Research On Power Capture Control Of Wind Turbines In Full Operation Area

Affected by factors such as latitude,season,and ground roughness,wind speed varies randomly in both horizontal and vertical directions,which brings great challenges to its energy capture.Due to the insufficient nonlinear tracking ability of the traditional control method,the wind turbine has low efficiency,poor output power quality and impact on the mechanical structure during the energy conversion process.In order to improve the overall quality of wind turbines and increase the output value of electric energy to meet the increasing energy demand,this paper has carried out a research on the wind energy capture control of the whole area of wind turbines.The main tasks of this research are:First,the current research status of control techniques corresponding to wind turbines under high and low wind speed conditions is introduced through a literature review,and the wind turbine is modeled mathematically according to the energy transfer process.The control objectives of the wind turbine for energy capture under different operating conditions are analyzed.On this basis,the main ideas of high wind speed pitch control technology and low wind speed maximum power tracking technology are described,and several common implementation methods and their characteristics are introduced.Second,corresponding control strategies are designed for different wind speeds.For high wind speeds,a fuzzy self-coupled PI controller is proposed to accomplish the basic pitch control purpose to achieve the limitation of the wind turbine output power.The stability of the selfcoupled PI for the closed-loop system is demonstrated based on the derivation of equations,and the control effect of the fuzzy self-coupled PI compared with other traditional control methods is initially compared by arithmetic simulation.For low wind speed,a variable step climbing search method is designed to maximize the output power.The idea of the hill-climbing search method and the disadvantages of the fixed-step implementation are obtained by theoretical analysis.Similarly,a preliminary comparison was made between the designed scheme and other schemes to verify its feasibility.Finally,a simulation model of a 2MW direct-drive permanent magnet synchronous wind turbine from air capture to grid connection is built.The designed control scheme for two wind speed bands is added to the simulation model,and virtual simulation experiments are conducted with step wind and random wind as the input wind speed.The results of the virtual simulation experiments show that the proposed control scheme for different wind speed zones achieves better response performance in power regulation than the traditional industrial methods,which verifies its value for industrial applications.This paper analyzes the feasibility of the proposed method from theoretical proof to experimental simulation,verifies the value of its industrial application,and improves the overall performance of the wind turbine.