Independent Variable-Pitch Control Strategy On Optimizing The Distribution Of MW Level Wind Turbines' Load

As an important kind of new sustainable development energy,wind power generation not merely can save the routine energy resources,but also may decrease pollution of the environment.Thus it can bring preferable economic benefits and society benefits.At present,wind power generation has caused more and more concern by governments all around the world.Because wind energy has lower density,instability and randomicity, wind turbines have strong nonlinear multivariable with many uncertain factors and disturbances.Therefore control technology is crucial to the efficiency and reliability of wind turbines.With the wind turbine becoming large and light,its components become more flexible and the natural frequency of the system reduce gradually.The longtime vibration of the components due to the load,will lead to fatigue destroy.Because of the wind's time varying characteristic,in order to get the most energy from wind,improve the power coefficient and avoid the damage from the gust,the loads of wind turbines must be controlled.Based on the aerodynamics,classical control theory and modern control theory,this article firstly studied how the load produce,classified and analyzed;Secondly according to building up the calculating model of the load to get the connection between load and wind and built up the independent variable-pitch state-space model;Then analyzed how the wind cutting disturbed load to get the connection between disturbance wind and the pitch angle and designed a control strategy on optimizing the distribution of MW wind turbines' load based on H∞Robust control arithmetic and eliminate the disturbance and reduced the load of wind turbines finally.According to the results from the simulation,the load of blades can be distributed uniformly,and the vibration of wind turbines is reduced distinctly.The wind turbines have better real-time performance and robustness and can be controlled better.The article was finished with the help of Wind Energy Institute Shenyang University of Technology based on the research of "Wind Turbines Design and software development",one of the state "863" projects in SUT(NO.2006AA05Z429),and the paper is one of the subject.