Extinction blocking for GTOs

Abstract

In a method and device, extinction blocking signals for gate-turn-off power semiconductors, particularly GTO thyristors, are formed in static converters in order to suppress unacceptable extinction attempts and to protect the power semiconductors against destruction. An extinction blocking signal is emitted when the sum of the actual load current of one phase of the converter and the product of the derivation with respect to time of the load current and the maximum storage time of one power semiconductor is greater than the maximum periodically interruptible anode current of one power semiconductor. Furthermore, an extinction blocking signal is emitted when the derivation of a branch current of the converter with respect to time exceeds a threshold value proportional to the voltage supplied to the converter and a short-circuit of the converter is therefore present.

Dependencies are inferred from the claim text.