| Since the beginning of the industrial revolution, mankind benefits a lot from the development and prosperity of the use of fossil fuels, however, which causes the energy crisis and environmental problems. That is demanded to change the energy structure and develop new energy by the consequence of industrialization forces. At the same time, the rapid development of urbanization has an urgent need of alternative energy to improve traditional lighting system in China. Photovoltaic power generation,especially stand-alone photovoltaic lighting, is one of the effective ways to solve these problems. However, the technical reasons and the high cost of application hin-dered the development of PV at present. So how to improve the efficiency of the MPPT method and enhance the management level of the storage battery charging and discharging will be studied in this article.The maximum power point tracking technology and battery charging strategies through the simulation analysis are mainly studied in the paper. Based on the software and the hardware platform, the street lamp control system was successfully designed.The theoretical study of the control strategy shows the system, hopefully will work with more efficiency.Firstly, the MPPT tracking control technology of photovoltaic cells is studied.This paper describes the basic principle, working characteristics of the photovoltaic cell. It also gives analysis of how to build the mathematical model, the photovoltaic cell Simulation model, along with the relationship among the output characteristics of photovoltaic cells and the ambient temperature, light intensity, load. On this basis, the maximum power point tracking method for photovoltaic cells is discussed and veri-fied by MATLAB/simulation. Finally, an improved variable step size INC algorithm based on MPPT is proposed.Secondly, the battery charging strategy is studied. The article describes the principle, characteristics and main parameters of the battery based on the equivalent mathematical model. And then it gives a study of the charge and discharge characte-ristics of battery on the Simulation. A conclusion was given to the advantages and disadvantages among analysis of the common charging and discharging methods of battery, and the charging technology of battery in photovoltaic power generation sys-tem. According to Maas charge laws, the concern of the fast-charging and battery po-larization problem was studied ways to improve charging and discharging strategy was also given in the article. Under simulation analysis, the battery mode, PV model,boost circuit model and other parts were adjusted to observe the battery voltage, cur-rent and terminal voltage change curve at each charging stage.Furthermore, the overall scheme is designed, and the hardware and software platform of street lamps control system is built. The hardware includes AVR control system,DC-DC converter,battery charge gand discharge protection circuit,sampling circuit and auxiliary circuit design; The software includes: program framework, PC function control process, battery charge, discharge management processes and related protection program (overvoltage, under-voltage, over-current, temperature compensa-tion program) .All of the above provide stable software and hardware platforms for the street lamps control system.Finally, the software and hardware of the system was tested. The function of the system is validated to be feasible and perfect, and the practical operation results of the improved incremental conductance method MPPT tracking control strategy and the improved battery charging and discharging control strategy are presented on the basis of the lamp control system. |
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