Research And Design Of Off-grid Wind And Solar Hybrid Power Generation System

Nowadays energy and the environment are two important issues in the world. Mankind is hard to find clean, efficient, renewable energy that can replace oil, coal and other conventional energy. Development and utilization of renewable energy is a basic choice of energy development strategy in the 21st century.Off-grid wind and solar hybrid power generation system is designed to compensate for the deficiencies of conventional electricity generation system. It is the most reasonable and independent power system, such as the most rational allocation of resources, the most reasonable technical proposal and the most reasonable price performance. Reasonable performance can assure a high reliability of wind and solar hybrid power generation system. Therefore, wind and solar power generation technology has important theoretical and practical value.In this paper off-grid wind and solar power generation system is made as research subjects. First of all, the development of wind and solar power generation system status is reviewed at home and abroad. The principle of photovoltaic arrays and wind turbine operating characteristics is analyzed. Battery charge and discharge process of electrochemical reaction mechanism and battery charge and discharge control principle is also introduced. These have laid a theoretical foundation for the proposed control strategy and design of the entire system. Secondly, DC/DC Chopper, the traditional solar, wind maximum power point tracking (MPPT) algorithms and other aspects is discussed and researched. A variable step perturbation and observation algorithm based on a perturbation and observation method is proposed. This algorithm can quickly and accurately track the maximum power point, and increase energy efficiency. The DC/DC circuit is designed to achieve MPPT of photovoltaic arrays and wind. Battery charging strategy in this paper adopted three paragraphs charging method that is constant current-constant voltage-float method. The strategy van increase battery cycle life. Then, according to the system control strategy, wind and solar hybrid controller based on ATmega8 is designed. It includes solar energy, wind maximum power tracking circuit, the battery charge and discharge control circuit, current and voltage sampling circuit, MOSFET driver circuit, battery overcharge and over discharge protection circuit, and the auxiliary power circuit and so on. The paper also gives the software design flow chart, including the main program, charge and discharge control subroutine, the maximum power point tracking subroutine of the sun and wind. The system hardware and software not only play the advantages of faster computing hardware, but also take use of the advantages of the software easy to use. Finally, parts of the system model for the MATLAB are built and are simulated by SIMULINK. Experimental results show that the thinking and design of hardware and software of the proposed wind and solar hybrid power generation system is feasible.