GaN HEMT power losses modeling and evaluation in resonant LLC converters

This paper aims to provide a power loss model for GaN HEMT devices when used in resonant LLC converters. Differently from other works, the proposed model is based on operative waveforms obtained from both simulations and experimental measurements. Such an approach has allowed evaluating each loss contribution. The loss model considers different equations depending on the operating conditions of the converter in order to obtain more accurate results. In such a context, the Eoss energy has been taken into consideration for a better analysis of the turn-off losses. It is worth noticing that the proposed equation used for modelling the dependence of the source-drain voltage on temperature has also enabled a better estimation of the GaN behavior in the third quadrant during dead time. The validation has been performed by comparing the estimated temperature of the device case with the measured one.