JPS5879483A - Controller for motor - Google Patents

Abstract

PURPOSE:To always achieve the highest controlling performance by varying the cut-off frequency of a control system and the cut-off frequency of a low pass filter proportionally to the rotating speed of a motor. CONSTITUTION:A motor 1 has a frequency generator 3. The output frequency of an oscillator 5 is divided by a frequency divider 4, thereby obtaining the rotating reference frequency of the motor 1. A phase comparator 7 produces the rotating phase error signal of the motor 1, which signal is supplied through a high pass compensator 7 and a low pass filter 8 to the drive circuit 9 of the motor 1. The folding frequency and the amplification factor of the compensator 7 are varied proportionally to the output frequency of the oscillator 5, and the cut-off frequency of the filter 8 is varied proportionally to the output frequency of the oscillator 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a motor that has several set rotational speeds or that is used by continuously changing the rotational speed. The purpose is to automatically vary the loop gain and always obtain the maximum possible loop gain at the set rotation speed, thereby maximizing the control performance of the motor.

Generally, when designing a motor control system, the gain of the control loop is designed to be as large as possible in order to reduce the rate of rotational speed fluctuation due to motor disturbances and to speed up the response time. is the maximum gain of the control loop, or in other words, the maximum possible cutoff frequency of the control system is limited by the value of the output frequency of the frequency generator, which outputs a frequency proportional to the motor rotation speed. Ru.

For example, in a motor control system that generally uses a sample-and-pole type speed discriminator, the output frequency of the frequency generator is approximately 2% to 1/! It is considered that approximately 0 is the maximum limit value of the response frequency of the control system.

For the above reasons, in order to always obtain the best control characteristics,
Each time the reference frequency is varied and the motor rotation speed setting is changed, it is necessary to set the control loop gain corresponding to each rotation speed, i.e., a low control loop gain for low speed rotation and a high control loop gain for high speed rotation. Therefore, it was necessary to switch the control loop gain at the same time as switching the reference frequency.

The present invention aims to provide a motor control device that eliminates the above-mentioned drawbacks, and when the reference frequency is varied to change the rotation speed of the motor, the loop gain of the control system is automatically adjusted according to the rotation speed. The aim is to always obtain the best control performance.

FIG. 1 is a block diagram of main parts showing one embodiment of the present invention. In the figure, 1 is a motor equipped with a frequency generator 3 that rotates a disk 2 and generates a frequency signal hct proportional to the number of rotations, and 4 is a frequency divider circuit that divides the output frequency of an oscillation circuit 6. The output frequency fR becomes the reference frequency of the rotation of the motor 1. 6 compares the reference frequency fR and the output frequency fFe of the frequency generator 3, and
7 is a phase comparator circuit that generates a phase error signal of the rotation of
The high frequency compensation circuit is designed to add damping to the entire control system, and its corner frequency f1 (when the amplification starts to increase,
(or the frequency at which the phase begins to advance) is varied in proportion to the output frequency f0 of the oscillation circuit g, and at the same time, its amplification degree is also varied.

That is, the value of the output frequency f0 of the oscillation circuit 6 is doubled, the corner frequency f of the high-frequency compensation circuit 7 is doubled, and the amplification is also doubled.

8 is a low-pass filter for removing noise and ripple components included in the output of the high-frequency compensation circuit 7, and its cutoff frequency fr is also varied in proportion to the output frequency 10 of the oscillation circuit 6. Reference numeral 9 denotes a drive circuit for amplifying the output voltage of the low-pass filter 7-router 8 and supplying current to the motor 1.

Motor 19 frequency generator 39 phase comparison circuit 6 described above
．． High frequency compensation circuit 7. The low-pass filter 8 and the drive circuit 9 constitute a phase control loop, and the motor 1 has a base frequency f
The rotation is controlled in proportion to H. Figures 2 and 3 show the motor 1
FIG. 7 is a diagram showing changes in the transfer characteristics of the high-frequency compensation circuit 7 and changes in the control characteristics (rotational speed fluctuation rate) of the motor when the rotation speed of the motor is set to 1/2 the speed.

In FIGS. 2 and 3, a corresponds to A and b corresponds to B. f1 + f1' is the corner frequency of the high-frequency compensation circuit 7, and % f2 * f2' is the cutoff frequency of the system that occurs when the loop of the control system is closed, and fl and f2, or f,
The geometric mean of ゛ and f2+ is the response frequency (natural frequency) of the system
shows.

