The Research Of Grid-connected PV Systems And MPPT

Along with the economic development and social progress, the demand of energy decreasing gradually is increasing in countries, at the same time, lots of fossil energy used cause great damage to the environment of human society, what makes a serious of threat to the survival of the human. As the guarantee for modern people’s life and the development and progress of the countries and society, to find a new green energy is very important for every country and the development of human society. In this condition, solar power technology which caused the worldwide attention because of all the advantages of clean and zero-emission came into being.The solar grid-connected power generation system controlled research is mainly committed to in this topic. Mainly from the following two aspects carries on the analysis and research:Part one of the paper the composition of grid-connected PV systems and various parts of the principle is firstly discussed, then the output characteristics of the photovoltaic cell is analyzed, combined with the Boost Converter, according to which the mathematical model of a PV and Boost Converter is constructed. Through the control of Boost Converter and the analysis and improve of the maximum power of a conventional controlling method, an improve maximum power point tracking control method——Improved Hysteresis Comparative method is presented in this paper, and then simulation and experimental validation of new control strategies is done to improve the utilization efficiency of solar energy.In part two of the paper a grid-connected control strategy research is made to mainly analysis the topology structure of the single-phase grid inverter, and construct the mathematical model of the grid-connected control according to the topology used. Based on topology determined, the grid modulation strategy is analyzed, and in order to improve grid-connected reliability PLL is made in this article, as well as simulation and experimental validation made to new control strategies.In a word, the research mainly aiming at the pre-stage Boost converter power generation system、maximum power control and post-stage grid-connected control、 grid-connected modulation、PLL is processed in this paper, in which a series of improvements is used to finish the subject need.