Analysis and Diagnosis of ITSC in Dual Rotor Air-Cored PMSG - Parallel Connected Stator Coils

Inter-turn short circuits (ITSCs) stands as one of the most challenging faults to detect in permanent magnet synchronous machines (PMSMs). This study Focusses on a dual-rotor, air-cored permanent magnet synchronous generator (PMSG) with parallel-connected coils. For the analysis of the ITSC, a finite element analysis (FEA) model has been developed and validated under healthy conditions. In order to investigate the impact of ITSC faults on the PMSG and to understand the progression of fault severity, multiple cases with varying levels of fault intensity were analyzed and validated using mathematical modeling. The severity of the fault depends on two key parameters: the contact resistance and the number of shorted turns. To detect ITSCs in PMSMs, current-based methods are commonly employed, particularly because these machines are typically connected to PWM-based power electronic converters. In this study, motor current signature analysis (MCSA) and the extended park's vector approach (EPVA) were implemented. However, both methods faced challenges in detecting low-severity faults as a result to the generator's low operating frequency. This findings showcases the necessity for alternative diagnostic strategies to detect the ITSC under low fault severity.