In the state shown in Fig. 3, assuming that the response frequency of the system, that is, the loop gain, is increased to a value close to the upper limit of the motor control characteristics, the rotational speed of motor 1 is reduced by setting the reference frequency fR to 1/2. When trying to reduce the loop gain to 1/2, if the loop gain is constant and does not change, the ratio of the output frequency of the frequency generator 3 and the cutoff frequency of the control system will be 6 times half the limit value, and the control system operation becomes unstable.

For this reason, as shown in FIG. 2, the high frequency compensation circuits C and T.

7, that is, by setting both the gain of the slope portion and the corner frequency to 1, the cutoff frequency of the control system can be lowered to 1, as shown in B in FIG. As a result, the ratio of the output frequency 1 of the frequency generator 3 to the cutoff frequency f21 of the control system becomes 12 times, and the stability of the control system is maintained. 7 is a diagram showing an example of the configuration of a high frequency compensation circuit 7 whose corner frequency is controlled. FIG. In the figure, reference numeral 11 denotes an electronic switch 11a composed of a field effect transistor (FICT).

11b and a capacitor 110, and the capacitance of the capacitor 110 is C.

When the switching period is T, the equivalent resistance value Ro is expressed as Ro/Co. Reference numeral 12 designates a switching pulse generation circuit for alternately repeating the period T (T soching operation) using the output frequency f0 of the oscillation circuit 6 as an input, and FIG. 6 shows a time chart of the output pulses φ1 and φ2. .

13 is an operational amplifier, and since it has a feedback resistor 14 with a resistance value Rf, the amplification G0 of the inverting amplifier circuit composed of the suinotide capacitor 11, the resistor 14, and the operational amplifier 13 is -, and the oscillation circuit 6 It can be seen that it changes in proportion to the output frequency f0.

Similarly to the switched capacitor 11, 16 is a switched capacitor composed of electronic switches 161L, 15b and a capacitor 50. When the capacitance of the capacitor 150 is C4, its equivalent resistance value R7 is RI -/
It is represented by G. 16 is the capacity C210.

The differential capacitor 17 is an operational amplifier having an oscillation prevention capacitor 18 and a resistor 19 having a resistance value Rd as feedback elements.

Switched capacitor 15, capacitor 16°18,
If the resistor 19 and the operational amplifier 17 form a high-frequency boost circuit (phase lead circuit) and the influence of the capacitor 18 is ignored, the transfer function fcB) is as follows, and the corner frequency 11 of this circuit is as follows. Therefore, the corner frequency f is also the oscillation circuit 5.
It changes in proportion to the output frequency f0.

FIG. 6 shows an example in which the characteristics of the high-frequency compensation circuit 7 in FIG. Set.

As explained above, the high frequency compensation circuit 7 shown in FIG. 4 is composed of an inverting amplifier circuit controlled by the frequency and a high frequency enhancement circuit, so its overall characteristics are as shown in FIG. , it can be seen that the amplification degree of the slope portion and the corner frequency are controlled simultaneously.

FIG. 7 is a diagram showing another configuration example of the high-frequency compensation circuit 7, in which the oscillation prevention capacitor 18 in FIG. 4 is removed and a resistor 21 is inserted in series with the differential capacitor 16 instead. With this, characteristics similar to those shown in FIG. 6 can be obtained.

8, the resistor 21 in FIG. 7 is replaced by the electronic switch 3.
1a, 31b and a capacitor 310, which has been replaced with a suinotide capacitor 31.
By driving the capacitors 16 and 31 with the same switching pulse, the frequency fH, which was fixed in the explanation of FIG. 6, can also be controlled at the same time. As a result, s fl and f
Since it is possible to vary the corner frequency while keeping the HO ratio constant, by setting the ratio of %f and fH so that it is about 10 times the relationship, high-frequency oscillation can be naturally prevented. , set the high-frequency loop gain to an appropriate value (lower the high-frequency gain while maintaining the amount of phase advance that provides appropriate damping).
) to achieve more stable control.

FIG. 9(&) shows a configuration example of a low-pass filter 8 whose cutoff frequency is controlled by frequency. In the figure, 41 is an electronic switch 41! L.

41b and a switched capacitor 41C, and 42 is an electronic switch 42a.

