介绍了LLC的拓扑结构，对LLC建立基波等效模型，分析了它的工作原理，并对LLC三种工作区域下的工作过程 做了详细分析，然后设计了一个输入DC350~640V，输出DC440V，功率为3KW的直流电源，最后在PLECS仿真软件上建立仿 真模型，搭建电压闭环，验证了设计的可行性。

This paper introduces the topology of LLC, establishes the fundamental equivalent model of LLC, analyzes its working principle, and makes a detailed analysis of the working process of LLC in three working areas, then designs a DC power supply with input of DC350 ~ 640V, output of DC440v and power of 3KW, and finally establishes a simulation model on PLECS simulation software to build a voltage closed loop to verify the design