Research On Variable Pitch Control Of Wind Turbine

With the global emphasis on environmental protection,wind energy had been used globally as a renewable energy source.Wind power has the advantages of less pollutant emissions and lower greenhouse gas emissions.However,wind energy has the shortcomings of randomness and difficult to control,which causes the wind power to affect the smooth and safe operation of the power grid when it is integrated into the power grid.At the same time,the fluctuation of wind power also affects the power quality in the power grid,which has a certain impact on production and life.Wind power quality is of great significance.In order to improve the quality of wind power,this study predicts the wind speed of the wind farm,proposes three wind speed prediction models,compares the predicted values obtained by the three prediction models with the actual wind speed,and analyzes the errors to obtain a way to improve the wind speed prediction errors.Based on the 1.5 MW wind turbine,a variable pitch control strategy is designed,the output power of the wind turbine is obtained through simulation,and the stability of the output power when the wind speed changes is analyzed.The main research contents and conclusions are summarized as follows:(1)Establish a wind turbine model.Analyze the research on the basic theory of wind turbines,build models of wind speed,wind wheel,generator,transmission system,and pitch system one by one,and combine the various models to build a wind turbine model.The wind turbine model is simulated at random wind speeds to obtain the fluctuation of the output power of the wind turbine without a control strategy,and it is determined that the wind turbine model is reasonable.(2)Research on wind speed prediction algorithm.Analyze the characteristics of wind speed,propose time series model,empirical mode decomposition and time series combination method,and local mean decomposition method and time series combination method to predict wind speed,compare the predicted data with actual wind speed,and perform error analysis.The error of the obtained local mean decomposition method and time series combination model is smaller,and the prediction data is more accurate.(3)Design and analyze the pitch control strategy.Based on PID control,a fuzzy PID control strategy is designed.The fuzzy algorithm is used to determine the PID controller parameters.Simulations at random wind speeds show that the fuzzy PID strategy reduces the control response time and makes the wind turbine power output more stable.(4)Optimize variable pitch control strategy.In designing the fuzzy PID control strategy,it is found that it has shortcomings such as difficult to determine parameters,so the particle swarm optimization algorithm is proposed to optimize the fuzzy PID control strategy.Design the particle swarm-fuzzy PID control strategy,use the particle swarm algorithm to determine the parameters of the fuzzy PID control strategy,make the parameters more accurate,and simulate in random wind speed.The simulation shows that the particle swarmfuzzy PID control strategy has better control effect and shorter response time.