Control For Grid Connected Photovoltaic Generation System

Grid connected photovoltaic generator is more convenient than the other renewable sources in transforming green energy into electric energy, which is convenience to use. So, the research on the grid connected photovoltaic generator has an important meaning in nowadays especially the electric energy is widely used.Firstly, this thesis is reviewed the development history, the key technologies and the researchful focuses of grid connected photovoltaic generator. Then the topologies of grid-connected inverter are studied, and the topology of single-stage with transformer is chosen, based on the factual circs.The key point of this paper is the research on the control technology. Based on the study of the phase tracking method, the Soft-PLL technology is carry on the grid-connect control; several methods of MPPT (Maximum Power Point Tracking) is analyzed, the desirably observe method is researched and adopted to solve MPPT; the significance and strategy of Island protecting is dissertated, and came true by observing the RMS and frequency of grid continually.It's very important part that the techniques of maximum power point tracking and islanding protecting, but also the technique for inverter to connected with grid are discussed at emphasis.Finally, a sample of 100Wp grid-connected photovoltaic generator is designed, which is controlled by DSP. The experimental result proves the feasibility and reliability of the system, which solves three key techniques, including grid-connect control, maximum power point tracking and islanding protecting, and set up groundwork for the future research.