Research On Power Control Of Variable-speed Variable-pitch Wind Turbine

New energy,represented by wind energy,has undergone rapid development and make considerable progress during the past decades.Wind is mainly used to generate electricity in terms of exploiting wind energy.The variable pitch and speed technology is applied in controlling the safety and stable operation of the wind turbine.Variable-speed variable-pitch wind turbine was investigated in this paper to achieve both capturing maximum wind energy and smoothing the output power without additional equipment thus obtaining a strategy to effectively control power of wind turbines.The focuses of the study are as follows:(1)The simulation model was established on Matlab/Simulink platform through the analysis of the characteristics of the variable-speed variable-pitch wind turbine under the condition of safe and stable operation.The model will then lay foundation for predicating the short-term and real-time wind speed and optimizing the power control of wind turbine.(2)The short-term power prediction model was proposed based on improved empirical model decomposition(IEMD)and radial basis function(RBF)neural network,and the wind power prediction value was obtained through the convertible relationship between wind speed and power.The results showed that more stationary intrinsic characteristics of component could be obtained by decomposing the original speed with IEMD.Therefore,the stabilization of wind speed time series would be realized and the precision of wind power forecasting could be achieved.(3)The optimized power control scheme of the wind turbine was proposed based on the short term wind speed and wind power.The scheme can predict power one step ahead,and a weighted multi-objective optimization model was established in this study.In this model,the speed and pitch angle are set up as control variables,fuzzy PID algorithm was adopted to calculate pitch angle,turbine speed was calculated by applying the minimization control criterion in the model.Pitch angle and speed then are applied in variable-speed variable-pitch wind turbine to capture the maximum wind energy and get stable output power thus controlling power of variable speed pitch wind turbine.Finally,the comparative analysis was conducted on two simulation models that were established by applying the proposed control scheme and the traditional control strategy were respectively to the 1.5MW double fed wind turbine.The results showed that the proposed strategy for controlling power of variable-speed variable-pitch wind turbine in this paper based on prediction and optimization model displayed good control effect,not only can improve the wind energy utilization efficiency,but also smooth wind power output,optimize the power control of the wind turbine.