Research On Unified Control System Of Photovoltaic Grid - Connected And Active Filter Based On SDFT Algorithm

Solar energy is a very environmentally friendly and inexhaustible, has becomeone of the world’s new energy most promising. In American and European countries,photovoltaic technology has been widely applied, also gradually extend our currentstage. PV prospects are very good. Meanwhile, with the continuous progress ofscience and technology development, and power electronics technology, theapplication of power electronic devices has become increasingly widespread. This hasresulted in large numbers of non-linear loads, they produce harmful harmonics andreactive current on the grid has become increasingly serious. The traditional passivefiltering technology can not meet the needs of the current grid management, andactive power filter with its good performance has now become the focus of research athome and abroad.While the prospect of active power filter and photovoltaic power generation isgood, but they are both there are some shortcomings, such as photovoltaic systemsaffected by weather conditions impact, can only work in the daytime; relatively highcost of both economic efficiency lower. For their shortcomings, this paper studies thephotovoltaic grid and active power filter unified control system, a unified controlsystem has both photovoltaic and active filtering function, more suitable forapplication.First, this paper introduces the research status and development prospects of thephotovoltaic industry and active power filter, and analyzed the shortcomings andobstacles to development of their respective existence. On this basis, a detailed studyof the structure and the working principle of photovoltaic grid-connected systems andactive power filter, discussed the significance of their unified control. By comparingthe similarities and differences between the two, both concluded that it is feasible forunified control and gives a unified control system block diagram of the system.Then, the paper currently used in several harmonic current detection methods areintroduced. The main purpose of this paper is a unified control system for a particularharmonic detection and compensation, so the use of harmonic detection method basedon improved methods of discrete Fourier algorithm as a unified control system, thisalgorithm has detected a particular harmonic aspects a great advantage, and thisalgorithm simulation.Finally, the proposed control strategy unified control system, the mainparameters of the system design. Built in matlab simulation model of the system, thesimulation results were analyzed to verify the feasibility of a unified control system toachieve a specific harmonic compensation.