Enhanced Modulation Strategy and Magnetic Component Parameter Design for Dual Active Bridge Converters to Improve Efficiency Under Variable Load Conditions

Dual active bridge (DAB) converter serves as the hub for energy exchange, with efficiency being its paramount indicator. A comprehensive optimization solution for efficiency improvement is proposed in this paper, which consists of two parts. The part one is an optimal modulation strategy that achieves full soft switching under light-load conditions, minimizes peak current under heavy-load conditions, and enables seamless transitions between different modes. The part two is the optimization of magnetic component parameters, specifically the turns ratio and inductance, based on this modulation strategy to further reduce the current stress and enhance overall efficiency. Distinct from the previous work, the proposed solution offers noteworthy advantages: 1) the modulation strategy attains zero-voltage switching (ZVS) instead of quasi-zero-voltage switching (QZVS) under light-load conditions and facilitates seamless mode transitions; 2) the turns ratio and inductance are tailored for variable load conditions, rendering them applicable to a more extensive array of scenarios; 3) the analytical design method for magnetic component parameters enhances both the portability and accuracy compared to traditional exhaustive search methods. The experimental results confirm the theoretical analysis and illustrate the effectiveness and superiority of the proposed solution.