Variable Pitch Control Of Wind Turbine Based On Wind Speed Estimation

With the energy consumption growing,environmental pollution becoming serious increasingly,wind power as a renewable green energy has been paid more and more attention.Wind power is the main way of the wind energy utilization.With the stochastic nature of wind speed,variable pitch wind turbine is attracted researchers' interests owing to its characteristic of keeping stable output power through adjusting pitch angle,improving the quality of power generation and increasing the age of wind turbine.However,because the system of variable pitch wind turbine is a multi-disciplinary and comprehensive hi-tech system with the characteristic of strong nonlinear and time varying uncertainty,it is still an important task of the research of wind power technology to seek more effective variable pitch control strategy.The paper take certain type of 1.5MW variable pitch wind turbine as research object,based on the analysis of aerodynamic characteristics and operating condition of wind turbine,build the wind estimation model took on the method of SVM compensation,further,design the variable pitch controller adopting wind speed estimation,reduce the fluctuation of the output power of wind turbine caused by the stochastic and instability of wind,improve the power regulation mode and the quality of electric energy,provide a new idea to design variable pitch controller of wind turbine,specific works are as follows:(1)To the immeasurable effective wind speed which function on frontal area of turbine blades under the influence of wake effect,wind shear effect,installation site and uncertain factors on wind speed,though the analysis of operating characteristic of wind turbine,the paper take pitch angle,wind turbine output power,rotor angular velocity,rotor angular velocity derivative as the input variable of estimation model,build the wind speed estimation model of variable pitch wind turbine using the SVM compensation method.To improve the precision of wind speed estimation,the paper adopt particle swarm optimization algorithm to pick over parameters,build parameters optimized SVM compensation model which to estimate effective wind speed.The simulation reveals that wind speed estimation precision is improved,which also laid the foundation for adopting wind speed into variable pitch control of wind turbines.(2)According to the problem of the stability of the output power of the wind turbine generator system affected by the random wind speed,to design the variable pitch controller of wind turbine designed which based on wind speed estimation.First,design the Fuzzy-PID controller according to the feature of nonlinearity and time-variation and adopt the design based on smoothing factor function to make control arithmetic switch smoothly.Second,design feedforward compensator with wind speed estimation aiming at solving the problem of power feeds back signal lagging.According to the proper pitch angle given by the estimated effective wind speed,make dynamic feedforward compensation,improve dynamic performance of the system,realizing the fusion of wind speed estimation and variable pitch control.Finally,taking 1.5MW variable pitch wind turbine generator as experiment object,take simulation research for the proposed variable pitch control strategy based on Matlab software platform.The stimulation result shows that the proposed method in the paper is effective.