Design of Active-Clamped PushPull-Based DCDC Converter With High Step-Up Ratio and High Power Conversion Efficiency

This article proposes an active-clamped push-pull-based dc/dc converter with a high step-up ratio and a high conversion efficiency. Using an active-clamped circuit on the primary side of a transformer in the proposed framework can reduce the voltage stress requirements ofmain switches. Moreover, all power switches' zero-voltage switching operation helps achieve high power conversion efficiency. Using a single input energy storage inductor with a center-tapped transformer structure to make the input current frequency twice the switching frequency, the input current ripple and the inductance of an input inductor can be relatively reduced. In addition, a voltage doubler circuit composed of capacitors and diodes to be used on the secondary side of the transformer can double the corresponding voltage gain via only one capacitor and two diodes. The effectiveness of the proposed converter is verified by an experimental prototype with the specifications of an input voltage from 25 to 40 V, an output voltage of 400 V, and a maximum output power of 2 kW. By observing experimental results, the maximum conversion efficiency is 97.5%, and the full-load conversion efficiency is 96.2% when the input voltage is 40 V. When the input voltage is 25 V, the maximum conversion efficiency is 96.4% and the full-load conversion efficiency is 92.3%.