This paper presents two phase-locked methods of wind power generation three-phase grid-connected inverter. First establishes the mathematical model of the inverter, on this basis analyzes why the power voltage phase must be known. And then studies the direct calculation method in α-β coordinates, and analyzes the shortcomings of this approach for three-phase imbalance; then focusing on the phase locked loop (PLL) approach in d-q coordinate system. To solve dynamic response problem of the PLL, a new signal delay cancellation method is put forward. With this improved method, the PLL can have a better performance. Experimental results show that the theoretical analysis is real.