基于耦合电感的自均流LLC谐振变换器的设计

Design of Self-Equalizing LLC Resonant Converter Based on Coupled Inductors

针对LLC谐振变换器并联均流难的问题,文章提出了一种采用耦合电感作为不同LLC谐振腔的谐振电感的方法来实现并联LLC谐振腔支路电流的自动均流。该拓扑具有结构简单、控制方便、效率高以及成本低等优点,非常适用于LLC并联的大功率输出场合。介绍了该拓扑的基本工作原理,并详细解释均流的实现过程。先通过SABER仿真验证了谐振电感差异给并联支路不均流度带来的影响,后搭建一台输入750~800V、输出200-400V/20A的实验样机,给出了实际样机的实验波形。通过实际样机的实验结果证明了设计方法的正确性。

In view of the problem that the LLC resonant converter is difficult to parallel current sharing, this paper proposed a method of using the coupled inductor as the resonant inductor of different LLC resonant cavities to realize the automatic current sharing of the branch current of the parallel LLC resonant cavity. The topology has the advantages of simple structure, convenient control, high efficiency, low cost, etc. It is very suitable for LLC high-power output applications in parallel. The basic working principle of the topology was introduced, and the implementation process of the current sharing was explained in detail. Firstly, SABER simulation was used to verify the influence of the difference of resonant inductance on the non-uniform flow of the parallel branch. After that, an experimental prototype with input of 750-800 V and output of 200-400 V/20 A was built, and the experimental waveform of the actual prototype was given. The experimental results of the actual prototype proved the correctness of the design method.