基于NLESO的永磁直驱风力发电最大功率追踪滑模控制

Maximum power tracking sliding mode control of permanent magnet direct drive wind power heneration based on NLESO

针对传统控制器在永磁直驱风力发电机中进行最大功率跟踪时响应速度慢、追踪精度低等问题,提出了一种基于改进指数趋近律和非线性扩张状态观测器(non-linear extended state observer,NLESO)的滑模控制方法。该方法使用连续函数代替符号函数sign(s),引入增益函数设计改进指数趋近律以加快系统响应速度;将传统扩张状态观测器(extended state observer,ESO)中fal函数替换成一种非线性函数,并基于此设计NLESO以提升系统抗扰动能力,结合二者设计改进滑模控制器取代传统PI控制器。在MATLAB/Simulink上构建模型,结果表明,渐变风突变过程无超调,风速突变后再次平衡时间从0.054 s减少到0.028 s,自然风过程中系统能精准追踪上额定转速,证明了该控制方法具有超调量小、响应速度快、追踪精度高等特点。

A sliding mode control method based on an improved exponential convergence law and a non-linear extended state observer(NLESO)is proposed to address the problems of slow response and low tracking accuracy of conventional controllers for maximum power tracking in permanent magnet direct-drive wind turbines.The method uses a continuous function instead of the sign(s)function,and introduces a gain function to improve the exponential convergence law to speed up the system response;replaces the fal function in the traditional extended state observer(ESO)with a nonlinear function,and designs NLESO based on this to improve the system immunity to disturbance,and combines the two to design an improved sliding mode controller instead of the traditional PI controller.The model was constructed on MATLAB/Simulink and the results show that there is no overshoot during the sudden change of the gradual wind,the re-equilibration time after the sudden change of wind speed is reduced from 0.054 s to 0.028 s,and the system can accurately track the upper rated speed during the natural wind,which proves that the control method has the characteristics of small overshoot,fast response speed and high tracking accuracy.