基于Sepic和Flyback混合拓扑的辅助电源设计

分析了Sepic和Flyback拓扑结构，根据DC/DC模块电源对辅助电源的需求，提出了Sepic和Flyback混合拓扑的辅助电源，能够输出多路不同幅值电压，并且可以实现各路输出电压之间的隔离。利用状态空间平均法建立了Sepic拓扑的小信号模型，设计了电压和电流双环控制的补偿器，并用Matlab仿真软件进行了分析。该辅助电源应用于一款非隔离的宽范围输入且输出可调的DC/DC模块电源，实现了三路互相隔离的12 V输出电压，一路非隔离的6 V输出电压，输出电压波形稳定，能够满足隔离悬浮供电，也能满足不同芯片对电压范围的要求。

Design of Auxiliary Supply Power Based on Sepic and Flyback Mixed Topology

Sepic and Flyback topology were analyzed in this paper. To meet the requirements of DC/DC module power,auxiliary supply voltage was designed based on Sepic and Flyback mixed topology. The auxiliary supply voltage had multiple outputs and could realize the isolation of outputs. The model was derived by the state space averaging method. A closed loop control for Sepic converter was discussed in detail. The closed loop control had two control loops, voltage loop and current loop. Simulation were carried out to confirm the effectiveness of the topology by Matlab. The auxiliary supply voltage based on Sepic and Flyback mixed topology with three isolated 12 V and one non-isolated 6 V outputs was applied in a DC/DC converter that has wide input range and wide output range. Experimental verifications confirm the validity of the auxiliary supply voltage based on Sepic and Flyback mixed topology.