Abstract: With the increasing operating frequency of dual active bridge(DAB) converter, the influence of switching loss on transmission efficiency is also increasing. The DAB converter realizes the soft switching of the full switching device as much as possible by adopting the appropriate soft switching control strategy, but the dead-time overlap phenomenon under the light load condition causes the soft switching condition to conflict, which is particularly prominent under the high frequency light load condition. In order to improve the energy transmission efficiency of DAB converter under high frequency and light load conditions, the dead-time overlap phenomenon under light load conditions is analyzed. Combined with the influence of buffer capacitance on the dead-time process, a three-degree-of-freedom control strategy with current stress as the optimization objective is proposed. Finally, the correctness of the analysis process and the effectiveness of the proposed control strategy are verified by experiments.