An improved gate control scheme for snubberless operation of high power IGBTs

This paper proposes a new gate drive circuit for IGBTs which can actively suppress the voltage overshoot across the driven IGBT at turn-off and the voltage overshoot across the opposite IGBT at turn-on while preserving the most simple and reliable power circuit. The turn-off driving scheme has an adaptive feature to the amplitude of collector current, so that the overvoltage is limited much more effectively at the fault collector current. The turn-on scheme is used to decrease the rise rate of the collector current by increasing input capacitance during turn-on transients when the gate-emitter voltage is greater than the threshold voltage. Experimental results under various normal and fault conditions prove the effectiveness of the proposed circuit.