Integrity monitoring of induction machines: A frequency domain model-based approach

A model-based approach for off-line fault diagnosis in induction machines is presented. The faults to be diagnosed correspond to broken bars in the rotor cage and asymmetry in the stator, arising due to an interturn fault resulting in an opening or shorting of one or more circuits of stator phase windings. The method is based on model invalidation theory for robust models (H_∞/μ-framework models). The experimental model consists of a nominal model estimated by means of a subspace identification algorithm, together with linear fractional norm bounded perturbations and norm bounded unknown inputs.