State-model based time-domain diagnosis of internal faults for permanent magnet synchronous machine -wind application

Upon occurrence of an internal fault on the permanent magnet synchronous machine (PMSM), the topology of the stator is amended causing structural imbalances due to the change of the connection within the windings. In this work, a state model of internal faults of the PMSM is developed. This model is in the (abc) reference frame. The modeling approach is based on the assumption that each stator phase is replaced by two major and minor sub-windings. This model is used subsequently in the residual generation for diagnosis. The fault indicators are obtained by the projection in parity space and estimated using the Luenberger observer. A scenario of fault inter-turn by the short-circuit occurring between phase (a and b) is validated by simulation.