Design and Optimization of the High Frequency Transformer for 100kW CLLC Converter

The CLLC converter is widely used in the power electronic applications as a DC transformer, which can provide galvanic isolation, bidirectional power flow and an adjustable output voltage with the use of proper controls. As the most critical component in the CLLC converter, the high frequency (HF) transformer should be optimized according to the design targets, such as efficiency and power density. Starting with the analysis of the CLLC operating characteristics, this paper proposes a formal approach to design the HF transformer of a 100kW CLLC converter for a grid-tied application. The optimization method for the HF transformer is presented and the effect of the resonant inductor is analyzed. The optimized transformer is simulated with the finite element analysis (FEA) and Matlab/Simulink.