SU1295491A1 - Vpriable a.c.voltage-to-a.c.voltage converter - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used to regulate power on an AC load. The purpose of the invention is to increase the service life of the thyristor unit and expand the functionality. Power control is carried out by changing the turn-on time of the thyristor unit 1. The thyristor unit 1 is switched on for an integer number of half-periods of the network only if there is a logical 1 at the output of the generator 10 control pulses. When the resistance of the load 3 decreases below the value specified by the threshold device 6, a logical O is established at the output of the trigger 8. With an increase in the load current above the value specified by the threshold device 7, the logical output is established at the output of the trigger 9. In the presence of the overload mode, the voltage of the triggers 8, 9, acting on the circuits 11, 14, prevent the passage of the signal from the output of the generator 10 to the control inputs of the thyristor unit 1. The trigger 17 and the isolation transformer I5 ensure that the thyristor unit 1 is re-enabled times at zero crossing of the load current, whereby the goal is achieved. 1 il. (L: l

Description

1129

This invention relates to electrical engineering, in particular to automatic power control.

The purpose of the invention is an increase in the service life of the thyristor unit and the expansion of functionality by eliminating a single-wave mode when operating on an active-inductive load.

The drawing shows the functional scheme of the device.

The converter contains a thyristor unit 1, the power outputs of which are connected to the alternating current source 2 and to the volume of the regulated NIN - load 3 with the load resistance sensors 4 installed on it and the load current sensor 5, each of which is connected to the series-connected threshold elements 6 and 7 and triggers 8 and 9, the generator 10 control pulses, the output of which is connected to one of the inputs of the circuit And 11 and to the input of the driver I2 pulses on the falling edge of the signal, the output of which is connected to the reset inputs of the triggers 8 and 9, the output of the circuit NOT i3 is connected to the input of the sensor 4, the second circuit AND 4, each of the inputs of which with

the outputs of flip-flops 8 and 9, and the output of the AND I4 circuit - with another input of the first AI circuit, the isolation transformer 15, the primary winding of which is connected parallel to the thyristor unit 1, and the secondary winding - to the input of the windrower 16 sync pulses, trigger 17, direct and inverse outputs connected to the control inputs of the thyristor unit 1, the first direct and inverse inputs of the trigger 17 are connected respectively to the first and second outputs of the driver 16 sync pulses, and the second direct and inverse inputs of the trigger 17 to the output of the first AND circuit eleven.

The device works as follows.

The voltage taken from the outputs of the thyristor unit 1 is fed to the isolation transformer 15, the secondary winding of which is fed to the driver of 16 clock pulses. The latter forms pulses at times corresponding to the passage of the load current through zero. These sync pulses arrive at the first direct and inverse inputs of trigger 17. At

five

ABOUT

0

five

thirty

35

12

Signal-signal log, 1 on the second direct and inverse inputs of trigger 1.7 on the direct and inverse outputs of trigger 17 every 180 e. hail, control pulses are generated, arriving at the control input of the thyristor unit 1. Signal Log.1 at the output of the first circuit AND I1 and, therefore, Log.1 at the second direct and inverse trigger input 17, occurs if the Log .1 at the output of the generator O and at the output of the second circuit AND 14. The generator 10 is controlled from some external controller, for example a temperature controller. Both inputs of the second circuit And 14 are interlocking.

In the pause of the output signal of the generator 10, the load resistance of the sensor 4 is measured. If resist. unacceptably low, the first threshold element 6 is triggered, the first trigger 8 overturns and the second AND 4 scheme locks the control signal coming to the second direct and inverse inputs of the trigger G 7 until the next pause of the generator 10. the formation of control pulses arriving at the control input of triristor unit 1, the voltage across the load becomes zero. If at the moment of switching the thyristors the load current exceeds the permissible value, the sensor 5 overturns through the threshold element 7; trigger 9, blocking the circuit I I4 on the second input, which also leads to the disconnection of the thyristor unit 1 from the load. The shaper 12, on the back of the signal of the generator IO, forms a short pulse of resetting the triggers 8 and 9 to zero, ensuring the periodicity of operation of the interlocks and automatic recovery of the device after removal of the short circuit or overload. Since the formation of the control pulses is performed by the trigger 17, each subsequent activation of the regulator occurs at strictly defined moments regardless of the moment the generator 10 is turned on.

For example, if the disconnection of the thyristor unit I occurred at the time when the negative half-wave of the supply

regardless of the time of switching on the generator, the switching on of the thyristor unit 1 occurs at the moment when the positive voltage half-wave is applied to the load.

Form, inventive invention Adjustable AC / AC voltage converter containing a thyristor unit connected between input and output terminals, clock generator, first AND circuit, the first input of which is connected to the generator output of control pulses, load current sensor and load resistance sensor, two threshold elements, two flip-flops, pulse shaper on the falling edge of the signal and the NOT circuit, with this the load current sensor and the load resistance sensor are connected to the inputs the corresponding threshold elements, the outputs of which are connected to the inputs of the corresponding triggers, the output of the generator of control pulses through the circuit is NOT connected to the trigger input of the sensor

Compiled by I.Golovinova Editor N. Bobkova Tehred L. Serdyukova Proofreader I. Muska

Order 625/60 Circulation 661 Subscription

VNIIGSh of the USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

 , fO

f5

20

25

load and through the pulse shaper on the falling edge with the trigger reset inputs, characterized in that, in order to increase the service life of the thyristor unit and enhance functionality by eliminating the single-Bolnova mode: with active-inductive load, the second And and the third trigger are introduced In addition, the driver of the clock pulses contains an isolating transformer, the primary winding of which is connected in parallel with the thyristor unit, and two outputs working in antiphase, connected correspondingly with the first direct and inverse inputs of the third trigger, the direct and inverse outputs of which are connected to the control inputs of the thyristor unit, and the second direct and inverse inputs of the third trigger are combined and connected to the output of the first I circuit, the second input of which is connected to the output of the second circuit And, the first and second inputs of which are connected to the outputs of the first and second, respectively. rygo triggers.

Claims (1)

Form, for la inventions Adjustable transducer trans; alternating voltage to an alternating current, containing a thyristor unit connected between input and output terminals, a clock driver, a first I circuit, the first input of which is connected to the output of a control pulse generator, a load current sensor and a load resistance sensor, two threshold elements, two triggers, a pulse shaper on the trailing edge of the signal and the circuit NOT, while the outputs of the load current sensor and the load resistance sensor are connected to the inputs of the corresponding threshold elements, the outputs of which are connected to by the strokes of the corresponding triggers, the output of the control pulse generator through the circuit is NOT connected to the trigger input of the load resistance sensor and through the pulse shaper on the trailing edge with trigger reset inputs, characterized in that, with the aim of 5 increasing the life of the thyristor unit and expanding functionality by eliminating single-wave mode when operating on an active-inductive load, a second AND circuit and a third trigger are introduced, in addition, the clock generator contains a dividing transf a motor, the primary winding of which is connected in parallel with the thyristor unit, and two out-of-phase outputs connected respectively to the first direct and inverse inputs of the third trigger, the direct and inverse outputs of which are connected to the control inputs of the thyristor unit, and the second direct and inverse inputs of the third trigger are combined and connected to the output of the first circuit And, 25, the second input of which is connected to the output of the second circuit And, the first and second inputs of which are connected to the outputs of the first and second, respectively. horn triggers.