SCHALTUNGSANORDNUNG ZUR UEBERWACHUNG EINES MEHRPULS-STROMRICHTERS

A circuit arrangement for monitoring the operation of the semiconductor switches (TH1 ... TH6) in a multi-pulse converter is specified. This circuit analyses the ripple on the unsmoothed output voltage of the converter and allocates the fixed voltage changes to the current pulses flowing through the individual semiconductor switches. Missing current pulses and the failure of individual semiconductor switches are reliably detected. The voltage changes forming the ripple are passed through filters (EF1, EF2) of an evaluation circuit which checks for the occurrence of voltage changes within specific time intervals by means of a timer circuit (MF1 ... MF3) whose delay time is set to the frequency of the respective current pulse sequence. A suitably programmed computer can also be used as the evaluation circuit.