Short-circuit behavior of high-voltage IGBTs

A load fault or a semiconductor breakdown in a high-power inverter results in very challenging shorts for the remaining semiconductors. Understanding the short-circuit behavior improves the robustness of the semiconductor and the inverters. However, this important topic is not very well analyzed and only few literature exist. Up to now, five different short-circuit types are known which can occur in two or multilevel inverters. The five short-circuit types differ in the starting condition and the dominating semiconductor during the short. Despite the different initial conditions, the behavior of the high-voltage IGBT and diode during short-circuit can be explained with the help of a capacitive equivalent circuit. The resulting dv/dt, the current distribution between the semiconductors, and the influence of the gate-drive unit on the short-circuit behavior can be explained. To validate the results retrieved from the equivalent circuit, measurements on a high voltage IGBT and simulations with a semiconductor simulator are presented.