Design of the parameters in LLC resonant converter

For LLC resonant converter,the design of resonant tank parameter is very important to improve the converter's performance.With the method of the first harmonic approximation analysis combining with simulation in frequency domain,based on detailed analysis about LLC resonant converter's DC voltage gain characteristic,zero voltage switching(ZVS) restriction and transmission efficiency of resonant tank,a simple and efficient design methodology was developed,and a detailed designing process was also proposed.Finally a 300kHz,-60W LLC converter with 90% efficiency was designed based on the proposed method,and the experimental results verified the feasibility of the strategy.