A gate drive circuit of high power IGBTs for improved turn-on characteristics under hard switching conditions

The issues of turn-on performance of a high power insulated gate bipolar transistor (IGBT) that works in hard switching conditions are discussed in detail. First, the turn-on delay time, switching loss, reverse recovery current of the associated free-wheeling diode, and EMI noise are analyzed for an IGBT phase-leg module with an inductive load. Based on the analysis, a novel gate drive circuit combining the slow drive requirements to minimize noise and switching stress, and the fast drive requirements for high-speed switching and low switching energy loss is proposed. Compared to a conventional gate drive circuit, the proposed gate driving strategy is able to effectively reduce the switching loss, delay time, and total switching time during the turn-on transient while the turn-off performance remains unchanged. Simulation and experimental results verify the validity and effectiveness of the proposed gate driving method.