A novel efficiency promotion strategy for three-level ANPC-DAB-based DC-DC converter under new-typed optimization method

As the demand for higher-voltage withstand capability, greater modulation flexibility, reduced prototype development costs, broader zero-voltage-switching (ZVS) range adjustment, and the ability to realize bidirectional power transfer increases, a three voltage level active neutral-point-clamped dual active bridge (ANPC-DAB) converter is introduced to meet these objectives. In order to ensure efficient power transfer within the ANPC-DAB converter, a double-side variable duty modulation (DVDM) approach is also proposed. On one hand, the switching states and soft-switching conditions of the ANPC half-bridge circuit are thoroughly analyzed. The strategies to achieve ZVS turn-on for both clamping and non-clamping switches are explored. Additionally, typical mode illustrations, along with the power and current characteristics under various DVDM operation modes, are presented in detail. On the other hand, to optimize power transmission within the ANPC-DAB converter, a genetic algorithm-based approach is employed. This method ensures that, for a given transmission power, the peak current is minimized. Moreover, a comprehensive optimization strategy is developed using a complete differential algorithm, which not only reduces RMS current but also extends the ZVS region. Through a series of comparisons with existing modulation techniques for the ANPC-DAB converter, it is demonstrated that the proposed DVDM strategy delivers superior efficiency performance. Finally, a prototype of the ANPC-DAB converter is constructed, confirming the correctness, effectiveness and application of the proposed methodology.