SAETT OCH ANORDNING FOER PULSSTYRNING AV EN TYRISTORFOERSEDD HOEGSPAENNINGSVENTIL

摘要

The proposed method consists in that a narrow control pulse is applied to the thyristors of the arrangement at the beginning of the conduction interval of the arrangement. The positive voltage across the monitored thyristors is measured and a monitor signal is formed at the point in time when the voltage reaches a preset level. Using the received monitor signals, one can count the number of the thyristors whose positive voltage exceeds a preset level. At the point in time when the number of the monitor signals reaches a preset value, additional narrow control pulses are applied to the thyristors. The proposed control system comprises devices for measuring the positive voltage across the monitored thyristors and an adder connected to the devices. The adder and a reference signal source are coupled to a comparison circuit which, like a sync pulse source, is connected to an AND gate. The AND gate and the sync pulse source are connected to an OR gate which couples an amplifier-former connected to the arrangement. The present invention provides for improved operational reliability of the arrangement.