Research on Switching Characteristics of SiC MOSFET in Pulsed Power Supply with Analytical Model

The switching devices in pulsed power supplies need to be able to withstand high voltage and large current, and the switching characteristics of the devices are closely related to the rising/falling edge of the output pulse and the switching losses. Compared with Si IGBT, SiC MOSFET has advantages of high voltage, high efficiency, high switching frequency and high junction temperature tolerance, which are beneficial to greatly improve the performance of pulsed power supplies. However, SiC MOSFET is rarely used in pulsed power supplies at present. Therefore, an equivalent simplified analytical model is established to research the switching characteristics of SiC MOSFET. The ode45 in MATLAB is used to solve the circuit differential equations. With the model, the turn-on and turn-off process are analyzed in detail, and the change regulation of characteristic parameters such as drain-source voltage, drain current and switching losses can be obtained. Finally, the analytical model is verified by experiment. It can be seen that the fast switching speed of SiC MOSFET helps to make the rising/falling edge of the output pulse steeper, but it is easily affected by the parasitic inductance, so the appropriate gate driving resistance should be selected in the circuit design.