection sensor, the disadvantage that the rotation speed-torque characteristic deteriorates as the rotation speed increases is more remarkable. become.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for a motor in which deterioration of rotation speed-torque characteristics is prevented.

[0007]

In order to achieve the above object, the present invention provides a position detection sensor capable of detecting the position of a synchronous motor, and a current command formed from a position detection signal from the position detection sensor and a position command. A position / speed control device, a distribution device that forms a power conversion command signal for each phase based on a current command, and a power conversion unit that performs power conversion based on the power command signal. The position / speed control device has a speed compensator, a disturbance compensator for compensating disturbance and the like to a current command by compensating disturbance and the like with respect to a state command signal obtained from a position detection signal, and the like , and a control model of the motor. estimating the state of the control model is provided and observer for outputting a state estimation value when the input position detection signal及beauty state command signal, the observer takes the position detection signal and the state command signal , Z: advance operator, α ₀ , α ₁ : Observer stable filter
Constants, b _i , C _i : nominal value and control model of the controlled system
Coefficient: θ: position detection signal, x ′: deviation,
x: At the estimated state value, x = [(b ₁ Z + b ₀ ) · x ′ / (Z ² + α ₁ Z + α ₀ )] + [(C ₂ Z ² + C ₁ Z + C ₀ ) · θ / (Z ² + α ₁₎ Z + α ₀ )] corresponds to the speed of the control model for which disturbance compensation has been performed.
Forming a state estimate, and the distributing device:
It is provided with a compensating means for compensating a signal actually obtained from the position detection sensor with a state estimation value obtained by the observer.

[0008]

Therefore, for example, in the case of a three-phase synchronous motor, in the position / speed control device, the disturbance of the state command signal is compensated by a disturbance compensator and input to the three-phase distribution device as a current command. In the position / speed control device, the observer has a control model of the electric motor, and inputs the position detection signal and the state command signal to the control model to estimate the state of the control model. The state estimation value obtained by the observer is input to the compensation means of the three-phase distribution device. In addition, the position detection signal from the position detection sensor is actually counted in the three-phase distribution device, converted into a signal corresponding to a predetermined speed, and input to the compensation means. The compensating means compensates the signal corresponding to the speed with the state estimated value. With this compensated signal, it is three-phase distribution. In addition, the observer having the configuration shown in the equation fetches the deviation x ′ and the position detection signal θ to obtain the state estimation value x.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described below in detail with reference to the embodiments shown in the drawings. This embodiment is applied to a three-phase synchronous motor.

FIG. 1 shows an embodiment of a motor control device according to the present invention. The control device for this motor is a three-phase synchronous motor 1
And comprises a PWM power conversion unit 3, a three-phase distribution device 5, a position / speed control device 7, and an encoder 9 as a position detection sensor. In the motor control device of the present embodiment, the current feedback system and the like are omitted.

In such an electric motor control device, the position / speed control device 7 is provided with a disturbance compensator 71 in order to enhance robustness against disturbances and the like, and an observer 72 estimates state values such as speed. And by feeding back these state estimation values, a desired control performance is obtained.

Next, an encoder 9 is fixed to the rotating shaft of the three-phase synchronous motor 1, and the encoder 9 detects the position of the rotor of the three-phase synchronous motor 1. The position detection signal θ from the encoder 9 is input to the PWM power converter 3 and the position / speed controller 7.

The position / speed controller 7 includes a disturbance compensator 7
1, observer 72, subtractors 73 and 74, control gain G
_It consists of a control amplifier 75 which gives ₁ . Here, the position detection signal θ from the encoder 9 is input to the observer 72 and the subtractor 73. The subtractor 73 subtracts the position command θ ^* (in this specification, the mark “ ^* ” indicates a command signal) from the position detection signal θ, and inputs the result of the subtraction to the control amplifier 75. The control amplifier 75 amplifies the result of the subtraction with the control gain G ₁ and supplies the result to the subtractor 74. The subtractor 74 subtracts the output signal from the control amplifier 75 by the state estimation value x from the observer 72 to form a deviation x ′ (in the present specification, a mark “′” indicates an internal signal). The deviation x 'is supplied to the disturbance compensator 71 and the observer 72. The disturbance compensator 71 is configured by a digital filter as shown in Expression 1.

[0014]

I ^* = (Z−1 + α _c ) · x ′ / (Z−1) Here, Z is a leading operator, and α _c is an integration constant. That is, the disturbance compensator 71 forms the current command i ^* by applying Equation 1 to the deviation x ′.

The observer 72 is configured as shown by the following equation (2).

