α-β坐标系下瞬时无功功率的笼型异步电机转子故障诊断

Rotor Fault Diagnosis of Squirrel Cage Asynchronous Motor Based on Instantaneous Reactive Power in α-β Coordinates

根据α-β两相静止坐标下的瞬时无功功率理论,推导出笼型异步电动机定子瞬时无功功率在正常状态、转子断条故障、转子偏心故障、以及两者的复合故障状态下的表达式,并提取出不易被基频淹没、易于辨识的故障特征频率,以此达到诊断电机的目的。同时,转子复合状态下的故障特征频率得到有效分离。最后,利用双Hilbert变换,滤除瞬时无功功率频谱中的直流成分,更好地突出故障特征分量。实验采集定子三相电压电流,经过坐标变换,运用两相静止坐标系瞬时无功功率理论得到瞬时无功功率,进行频谱分析,验证了此法对电机转子各种故障诊断的准确性。

The instantaneous reactive power's expression of the squirrel-cage asynchronous motor is based on the instantaneous reactive power theory of the two-phase static coordinate,which is derived on the condition of normal motor,broken bar,rotor eccentricity and the rotor composite fault.Meanwhile,the fault characteristic frequency components are extracted,which are effectively exempted to be drowned easily by the base wave frequency.The fault characteristic frequency is identified easily and the purpose of the diagnosis of motor is achievable.The approach separates characteristic frequency of the rotor composite fault.Lastly,using double Hilbert transformation,DC component in reactive power was eliminated,which is helpful to emphasize the fault characteristic frequency.The stator current and voltage were collected by the experiment and the instantaneous reactive power was obtained by the theory of the coordinate transformation.The approach has been successfully verified by spectrum analysis of experimental results.