CHARACTERISTICS OF GTOS AND HIGH-VOLTAGE MCTS IN HIGH-POWER SOFT-SWITCHING CONVERTERS

Presently, high-power soft-switching resonant pole converters, such as the auxiliary resonant commutated pole (ARCP) converter, that have internal de link voltages above 1.5 kV, can only use gate turn off thyristors (GTO's) as main switching devices. For these applications, considerable effort has been spent to design, evaluate, and enhance the dynamic performance of high-voltage MOS-controlled thyristors (HVMCT's). It is expected that in the near future HVMCT's, which require little gate power because of their high gate impedance, will gradually replace high-voltage GTO's. The purpose of this paper is to present and summarize key HVMCT characterization results gathered to date as they relate to their dynamic performance during zero-voltage switching. HVMCT devices capable of turning off 300 A and withstanding 3000 V are presented. The paper concludes with a comparison of the soft-switching performance of HVMCT's and GTO's in an ARCP converter phase leg.