A hybrid push-pull converter with series-parallel structure in the primary windings

This paper describes a hybrid current-fed push-pull converter with wide input voltage range and low input current ripple for voltage step up applications. With the proposed topology the primary windings of the transformers work in series when the input voltage is high, and in parallel when the input voltage is low. In this way, the conversion gain of the converter is extended, which makes this topology suitable for wide input voltage range applications. Meanwhile, interleaved operation reduces the current ripple in the input filter and minimizes the current sharing problem. Design procedures and parameters are introduced, and a prototype with 20-75V input voltage and 200 V/2.5 A output was built to verify the analysis.