The Influence of the Gate Driver and Common-Source Inductance on the Short-Circuit Behavior of IGBT Modules and Protection

In this article, the influence of the gate drive unit on the short-circuit (SC) type II and III behavior of insulated gate bipolar transistor (IGBT) modules was investigated in detail. It is found that the real gate voltage of the IGBT chip contacts cannot be measured across the auxiliary pins of a power module. The difference between applied gate voltage at the sense contacts and the real gate voltage at the IGBT gate contact is shown to be highly dependent on the common-source inductance and hence, the packaging concept. The value of the gate resistance has a significant effect on SC behavior. A gate voltage self-clamping effect during SC was found and verified with the help of circuit simulation. Finally, a gate voltage clamping circuit for improved SC ruggedness of the IGBT modules is introduced. Based on the clamping circuit, a new fast SC type II and III detection method is developed and tested, which can detect and turn-off the SC event within 400 ns.