Efficiency Promotion Strategy for Three-Level ANPC-DAB-Based DC-DC Converter with Wide-Range Multi-Objective Optimization Method

Because of the increasing demands of higher-voltage withstanding ability, higher modulation flexibility, lower cost for prototype establishment, wider zero-voltage-switching (ZVS) range adjustment ability and bidirectional power transmission ability, three-level active neutral-point-clamped dual active bridge (ANPC-DAB) converter is required to achieve goals which are mentioned. To establish efficient power transmission inside ANPC-DAB converter, double-side variable duty modulation (DVDM) strategy is also proposed. First, switching states and soft-switching conditions of ANPC half-bridge circuit are discussed minutely. The methods to realize ZVS turn-on of clamping switches and non-clamping switches are discussed similarly. At the same time, typical mode illustrations, power characteristics and current characteristics under different DVDM operation modes are demonstrated completely. Second, to achieve efficient power transfer inside ANPC-DAB converter, based on genetic algorithm, under certain transmission power, can achieve lowest peak current. Concurrently, based on complete differential algorithm, a integrated optimization method is created to reduce RMS current and extend ZVS region concurrently. Proposed DVDM strategy can achieve better efficiency performance by the comprehensive comparisons among existing modulation methods. At last, an ANPC-DAB prototype is designed, and proving effectiveness and correctness of proposed method.