Influences of Leakage Inductances in Integrated Transformer of Input-Series Flyback Converter

In this paper, the influences of leakage inductances are investigated for the integrated transformer of an input-series flyback converter, in which each input-series circuit is based on the single-switch flyback topology. First, the configuration of this converter is introduced, and a novel multiple-inductor coupling model is proposed for its flyback integrated transformer. Second, the operational process of this converter is analyzed by considering the leakage inductances between the primary and secondary windings of its integrated transformer. Third, the influences of these leakage inductances are analyzed; on this basis, the essential design considerations of the flyback integrated transformer are summarized. Finally, an experimental prototype of this input-series converter is built. Based on this, the analysis is verified by the experimental comparisons among three flyback integrated transformers with various winding layouts.