利用逆同步速坐标变换检测感应电机定子故障

针对感应电机电流中谐波和噪声影响定子匝间短路故障诊断结果的问题,提出了利用逆同步速坐标变换提取定子故障特征的方法.利用改进的相关算法准确提取三相定子电流基波信息,通过逆同步速坐标变换将基波正序分量转换成二倍频交流量,负序分量转换成直流量.采用均值法提取直流分量,导出了负序分量在逆同步速旋转坐标系下合成矢量幅值,并考虑电机先天不平衡因素定义了表征匝间短路故障程度的灵敏度因子.实验结果表明,该方法避开了先天不平衡、谐波及噪声对诊断结果的影响,灵敏度因子可准确反映定子匝间短路故障特征.系统只需采样电压频率和电流信号,易于工程实现.

Stator fault detection on induction motors via anti-synchronousspeed coordinate transformation

In order to solve the problem that inter-turn-short-circuit fault diagnosis is influenced by the harmonics and noise in the stator current of induction motor,a method based on the anti-synchronous-speed coordinate transformation was presented to extract the stator fault characteristics.With the advanced correlation algorithm,the fundamental component in the stator current was obtained accurately.Via the anti-synchronous-speed coordinate transformation,the positive sequence component was turned into the second harmonic,and the negative one was transformed into DC component which was extracted with the mean algorithm,then the amplitude of synthetic vector of the negative sequence component in new coordinate was derived.A sensitivity factor was defined to evaluate the severity extension of the inter-turn-short-circuit faults,which took the manufactured asymmetry of the induction motor into account.Experiment results indicate that the influences of manufactured asymmetry,harmonics and noise are avoided,the sensitivity factor reflects the stator fault characteristics accurately.Only voltage frequency and current signals are needed,so it can be easily achieved in engineering.