An Integrated Strategy for the Real-Time Detection and Discrimination of Stator Inter-Turn Short-Circuits and Converter Faults in Asymmetrical Six-Phase Induction Motors

Multiphase machines are becoming a potential solution for several high-power applications since they provide intrinsic fault-tolerance capability. Due to the various stator phase arrangements, standard fault detection techniques are unfeasible and cannot be considered to diagnose faults in the various configurations of multiphase machines, especially those employing closed-loop control strategies and under Fault Tolerant Operating (FTO) conditions. This paper evaluates two distinctive indicators for diagnosing both inter-turn short-circuit faults (ITSCFs) and open- circuit faults (OCFs), resorting to the Short Time Least Square Prony's algorithm (STLSP). The indicators are employed in an asymmetrical six-phase induction motor (ASPIM), controlled by a model predictive control (MPC) algorithm. MPC is selected since it offers an attractive control scheme for the regulation of multiphase electric drives, exploiting their inherent advantages. A variety of operating scenarios confirm the excellent generalization capability of the proposed indicators, high accuracy and robustness, along with the ability to distinguish between the occurrence of motor ITSCFs and converter faults (OCFs), under FTO conditions.