A Novel Wireless-Power-Transfer-Based Snubber Circuit for Suppressing High-Frequency Oscillation of SiC Power MOSFETs

The high dv/dt and di/dt during the high-speed switching transient of SiC MOSFET cause serious switching oscillations, producing severe EMI and affecting device reliability. This paper proposes a novel wireless power transfer (WPT) based snubber circuit to suppress switching oscillations. It can achieve galvanic isolation and does not require high-voltage components. This paper not only analyzes the detailed switching process and oscillation mechanism but also estimates the parasitic parameters by experiment. Moreover, the optimal oscillation suppression point is determined by adjusting the damping of the WPT system. Finally, based on the double-pulse test platform, the experimental results show that the proposed method can significantly shorten the damping time of voltage oscillation by 60% when the SiC MOSFETs frequency is at 20 kHz.