A Backflow Power Optimization Method for Three-Level ANPC-DAB Converter

With the increasing demands of high voltage level and high power level, conventional two voltage-level dual active bridge (DAB) applications are restricted, and the active neutral-point-clamped dual active bridge (ANPC-DAB) topology is introduced. In this paper, a minimization method of backflow power for three-level ANPC-DAB with low current stress under triple-phase-shift (TPS) modulation is proposed. Firstly, the operation principle and operation modes of ANPC-DAB converter are analyzed. Then, the mathematical model of the converter under different operating modes are established. On this basis, a minimum backflow power model is built, the optimal solution is obtained by MATLAB/Fmincon solver, and the mode transition principle is also discussed. Finally, experiments were conducted on an experimental prototype and the correctness and effectiveness of the proposed method is verified.