Abstract: With the increasing of the dual active full bridge (DAB) converter's operating frequency, the proportion of active semiconductors' switching loss is prominent, resulting in the fact that the single-objective optimization strategies based on the backflow power, peak or RMS inductor current are gradually losing the efficiency advantages. To improve the high-frequency operation efficiency, this paper carries out a quantitative analysis of optimal operation modes and optimization objectives of DAB, and further proposes a control scheme by which the quasi-optimal inductor RMS current and wide zero voltage switching (ZVS) operation can be realized simultaneously. Specifically, the ZVS operation of all switches can be realized in light and heavy loads, and the ZVS operation of six switches can be achieved in medium load. Furthermore, for the reliability of ZVS operation, the unified current expressions required for the ZVS process are derived based on the charge exchange and dead time. The ZVS resonance process is linearized in this paper, and the ZVS current can be combined with the phase-shifting mode, by which the realization of ZVS of all switches in all modes can be guaranteed. Finally, a 6.6 kW/150 kHz SiC experimental platform is built, and the experimental results show that the switching loss and conduction loss can be reduced simultaneously by the multi-objective optimization strategy, effectively improving the operation efficiency of DAB converter at high frequency.