CN2106443U

CN2106443U - Asynchronous motor phase control type frequency conversion step governor

Info

Publication number: CN2106443U
Application number: CN 91229751
Authority: CN
Inventors: 卢诚
Original assignee: KUNMING ELECTRONIC SPEED REGULATION EQUIPMENT GENERAL FACTORY
Current assignee: KUNMING ELECTRONIC SPEED REGULATION EQUIPMENT GENERAL FACTORY
Priority date: 1991-11-29
Filing date: 1991-11-29
Publication date: 1992-06-03

Abstract

The utility model discloses an asynchronous motor phase control type frequency conversion step governor, comprising a frequency conversion main loop and a control circuit. When the utility model works, the triggering angle of the thyristor of the frequency conversion main loop performs phase splitting sequence control and triggering phase control to conduct step frequency conversion speed governing under the precondition that the working magnetic flux of the motor is constant.

Description

Asynchronous motor phase control type frequency conversion step governor

The utility model belongs to the motor speed adjusting regulation device, also is the speed-regulating electricity-saving device that is attached to motor.

In the prior art in " the multiple speed of asynchronous motor economize on electricity speed regulating device CN882132415 " this technology main circuit with control circuit motor is carried out phase-splitting and controls, change the speed of its rotating magnetic field, to realize two kinds of speed AC/AC (alternating current) variable-frequencies of 1/3 and 2/3 power frequency.

But, with regard to the operation principle of asynchronous motor, desire to make motor to carry out frequency control, the supply frequency f that need satisfy input motor changes, input power source voltage value U is respective change thereupon also, and keep U/f ratio constant, above-mentioned patented technology is not carried out phase angle control to thyristor in the frequency conversion major loop, form no matter how electromotor velocity changes, the input voltage of motor does not all change, and therefore along with output frequency f reduces, the work magnetic flux φ of motor is too saturated, cause motor seriously to generate heat, even burn.

Secondly, see that according to the input and output voltage waveform (line voltage) that this technology is drawn Fig. 3, motor are rotary, but noise is very big, and electric motor overheating is serious.

The utility model purpose is to provide a kind of asynchronous motor step speed regulation device that adopts phased variable frequency control.

The utility model is controlled triggering the phase angle at above-mentioned defective, and when the supply frequency f of motor changed, the U/f ratio that remains motor was constant.It is continuous adjustable to trigger phase angle [alpha]=30 °～150 °, can satisfy the requirement of the ventilation blower and the pump class electric machine speed regulation of varying duty.

Description of drawings

Fig. 1 the utility model electrical principle block diagram

The circuit diagram of Fig. 2 the utility model major loop

Fig. 3 known technology output line voltage oscillogram

A. input voltage waveform power frequency line voltage waveform b.1/3

C.2/3 power frequency line voltage waveform

Fig. 4 the utility model output line voltage oscillogram

A. input voltage waveform power frequency line voltage waveform b.1/3

C.2/3 power frequency line voltage waveform

Fig. 5 the utility model control circuit figure

System shown in Figure 1 is on the basis of phase-splitting sequential control, increase phase angle control, make the triggering phase angle continuous adjustable, through pulse distribution, Pulse Power Magnification from 30 ° to 150 °, trigger impulse to 12 thyristors is controlled, thereby reaches the effect of motor frequency change speed governing.

Fig. 5 shows native system phase place trigger angle α control unit link circuit (principle), its course of work: the sinusoidal all-wave of synchrotrans input is become half-wave; Become square wave from half-wave; Become sawtooth waveforms from square wave; Become the adjustable square wave in forward position from sawtooth waveforms, output to the pulse distribution link.

Facts have proved that this output voltage waveforms can make the motor steady running, continuous operation is 33,000 hours, and superheating phenomenon does not take place.

In addition, also increased measures in the line:

1. for keeping output voltage stability, in system, adopt voltage feedback circuit, meet voltage ripple of power network when big, can guarantee the relatively stable of motor terminal voltage.

2. in system, adopt multiple current protection measure, promptly in major loop, adopted air switch, thermal relay and protective tube; in control circuit, adopt the maximum phase angle clamp circuit that triggers, simultaneously in case something unexpected happened; as motor rotation blockage, the also unlikely motor that burns out.

Claims

1, a kind of asynchronous motor phase control type frequency conversion step speed regulation device comprises the thyristor grouping control circuit that triggers control, main circuit and be made up of synchronous generator circuit, logic control circuit, thyristor triggering power amplifier in parallel, it is characterized in that:

a。Thyristor in the frequency conversion major loop is carried out the phase-splitting sequential control and triggers phase angle control, and trigger phase angle [alpha]=30 °～150 °, adjustable continuously therebetween, constant with the u/f ratio that keeps motor,

b。In governing system, trigger phase angle clamp circuit restriction maximum operating currenbt with regulated output voltage and with maximum with voltage feedback circuit.