Triple-Mode Wide-Input Range Resonant DC-DC Converter with Extended Asymmetric Modulation

This article proposes a triple-mode resonant converter operating over a wide input voltage range for renewable energy harvesting applications. The proposed converter operates in a pure series-resonant mode with a nominal input voltage, an asymmetric resonant boost mode with a low-input voltage, and an asymmetric pulse-width-modulation series-resonant buck mode with a high-input voltage. This converter adopts an asymmetric half-bridge-type voltage-doubler to reduce the transformer turns ratio and number of active components. Moreover, its extended asymmetric modulation reduces hard switching turn-on losses compared to conventional symmetric modulations. Consequently, the proposed converter attains high power conversion efficiency and power density over a wide input voltage range. The operating principles and steady-state analysis are presented in detail herein. Finally, a 300-W/380-V prototype is presented to validate the feasibility of the proposed converter over an input voltage range of 30-60 V.