A Switching Oscillation Suppression Method with Clamping Function and Quantitative Design for SiC MOSFETs

SiC MOSFETs offer significant benefits for power electronics applications due to their material properties, including increased switching speeds, reduced switching losses and improved power density. However, these benefits can also result in severe switching oscillation and electromagnetic interference (EMI) in SiC MOSFETs, which can cause device breakdown or damage. In this paper, an oscillation suppression method with clamping function and quantitative design is presented, which not only effectively clamps the drain-source voltage overshoot but also does not reduce the switching speed and increase the switching loss. Firstly, the clamping circuit based on a double-pulse circuit is proposed and its operating principle is described. Then, in order to achieve full suppression of oscillation below the clamping capacitor voltage, the high frequency equivalent circuit in the oscillation stage is derived and the snubber parameters are further quantitatively designed. Finally, an experimental platform is developed to verify the effectiveness of the proposed method. The experimental results show that the proposed method can effectively clamp the overshoot and suppress the switching oscillations, which will significantly improve the device application reliability.