Three-level active neutral-point-clamped zero-current-transition converter

This paper proposes a novel three-level active neutral-point-clamped zero-current-transition (ANPC-3L ZCT) converter. The proposed soft-switching topology employs two auxiliary switches and an LC resonant tank for each phase leg to achieve soft commutation of main switching devices. The voltage stress of all the switches is clamped to half of dc link voltage and the auxiliary switches have a much lower current rating than the main switches. Besides that the auxiliary switches have no switching losses. The operation principle and design of resonant tank is analyzed in details in this paper. An 80kW half-bridge prototype of the ANPC-3L ZCT inverter is built. The effectiveness and advantages of the proposed topology are verified experimentally.