SU1026271A1 - Device for controlling two-phase induction motor - Google Patents

Abstract

A DEVICE FOR CONTROLLING “NON-PHASE ASYNCHRONOUS DIATOR” containing a control unit, the first output through element I is connected to the counting input code, and the second with the installation input of the N-discharge counter SP information informational headers and the first control panel. with the output of the counter, and the video output is connected to the second input of the element I and the input of the switch, the outputs of which are connected to a power amplifier, characterized in that with an increase in the range of the linear regulator neither the motor, it is supplied (often by a divider often) gy, whose input is connected to the third output of the control unit, and the output to the second input of the switch. (L

Description

Yu

about: to

ffiif. one

The invention relates to electrical engineering, in particular, to pulsed automation devices with pulse-width modulated signal, and can be widely used in control systems of two-phase asynchronous motors in those cases when it is necessary to have linear control over the entire range of the torque characteristic of the engine.

A digital device for controlling an asynchronous two-phase motor is known comprising a control unit, a digital counter, a switch and a power amplifier.

The disadvantage of the device is the poor linearity of the adjustment.

It is also known a digital device for controlling an asynchronous motor containing an N-bit binary counter having counting triggers, an AND and register register, a control unit including a pulse generator, a synchronization circuit and a trigger, a switch having AND circuits, a sign trigger and a power amplifier 2 .

The disadvantage of this device is the effect on the phase of the first harmonic of the output voltage, which leads to a deterioration in the linearity of the torque characteristic of the engine.

The closest in technical essence to the present invention is a device for controlling a two-phase asynchronous motor, comprising a control unit, the first output of which is connected to the counting device through element I, as well. the second - with the installation input of the N-bit counter with information inputs and the first installation input of a static trigger, the second installation input of which is connected to the output of the counter, and the output connected to the second input of the And element and the first input of the switch, the outputs of which are connected to the power amplifier .

A disadvantage of the known device is the poor linearity of the adjustment characteristic of the engine.

The purpose of the invention is to increase the range of linear regulation.

The goal is achieved by the fact that a device for controlling a two-phase asynchronous motor, which contains a control unit, the first output of which is connected to the counting input through the I element, and the second output to the set input of the N-discharge counter with the information inputs and the first setting input of the static trigger , the second installation input of which is connected to the output of the counter, and the output is connected to the second input of the element I and the first input of the switch, the outputs of which are connected to the power amplifier, is equipped with a divider m frequencies, the input of which is connected to the third input control unit and output - to the second input of the switch.

FIG. 1 shows a block diagram of the device; in fig. 2 is a control block diagram; in fig. 3 - time diagrams of signals.

The device comprises a control unit 1, a static trigger 2, an AND 3 element, an N-digit counter 4, a switch 5, a power amplifier 6 and a frequency divider 7. The first output of control unit 1 is connected via element I 3 to the counting input of the N-bit counter 4.. The second output of the control unit 1 is connected to the first installation input of the STATIC trigger 2 and the installation input of the N -digit counter 4, to the information inputs of which the input signal is supplied in the form of a binary code. The transfer output of the counter 4 is connected to the second installation input of the static trigger 2, the output of which is connected to

0 to the second input of the AND 3 element and the first input of the switch 5. The third output of the control unit 1 is connected to a divider

7 frequencies, the output of which is connected to the second input of the switch 5. The first

5 and the second switch 5 is connected to the amplifier. 6 power.

Control unit 1 contains a generator

8 pulses, second N-bit counter 9, counting trigger 10,

0 The generator output 8 pulses are connected to the first output of the control unit 1 and connected to the counter 9. The transfer output of the counter 9 is connected to the second output of the control unit 1 and the counting

5 by trigger 10, the output of the latter is connected to the third output of the control unit. Positions 11 to 17 designate the output signals of the device elements.

In the first half of the working frequency

The engine device operates as follows.

From the second output of control unit 1, pulses with a frequency of 2Ki (where is the working frequency of the induction motor) are fed to the control input of the N-digit counter 4, the input signal is written as a binary code, and the installation of the static trigger 2 is set to allow passage Imputzov: clock P from the first output of the control unit 1 through the elements And 3 to the cash input of the N-discharge slider 4, the frequency of the pulses is determined by

FrZKiQ,

. {N

- working asynchronous frequency

where is the engine;

- the number of bits of the control code;

K is the required number of control pulses in one half period.

 transferring the M - bit counter 4 when it is filled switches the static trigger 2, prohibiting the passage of pulses from the first output of control unit 1 to the counting input of the tl-discharge counter 4. Pulses from the top of the static trigger 2, the duration of which is proportional to the input signal I Mim

l y go to the first input of the switch 5. And the second input of the switch 5 is fed to the 5 direct reference signal of the counter 4 (Fig. 3) from the third output of the control unit 1 through the frequency divider 7. As a result, the switch 5 generates a pulse-width control signal (Fig. 3), which is fed to the power systenber 6. FIG. 3 depicts stress plots at K 2

In the second half-cycle, the device works in the same way as the first.

An introduction to the proposed frequency splitter with corresponding links between it and the control unit and the switch provides an opportunity to increase the number of control pulses over a period of time corresponding to one half-period of the supply voltage, which allows extending the linear regugaring range.

P

I j

/

t 3

/. iJiiiiiiiiiiiiiMiiiiiiiiiJiiiHiiiiiiiiJJJUiilli

Claims (1)

DEVICE FOR CONTROLLING A TWO PHASE ASYNCHRONOUS MOTOR, comprising a control unit, the first output of which is connected via a And element to the counting input, and the second to the installation input of the N-digit counter with η information inputs and the first installation input of the static trigger, the second installation input of which is connected to the count output and the output is connected to the second input of the And element and the first input of the switch, the outputs of which are connected to a power amplifier, characterized in that, in order to increase the range of the linear reg lation of the engine, it is provided a frequency divider whose input is connected to the third output of the control unit and output - to the second input of the switch. P'