Bidirectional Asymmetric PWM Resonant DC/DC Converter With Wide Voltage-Conversion Ratio

This article proposes a reconfigurable bidirectional resonant dc/dc converter that can operate under wide ranges of forward voltage-conversion ratioMfand backward voltage-conversion ratioMb. In the forward direction, the proposed converter operates as a full-wave resonant buck converter with two-level voltageVcd(whenMf < $1), as a half-wave resonant boost converter with three-level voltage${Vcd}$(when 1$≤ Mf< $2), and as a half-wave resonant boost converter with two-level${Vcd}$(when${Mf}≥2). In the backward direction, the proposed converter operates as a full-wave resonant boost converter with two-level voltageVcd(whenMb≥ $1), as a half-wave resonant buck converter with three-level${Vcd}$(when 0.5$≤ Mb< $1), and as a half-wave resonant buck converter with two-level${Vcd}$(when${Mb}<0.5). We acquire accurate voltage-gain equations according to the duty and the output power for the half-wave resonant boost converter that has three-levelVcdin the forward direction and for the half-wave resonant buck converter that has three-levelVcdin the backward direction. We provide a detailed design guideline for the proposed converter, considering three operation modes in each power-flow direction. The proposed bidirectional converter and its switching modulation scheme were verified experimentally using a 200-V~1000-V/1-kW hardware prototype that was fed 400-V input.