IGBT device application aspects for 50 kW zero-current-transition inverters

This paper addresses two application aspects of IGBT devices for two different types of three-phase zero-current-transition (ZCT) soft-switching inverters, which are built with 50 kW power rating for electric vehicles (EV) traction motor drives. One aspect is the characterization of main IGBTs under different ZCT conditions, for which switching loss reductions are quantified, and variations of soft-switching behaviors and mechanisms under different resonant tank designs are investigated and compared. The other is the selection and characterization of auxiliary switches. From the analysis on the unique operation conditions of the auxiliary switches, it is concluded that the current ratings specified for commercial IGBTs cannot meet the requirements for the auxiliary switches. Accordingly, methods to select and characterize suitable auxiliary switches are proposed, and IGBTs from different manufacturers are tested and compared using the proposed methods. Hardware implementation and experimental results of the 50 kW prototypes are provided.