RU2546504C1 - Valve reversible converter - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: if through current arises, a protection tripping relay (3) or a protection tripping relay (7) actuates and disconnects a load (6) and DC sources (1 and 2).

EFFECT: increased reliability.

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Description

The proposal relates to the field of electrical engineering and can be used to convert direct current to alternating current.

The well-known reversible valve converter [1] contains two different-polarity DC sources connected to the load. The disadvantage of this device is its relatively low reliability, since in emergency situations, for example, when a through current occurs, there is no protection.

The closest in technical essence and the achieved results is the converter [2], which contains two multidirectional controlled direct current sources connected by one terminal designed to connect the load. In series with each source, an automatic circuit breaker is protected against short circuits and overloads. The disadvantage of this device is that the protection is triggered at relatively high currents, which reduces reliability.

The technical result of this proposal is to increase reliability.

The technical problem is solved due to the fact that the converter is equipped with two two-pass residual current circuit breakers (RCDs), which are connected with two passages * between the second leads of the sources, and the ends of the second passages of the RCD are connected to their common point, which are connected through the directional diodes to the second terminal load.

The drawing shows a diagram of a reversing converter. It contains two sources 1 and 2, the first residual current device (RCD) 3, diodes 4, 5 and load 6, the second residual current device (RCD) 7.

The converter operates as follows. In the standard (fully working) state of the RCD 3 is on, regulated sources 1 and 2, for example, controlled transistor or thyristor rectifiers, working alternately, form an alternating voltage of the required form on load 6. In this mode, the equalizing (through) current between the sources 1 and 2 is absent and therefore the RCD 3, 7 does not work, since the windings of the RCD 3, 7 are mutually compensated at different half-periods of voltage. When the through current appears, there is no mutual compensation of currents in the windings of RCD 3 or 7, the RCD trips, disconnecting load 6 and one of the sources. Possibilities for passing through current between sources 1 and 2 are excluded. The trip current of the RCD is 30-60 mA, so the emergency process is interrupted at the initial stage. Diodes 4,5 can be made in the form of Schottky diodes, which provide a low voltage drop in the forward direction and, accordingly, have small losses. Thus, higher reliability is provided.

* Under the passage refers to the series-connected contact and winding of the RCD.

Information sources

1. Horowitz P., Hill W. Art of circuitry M., 1993, World, p. 349.

2. Kapuntsov Yu.D. and others. Electrical equipment and electric drive of industrial installations. M., 1979, Higher School, p. 319, Fig. 12.9.

Claims (1)

A reversible valve converter containing two multidirectional controlled direct current sources connected by one terminal designed to connect to the load, characterized in that it is equipped with two two-pass residual current circuit breakers (RCD), which are connected with two passages between the second terminals of the sources, and to their common the point is connected to the ends of the second passes of the RCD, which are connected through the opposite directional diodes to the second terminal of the load.