Wide Voltage Gain Current-Fed Isolated Buck-Boost Series-Resonant Dc-Dc Converter With Active Clamp for Dc Microgrid Applications

This paper presents a current-fed isolated buck-boost converter with active clamping for a wide input voltage range, such as PV applications in dc microgrids. The currentfed configuration at the primary side minimizes input current ripple, thereby enhancing system stability. Through topology morphing control (TMC), the converter operates in five distinct modes, thereby extending both the voltage gain and the ZVS range. Additionally, the active clamp circuit limits the peak voltage across the switches and absorbs the voltage spikes, allowing the use of MOSFETs with relatively low $V_{D S}$ and $\mathbf{R}_{\text {DS }}($ on) ratings. The operation principle and working modes of the converter are briefly explained. A 350 W prototype with an input voltage range of 10 to 60 V was built and experimentally tested, demonstrating high efficiency and a wide gain range.