Modeling of SEPIC converter with SiC FET taking into account self-heating in semiconductor and reactance components

This paper considers the problem of modeling characteristics of SEPIC converter, taking into account the selfheating effect in semiconductor and reactance components. Compact electrothermal models of these components in the form of subcircuits for SPICE were formulated. In particular, a hybrid electrothermal model of the SiC FET was proposed based on the model of this component offered by its manufacturer. By combining the models of these components, an electrothermal model of the SEPIC converter was formulated. Using this model, the output voltage, the energy efficiency of the considered converter and the temperatures of all semiconductor devices, inductors and capacitors were determined for selected values of load resistance. Correctness of theoretical considerations was experimentally verified for a converter with inductors containing cores made of different ferromagnetic materials.