Monitoring of Wind Turbine Blades Based on Dual-Tree Complex Wavelet Transform  

基于双树复小波变换的风力叶片监测研究

作　　者：LIU Rongmei ZHOU Keyin YAO Entao 刘荣梅;周克印;姚恩涛(南京航空航天大学航空学院,南京210016;南京航空航天大学自动化学院,南京210016)

机构地区：[1]College of Aerospace Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,P.R.China [2]College of Automation Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,P.R.China

出　　处：《Transactions of Nanjing University of Aeronautics and Astronautics》2021年第1期140-152,共13页南京航空航天大学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.11402112);the National Key Technology Support Program (No.2012BAA01B02)。

摘　　要：Structural health monitoring(SHM)in-service is very important for wind turbine system.Because the central wavelength of a fiber Bragg grating(FBG)sensor changes linearly with strain or temperature,FBG-based sensors are easily applied to structural tests.Therefore,the monitoring of wind turbine blades by FBG sensors is proposed.The method is experimentally proved to be feasible.Five FBG sensors were set along the blade length in order to measure distributed strain.However,environmental or measurement noise may cover the structural signals.Dual-tree complex wavelet transform(DT-CWT)is suggested to wipe off the noise.The experimental studies indicate that the tested strain fluctuate distinctly as one of the blades is broken.The rotation period is about 1 s at the given working condition.However,the period is about 0.3 s if all the wind blades are in good conditions.Therefore,strain monitoring by FBG sensors could predict damage of a wind turbine blade system.Moreover,the studies indicate that monitoring of one blade is adequate to diagnose the status of a wind generator.对风力发电系统而言,结构服役期间的健康监测非常重要。由于布拉格光纤光栅(Fiber Bragg grating,FBG)传感器的中心波长随应变或温度呈线性变化,因此FBG传感器广泛应用于结构测试。本文提出了基于FBG传感器的风力叶片监测方法,并通过实验验证该方法。沿着叶片长度方向粘贴5个FBG传感器进行应变测量。由于环境及测试噪声会掩盖结构真实信号,文中采用双树复小波变换(Dual-tree complex wavelet transform,DT-CWT)方法,进行数据处理,滤去噪声信号。实验验证结果表明,当其中一根叶片出现损坏时,测量应变出现明显波动,给定工作条件下,旋转周期为1 s,而结构完好时的周期为0.3 s。因此,利用布拉格光纤光栅传感系统进行应变测量,可以预测风力叶片系统的损坏。进一步研究表明,可以通过监测其中一根叶片,从而对整个风力发电系统进行故障预测。

关 键 词：wind turbine blade structural health monitoring(SHM) fiber Bragg grating(FBG) dual-tree complex wavelet transform(DT-CWT) 

分 类 号：TP29[自动化与计算机技术—检测技术与自动化装置]