Design and Experimental Validation of a 25-kW Dual DAB–CLLC Bidirectional DC/DC Converter With an Ultrawide 200–1000 V Operating Range

This article presents the design and experimental validation of a 25-kW bidirectional DC/DC converter employing a dual DAB-CLLC resonant architecture to achieve high efficiency across an ultrawide 200–1000-V operating range. The proposed topology connects two DAB–CLLC submodules in parallel on the input side and reconfigures them in series or parallel on the battery side according to the voltage level. This reconfigurable dual-module structure enables high power density, balanced current sharing, and minimized conduction losses under low-voltage conditions, while reducing switching stress during high-voltage operation. Furthermore, a dynamic DC-link voltage control and an integrated control algorithm are developed to coordinate bidirectional power flow and maintain stable transition between charging and discharging modes. Analytical derivation of the resonant-tank parameters and gain characteristics is provided, followed by an optimal design guideline ensuring Zero-Voltage Switching (ZVS) under both directions of power flow. A 25-kW prototype implemented with 1200-V-class SiC devices achieves 98.37-% peak efficiency in charging and 97.82-% in discharging, verified experimentally over the full 200–1000-V range. Compared with previously reported DAB-CLLC and reconfigurable resonant converters, the proposed system demonstrates wider voltage adaptability, simpler hardware implementation, and superior thermal reliability, proving its suitability for next-generation bidirectional fast-charging systems for electric vehicles.