Analytical Methodology for Loss Calculation of SiC MOSFETs

For evaluating and optimizing the efficiency of power converters, the loss model of the power semiconductor devices is needed. The analytical loss model is favorable for its simplicity. However, the model accuracy needs to be improved. This paper proposes an analytical loss model for the commutation pair of silicon carbide (SiC) MOSFETs and SiC Schottky barrier diodes. Compared to the conventional loss calculation method, the proposed model is derived based on the conservation of energy, which considers the impact of the displacement currents on estimating the turn-on and turn-off losses. The modeling and extraction methodology of the model parameters are given, and the impact of operational conditions on the model parameters is studied. Using the proposed model, the losses can be calculated analytically and also the switching trajectories can be predicted with good consistency. A double pulse tester is built to verify the proposed model. The results show that an average modeling error is reduced from 20% using the conventional piecewise linear model, to around 10% using the proposed model under various operational conditions, and the time cost is at least 3000 times smaller compared to the existing SiC MOSFETs models.