X = [(b ₁ Z + b ₀ ) · x ′ / (Z ₂ + α ₁ Z + α ₀ )] + [(C ₂ Z ₂ + C ₁ Z + C ₀ ) · θ / (Z ₂ + α ₁ Z + α ₀ )] Here, α ₁ and α ₂ are stable filter coefficients of the observer 72, and b _i and c _i are coefficients determined by the nominal value of the control target system and the control model.

The observer 72 configured as described above takes in the deviation x ′ and the position detection signal θ, and forms the state estimation value x by applying the above equation (2).

[0017] 3-phase system 5, an amplifier 51 providing a gain G _C, limiter 52, multiplier 53a, 53b, digital-to-analog converter (DAC) 54u, 54v,
54w, adder 55, generators 56a and 56b, adder 5
7, 58, setter 59 for initial correction value φ ₀ , counter 6
0, an amplifier 61 for providing a compensation gain Gph.

The amplifier 51 multiplies the current command i ^* given the gain G _C through the limiter 52 to multipliers 53a and 53b.
To supply. The multiplier 53a multiplies the current command i ^* passed through the limiter 52 by the signal from the generator 56a to obtain D
AC54u and adder 55. Multiplier 53b
Corresponds to the current command i ^* passing through the limiter 52 and the generator 56b.
Are multiplied and supplied to the DAC 54v and the adder 55. The adder 55 adds the signals Vv ^* and Vu ^* from the multipliers 53a and 53b, and gives the addition result Vw ^* to the DAC 54w. DAC 54u, 54v, 54w
, Power conversion command signals Vu, Vv, Vw are formed and supplied to the PWM power conversion unit 3.

The counter 60 counts the position detection signal θ (pulse) from the encoder 9 and counts the value θ _0.
Is given to the adder 58. Note that the counter 60 is reset every rotation.

The state estimated value x from the observer 72 of the position / speed control device 7 is provided with a compensation gain Gph by the amplifier 61 and supplied to the adder 58. As a result, the state estimation value x is added to the count value θ ₀ from the counter 60 to compensate for the synchronization deviation. Note that this adder 5
8 and the amplifier 61 constitute compensating means. The output of the adder 58 is corrected by the adder 57 with the initial correction value φ ₀ from the setter 59, and then the generators 56 a and 5
6b.

The PWM power converter 3 converts DC into AC based on the power conversion command signals Vu, Vv, Vw from the three-phase distribution device 5 and supplies the DC to the stator 11 of the three-phase synchronous motor 1. It has become. Note that the rotor 12 of the three-phase synchronous motor 1 rotates according to the current command vector of the stator 11.

The operation of the embodiment configured as described above will be described.

First, a position command θ is given to the position / speed control device 7. Then, in the position / speed control device 7, the position command θ is subtracted from the position detection signal θ from the encoder 9. The result of the subtraction is supplied to the control amplifier 75. The subtraction result amplified by the gain G ₁ by the control amplifier 75 is given to the subtractor 74. Also, the subtractor 74
, The state estimated value x from the observer 72 is also input.

The observer 72 obtains a state estimated value x from the output signal x ′ from the subtractor 74 and the position detection signal θ from the encoder 9 using the above equation (2). This observer 72 is, in short, a real three-phase synchronous motor 1
Is not detected by the difference, but a state variable corresponding to the speed of the disturbance-compensated control model of the three-phase synchronous motor 1 in the software is obtained. Therefore, the rotor 11 of the ordinary three-phase synchronous motor 1
Unlike the speed detection based on the difference between the two, there is no phase delay. The state estimated value x obtained by the observer 72 in this manner is also supplied to the three-phase distributor 5. still,
The control model is a theoretical motor having the same characteristics as an actual motor.

The output signal x 'from the subtractor 74 is an integral type signal.
Equation 1 is applied by passing through the disturbance compensator 71.
The disturbance is compensated and the current command i^* Becomes This current finger
Order i ^* Is supplied to the three-phase distribution device 5.

Next, the current command i ^* input from the position / speed control device 7 and the estimated state value x from the observer 72
Is input to the three-phase distribution device 5.

In the three-phase distribution device 5, the input current command i ^* is given a gain GC by an amplifier 51 and is input to a limiter 52. In the limiter 52, the current command i
^* Large part of amplitude is limited. The limited current command i ^* is input to multipliers 53a and 53b.

