Multiple transistor open-circuit faults diagnosis in a vector-controlled induction motor drive

The paper deals with a transistor open-circuit faults diagnosis in a rotor field oriented controlled induction motor drive fed by a two-level voltage inverter. The diagnostic procedure ensures to detect and localize single power switch failures as well as single-phase transistor faults in a time shorter than one period of a stator current fundamental harmonic, without regard to a drive operation point. In accordance with this paper, a new simplified scheme of the diagnostic system is proposed. The presented solution requires a low-computational effort and it is easy applicable in modern electrical drives. In order to validate the proposed faults diagnostic method, detailed experimental tests were carried out and some of them are shown in this paper.