Light-load Conversion Efficiency Enhancement for Three-Phase Dual Active Bridge DC-DC Converters

With the development of electric vehicles and energy storage systems, the future demand for bidirectional power converters is expected to increase significantly. However, bidirectional power converters typically exhibit low conversion efficiency under light-load conditions, which can lead to unnecessary energy consumption. This paper proposes a smart control scheme comprising single-phase and three-phase modes to enhance the light-load conversion efficiency of a Three-Phase Dual Active Bridge (TPDAB) DC-DC converter. The smart control scheme dynamically exchanges between the single-phase and three-phase modes based on the load conditions. Apart from improving light-load conversion efficiency, the proposed control method also extends the service life of power switches by reducing their operation time, thus enhancing the overall reliability of the converter. A prototype of the TPDAB DC-DC converter is implemented in this paper, featuring a rated high voltage of 380V, a rated low voltage of 48V, and a rated power of 720W. Experimental results validate the effectiveness of the proposed smart control scheme, demonstrating an approximately 10% conversion efficiency enhancement at light loads for the implemented TPDAB DC-DC converter.