Investigation of induction machine phase open circuit faults using a simplified equivalent circuit model

An induction motor model based on the per-phase equivalent circuit is used to simulate operation with an open circuit fault. The model considers both spatial field harmonics as well as saturation effects to correctly model the motor´s behaviour under faulty conditions, where the non-linearities may produce problematic torque pulsations due to the unbalanced nature of the winding distribution. A model is presented which takes into account the most prominent nonlinearities, however keeping simulation times low in order to enable the development of fault tolerant control strategies. In addition, this paper presents a study of the behaviour of an induction motor drive with a phase open circuit fault. A new fault remedial control strategy for this type of fault will also be described. Experimental tests on an instrumented vector controlled rig have been used to verify simulation results.