Simple sensorless diagnosis method for open-switch faults in SVM-VSI-fed induction motor drive

In this paper a new simple diagnostic technique of single IGBT open-circuit faults for a two level voltage inverter-fed field oriented controlled induction motor drive is presented. A failure diagnosis is carried out utilizing a reference voltage vector analysis in stationary coordinates, without additional sensors. An extraction of fault information is based on monitoring the voltage vector time presence in specific sectors of the complex stationary plane. Thanks to diagnostic signal normalization, high robustness to false alarms is guaranteed. To validate the proposed method, simulation tests under a wide range of working conditions of the induction motor are presented for the direct field-oriented controlled drive system.