Short-Circuit Fault Detection Observer Design in a PMSM

This paper explores detecting interturn short-circuit (ITSC) faults in surface permanent magnet synchronous machines (SPMSM) while simultaneously estimating the (typically large) fault current to determine if operation is within thermal limits. ITSC faults are caused by electrical insulation failures in the stator windings and can lead to shorts to ground resulting in oscillations in torque, localized heating, and even fires. This paper proposes a moving horizon observer methodology for detecting such faults, the level of fault, the motor state, and a thermally sensitive parameter in SPMSM. Theoretical verification of the observability and detection of fault levels and currents is also set forth. Fault detection, fault current estimation, and parameter estimation are verified via simulation for a set of ITSC faults using noisy measurements.