半桥电流馈入型LLC变换器的研究

针对传统的LLC变换器无法实现较高的转换效率问题,本文采用基波分析法,研究了一款适用于低电压输入,且可实现零电流关断的半桥电流馈入型LLC变换器。分析了该变换器的工作原理,比较了其与传统LLC变换器的异同,在借鉴传统LLC变换器建模方法的基础上,对半桥电流馈入型LLC变换器进行建模分析,同时运用基波分析法推导了该变换器的开关网络、输出网络和谐振网络模型,并利用Saber仿真软件对半桥电流馈入型LLC变换器进行仿真分析。仿真结果表明,在不同负载情况下,该变换器可通过谐振获得较高的电压增益,且在一定范围内谐振频率越高,增益越大;当流过开关管的电流过零,且有较小的反向电流时,开关管关断,说明半桥电流馈入型LLC变换器能够稳定、可靠地实现零电流关断。该研究具有广阔的应用前景。

Research on Half Bridge Current Fed LLC Converter

Traditional LLC converter could not achieve high efficiency.To address this issue,this paper researched on a half bridge current fed LLC converter with Zero Current Switching which is suitable for occasions with low input voltage by fundamental analysis.Analysis of the converter＇s operating principle and differences between the two converters were proposed.Modeling analysis and the model of switch network,output network and resonant network were deduced by fundamental analysis on the basis of the traditional modeling approach.The simulation was achieved by Saber.The simulation results verified that,through resonance,the converter can obtain a high voltage gain under different load conditions.Within a certain range,the higher the resonant frequency is,the higher the gain is.When the current flowed through the switch cross zero and has a small reverse current,the switch turns off,which means ZCS can be achieved stably and reliably.The study has broad application prospects.