Analytical Switching Model of a 1200V SiC MOSFET in a High-Frequency Series Resonant Pulsed Power Converter for Plasma Generation

The circuit parasitic components have a significant effect on switching performance in the high-voltage and high-frequency pulsed power converter. The SiC MOSFET has better electrical characteristics than Si MOSFET and it is preferable in this application. In this paper, the characteristics of comparative study between Si and SiC MOSFET is provided first. Then, a converter-level analytical switching model for a 1200 V SiC MOSFET is proposed in a high-frequency series resonant pulsed power converter for the application of plasma generation. To increase the accuracy of predicting the behavior of the SiC MOSFET, the proposed analytical model involves all parasitic components in the converter, including the nonlinearity of the junction capacitances and transconductance, stray inductances from the package, printed circuit board (PCB) and transformer, parasitic capacitances from the transformer, and the capacitive load of plasma. The turn-on and turn-off transitions are analyzed in detail and the modeling mathematical equations are resolved by the MATLAB ode-45 command. The accuracy of this model is validated by comparing the analytical, LTspice simulated and experimental waveforms of a 400 VDC input, -8.2kV output prototype. The proposed model enables us to evaluate and optimize the switching solution of a SiC MOSFET for the pulsed power converter.