Enhancing Turn-Off Performance in IGCT-Based High Power Applications—Part Ⅱ: Hybrid Switch With IGBT Integration and Experimental Validation

Integrated gate-commutated thyristor (IGCT) is a promising device in high-power applications thanks to its low on-state voltage, large surge capacity and considerably low cost ratio. However, IGCT's current-controlled nature restricts its turn-off capability, which in turn limits the fault current handling ability in high-voltage direct current power systems. It has been identified that IGCT has the potential of over-current interruption under ultralow turn-off voltage in the companion paper. Thereby, this article proposes to utilize the insulated-gate bipolar transistor (IGBT) in parallel to form an IGCT-IGBT hybrid switch, which facilitates the IGCT with quasi-zero voltage switching condition as well as current turn-off assistance. To testify the effectiveness, the prototype platform of the hybrid switch is developed with a 4-inch 4.5 kV/2.67 kA IGCT and the 4.5 kV/1.2 kA IGBT modules, and a series of current switching tests up to 20 kA are carried out, which reaches five times of IGCT's official turn-off capability. This article provides generalized insight and extensive experimental validation for the hybrid switch, highlighting its possibility for reliability and efficiency improvement in high power applications.