Detection of stator and rotor fault induced asymmetries in induction machines using voltage pulse excitation

Abstract

The present work is concerned with a method for fault detection in inverter-fed induction machines which makes it possible to detect different fault conditions in an early stage. The method is based on the identification of the transient leakage inductance, which can be seen as an image of the machine or of the machine condition. The transient leakage inductance is an parameter especially in converter-fed machines, not only for fault detection but also for the position detection of the rotor without a rotor position sensor, in so-called sensorless control methods. The transient leakage inductance is usually not apparent, considering the fundamental wave operation. The use of converters with the fast-switching power semiconductors and the associated current measuring hardware make it possible to identify this parameter. By coupling this information with the rotor and flux position, one can extract characteristic signal components of the machine by a frequency analysis technique (e.g., FFT) and use it for condition monitoring.