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 article 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 a MOV-resistor-capacitor(RC) combination clamp designated as types I and II PEI modules, respectively. Comprehensive measurements are used to analyze the device turnoff behavior under each PEI module type to determine their limitations, as well as their failure modes. The type I PEI is limited by the turnoff thermal stresses arising from the hard switching dynamics. The type II PEI, on the contrary, has the potential to achieve lower turnoff 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 turnoff, and in turn, explain the failure mechanism. Finally, the influence of the various circuit parameters on the turnoff process is evaluated, and methods to enhance the SCC of the IGBT-based PEI are presented.