SU1249639A2 - Device for checking conduction of converter rectifiers - Google Patents

Abstract

The invention relates to electrical engineering, can be used in devices for the development of reversible and non-reversible thyristor converters and is an improvement of the invention according to the author. ev No. 1025006. The purpose of the invention is to increase the reliability of the functions

Description

full range of adjustment and simplification of the device. In the case of an open (conductive) state, none of the valves of the anode group of the reversing converter (RP) 4 shunts the input of the corresponding control unit (KB) 5, 6 or 7. At the same time, the current of the corresponding phase is closed through the diode 16 and the corresponding open thyristor . The absence of current in the base circuits of transistors 18 and 19 of at least one KB 5, 6 or 7 leads to the appearance of a signal of a logical unit at the corresponding

I

The invention relates to electrical engineering, can be used in control devices of reversible and non-reversible thyristor converters and is an improvement of the device according to the author. St. No. 1025006.

The purpose of the invention is to increase the reliability of operation in the full range of control and simplify the device.

FIG. I shows a diagram of the device for controlling the conductivity of the valves of a three-phase converter; in fig. 2 - logical element circuit OR.

The device contains limiting resistors 1–3 for connecting to the phases of the converter 4, controlling units 5d7, capacitor 8, diodes 9–11, element ШШ 12, optocoupler element 13, output unit 14, additional diodes 15–17. As the diode 16, a zener diode can be used. Each of the controlling blocks contains transistors 18 and 19 and resistors 20 and 21. The IL element contains transistors 22-24, resistors 25-28.

The device works as follows.

In the closed state of the gates of the converter 4, currents from the corresponding phases of the transducer flow through the limiting resistors 1-3 and the base-emitter circuit of the transistors 18 and 19 of each end of the blocking unit

the input element OR 12. As a result, the output of block 14 generates a signal prohibiting the supply of control pulses to the cathode group of RP RP 4. In the case of the open state of one of the cathode group RP 4, the input of the corresponding CB 5, 6 or 7 is shunted via the circuit: open valve - diode 15 - IL 12 element - diode 17. As a result, at the output of block 14, a signal is generated that prohibits the supply of control pulses to the valves of the RP4 anode group. 2 Il.

tel. The transistors 18 and 19 in the control units perform two functions: they rectify the alternating current and form logic signals of zero or one in the collector circuit.

When the converter converter gates 4 are closed, the transistors I8 and 19 of the control units 5-7 are open and form signals in the collector circuits

logical zero, which arrive at the corresponding inputs of the SHSh 12 element and through the optocoupler element 13 to the output block 14. The output block generates a logic signal to

enabling the supply of pulses to control the reversing converter valves.

In case of open (conducting)

the state of none of the anode valves

the group (common anodes) of the converter 4 is shunted by the input of the corresponding control unit, while the current of the corresponding phase is closed through the diode 16 and the corresponding open

ty thyristor. For example, the valve of the anode group in phase C is open (Fig. 1). The input of the control unit 7 is shunted by a diode 16 and an open valve in phase C. There is no current in the base

The circuits of the transistors 18 and 19 of at least one control unit 5-7 result in the appearance of a signal of a logical unit at the corresponding input of the element 1 SH 12, as a result of the transmission

of this signal through the optocoupler element 13 to the output unit 14, the state of the latter is changed by

Positive, i.e. a signal is generated prohibiting the supply of control pulses to the opposite (cathodic) group of valves of the reversing converter 4.

In the case of the open state of one of the cathode group valves (common cathodes) of the converter 4, the input of the corresponding control unit 5-7 is shunted through a circuit: an open valve (for example, in phase c) - diode 15 - OR element 12 - diode 17. The values of the resistors 3, 20 and 21 (Fig. 1) and 25-28 (Fig. 2) are chosen so that transistors 18 and 19 are locked in this mode. A chain of resistor 2.1 and diode 17 is designed to form a negative (blocking) bias voltage applied to the base of transistor 18 of each control unit 5-7. In addition, using the resistor 21, you can select the required threshold for unlocking the transistor 18. As a result of shunting the input circuit of one of the control units, a logical unit signal is sent to the corresponding input of the OR element 12, and the output unit 14 generates a signal that prohibits supply of control pulses to the valves of the anode group of the reversing converter 4.

Supply voltage for elements.

the circuits are formed from the controlled ,, conclusions of the control units of the

voltage, and an additional power source that is electrically isolated, is not necessary. In contrast to the known device, in the proposed invention, a two-half-period voltage rectifying is taken from the anodic and cathodic groups of the reversing converter 4. The positive voltage removed from the valves of the converter 4 with respect to the common point O, is rectified by diodes 9- 11, negative - diode 15.

Fulfillment of the mitels in the proposed device according to the full-wave 50 scheme makes it possible to obtain a supply voltage with small pulsations, which

The collectors of the first and second transistors, the third output pins of the control units are formed by the emitters of the first transistors and connected to the anode of the third diode, the inputs of the control units are formed by the emitters of the second transistors and some of the first resistors, the second pins of which are connected to the bases of the first transistors, the second resistors controlling blocks are connected between the bases of the first and second transistors, the cathode of the first and the anode of the third diode are connected respectively to the positive and negative CB vshodam power OR element.

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in turn, it leads to a simplification of the device (a significant decrease - by 10-100 times - the capacitance of the capacitor 8, the use of resistors 20 in the control units 5-7 instead of zener diodes). The implementation of a full-wave rectifier eliminates the supply voltage and thus ensures reliable operation of the device in the full range of the phase control angle (almost from

About up to 180).

Claims (1)

Invention Formula Device for controlling the conductivity of the converter valves on the author. St. No. 1025006, characterized by iTeM, that, in order to increase the reliability of operation in the full range of phase control and simplification, it is equipped with first, second and third diodes, and the control units are each filled as first and second transistors, and first and second resistors, and the anode the first and the cathode of the second diode are connected and intended to be connected to the common point of the converter valves, the anode of the second and the cathode of the third diode are connected to one output pins of the control units formed by the bases of the second pipe Nzistorov, other weekend The collectors of the first and second transistors, the third output pins of the control units are formed by the emitters of the first transistors and connected to the anode of the third diode, the inputs of the control units are formed by the emitters of the second transistors and some of the first resistors, the second pins of which are connected to the bases of the first transistors, the second resistors controlling blocks are connected between the bases of the first and second transistors, the cathode of the first and the anode of the third diode are connected respectively to the positive and negative Nomi vododam nutrition element OR. . AND CpU2.2