Fast and Accurate Data Sheet Based Analytical Switching Loss Model for a SiC MOSFET and Schottky Diode Half-Bridge

Abstract

Fast and accurate switching loss models that can be used for different devices are crucial for optimization-based converter design. This paper proposes a novel data sheet based, fully analytical loss model for a SiC MOSFET and Schottky diode half-bridge including parasitics. In the model, nonlinear device characteristics are approximated by multi-step piecewise constants. Furthermore, a small number of assumptions are used to derive and to solve the approximated nonlinear differential equations for obtaining the switching losses. To evaluate the model, a new accuracy measure is proposed for a fair accuracy comparison with existing models. The proposed model is also comprehensively verified by double pulse tests using 5 SiC MOSFET (with different structures) and Schottky diode pairs from different manufacturers. The proposed fully analytical model exhibits on average the best accuracy with a high computational efficiency (less than 1 ms per operating point) compared to state-of-the-art analytical switching loss models, as validated by using both data sheet information and measured device characteristics.

Keywords

• Analytical model
• converter optimization
• SiC MOSFET
• switching losses