Study on the Effect of External Drain-Source Capacitance on the Turn-On Switching Characteristics of SiC MOSFET Using an Analytical Model

The application of SiC MOSFET helps improve the efficiency and power density of power electronic converters due to its high frequency, high efficiency, and high temperature advantages. By connecting an external capacitance C
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in parallel with the drain and source of SiC MOSFET, the soft turn-off switching of SiC MOSFET can be achieved. However, the impact of C
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on the turn-on switching process of SiC MOSFET is unclear. In this paper, an analytical model based on a half-bridge configuration is established to study the turn-on switching characteristics of SiC MOSFET. The nonlinearity of parasitic capacitances, transfer characteristic, and output characteristics are considered in the model to ensure accuracy. Besides, the reverse recovery characteristics of the body diode as a freewheeling diode are measured experimentally. Based on the model, the effect of C
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on the turn-on switching characteristics of SiC MOSFET is deeply analyzed. Finally, an experimental platform is built to verify the model.