Modeling and Optimization of High-Frequency Litz-Wire Transformer for 10 kW GaN-Based LLC Resonant Converter

High switching frequency enabled by wide-bandgap devices has been verified as an effective approach to shrink passive component volume, increasing converter power density significantly. This paper presents a novel litz-wire transformer for a 10 kW gallium-nitride-based LLC resonant converter switching at 200 kHz to 400 kHz with wide regulation range. A detailed modeling for the inductance, core loss and winding loss for the transformer and a transformer optimization process are illustrated. Experimental results with the converter are provided to validate the transformer loss estimation.