SiC MOSFET配SiC肖特基二极管半桥配置串扰诱导栅源电压峰值精确预测的改进模型

Fast switching transients of silicon carbide (SiC) MOSFETs reduce switching loss but generate high (dv/dt) . During the active device’s turn-on transition, high (dv/dt) increases the complementary device’s gate-source voltage, potentially causing false turn-on, resulting in positive crosstalk. Conversely, during turn-off, the complementary device’s gate-source voltage decreases, causing negative crosstalk. Negative gate voltage (NGV) can limit positive crosstalk peaks below the threshold but may intensify negative crosstalk peaks, possibly exceeding safe ratings and impacting reliability of SiC MOSFETs. This article presents an improved model to accurately predict crosstalk-induced gate-source voltage peaks of SiC MOSFETs. SiC Schottky diodes are utilized to avoid the reverse recovery of SiC MOSFET’s body diode. In addition to modeling nonlinear capacitances, parasitic inductances, and time-varying (dv/dt) from the existing approaches, this article incorporates detailed channel current model and printed circuit board (PCB) parasitic capacitances for enhanced accuracy in predicting drain-source voltage gradient (dv/dt) of the active device and gate-source voltage peaks of the complementary device. Experimental results for two 1200-V SiC MOSFETs from different manufacturers validate the proposed model. Using the model, optimal value of NGV and gate resistances is estimated to mitigate negative crosstalk and avoid false turn-on. Additionally, this article analyses post false turn-on dynamics, providing critical insights into the process.