基于Park矢量模信号小波分解的感应电机轴承故障诊断方法

BEARING FAULT DIAGNOSIS METHOD OF INDUCTION MOTOR VIA WAVELET DECOMPOSITION OF PARK'S VECTOR MODULUS SIGNAL

在分析小波包分频特性的基础上,总结出小波包分解子频带按频率高低排列的通式;对三相定子电流的Park矢量模信号进行小波包分解,求相应子频带的小波包分解系数的均方根值(RMS),并用其表征轴承的故障特征,以此作为轴承故障诊断的依据。研究表明,该方法降低了基频电流及电流中噪声的影响,克服了由于受负载变化引起故障特征频率波动使得难以准确提取故障特征频率的缺陷;实验结果证明了该方法应用于电机轴承故障诊断的可行性。

By analyzing the frequency separation characteristic of Wavelet Packet Decomposition （WPD）, a general expression is given to decide the sequence of WPD sub-band at the same level from low to high frequencies. An induction motor experiment with the known faults of bearing was done. Then the RMS values of the WPD coefficients of Park＇s Vector Modulus signals of the three-phase current was calculated, and could be the symptom of bearing fault. The experimental and the calculated results demonstrated that the influences of the fundamental frequency current as well as the noises in current were reduced. The limitation to extract the fault characteristic frequency resulting from the fluctuation of the characteristic frequency and the variation of the load is overcome.