Turn-Off Performance Comparison of High-Power SiC MOSFET and IGBT Modules in Near-ZCS Operation

In medium-voltage, medium-frequency applications, high-power silicon carbide (SiC) MOSFET and insulated gate bipolar transistor (IGBT) modules commonly employ near-zero current switching (near-ZCS) technology to minimize turn-off losses. In these scenarios, the turn-off behavior of the IGBT module is determined not only by the gate drive parameters and turn-off current but is also significantly influenced by the dynamic stored charge in the N-base region during the conduction phase. However, existing comparative studies fail to consider the effect of the dynamic stored charge, leading to incomplete and less precise performance evaluations between SiC MOSFETs and IGBTs. To overcome this limitation, this paper investigates the turn-off mechanisms of both devices under near-ZCS conditions and introduces an analytical model for the turn-off transient process of the IGBT, taking into account the effect of the dynamic stored charge during the conduction phase. Using this model, the turn-off performance of SiC MOSFETs and IGBTs is compared and experimentally validated under varying conditions, including turn-off currents, turn-off gate resistors, junction temperatures, and dynamic charge effects. Furthermore, the proposed IGBT turn-off model is verified using both simulation and experimental results. Compared to existing literature, the model proposed in this paper offers a more precise prediction of IGBT turn-off behavior, providing clearer guidelines for device selection in the design of converters for medium-voltage, medium-frequency applications.