The state estimated value x from the observer 72
Is supplied to the adder 58 after being given the compensation gain Gph by the amplifier 61. In the adder 58, the position detection signal θ from the encoder 9 is counted by a counter
By adding the state estimation value x passed through the amplifier 61 to ₀ , the synchronization deviation is compensated. The signal compensated for the synchronization deviation by adding the state estimation value x to the count value θ ₀ in this manner is added to the initial correction value φ _{0 by the} adder 57.
Are added to obtain the rotor angle φ. This rotor angle φ
Is supplied to the generators 56a and 56b.

The generator 56a generates a signal Sinφ from the rotor angle φ from the adder 57 and multiplies the signal Sinφ by a multiplier 53a.
Give to. The generator 56b generates a signal Sin (φ + 120 °) from the rotor angle φ from the adder 57 and supplies the signal Sin (φ + 120 °) to the multiplier 53b. The multiplier 53a forms a command Vu ^* from the current command i ^* from the limiter 52, and
Give to 54u. The multiplier 53b forms a command Vv ^* from the current command i ^* from the limiter 52, and
Give to. The command V from the multipliers 53a and 53b
u ^* and Vv ^* are added by the adder 55 to form a command Vw ^* , which is supplied to the DAC 54w.

The DACs 54u, 54v, and 54w form analog power conversion commands Vu, Vv, and Vw from the digital commands Vu ^* , Vv ^* , and Vw ^* , and provide them to the PWM power conversion unit 3.

In the PWM power converter 3, the power conversion command V
A PWM signal is generated based on u, Vv, and Vw, and a predetermined alternating current is obtained from the direct current by driving the semiconductor switching element with this.

The alternating current from the PWM power converter 3 is supplied to the stator 11 of the three-phase synchronous motor 1. Therefore, the rotor 12 of the three-phase synchronous motor 1 rotates.

As described above, in the control device of the present embodiment, the control model of the three-phase synchronous motor 1 is provided inside the position / speed control device 7, and the state estimation value x estimated by this control model is actually used. Since the actual delay of the three-phase synchronous motor 1 is compensated by compensating the signal θ ₀ obtained from the position detection sensor (the encoder 9 and the counter 60),
Synchronization deviation due to an increase in the rotation speed can be compensated without adding hardware such as a speed detection sensor.

The above embodiment is a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, the present embodiment has mainly been described for a case where the present invention is applied to a three-phase synchronous motor. However, the present invention is not particularly limited to this, and can be applied to other synchronous motors having three or more phases or less.

[0035]

As described above, according to the present invention, the position / speed control device has the control model of the electric motor, and the observer for estimating the state of the control model when a predetermined signal is input thereto. Since the state estimation value obtained by this observer compensates for the signal actually obtained from the position detection sensor, the synchronization shift that occurs with the increase in the rotation speed is
Without adding hardware such as a speed detection sensor,
Compensation can be made, and the electric motor can be driven efficiently. Further, captures the deviation x 'and the position detection signal θ by observer, it is possible to determine the state estimate x.

[Brief description of the drawings]

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 three-phase synchronous motor 3 PWM power conversion unit 5 three-phase distribution device 7 position / speed control device 9 encoder (position detection sensor) 58 adder 60 counter 61 amplifier 71 disturbance compensator 72 observer

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02P 5/00-7/80

Claims (1)

(57) [Claims] 1. A position detection sensor capable of detecting a position of a synchronous motor, a position / speed control device for forming a current command from a position detection signal and a position command from the position detection sensor, A distribution device that forms a phase power conversion command signal, and a motor control device including a power conversion unit that performs power conversion based on the power command signal,
The position / speed control device has a speed command, a disturbance compensator that compensates for a disturbance or the like with respect to a state command signal obtained from a position detection signal or the like, and sets a current command, and a control model of a motor.
The position detection signal to the control model and to estimate the state of the control model when entering the state command signal is provided and the observer for outputting the state estimate, the observer
Capture a position detection signal and the state command signal, Z: advances operator, α _0, α _1: stability of the observer Fi
Filter constant, b _i, C _i: nominal value of the control object system and a control motor
Coefficient determined by Dell, θ: position detection signal, x ′: bias
Difference, x: when estimated state value, x = [(b ₁ Z + b ₀ ) · x ′ / (Z ² + α ₁ Z + α ₀ )] + [(C ₂ Z ² + C ₁ Z + C ₀ ) · θ / (Z ² + Α ₁ Z + α ₀ )] , which corresponds to the speed of the control model which has been subjected to disturbance compensation.
Is intended to form the state estimation value to be, and the dispensing device, by including a compensating means for compensating a signal obtained from actually the <br/> position detection sensor in a state estimation value obtained in the observer A control device for a motor.