Simulation Research of the Single-phase PV Grid-connected System and Its Islanding

The operational principles of PV grid-connected system and its islanding are analyzed in this paper. Then a simulation model of the PV grid-connected system is established in Matlab.In our model,the gridconnected inverter adopts the PI control method based on repetitive control current feedback,and the identification method of islanding relies on active frequency drift method.The simulation results prove that the output wave of the grid-connected current is good and has the same frequency and phase as the utility grid.Meanwhile,the islanding can be detected effectively in this model.