Simplified Analytical Model for Estimation of Switching Loss of Cascode GaN HEMTs in Totem-pole PFC Converters

A practical analytical model to calculate the switching loss of cascode gallium nitride high electron mobility transistors(GaN HEMTs)is proposed.To facilitate analysis and application,the transmission delays introduced by Si MOSFET and interconnection inductances are ignored in modeling.Meanwhile,the nonlinear junction capacitances of the device and circuit stray inductances are also incorporated to increase the accuracy of the model.The turn-on and turn-off switching processes are described in detail and the simplified equations can be easily solved by using mathematical tools.Based on the analytical model,loss evaluation of totem-pole PFC converter is introduced briefly.Finally,the accuracy of the model is validated by comparing the calculated loss and converter’s efficiency with experiment results.Peak efficiency of 99.26%is achieved for a 3.6 kW single phase CCM Totem-Pole PFC AC/DC converter switching at 50 kHz based on 650 V cascode GaN HEMTs.