The paper proposed a novel three-phase single stage AC-DC converter for grid energy storage applications. Variable-frequency (VF) and dual-phase-shift (DPS) modulation are utilized in this Dual-Active-Bridge (DAB) converter to realize power-factor correction (PFC) and zero voltage switching (ZVS). An optimal control is applied to reduce switching loss and increase system efficiency. The prototype is tested to verify the novel control. An efficient of 96.5% is achieved at 6.6 kW power.