SU1341707A1 - A.c.-to-a.c.voltage thyristor converter - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to reduce power losses. When the thyristors 1 and 2 are closed, the capacitor 5 is charged. When the voltage on the capacitor 5 reaches the value of the voltage of the dynistor 8, the latter is turned on and the capacitor 5 is discharged. As a result of the discharge of the capacitor 5, a control pulse is formed, including the corresponding thyristor

Description

134

The invention relates to electrical engineering and can be used in power converter equipment, in particular, to control the voltage in single phase AC networks.

The aim of the invention is to reduce power loss.

The drawing shows a schematic diagram of the proposed device.

The device contains thyristors 1 and 2, connected in parallel with the load 3 to the AC network. The device also contains an RC-chain of resistor 4 and capacitor 5, switch 6, the middle bridge 7 and dynistor 8.

The CS circuit is connected via switch 6 to thyristors 1 and 2. Capacitor 5 is connected to the rectifier bridge 7, the DC output of which is connected to the distor 8. The primary windings are connected between the cathode of the dynstor 8 and the adjacent arms of the rectifier bridge formed by the diodes pulse transformers 9 and 10, the secondary windings of which are connected to the control electrode of the corresponding power thyristor (1,2),

The device works as follows.

In the initial state, the thyristors 1 and 2 are locked and connected through the load 3 to the AC mains voltage. The pulsed-phase control device is powered from the anode voltage of thyristors 1 and 2, which through the switch 6 enters the RC-chain. At the moment when the voltage on the capacitor 5 reaches the switching voltage of the dynistor 8, it switches on. As a result of switching on the dynistor and discharging the capacitor 5, a control pulse is formed, including the corresponding

Editor T. Parfenova

Compiled by A. Zenchenko.

Tehred M. Khodanich Proofreader S. Shekmar

Order 4443/56 Circulation 659 Subscription

VNIIPI USSR State Committee

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

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

7072

thyristor U, 2). The control of the phase of the control pulses in relation to the phase of the anode voltage is thyristic. Levels 1 and 2 are achieved by changing the charging time of capacitor 5 by changing the resistance value of resistor 4.

The device provides the supply voltage of control pulses to the power thyristors 1 and 2, which is one-time per half-period, because as a result of the transition to the propying state, the anode voltage of the thyristors 15 decreases to the minimum value, which eliminates the possibility of recharging the capacitor 5 to the magnitude of the switching voltage of the dynistor 8 and increases reliability.

20

Claims (1)

Formula and inventions A thyristor converter of alternating voltage to alternating current, containing 25 oppositely connected thyristors connected between the input and output terminals, the first pulse transformer, a rectifying bridge, an RC-chain and a threshold 30 element, characterized in that, in order to reduce power losses, a second pulse transformer is inserted, the RC chain is switched on parallel to the thyristors through an input key, the capacitor of the RC chain is connected in parallel to the AC terminals of the rectifier bridge, the outputs of a constant the current of which is connected to a threshold element, 40 made in the form of a dynistor, between the cathode of which and the anodes of the diodes forming the adjacent arms of the rectifying bridge, include the primary windings of the pulse transformers, 5 secondary voltages heel which are connected to the control electrodes of respective thyristors.