An evaluation of resonant snubbers applied to GTO converters

Abstract

Aspects of the application of resonant snubber technology to gate-turn-off (GTO) converters are investigated. GTO power switches require snubbing at turn-off when applied in converters. This leads to the extensive use of regenerative snubber circuits in GTO converters due to the difficulties involved in using dissipative snubbers. At present, it is accepted that the repetition switching frequency of GTO pulse-width modulated (PWM) circuits is largely determined by the resettling time of regenerative snubbers. The resonant DC link may be seen as a nondissipative snubber and holds the promise of a faster resettling time. The behavior of GTO devices is investigated under the conditions applied to them by this kind of snubbing and its application in GTO converters. The concept has been demonstrated with 90 A 1200 V GTOs.