Performance investigation of dual active bridge converter in CLLLC mode with current regulator

The Dual Active Bridge (DAB) converter is a commonly accepted topology for Level 3 electric vehicle (EV) charging due to its bidirectional power transfer capability. However, conventional DAB suffers from high switching losses, limited voltage gain, and lower efficiency. This research presents an enhanced DAB architecture by implementing current regulation control in both conventional series inductor-based DAB and the proposed capacitor-inductor-inductor-inductor-capacitor (CLLLC) mode. The study evaluates the performance of an 800V input, 450V output DAB converter, comparing its operation in conventional and CLLLC configurations. A comprehensive analysis of conduction modes, and power transfer characteristics is provided. The results demonstrate that conventional DAB exhibits reduced output power, partial Zero Voltage Switching (ZVS), lower efficiency, and higher secondary current stress. In contrast, the DAB-CLLLC mode significantly enhances ZVS operation, improves power efficiency to 94.1%, and reduces secondary peak current, making it more appropriate for high-power applications. This investigation validates that DAB with CLLLC mode offers superior performance, making it an optimal choice for high-efficiency, high-power EV charging system.