LCC-Resonant-Type Current-Fed-Out Three-Port DC–DC Converter for PV Electrolytic Hydrogen Production Integrated With Energy Storage

Abstract

The three-port dc–dc converter is an attractive solution in off-grid PV hydrogen production systems for the integration of the photovoltaic cells, energy storage and electrolyzer due to simple structure, low cost, and high-power density. Taking working characteristics of low-voltage high-current and sensitivity to current ripples of the electrolyzer into account, a LCC-resonant-type current-fed-out partially isolated three-port dc–dc converter (LCC-CFO-TPC) is proposed in this article. By employing the PWM+PFM method, the converter can achieve high step-down ratio and low output current ripples for the electrolyzer, low current stress for secondary-side rectifier diodes, zero-voltage switching (ZVS) for the primary-side full-bridge across the full power range. A 500 W prototype is built in the laboratory to verify the feasibility and effectiveness of the proposed converter, and the advantages of the proposed converter are also presented by experimental comparison with the LLC-based interleaved-boost-integrated partially isolated three-port converter (LLC-TPC) employing the PWM+PFM method and the phase-shift full-bridge based partially isolated three-port converter (PSFB-TPC) employing the PWM+PSM method.