The Soft-Switching Technique for RB-IGBT based T-Type Three-Level Inverter

In this paper, the reverse-blocking IGBT (RB-IGBT) based soft-switching T-type three-level inverter is proposed. With traditional PWM control scheme, zero current switching (ZCS) at turning on and zero voltage switching (ZVS) at turning off are achieved for reducing extra switching loss by passive snubber. The operating principles are given in detail and the parameter design of resonant tank is analyzed based on the state-plane trajectory. Besides, the oscillations caused by device's parasitic capacitance have been analyzed, and an oscillation suppression measure is also presented using root locus method. Finally, experiments with a single phase prototype are provided to verify the effectiveness of the proposed inverter.