On-line diagnosis of three-phase closed loop induction motor drives using an eigenvalue αβ-vector approach

Non-invasive diagnosis of induction machine stator winding turn faults is a well established technique, allowing accurate results and cost-savings. This diagnosis is based on the analysis of the machine input line currents. However inverter-fed machines are becoming a common solution for industrial purposes. Power electronics technological advances allow good performance with competitive costs. Closed-loop drives represent a problem when current based fault detection techniques are used because in this kind of drives the controller regulates the machine input current. In order to keep the detection procedure non-invasive one should monitor the machine input voltage. In this paper the αβ-vector approach fault detection method is extended to inverter-fed induction machines. Results are presented in order to fully understand the advantages of the proposed method.