Three-phase Photovoltaic (pv) Grid Inverter Based On Dsp Technology Research

With the progress of human society, energy demand is constantly increasing andenergy is mostly consumed in its converted form—electricity. According to the data ofU.S. Energy Information Administration, the global demand for electricity is growing ina rate of2.3percents per year. The fossil fuels still share the majority of the currentenergy structure; however, fossil fuels consumption caused the greenhouse effect whichis the environmental problem that the whole world must be confronted with. Becausefossil fuels are non-renewable resources, new energy must be developed to replace it. Inrenewable energy, solar power has become the top choice with its characteristics ofclean, non-pollution and inexhaustible etc. Grid-connected PV system is an importantform to use solar power, and grid-connected technology is the key to use solar powerand also the hot spot in domestic and foreign research.Taking three-phase grid-connected photovoltaic (PV) system as the research object,this paper does some detail researches on key technologies of the grid-connectedphotovoltaic (PV) system, this paper mainly includes following parts:Firstly, the author studies the present situation of the photovoltaic (PV) marketdevelopment both at home and abroad including some developed countries like Japan,Germany, the United States; also the author gives briefly introduction to the countries’policies on PV industry and sums up the shortage of China in this respect. Theclassification of (PV) power system and the topological structure have also beenintroduced in detail.Secondly, the author makes mathematical modeling for the solar cells in (PV)power system and simulation analysis with the simulation tool Matlab/Simulink, it isconcluded that it is necessary to do MPPT. The author studies the common algorithmsof MPPT in detail and summarizes their respective advantages and disadvantages, andthen gives the flow chart on how the algorithms are implemented.Thirdly, the author studies the control strategies on current control ofGrid-connected PV system and introduces some common control algorithms, also summarizes their advantages and disadvantages. In this paper, theoretical analysisprocess about the strategy of PI current control bases on SVPWM is given in detail. Inorder to reduce the control delay that caused by sampling in actual control, samplingprediction algorithm bases on median average filtering is proposed on the basis ofdouble timer sampling, and the algorithm is proved to be reliable through theexperiments.Fourthly, the system take TMS320F2407as the main control chip to set up theexperimental platform, the author designs the main hardware circuit for the10KWtechnology parameters of three-phase grid inverter, and the rationality of design isverified by experiments.