Switching noise suppression for hybrid IGBT modules

In a hybrid IGBT module with SiC diodes as free-wheeling diodes, high frequency oscillation occurs during turn-on, which will cause higher EMI noise due to the larger capacitance of SiC diode. To evaluate the influence of gate drive parameters on turn-on oscillation, different gate voltages and gate charge currents are used. It is found that by changing gate drive parameters alone cannot reduce the settling time of the oscillation significantly. Then an oscillation suppression method with damping circuits is proposed. According to the analytical and experimental results, the damping circuits are able to effectively accelerate the damping of turn-on oscillation without significant increase in current overshoot and turn-on energy loss. Finally to suppress the turn-on current overshoot, active gate driver method is also used without large increase in the turn-on energy loss. The combination of damping circuit and active gate driver may be an optimized choice to achieve the lowest EMI noise.