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 paper presents an accurate method to detect stator Inter-Turn 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 signal 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, IPMSM and an induction motor, all re-wounded to mimic inter turn short circuit 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.