Integrated boost-forward-flyback converter with high step-up for green energy power-conversion applications

Abstract

An isolated high step-up converter is proposed for renewable energy sources with low voltages, such as photovoltaic (PV) cells of solar energy and fuel cells of hydrogen energy, to achieve high voltage levels for series-connection batteries and DC-bus voltage sources. The proposed integrated boost-forward-flyback converter (IBFFC) is achieved by integrating a boost converter, a forward-flyback converter and a voltage doubler. Moreover, an active-clamp function is employed to recycle the energy of leakage inductance. An 800 W-rated prototype has been implemented to verify the functionality of the presented converter; it offers an input voltage of 48 V and an output voltage of 400 V. In addition, the maximum efficiency is approximately 94%.