一种改进的LLC变换器谐振网络参数设计方法

An Improved Design Method for Resonant Tank Parameters of LLC Resonant Converter

对于LLC谐振式直流变换器,提出一种基波分析法结合时域仿真的改进型谐振网络参数设计方法。在LLC谐振式变换器的设计中,谐振网络参数的设计对于变换器的性能具有重要影响。该文在采用基波分析法对LLC谐振式直流变换器的电压增益特性、零电压开通(zero voltage switching,ZVS)条件、器件应力和谐振网络传输效率进行详细分析的基础上,指出基波近似分析方法不能准确反映谐振变换器电压增益特性的缺点,并提出一种基波分析法结合时域仿真的改进型谐振网络参数设计方法,给出其设计过程。基于所提出的方法设计的参数建立一台220W的样机,实验结果证实了所提出改进型设计方法的正确性和可行性。

For design of resonant tank in LLC resonant DC/DC converter, an improved design method is proposed based on first harmonic analysis and simulation in time domain. A well designed resonant tank could improve the performance of LLC resonant converter. Based on detailed analysis about LLC resonant converter＇s voltage gain characteristic, zero voltage switching （ZVS） restriction, device stress and transmission efficiency of resonant tank with the first harmonic approximation method, the limitation that the first harmonic approximation method could not describe voltage gain characteristic precisely was pointed out. Then an improved design method of resonant tank combining first harmonic approximation and simulation in time domain was proposed. The design procedure was presented. By the resonant tank parameters obtained from the proposed method, a 220W phototype was built up, and the experimental results verified the improved design method.