SU964897A2 - Device for control of thyristors of three-phase pulsed voltage source - Google Patents

Description

(W) DEVICE TO CONTROL THIRISTORS OF THREE-PHASE PULSE SOURCE OF VOLTAGE

; The invention relates to converter technology and can be used to control thyristors of three-phase pulsed voltage sources used in electrochemical processing plants and other devices.

According to the main author. St. ff 7 1385 a device is known for controlling the thyristors of a three-phase pulsed voltage source, which contains diodes and, in each phase, a synchronization unit, the output of which through the separation diode is connected to the shunt electronic key circuit, and the output driver of the pulses, which includes a cell memory, moreover, the synchronization unit is designed as a generator on a single junction transistor (|) with an azo-shifting RC circuit in the base circuit, and the magnetic memory unit is designed as a three-phase ring shift register rt transistor cells

which holes are connected via diodes to the outputs of synchronization blocks of the corresponding phase

A disadvantage of the known device is the low reliability due to the impossibility of obtaining pulses on a load with a steep falling edge and adjustable duration without varying the amplitude.

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

Claims (1)

The goal is achieved by the fact that the known device is equipped with locking blocks for the number of main thyristors, each of which contains an additional thyristor and a series-connected capacitor, diode and resistor, and switching thyristors for the number of main thyristors, the control electrodes of which are connected to the outputs of the corresponding amplifiers -formers, each of which is connected by its input through the synchronization unit to the corresponding input of the magnetic memory unit, with the additional The common and commuting thyristors are connected in parallel to the main thyristor, the commutator agrees with the main thyristor and an additional one - towards it, and the locking terminals are connected between the cathodes of the corresponding main and commutating thyristors of the same network phase, and the diodes and resistors are connected between the cathodes of the switching thyristors of the previous phase and the anodes additional thyristors of the following phase. The drawing shows the circuit diagram of the device. To control the thyristors of a three-phase pulsed source, the device for controlling the thyristors contains an additional thyristor 1 in each phase, terminals for connecting the main thyristor 2, a switching thyristor 3 and, respectively, the other two phases - additional thyristors k and 5 and switching thyristors 3, the cathodes of which are connected to the primary windings of the three-phase transformer 6, as well as the capacitor 7, the locking blocks, each of which consists t from diode 8, resistor 9, additional and switching thyristors, which are triggered by form-amplifiers 10. The inputs of form-formers 10 are connected via differentiating circuits from capacitor 1 1, diode 12 and resistor 13 to the outputs of the corresponding waiting multivibrators 14, the input of each of which is through the second A differentiating circuit consisting of a capacitor 15, a diode 16 and a resistor 17 is connected through an appropriate amplifier 18 to a magnetic memory block 19. The output windings of a three-phase transformer 6 connect Inen to the terminals for connecting the load 20 through a diode rectifier 21. The device operates as follows. A pulse from amplifier 18 triggers the thyristor 2 phase A and thyristors 5. At the same time, capacitor 7 of phase A is charged through open power thyristor 2, diode 8, resistor 9 and open thyristor 5. At the same time, the pulse from amplifier 18 passes through the differential A chain consisting of a capacitor 15, a resistor 17 and a diode 16 starts the waiting multivibrator 1. The impulse from the waiting multivibrator Vk through the differentiating chain 11-13 and amplify-shaper 10 switches on the switching thyristor 3 which connects the negatively charged electrode nsatora 7 to the anode 2 Open-power thyristor phase A, thereby closing it. Similarly, the scheme works on all other phases. The forced closing of the power thyristors 2 allows to obtain short pulses close to square on load 20, the duration of which is controlled by a waiting multivibrator I. Using the invention improves the reliability of the device by reducing the heat losses caused by receiving pulses close in shape to rectangular. Claims An apparatus for controlling thyristors of a three-phase pulsed voltage source according to ed. St. (f 7 1385, which means that, in order to increase reliability, it is equipped with locking blocks according to the number of main thyristors, each of which contains an additional thyristor and a series-connected capacitor, diode and per resistor, and by switching thyristors by the number of main thyristors, the control electrodes of which are connected to the outputs of the respective driver amplifiers, each of which is connected by its input through a synchronization unit to the corresponding input of the magnetic memory unit, and itelny and commutating thyristors connected in parallel with the main commuting thyristor in accordance with the basic and optional - to meet him, and capacitors at: zlov locking connected between cathodes of the respective main and commutating thyristors of one phase of the network, and the diodes and resistors 596 8976 included between the cathodes commuting-, Sources of information, thyristors of the previous phase and taken into account during examinations: additional thyristors for the next 1. Author's certificate of the USSR for the next phase., cl. H 02 M 1/08. 1980