| As environmental issues have become increasingly prominent, and energy supply become more tense, countries all over the world have put more emphasis on development and utilization of renewable energy, especially wind energy.Wind power has preferable economic and social benefits because of its cleanliness and free pollution, short construction period, flexible investment and few occupation of land. At present, there is a big gap between China the developed countries in wind turbine's theory and application research, research of wind turbine in China is very weak and many advanced wind turbine technologies are not solved. Therefore, in-depth study of wind turbine systems has very important meaning for persistent wind turbine development and home production. In this paper, the following aspects of the wind power generation systems have been studied:1. Discusses the advantages of wind power and wind power generation industry in China's development and current conditions.2. Researches on aerodynamic theories and methods. The aerodynamic theories are crucial to the modeling and analysis of wind turbines, At present, the usual methods used is bladed element theory (BEM theory). In this paper, a wind machine model diagram is established by Matlab software, and force analysis is done in wind turbine blades. Wind Turbine Model is established based on aerodynamics and on the bladed element theory.3. The solutions of variable pitch wind turbine power system is designed, the variable pitch system adopt 89C51 MCU to control, and the experimental prototype of electric variable pitch wind turbine is established. We can get some important data about wind turbine within an hour, and for the sampling interval is 5s shows the measured performance of wind turbine through testing for 3KW wind prototype. We simulate and analysis in both cases which the wind speeds below the rated wind speed and at rated wind speed through Matlab\simulink software. According to the variable pitch adjustment function, the final results of simulation show that the proposed control law can meet the wind turbine power control requirements for pave the way for future research work.4. The paper studied the boundary layer separation flowing characteristics of the NACA4415 airfoil under the environment of aerodynamic analysis software Profili, the characteristic curves of airfoil was obtained and the paper stated the effects of thickness and camber of airfoil on lift and drag characteristic. Following that, the use of Pro / E three-dimensional modeling software to obtain the model of the leaves. Static analysis and modal analysis were achieved by ANSYS software, and then we studied the 3KW blade model using ANSYS finite element software. We can obtain the blade natural frequencies and vibration modes by calculation, in this case, these studies can supply an analysis method for preventing blade resonance and increasing blade working life.5. The paper introduced the power control section about small isolated wind turbine system, a number of features and performance about the rectifier, chopper, inverter and battery can be obtained through analysis. Through analysis and modeling for single-phase inverter and three-phase inverter, and we can get work environment and characteristics of batteries and other parts.Wind turbine is a comprehensive system engineering of high technology which deals with aerodynamics, automatic control, mechanical drive and generator etc. This article focuses on the blade modal analysis, also as a base to make the calculation of structural strength and mechanical behavior for blades.
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