针对风力机叶片在恶劣环境下易发生故障且检测困难的问题,提出一种新的故障诊断方法。该方法结合了倍频程理论与梅尔频率倒谱系数(MFCC)算法,通过引入对称可变倍频程技术对传统MFCC算法进行了优化。在频带划分上,依据叶片声音信号的特性与倍频程理论,重构物理频率与Mel频率之间的映射关系,以增强算法对分布在中频段与高频段的故障特征的提取能力,并有效减少噪声干扰。接着,利用K-均值聚类算法对优化后MFCC算法所提取的声学特征进行聚类分析,通过手肘法则确定叶片不同状态下的最佳聚类数,并根据短时能量分布去除噪声簇,实现了对不同状态叶片声音信号的有效区分。最后,基于随机森林算法构建分类器,对叶片故障进行准确诊断,验证了改进后的MFCC算法提取叶片声学特征及抗干扰的能力。
Abstract
Aiming at the problem that wind turbine blades are prone to fault and difficult to detect in harsh environments, a new fault diagnosis method is proposed. This method combines the Frequency octave theory and the Mel Frequency Cepstrum Coefficient (MFCC) algorithm, and optimizes the traditional MFCC algorithm by introducing the symmetric variable frequency octave-based technology. In terms of frequency band division, according to the characteristics of blade sound signals and octave theory, the mapping relationship between physical frequency and Mel frequency is reconstructed to enhance the algorithm’s ability to extract fault features distributed in the middle frequency band and high frequency band, and effectively reduce noise interference. Then, the K-means clustering algorithm is used to cluster the acoustic features extracted by the optimized MFCC algorithm. The elbow rule is used to determine the optimal number of clusters under different states of blades, and the noise clusters are removed according to the short-term energy distribution, so as to effectively distinguish the sound signals of different states of blades. Finally, a classifier based on random forest algorithm was constructed to accurately diagnose blade faults. It verifies the ability of the improved MFCC algorithm to extract the acoustic features of the wind turbine blades and anti-interference.
关键词
风力机叶片 /
故障诊断 /
聚类分析 /
声信号处理 /
梅尔频率倒谱系数 /
特征提取
Key words
wind turbine blades /
fault detection /
clustering algorithms /
acoustic signal processing /
MFCC /
feature extraction
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基金
河北省自然科学基金创新研究群体延续资助项目(E2024202298)