And Research And Design Of Grid-connected Photovoltaic Systems

With the rapid exploitation and utilization of traditional fossil fuel and the increasingly severe environment pollution, governments from many countries have put the New Energy into emerging industry, with a representative of the solar, wind, tide and geothermal energy, among of them solar and wind energy have been widely developed and used. Because of the better stability of solar energy, the power generation grid-connected by solar energy will be faced with high speed continuous development.In the PV Grid-Connected power system, PV Grid-Connected Inverter is a kind of equipment that used to convert the DC energy which from solar panels into AC energy and deliver it to the grid, it is the core of energy conversion and control in PV Grid-Connected power system. This paper mainly researched the design principle of PV Grid-Connected Inverter, studied the Dual-Loop control strategy which take the DC voltage as the external loop and the AC current as the internal loop, the PI Controller is used for the external loop,the internal loop has been equipped with PI controller, too, in this way, it will make sure that the AC current can tracking the phase angle of grid voltage quickly and in a real-time, perform the Power Factor of the PV Grid-Connected power system runs at1.0. The main tasks of this paper are as follows:Firstly, introduced the background of PV industry,the research status in domestic and abroad about PV Grid-Connected power system, the characteristics of PV panels and the MPPT algorithm of PV panels based on the method of incremental conductance and the perturbation and observation method.Secondly, introduced the32-bits high performance Fixed-Point DSP TMS320F2812from TI, analysed the dual-loop control strategy of the PV Grid-Connected Inverter, mainly researched the principle of inverter control based on SPWM and the real-time tracking technology of the output current, and then researched the control system of PV Grid-Connected power system, especially the mathematical model of the current loop control system and the correction of the control system based on PI controller and PR controller, then came to the conclusion that the PR controller is better than the PI controller by making a comparision between them.Finally, introduced the designing ideas of hardware and software, developed a single phase20KW PV Grid-Connected Power System module in the environment of Matlab/Simulink, the analysis of the simulation results has been done, too.