宽增益高效率LLC谐振变换器拓扑

针对LLC谐振变换器增益负载敏感性强、与效率存在强耦合的不足，提出了一种由LLC 谐振变换器和两开关buck-boost构成的宽增益高效率LLC谐振变换器拓扑。通过采用输入并联与输出串联的方式，分别由LLC谐振变换器传输功率、buck-boost调节输出电压。其中，LLC谐振变换器运行于谐振频率，buck-boost采用PWM调节输出电压。分析了变换器的运行模式，给出了相应的参数设计方法，并进行了仿真验证。最后，对输入30 V、输出200~360 V、360 W样机进行了实验，实验样机增益范围和效率分别为6.67~12、97.4%。仿真与样机实验验证了所提出的宽增益高效率LLC变换器拓扑及其调制方法的有效性。

LLC resonant converter topology with wide gain and high efficiency

There are shortcomings of an LLC resonant converter with strong gain load sensitivity and strong coupling with efficiency. Thus this paper proposes a wide-gain and high-efficiency LLC resonant converter topology composed of LLC resonant converter and a two-switch buck-boost converter. Using parallel connection and output series, the LLC resonant converter transmits power and the buck-boost adjusts the output voltage. The LLC resonant converter operates at the resonant frequency, and uses PWM for the buck-boost to regulate the output voltage. The operation mode of the proposed converter is analyzed, the corresponding parameter design method is given, and the simulation verification is carried out. Finally, experiments are carried out on prototypes with input 30 V, output 200~360 V, and 360 W, and the gain range and efficiency of the experimental prototype are 6.67~12 and 97.4%, respectively. Simulation and prototype experiments verify the effectiveness of the proposed wide-gain and high-efficiency LLC converter topology and its modulation method.This work is supported by the National Key Research and Development Program of China (No. 2018YFB1503000 and No. 2018YFB1503001).