Voltage self-balance method for series connected IGBTs by using clamping diodes

Abstract

Series connected IGBTs provide a useful method to improve the voltage level, and which is a very important approach to achieve high-voltage power converters. However the imbalance of collector-emitter voltages across IGBTs is a key issue that must be addressed. This paper proposed a novel type of series connected IGBT circuit with voltage self-balance by using clamping diode and snubber capacitor, and an auxiliary circuit for energy feedback is designed. The operation principles and the various working states are analyzed in this paper. Furthermore the experiment prototype of three-phase inverter based on this topology is built. The experiment results validate the voltage self-balance performance of the series connected IGBTs.