As for the control issue of PV inverter under unbalanced and distorted grid

the phase lockedfunction module based on the second order generalized integrator（SOGI for short）is designed firstly in ac-cordance with obtaining fundamental amplitude and phase information of the grid. Its ability in obtainingquickly and correctly the amplitude and phase of voltage positive sequence component at unbalanced anddistorted grid is verified through experiment. Then

the hybrid control system for PI parallel repetitive con-troller is designed for high quality control of grid current in distorted and unbalanced grid. Finally

the sim-ulation model of grid-connected system for photovoltaic inverter is set up by the use of PSCAD and the cor-rectness of the designed scheme in this paper is verified by the simulation result.