SU150906A1 - Device to protect power semiconductor valves - Google Patents

Description

THE DEVICE FOR THE PROTECTION OF POWER SEMICONDUCTORIES On December 6, 1961 No. 754552 / 24-7 to the Committee on Inventions and Discoveries under the Council of Ministers of the USSR

Published in the Bulletin of Inventions No. 20, 1962.

In POWER semiconductor rectifying units, in those cases when it is necessary to obtain a sufficiently high rectified voltage, a series connection of semiconductor valves is used. To evenly distribute the voltages across the gates in the non-conducting half-period, the gates are bridged by active resistances.

Existing devices for protection (fuses, reverse current sensors) do not allow a signal to turn off the rectifier when one of the series-connected valves goes out of operation (when the junction is short-circuited, a significant increase in current or an open circuit). When the second valve is out of order, the entire arm will be short-circuited, and if the valve circuit is broken, they do not react at all. This leads, firstly, to EXIT} from the other valves connected in series with the shorted valve, and secondly, to the possible failure of the valves of the other arms due to overloading of the short circuit current due to an insufficiently fast switching off of the rectifier.

The proposed device for protection of power semiconductor valves against breaks or short circuits is made on two magnetic cores with a common control winding included in the diagonal of the bridge formed by the protected valves and their shunting resistances.

The bias windings of the device are powered from a DC source, the output windings are connected in series and connected to an operating relay. EXIT VENTS

No. 150906-2 -

This embodiment of the device provides increased speed protection.

The drawing shows the proposed device for the protection of semiconductor valves.

In the diagonal of the bridge formed by the valves 1, 2 and the resistances 3 n 4, a control winding is turned on, covering two cores 5 and 6, having a rectangular hysteresis loop. In addition to this winding, the cores have an offset winding 7 and S and output windings 9 and 10 connected in series. With serviceable valves, only a small unbalance current flows in the control winding, due to the inequality of forward and reverse valve resistances. The magnetizing bias force acts in such a way that both cores 5, 6 are saturated in opposite directions.

If one of the valves is damaged, the balance of the bridge is disturbed and

A large unbalance current flows through the control winding. In the winding

9 will be induced by emf. signal in many times superior emf interference. I influence the actuator, emf signal will disable the rectifier. If the other valve is damaged, the core 6 will be re-magnetized. When the rectifier bridge is protected, the output windings 9, 10 of all the arms can be connected in series and connected to the actuator. Three or more valves connected in series can be protected in the same way by adding a pair of cores to each valve and connecting the output windings accordingly.

The only case where the protection will not work is the case of simultaneous failure of both shoulder valves, however this case is practically excluded. If a semiconductor device, such as a two-stable trigger, is present at the output, the protection will be sufficient for about one millisecond to operate.

Subject invention

A device for protection of power semiconductor valves against breaks or short circuits when they are connected in series in a rectifier arm using equalizing shunt resistances, characterized in that, in order to increase the protection speed, it is made on two large cores with a common control winding included in the diagonal of the bridge formed by the protected valves and their shunting resistances, the bias windings fed from the DC source, and the output windings are connected E in series and included in the output relay.

0 K executable 5 unit