Sensorless Flux Observer-Based Fault Detection of Induction Machines

In this paper, we introduce a strategy for the design of a sensorless flux observer-based fault detection system for use with induction motors. To synthesise the flux observer for this machine, we use a third order model for induction machines expressed in term of complex differential equations. Since the equation of the rotor speed of the induction motor is complicated to analyse, we replace it by its behavioural model for the design of the flux observer. Moreover, we use the synthesised observer in order to investigate the effects of two common types of faults (i.e. voltage sag and the stator inter-turn short-circuit) that can occur in these machines. The validity of the proposed methodology is assessed via simulation results using a model of the induction motor.