4.5 kV GTO turn-off failure analysis under an inductive load including snubber, gate circuit and various parasitics

Abstract

GTO turn-off failure process has not yet been successfully analyzed by numerical methods while gateturn-off thyristors(GT0) have gained their reputation in various applications. Because conventional numerical analyses on GTO turn off processes had been performed under simplified external circuits to avoid the difficulties in obtaining numerical convergence. In this paper, the authors report for the fmt time that an exact simulation of the 4.5 kV GTO turn-off failure process has been successfully executed by taking into account complete external circuits including the snubber and all the parasitics. It has been shown that the failure process is closely coupled with impact ionization and the influence of the external circuits.