An On-line Diagnosis Method of Broken Rotor Bars Fault in Motor of Aerospace Surveying Vessel via Salient Characteristic Residual Signal from Dynamic Model

Diagnosis of broken rotor bar fault in induction motors is a hot research focus in recent years. The most common method of diagnosis of this fault is to analyse the spectral characteristics of stator current. However the characteristic frequencies are too close to both sides of power frequency and usually covered by it in early failure. To overcome this limitation, this paper presents a method by introducing a dynamic model based on field-oriented control (FOC), which was widely applied in control. The FOC technique is modified to generate an estimated stator current signal in a little computation. The residual signal of stator current is produced by comparing the measured one and the estimated one as the motor running. The result of simulation shows that power frequency component is greatly reduced and the feature of fault is more significant than the measured current signal.