Surge Current Interruption Capability of Discrete IGBT Devices in DC Hybrid Circuit Breakers

The power electronic interrupter (PEI) determines the current interruption rating of the dc hybrid circuit breaker (HCB). This paper deals with discrete insulated gate bipolar transistor (IGBT) based PEI modules. The influence of the voltage clamping circuit (VCC) on the surge current interruption capability (SCC) of the discrete IGBT is unveiled for the first time. Two commonly used VCC configurations are considered: a purely MOV based voltage clamp and an MOV-RC combination clamp designated as type I and type II PEI modules respectively. Comprehensive measurements are used to analyze the device turn-off behavior under each PEI module type to determine their limitations as well as their failure modes. The type I PEI is limited by the turn-off thermal stresses arising from the hard switching dynamics. The type II PEI, on the contrary, has the potential to achieve lower turn-off energy among other benefits but exhibits a unique failure mode during the tail current stage. Therefore, static and mixed-mode Technology Computer-Aided Design (TCAD) device simulations are introduced to provide further insights into the internal processes that alter the type II turn-off and in turn explain the failure mechanism. Finally, the influence of the various circuit parameters on the turn-off process are evaluated and methods to enhance the SCC of the IGBT based PEI are presented.