Optimization of High-Efficiency Half-bridge LLC Resonant Converter

In order to achieve zero voltage switch (ZVS) and zero current switch (ZCS) of half-bridge LLC resonant converter, an optimal design method of the converter was presented. In this work, a detailed optimization procedure is proposed to optimize LLC resonant converter parameters. The main circuit steady state equivalent circuit model was established based on fundamental harmonic approximation method (FHA). By means of the circuit normalization of DC gain, resonant current and zero-voltage-switching condition was theoretically analyzed, and the converter key parameters including quality factor, magnetic inductor, resonant inductor and resonant capacitor were optimized. Finally, a prototype 200W LLC converter was designed and built up using the optimization method. The experimental results verify that the proposed optimization procedure is effective.