Abstract: Due to its low component count, wide soft-switching range, and high efficiency, the dual-active- bridge (DAB) microinverter has advantages over other topologies. In this paper, the transfer power range, RMS value of transformer current as well as the zero-voltage switching (ZVS) range of the three modulation modes are analyzed and compared detailly. Based on the analysis, the mode-switching modulation strategy is proposed. By designing the trajectory of the inner phase-shift angle in the power frequency cycle, and using feedforward control to calculate the value of the outer phase-shift angle, the modulation mode switches between mode 2 and mode 3, which can not only reduce the RMS value of transformer current, but also achieve soft-switching of all switches in the whole line cycle, which enhance the efficiency. A 600W microinverter prototype is constructed using the optimum transformer parameters, and the proposed modulation strategy is verified via simulation and experiments.