SiC MOSFET半桥电路开关瞬态过电流,过电压建模与影响因素分析

Due to high switching speed and low on-resistance, the switching transient process of SiC MOSFETs is susceptible to the influences of circuit-level stray parameters and exhibits significant overvoltage, overcurrent and switching rings, which degrades the high-efficiency, high-quality and safe application and potential utilization of SiC MOSFETs. Half-bridge circuit is the fundamental modular for PWM rectifiers, inverters, multi-level converters and so on. Taking half-bridge configuration for example, the switching transient behavior of SiC MOSFETs in power electronic circuits is thoroughly examined based on measured results. The analytical model to calculate the transient current and voltage in the SiC MOSFET half-bridge configuration was derived, integrating the influences of the main parasitic parameters of the circuit, the nonlinear characteristics of the device junction capacitances and transconductance. Based on the model, the influences and their influencing rules of gate loop parameters and power loop parameters on current and voltage overshoot peaks were quantitatively explored. Then the sensitivity analysis results was presented. Simulation and experimental results validate the correctness of the derived analytical model and the theoretical analysis.