基于改进MFCC算法的风力机叶片故障诊断方法

WIND TURBINE BLADE FAULT DIAGNOSIS METHOD BASED ON IMPROVED MFCC ALGORITHM

针对传统声信号特征处理方法无法有效提取叶片声音特征、导致叶片故障诊断准确率低的问题,提出一种基于改进梅尔频率倒谱系数(MFCC)算法的风力机叶片故障诊断方法。首先采用快速傅里叶变换(FFT)分析不同风速下叶片声音信号和风噪的频率特性,明确叶片声音信号的频率分布区域,将全频段分为三部分;然后采用粒子群优化算法(PSO)对梅尔(Mel)函数在不同频段上的敏感度进行优化,在迭代过程中将MFCC算法提取的叶片声音特征进行聚类,以轮廓系数作为适应度函数;最后基于支持向量机(SVM)构建分类器,实现风力机叶片故障的准确识别。以华北某风电场的叶片声音采集数据为算例,考察该算法在不同风速工况下的适应性,验证该方法的有效性。

The traditional acoustic signal processing methods cannot effectively extract the acoustic features of wind turbine blades and the fault diagnosis accuracy is insufficient.Therefore,a fault feature extraction method based on improved Mel frequency cepstrum coefficient(MFCC)algorithm is proposed.Fast Fourier transform is used to analyze the frequency characteristics of the acoustic signal from wind turbine blade and wind noise at different wind speeds,and the corresponding frequency distribution regions are obtained.Meanwhile,we divide the whole frequency band into three parts,and use particle swarm optimization(PSO)to optimize the sensitivity of Mel function in different frequency bands.In the iterative optimization process,the sound characteristics of turbine blades extracted by MFCC algorithm are clustered,and the Silhouette coefficient is taken as the fitness function.Taking the blade sound acquisition data of a wind farm in North China as an example,the adaptability of the algorithm under different wind speeds is investigated,and a classifier based on support vector machine(SVM)is constructed to achieve accurate identification of wind turbine blade faults,which verifies the effectiveness of the method.