MORE | Spring 2022
Multi-Constraint Optimization and Co-Design of a 2-MHz All-GaN based 1kW 96% Efficient LLC Converter
With the objective of minimizing the power losses in a 2 MHz LLC resonant converter, a novel multi-variable multi-constraint design optimization algorithm is developed and analyzed in this manuscript. Intricately curated constraints and corresponding design-based trade-offs are explained for a complete co-design of a multi-MHz resonant converter that result in an efficiency enhancement of 3.46%, compared to relevant state-of-the-art. In addition, the paper focuses on accurate characterization and parametric minimization of the AC resistance by optimal selection of transformer winding configuration, while achieving a controllable leakage flux for the resonant inductor integration into the high frequency planar transformer (HFPT) thereby reducing the effective winding losses by 6%. Further, the proposed optimization algorithm is experimentally verified by developing an all-GaN based LLC converter rated at 1kW, designed at 2 MHz resonant frequency. While achieving a power density of 6.2 W/cm3, the efficiency at 20% load is experimentally reported to be 92%, while the peak efficiency is estimated to be 96.08%.