SU587571A1 - Thyristor conductivity control device for reversible frequency converter - Google Patents

Description

one

The proposed device relates to the field of electrical engineering and is intended for use in power converter equipment, in particular, to generate signals for blocking phase-control pulses of oppositely-connected gate groups of reverse frequency converters on thyristors.

A device for monitoring the conductivity of thyristors using a high-frequency signal source is known.

The disadvantage of this device is low selectivity.

It is also known a device for monitoring the conductivity of thyristors of a reverse frequency converter, comprising a high-frequency generator and two transformer sensors having a primary, secondary and measuring windings, the primary windings of which are connected in series and connected to the high-frequency generator, the secondary windings are connected in series and connected to the anode and thyristor cathode groups, in parallel with which are included VS - chains .2.

The disadvantage of this device is low selectivity.

2

The aim of the invention is to increase the selectivity of the device.

Claims (2)

This goal is achieved by the fact that in a device for controlling the conductivity of thyristors of a reversible frequency converter containing a high frequency generator and two transformer sensors having primary, secondary and measuring windings, the primary windings of which are connected in series and connected to the high frequency generator, the secondary windings are included: in series and connected to the anodic and cathodic groups of thyristors, in parallel of which are included RC. -chains, high and low frequency filters, a Fae detector, two comparators and a phase inverter, the measuring windings of the transformer sensors are connected to a symmetrical resistor in a bridge circuit, the middle terminal of the balancing resistor is connected to the high-frequency filter and the low filter is turned on frequency, the output of which is connected with the comparators with the inputs, and the second input of the phase detector through the phase shifter is connected to the output of the high-frequency generator. The invention is clear; drawing. The device contains the elements of the power circuit of the reversing converter, the opposing groups of thyristors 1 and the load resistance 2, shunting thyristor groups 3 C of the C-chain, as well as high-frequency transmitting sensors 4 and 5, having power windings 6 and 7, primary windings 8 and 9 measuring windings 10 and 11; a high-frequency generator 12, a balancing resistor 13, a high-frequency filter 14, a phase detector 15, a phase shifter 16, a low-frequency filter 17, comparators 18. The device operates as follows. When the thyristors are closed, the difference signal relative to the common point and midpoint of resistor 13 is caused only by the nonidentity of the measuring arms of the circuit, the phase of this signal is compensated by the phase shifter 16; therefore, after the low frequency filter 17, the voltage at the inputs of the comparators 18 is close to zero, and their output signals level of logic zero When opening any of the thyristors of the anodic or cathodic group, the equilibrium state of the bridge measuring circuit is violated. The amplitude increases and the phase of the difference signal at the input of the high-frequency filter 14 changes. In this case, a sequence of latitudinal modulated bipolar pulses appears at the output of phase detector 15. The low frequency filter 17 selects a constant component of the sTio signal. Further, this signal is fed to the Comparators 18, which are at a given level of this signal and depending; from its polarity, the signal of a logical unit, which is used to block the signals of the phase control of the corresponding thyristor group, is supplied to one of its outputs. Apparatus of the Invention A device for monitoring the conductivity of thyristors of a reverse frequency converter, comprising a high frequency generator and two transformer sensors having primary, secondary and measuring windings, the primary windings of which are connected in series and connected to the high frequency generator, the secondary windings are connected in series and connected to the anode and cathode groups of thyristors, in parallel with which are included the СС-chains, which, in order to increase the selectivity of the device, There are high and low frequency filters, a phase detector, two comparators and a phase shifter, the transformer sensor windings from the transformer sensors are connected to the bridge resistor in a bridge circuit, the middle terminal of the balancing resistor is connected to the high frequency filter and the phase detector is connected in series with the high frequency filter and a low-frequency filter whose output is connected to the inputs of the comparators, and the second input of the phase detector through the phase shifter is connected to the output of the high-frequency generator. Sources of information taken into account in the examination: 1. The author's certificate of the USSR 265261, cl. H Og M 1/08, 1968. 2.Dovganyuk I, I, and others. Thyristor state indication devices in frequency converter circuits with phase control. Electrical Engineering, Series Conversion Technology, 29.1972. tf one