42b and the switched capacitor 420, the capacitors 43 and 44, and the operational amplifier 46 constitute a second-order positive feedback filter. The switched capacitors 41 and 42 are switched by the switching pulse generation circuit 12 used in the explanation of FIG.
It has an equivalent resistance value proportional to its switching period. FIG. 9(b) is an equivalent circuit of FIG. 9(2L). Since the equivalent resistances 41' and 42' of the Swiss canonical shield are inversely proportional to the switching frequency, the cutoff frequency of this quadratic canonical shield is varied in proportion to the switching frequency.

As described above, the motor control device of the present invention can vary the cutoff frequency of the control system and the cutoff frequency of the low-pass filter in proportion to the reference frequency of the motor, that is, the rotation speed, and as a result, , at any rotation speed setting, the ratio of the output frequency of the frequency generator to the control system's power y-off frequency, as well as the ratio of the cutoff frequency of the low-pass filter, can be kept constant, so the maximum loop at that rotation speed can always be maintained. It is possible to obtain a gain and exhibit the best performance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention;
Figure 2 is a characteristic diagram of the high frequency compensation circuit, Figure 3 is a diagram showing the control characteristics of the motor, Figure 4 is a configuration example diagram of the high frequency compensation circuit, and Figure 5 is a diagram showing the configuration of the high frequency compensation circuit.
The figure is a time chart of the output pulse of the switching pulse generation circuit, and Figure 6 is a characteristic diagram of the high-frequency compensation circuit of Figure 4.
FIGS. 7 and 8 are diagrams showing other configuration examples of the high frequency compensation circuit, and FIG. 9(a). (b) is a configuration example of a low-pass filter and its isometric circuit diagram. 1... Motor, 3... Frequency generator,
4... Frequency divider circuit, 5... Oscillation circuit, 6
・・・・・・Phase comparison [Circuit, 7...High frequency compensation circuit L 8...Rono close filter, 9...
...Drive circuit, 11, 15, 31, 41.42...
...Switched Canopy. Name of agent Patent attorney Toshio Nakao and 1 other person 2 Figure 3 Figure 5 Figure 6 f Solid-liquid IK (Hz) Figure 7 Figure 9 U) ψI-2

Claims (1)

[Claims] (1) A motor equipped with a frequency generator that generates a frequency signal according to the number of surface rotations, and outputs a phase error signal by comparing a reference frequency signal and the output frequency signal of the frequency generator. a high frequency compensating means for advancing the phase of high frequency components included in the output signal of the phase comparing means;
A motor comprising filter means for removing ripple components included in the output signal of the high-frequency compensation means, and drive means for amplifying one output voltage of the filter means and supplying a drive current to the motor. What is claimed is: 1. A motor control device comprising: a phase control system; and a frequency signal proportional to the rotational speed of the motor to control the corner frequency and amplification degree of the high-frequency compensation means. (2. In the description of claim (1), a frequency signal having a frequency that is an integral multiple of the reference frequency signal,
A motor control device characterized in that the corner frequency and amplification degree of the high-frequency compensation means are controlled. (3) In the statement of claim (1) or (2), the reference frequency signal is obtained by dividing an output frequency signal of an oscillator, and the output frequency signal of the oscillator is 1. A motor control device characterized in that the corner frequency and amplification degree of the range compensation means are controlled. (4) In the recitation of claim 1 or 2, the reference frequency signal is obtained by dividing the output frequency signal of an oscillator, and the output frequency signal of the oscillator is used to A motor control device (Claim 59, Claim (1) Or, in the description of the fourth term, the high-frequency compensation means is an inverting amplifier whose input element is an equivalent resistance composed of a switched capacitor, and an equivalent resistance composed of a switched capacitor and a capacitor. A motor control device characterized in that it is configured to include an inverting amplifier with parallel elements as input elements. The input element is an inverting amplifier whose input element is an equivalent resistance consisting of a suinotide capacitor, and a composite element consisting of a series element of a capacitor and a resistor in parallel with an equivalent resistance consisting of a switched capacitor. A motor control device characterized in that it is configured to include an inverting amplifier having a An inverting amplifier with an equivalent resistance as an input element, and a series element consisting of an equivalent resistance and a capacitor made of a switched capacitor, are configured in parallel with an equivalent resistance made of another switched capacitor. A motor control device characterized in that it includes an inverting amplifier whose input element is a combining element. A motor control device characterized in that a constituent resistor is an equivalent resistor composed of a switched capacitor.