Detection of inter-coil short circuits in the stator winding of a PM machine by using saliency tracking schemes

This paper demonstrates the feasibility of using saliency tracking schemes (normally associated with sensorless control of drives) for the detection of inter-coil short circuits in the stator windings of a PM machine. This is obtained through a co-simulating of Matlab/Simulink and a Finite Element Model (FEM). Vector control and sensorless control schemes based on saliency tracking were implemented using Simulink, while FEM was used to implement a detailed model of the machine. This facilitates the evaluation of several winding faults while keeping a realistic drive representation. Two different schemes for saliency tracking were evaluated: The first is based on High Frequency injection -which was demonstrated by these authors to be a good alternative for winding condition monitoring-. The second approach is based on PWM transient excitation which is becoming very popular in sensorless drives applications. Even though both schemes use very different demodulation techniques, they share the advantage of having a good resolution for the detection of small changes in the machine saliency, which is beneficial for condition monitoring applications. This paper evaluates and compares both schemes in order to determine their suitability for the implementation of condition monitoring schemes.