SU1381646A1 - Device for checking current in semiconductor rectifiers - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to converter equipment, and can be used during the operation of reversible thyristor converters. The aim of the invention is to expand the scope. If one of the parallel thyristors, for example 1.1, does not conduct current either due to the absence of control pulses or due to the safety of the fuse, and the thyristors 1.2 ... 1.P normally conduct current, then the first output of the current presence sensor 5.1 and at the first output of the control key 7.1 a logical zero signal appears. As a result, a logical unit signal appears at the output of AND 12, which is an alarm signal. 1 il. (L

Description

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The invention relates to electrical engineering, in particular to converter equipment, and can be used in the operation of reverse thyristor converters.

The purpose of the invention is to expand the field of application of the known device to a bridge circuit of a reversible converter by controlling the flow of current through any of the thyristors of the counter-parallel bridge while maintaining the number of current meters and their installation sites.

The drawing shows the functional diagram of the device for controlling the current in semiconductor valves.

The device contains in one shoulder thyristors 1.1, 1.2-1.P of the Forward group and thyristors 2.1, 2.2-2.P of the Back group and in the other shoulder are thyristors 3.1, 3..p of the Forward group and thyristors 4.1, 4.2-4.P of the group Back

In each branch of the phase bus supplying the current to the individual parallel branch, a sensor 5.1, 5.2-5. P of the presence of current is installed, and in the common phase P1ine there is a sensor 6 of the presence of current, and current sensors sensitive to its direction are used: the output is intended to detect the flow of currents flowing from BP1NY (down arrow), which corresponds to the on state of thyristors 1 and 4; the second output is intended to register the currents flowing into the spine (up arrow), which corresponds to the on state of thyristors 2 and 3,

Sensors 5.1, 5.2-5.P and 6 of the presence of currents are equipped with respectively dual control keys 7.1, 7.2-7.P and 8, with the first information input of the specified element connected to the first output of the current presence sensor, the second information input with the second output sensor current presence; the control inputs of the keys are interconnected and with the clamp 9 for the railings. logical output

switching device

The device also contains the elements AND-NOT 10 and 11 and the elements AND 12 and 13, and the inputs of the element AND-NOT 10 are connected to the first outputs of the individual controlled keys 7.1, 7.2-7.P, and the input of the element IS-NOT 1 1 - with the second outputs of the individual controlled keys 7.1, 7.2-7.P, the output element

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AND-NE 10 - with the first input of the element AND 12, and the output of the element AND-NO 11 - with the first input of the element AND 13, the second input of the element AND 12 - with the first output of the controlled switch 8 of the channel for measuring the total phase current, and the second input of the element And 13 - with the second output of the controlled key 8.

The device control current operates as follows.

Suppose that during normal operation of the converter, characterized by the impossibility of simultaneously turning on the thyristors of the Forward and Back groups on the one hand and simultaneously turning on the thyristors of the two shoulders of the bridge fed from the same phase on the other hand, all parallel thyristors 1.1, 1.2-1 are connected. P. This state of the power circuit corresponds to the logic signal 1 at the first outputs of current meters 5.1, 5.2-5.P and 6th logic signal O at the second outputs of the indicated current meters, as well as the logic signal 1 at terminal 9.

This means the presence of signal 1 at the first outputs of the controlled keys 7.1, 1.2-1.p and 8, as well as at the output of the AND-NE element 11 and the presence of the signal O at the second outputs of the controlled keys, as well as at the output of the element IS-NOT 10 At the outputs of both elements And 12 and 13 there is a signal O, corresponding to the passage of current through all parallel thyristors.

Suppose that the current circuit does not pass at all. This state of the power circuit corresponds to O on both the codes of the sensors 5.1, 5.2-5.P and 6 of the presence of current, on both outputs of the controlled keys 7.1, 7.2-7.P, and the signal 1 at the output of the elements AND-NE 10 and 11, and also on the clamp 9. At the outputs of the elements And 12 and 13 there is a signal O.

Suppose one of the parallel thyristors, for example 1.1, does not conduct current either due to the absence of control pulses or due to the safety of the fuse, and the thyristors 1.2-l.n normally conduct the current. This entails, in contrast to the case when all parallel thyristors are conducted, the appearance of a logical signal O at the first output of the sensor 5.1, the presence of current and at the first output of the controlled key 7.1, and at the output of the elements

A NAND 10 n I 12 appears logical signal 1, corresponding to the absence of current in at least one of the parallel branches of the bridge arm shown on the left in fig. one.

The device can be realized, in particular, on the basis of contactless current sensors, each of which is a 0-shaped magnetic circuit with a gap surrounding the bus, in which two magnetically controlled logic circuits of the type K1116 KP1, KII2 are installed, oriented in space in such a way that The first one is sensitive to one direction of current (FIG. 1, down arrow), and the second to another (Figure 2, up arrow). For example, K155 series chips can be used as logical elements. For example, the K155 KP2 dual digital selector-multiplexer can be used as a controllable key.

The device can be used to control the operation of the fuses.

Claims (1)

Invention Formula A device for monitoring current in semiconductor valves connected in parallel and connected to each phase of a multiphase converter, containing individual sensors for the presence of current installed in each branch of the Aahn bus, sensor for the presence of a common phase current, the first NAND element and the first element AND, that in order to expand the field of application five 0 five 0 five 0 No, the second element AND, the second element AND-NOT, dual controllable keys according to the number of current presence sensors, a terminal for connecting the output of a logic switching device, and sensors that are sensitive to the direction of current flow with two outputs, signals from which correspond to two directions of current flow, with the first information input of each dual controlled key connected to the first output of the corresponding sensor on the current features, the second information input of each the dual control key is connected to the second output of the corresponding current presence sensor, the control inputs of the dual control keys are interconnected and connected to the terminal for connecting the output of the logic switching device, the first outputs of the dual control keys connected to the individual current presence sensors are connected to the inputs of the first element AND-NOT, and the second outputs to the inputs of the second element AND-NOT, the outputs of the first and second elements AND-NOT are connected respectively to the first inputs of the first and second o And, while the second input of the first element I is connected to the first output of the dual controlled key connected to the sensor having a common phase current, and the second input of the second element I to the second output of the same key, the outputs of the first and second elements I used in as device outputs.