Novel Unified Normalized DC Current-Based Diagnosis Scheme of Interturn and Open-Switch Faults for VSI-Fed Induction Motor Drive System

This article provides a novel real-time fault diagnosis unified approach of stator interturn short circuit faults (ISCFs) and open-switch faults (OSFs) in voltage source inverter-fed three-phase induction motor drive systems without requiring additional hardware even for ISCFs involving fewer turns. The proposed diagnosis approach leverages the normalized dc components of stator line currents and the normalized dc negativelyoriented motor line current components in the $dq$ reference frame. The proposed method is not only robust to load and speed variations, but also compatible with any motor irrespective of rating. Besides, rapid identification of various faults, especially ISCFs, is ensured. Extensive time-domain and experimental investigations are performed on 3 kW, 37 kW motors for single and double OSFs and interturn faults with percentages 1%, 2%, 5%, 10% with star or delta connection of stator windings. The obtained results revealed quick and reliable classification of various faults.