Experimental evaluations of a five-element multi-resonant DC-DC converter with an improved PFM control range

An LLC multi-resonant DC-DC converter with anti-resonant tank is presented in this paper. The five-element multi-resonant (LLC-LC) dc-dc converter can realize the wide range regulations of output voltage and power by pulse frequency modulation (PFM) under soft switching conditions. The resonant dc-dc converter proposed herein is suitable for renewable and sustainable energy applications such as battery chargers interfaced with a photovoltaic power generation system. In this paper, the design guideline of circuit parameters is originally described. Experiment results on the soft-switching performances and steady-state characteristics including the power loss analysis are demonstrated, thereby the effectiveness is verified from a practical point of view.