Abstract: A gate controlling circuit for a thyristor converter having a forward/reverse bias voltage detecting circuit connected between the anode and the cathode of one of a plurality of serially connected thyristors in a thyristor arm of the converter for determining whether the thyristor is forward or reverse biased. The output of the forward/reverse bias voltage detector is utilized to control the gate control signals supplied to the thyristors in the thyristor arm.

Abstract: In a gate control circuit for a thyristor converter, in which thyristor valves each having a plurality of series thyristors are connected to form a bridge, a detector for detecting a forward voltage applied across one of the thyristors and a circuit for supplying a gate signal to the gate of that thyristor valve are provided. The gate control circuit further comprises a circuit for supplying, when a bypass pair operation of the thyristor converter is switched over to a deblock operation, a signal to the gate of a continually conductive thyristor valve according to a control signal to a thyristor valve to be operated in deblock with the continually conductive thyristor valve and also a gate signal to the continually conductive thyristor valve.

Abstract: A gate controlling circuit for a thyristor converter having an inverse bias voltage detecting circuit which detects the inverse bias voltage across a thyristor and is connected between the anode and cathode of serially connected thyristors in a thyristor valve. A gate signal to all of the thyristors is supplied when the output of the inverse bias voltage detecting circuit drops or becomes zero after all of the thyristors are turned off.