Loss Prediction of Medium Voltage Power Modules: Trade-offs between Accuracy and Complexity

Advances in high breakdown voltage SiC MOSFETs allows design of medium voltage power modules with simpler topologies, however, high dv/dt in addition to high di/dt makes parasitics of power modules more important to consider in loss estimations. Correct estimations can help prevent costly and time-consuming problems in a design process. Data sheet values can be used directly for loss estimation, but more detailed approaches in using device-level SPICE model fitting and inclusion of power module parasitics will give a more detailed estimation and may be used to predict transient behavior at a cost of increased complexity. This paper will quantitatively compare the switching loss predictive capability of different approaches in the case study of a custom-built medium voltage power module for varying operating conditions. It is found that by including parasitics loss prediction error is reduced from 15-25% to a few percent at high DC-link voltage for the case-study chosen.