Research on Multi-objective Optimization Modulation Strategy of Wide Range DAB Converter Based on Power Segmentation

The traditional single-objective optimization strategy is difficult to balance the efficiency requirements of wide-range dual active bridge (DAB) converters at light load, medium and heavy load. Aiming at the efficiency optimization problem under different load conditions, this paper proposes two multi-objective optimization modulation strategies (MS1 and MS2) based on power segmentation by combining different modulation strategies. At light load, both modulation strategies achieve ZVS to reduce switching loss. The conduction loss gradually dominates at medium and heavy loads. Therefore, MS1 combined with inductor current RMS optimal strategy, while MS2 combined with inductor current peak optimal strategy. Both modulation strategies can achieve smooth transition. Through the established switching loss model, the two proposed modulation strategies are compared and analyzed. The second multi-objective optimization strategy performs best under wide output range and wide load, and the loss caused by all switches does not exceed 2 %.