Photovoltaic (pv) Grid Inverter Filtering And Control Technology Research

Along with the reduce of petrochemical energy, new energy development and utilization has become an important strategy. Solar energy as one of the green energy has been widely used in all fields, solar photovoltaic power generation is the main use in electric power systems. It has two working modes in solar photovoltaic power generation:independent of power grid and grid-connected. Independent power systems need battery for energy storage, energy loss is bigger; grid generation has reduce loss, saving investment, optimize the structure of electric power relative to the independent power, etc. Therefore, photovoltaic grid power become a hot research point.Grid-connected photovoltaic (pv) generation system consists of solar cell array and inverter composition. In order to achieve needed voltage level, the cells should in series or parallel combination, the dc power generated in solar cells invert into alternating current (ac) by inverter, and inject into the power grid. In an ideal working status, photovoltaic (pv) grid system as a current source transmit current to the grid transmission, but it cannot void current harmonic in the process of inverting, in order not to influence the quality of power, we must use filtering equipment; In order to ensure the grid-connected current produced by inverter inject to the power grid does not affect the voltage frequency and phase of the grid, therefore, it should be keep the same frequency and phase between grid-connected current and power grid voltage.Background of this article is based on the author as an intern for the company to participate in the research of single-phase photovoltaic (pv) grid-connected inverter, firstly, for photovoltaic (pv) grid-connected inverter, the working principle and the topological structure has made the brief description and analysis of harmonic produced by inverting process; Secondly, system model by L and LCL filter is set up respectively, make a detailed analysis on the influential factors of the inverter output current waveform, and put forward corresponding suppression method; Thirdly, control method of LCL filter is studied, when using different parameters as control variables, the corresponding control method make the system meet the requirements of interconnection standards; Finally, according to the actual project requirements, this paper puts forward two kinds design method of filter parameters and simulation in Matlab.