Voltage-boost resonant LLC-converter with bipolar output voltage

Abstract: This paper presents a comparative analysis of voltage-boost and isolated topologies of a resonant LLC-converter with a bipolar output voltage. It is shown that the voltage-boost topology can reduce size and weight and decrease transformer losses while maintaining the required output parameters under load varia-tions. An assessment of the root mean square (RMS) current values in the resonant circuits, which determine static losses, revealed a 1.5-fold increase in the resonant circuit current of the voltage-boost topology compared to the isolated counterpart. The results demonstrate a significant improvement in size‑and‑weight metrics while maintaining comparable energy efficiency of the proposed converter relative to conventional isolated solutions.

Keywords: soft switching, zvs, autotransformer, push-pull converter, resonant llc-converter