Drive Integrated Start-Up and Online ITSC Fault Monitoring Through Spatial Inductance Profiling

Fault diagnosis and condition monitoring of electric machines using readily available drive sensors are highly critical in safety-critical applications. This article presents an accurate method to detect stator interturn short-circuit (ITSC) fault using the spatial inductance profile, which can be implemented both at start-up (standstill) or in real time. For this purpose, ac motor drive spatially scans the motor at each start-up in milliseconds by injecting high-frequency signals to obtain spatial inductance profile, analyze the fault status, and locate faulty phase. Using the start-up inductance profiling as reference, online detection version is implanted successfully, which is essential for real-time condition monitoring. This approach is highly sensitive ITSC faults, agnostic to temperature variations, and takes inverter nonlinearities into account caused by dead time and voltage drop across the power devices. To demonstrate the efficacy and practicability of the proposed algorithm, it is experimentally verified on two PMSMs, interior permanent magnet synchronous motor (IPMSM) and an induction motor, all rewounded to mimic ITSC faults. It is shown that the algorithm can detect ITSC faults very accurately in the order of milliseconds even if the number of shorted turns is very low.