SiC-based T-type modules for multi-pulse inverter with coupled inductors

Abstract

The paper presents SiC-based three-level T-type modules designed for a high-performance 30kVA DC/AC inverter operating at high frequency 85 kHz with low THD of the output voltage. This inverter system consists of two integrated parts. The first part is active and contains three parallel-connected three-phase T-type modules built with fast-switching SiC power transistors. The second, passive part of the system is a set of inductors magnetically coupled in the system 18-pulse. Such a system is able to generate near sinusoidal output voltage without PWM operation - transistors operate at switching frequency close to output frequency. The paper discusses design issues of the module with SiC transistors including design of the gate drivers. Moreover, experiments with single phase leg operating at nominal conditions are also presented.