SU1297196A1 - Control device for reversible thyristor converter - Google Patents

Abstract

The invention relates to devices for controlling reversible thyristor AC-to-DC converters and can be used to power and regulate the speed of a reversible DC motor. The aim of the invention is to improve the reliability of the device. (L

Description

The purpose of the invention is achieved by the fact that when the pulse amplification unit i is operating, the current through the LED 21 in block 4 is continuous, since the LED 21 is connected parallel to the windings of the pulse transformers 8 and the voltage of these windings is in the form of a sequence of pulses applied to the LED 21 and the capacitor 19. During the passage of a pulse, the capacitor 19 is charged, and during the pause time it is discharged to the LED 21

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The invention relates to devices for controlling reversible thyristor AC-to-DC converters and can be used to power and regulate the speed of a reversible DC motor.

The aim of the invention is to improve the reliability of the device,

The drawing shows a diagram of the proposed device.

The device contains two thyristor bridges 1 and 2, connected by alternating current clips to the mains, and alternating current clips oppositely parallel to the load 3. The outputs of the blocks 4 and 5 of the amplifiers are connected to the thyristor control electrodes of the said bridges. pulses of the control unit, the inputs of which are connected to the outputs of the block 6 of the pulse-phase control, the input of this block is connected to the output of the logical switching unit 7.

The pulse amplification units in each channel contain ha pulse transformers 8, current-limiting resistors 9 and key transistors 10 connected in series, the common primary windings of the pulse transformers are connected to the plus, and the emitters of the transistors to the power supply minus. The secondary windings of the pulse transformers are connected through dividing diodes ... 1 to the control electrodes of the power thyristors of bridges 1 and 2. Since each is 19196

through the resistor 16. Thus, the photothyristor 20 in the pulse amplifying unit 5 for the whole operation time of the unit 4 is turned on, the primary windings im-. the pulse transformers 8 in the inoperative block 5 are shorted, and any failure in the switching logic unit 6 and the pulse phase control unit 7 cannot lead to the appearance of pulses at the output of the unit 5. 1 sludge.

The second gain block contains m identical channels, the drawing shows only one channel, for example, the first one and the connection of windings is shown.

Pulse transformer of any other channel, for example, r-th. The device is also equipped with a current sensor of the converter 12, the output of which is connected to the input of block 7. Blocks 4

and 5 pulse amplifiers each contain one thyristor optocoupler, with the photo thyristor 13 connected in block 4. by an anode to a common positive terminal of the primary windings of the pulse transformers, and a cathode through an open diode chain 14 to the negative terminals of the primary windings of the pulse transformers. The LED 15 is connected in block 5 anode

to the common plus terminals of the primary windings of the pulse transformers, and the cathode through the resistors 16 and 17 (in block 5) and the decoupling diode chain 18 to the negative terminals of the primary windings of the pulse transformers. A capacitor 19 is connected between the common point of the resistors 16 and 17 and the anode of the LED 15. Accordingly, the photo thyristor 20 is turned on

in block 5, and its LED 21 - in block 4.

The device works as follows.

Suppose that at the considered time moment thyristor bridge 1 is turned on, i.e. the pulse-phase control unit is connected to unit 4, which provides control pulses to the thyristors of the power bridge

five

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1. Since the LED 21 in block 4 is connected through resistors and diodes parallel to the windings of the pulse transformer1, the voltage of these windings as a sequence of pulses with a frequency m for the period of the network current is applied to the LED 21 and the capacitor 19. During the passage of a single pulse, the capacitor 19 is charged, and during the pause between pulses, it is discharged to the LED through the resistor 16. Thus, the current through the LED is continuous and the photo thyristor 20 in block 5 for the entire time that unit 4 is turned on, i.e. is in a conducting state. This means that the primary windings of all pulse transformers in non- (the booster unit 5 are short-circuited, hence any malfunction or interference in the preamplifier stages, in blocks 6 and 7, cannot lead to impulses at the output of the unit 5. Operation of the device when switching block 6 to block 5, i.e. when switching on bridge 2 is similar to that described.

Thus, the essence of the invention lies in the automatic shorting of the currently inactive time cascades of amplification of the impulses controlling the thyristor bridge, which dramatically increases the reliability of the separate control device.

Claims (1)

Invention Formula A device for controlling a reversible thyristor converter containing a logical switching unit, the input of which is connected to the current sensor of the converter, and the output is connected to the control input of the re-editor Y. Sereda Order 792/59 Compiled by A. Merkulova Tehred L. Serdyukova Proofreader N. Korol Circulation 661 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production polygraphic enterprise, Uzhgorod, st. Project, 4 five 71964 the key switch of the pulse-phase control unit, the outputs of which are connected to the inputs of the pulse-amplifying units, each 5 of the m channels of which contains a series-connected key transistor, a current-limiting resistor and a pulse transformer, one output of the secondary winding of which is intended to be connected to the control input of the corresponding thyristor of the converter, in order to increase the reliability it is equipped with two thyristor optocouplers, two for each pulse amplification unit with chains of m disconnecting diodes with common 1-1 anodes and two resistance-capacitance drives in the form of resistors and condi- the photothyristor of one optocoupler by the anode is connected to the common positive output of the primary windings of the pulse transformers in one pulse amplification unit, and the cathode to the common point of the anodes of the decoupling diodes, the cathodes of which are connected to the points of the negative output of the primary windings of the pulse transformers and current-limiting resistors of the corresponding channels, the anode of the diode of this optocoupler is connected to the common positive terminal of the primary windings of the pulse transformers 5 of the other pulse amplification unit, and the cathode through two series-connected resistors to the common point of the anodes of the diodes of the second isolating circuit, with this capacitor in each block being connected between the common point of the said resistors and the anode of the LED. 0 five 0