Design Of Small Off-grid Wind Turbine Control System

With the intensification of the shortage of non renewable energy,the development and utilization of wind power systems are receiving increasing attention.The improvement of wind power utilization efficiency and output power quality is the main research direction of the system.Maximum Power Point Tracking(MPPT)technology and hybrid energy storage system technology have gradually become research hotspots in wind energy development.This article takes the 300 W direct drive permanent magnet wind power system as the research object,and focuses on the problems of low wind energy utilization efficiency and poor output power quality.MPPT strategy and hybrid energy storage control strategy are studied.Firstly,in order to improve the power generation efficiency of the system,the basic theory of wind power systems was studied,and it was determined that the system can capture maximum power by changing the blade tip speed ratio.By comparing different MPPT strategies,a composite control method combining the optimal tip speed ratio method based on wind speed estimation and the duty cycle disturbance method is determined.In order to improve the accuracy of wind speed estimation,a wind speed estimation model was established using Support Vector Machine Regression(SVR)optimized by the Bat Algorithm(BA).In order to avoid problems such as uneven initial population distribution,falling into local optima,and slow convergence speed of BA,improvements were made to BA through Tent initialization of bat population initial position,adaptive weight position search,optimization of loudness,and update of pulse emission frequency.Build a simulation experimental platform using Simulink,and verify the superiority of the improved BA optimized SVR wind speed estimation model and the superiority of the improved maximum power tracking strategy through comparative experiments of different control methods.Then,in order to improve the output power quality of the wind power system and extend the battery life,a hybrid energy storage method of lithium batteries and supercapacitors is selected to store the electricity generated by the system.And a control strategy combining a first-order low-pass filter with a variable time constant and Active Disturbance Rejection Control(ADRC)with dual closed-loop is proposed.Establish an auto-disturbance rejection controller and use fuzzy control to optimize the control gain parameters of the outer loop feedback control law,achieving adaptive adjustment of the parameters.In order to avoid damage to lithium batteries caused by high-frequency components of captured power,a first-order low-pass filter with variable time constant is designed to allocate the captured power of the system and reduce the residual high-frequency components in the low-frequency components.Building a simulation experimental platform based on Simulink,and conducting simulation comparative experiments on different hybrid energy storage control methods,the superiority of the control strategy designed in this paper in improving the quality of system output voltage was verified.Finally,the hardware framework of the wind power control system is established,the main circuit of the system is designed and tested,the system software framework is built,and the human-computer interface is designed based on the QT platform.Build a physical experimental platform to test the performance of the small wind power system controller designed in this paper.The experimental results show that: 1)improving the MPPT strategy results in shorter tracking time and higher tracking power under constant wind speed;It can effectively track the maximum power corresponding to different wind speeds under variable wind speeds.2)The optimized wind speed estimation model can effectively predict changing wind speeds.3)The improved hybrid energy storage system can suppress voltage fluctuations in the main circuit and meet the requirements of segmented charging of lithium batteries.