双管反激电源的分析与设计

针对反激电源主开关管关断时候的电压应力过大和变压器气隙漏感导致的电压尖峰过大的问题，对双管反激电源的拓扑结构及工作原理进行了详细分析，构建了双管反激电源工作在DCM模式时的能量传递模型，论证了变压器匝比与变压器原边漏感的磁复位时间及最大占空比和回馈能量大小的关系，推导出了双管反激电源主要参数的通用设计公式；利用其设计公式，设计了一个实际工作于DCM模式的30W双管反激电源，同时利用Saber仿真软件，研究了双管反激电源的主开关管、副边整流二极管和原边续流二极管的工作电流。仿真结果表明：变压器匝比参数选择合适，充分削弱了通过续流二极管回馈的能量，电源工作稳定。将仿真结果与实验样机所测结果进行了比较，结果显示两者基本吻合，说明设计公式可用作双管反激电源主要参数的设计工具。

Analysis and design of dual switch flyback

Aiming at too much voltage stress on the main switch and voltage spikes from transformer air gap leakage inductance when switching off , experimental study on the topology and operation principle of dual switch flyback were carried out. The energy transfer model of dual switch flyback in DCM was built, and the result was revealed that the transformer turns ratio impacts magnetic reset time of the primary leakage inductance which has influence on maximum duty cycle and energy returned. The design formulas on the main parameters of the dual switch flyback was deduced. With the design formulas, a 30 W dual switch flyback in DCM was designed. The Saber simulation was established, to research the operating current in main switches. The results indicate that the transformer turns ratio is appropriate and energy feedback is weakened. Some calculated results are verified by the experimental data, which shows they are reasonable. The design formulas can be used as a design tool to develop more efficient dual switch flyback.