Abstract:The model of three-phase phase-locked loop based on double d-q rotating shaft is proposed in view of the shortcomings that common three-phase phase-locked ring is not easy to eliminate the second harmonic under asymmetrical three-phase voltages,and the modeling and simulation of the proposed model is carried out.The simulation results show that double d-q rotating shaft three-phase phase-locked loop can lock phase accurately in the conditions of balanced and unbalanced voltage of the three-phase power grid.