双管双变压器正-反激组合变换器研究

Analysis of a Forward-flyback Converter employing Two Switches and Two Transformers

提出了一种双管双变压器结构的正反激组合变换器,并分最大占空比限制、输出电流波形、输出特性、对正反激变压器传输功率分配的影响、正反激变压器功率分配与匝数比的关系5个方面对两变压器匝比相等和不等的情况进行了分析比较,指出匝比不等时虽然电流纹波大些,但可通过改变匝比灵活分配两变压器的功率,提高效率,改善性能。实验结果验证了理论分析的正确性。

A novel forward-flyback converter employing two transformers and two switches is presented.The use of two diodes at primary side enables the voltage stress of lwo switches to be clamped at input vohage,whieh is lower than that of a conventional forward-flyback converter.The use of two separate transformers offers the advantages as follows：the turns of primary transformer winding is reduced to half of a conventional forward-flyback converter with a single transfornler,the use of two separate transformers enables the smaller low-profile cores to be utilized,thereby facilitating a low-profile design.This paper analyzes the conditions that turn ratios of two windings are equal and non-equal.When the turn ratios are not equal,the power distribution between two transformers can be designed easily.Experiment verified the above analysis.