Experimental assessment of winding inter-turn short-circuits fault signatures in six-phase AC permanent magnet synchronous motors

The interest for multiphase permanent magnet synchronous machines, in modern renewable power generation systems, is increasing rapidly due principally to their high efficiency and fault-tolerant capability. To meet the high-performance requirements, monitoring the stator winding state is a key item. The detectability of a stator winding inter-turn short-circuit (ITSC), for an asymmetrical six-phase surface-mounted permanent magnet synchronous motor, is analysed in this study. The impact of an ITSC on the stator back-emfs, stator currents and voltages is examined by spectral analysis of the corresponding space-vectors, in different α–β planes. In particular, the detectability of a stator ITSC, in closed-loop operating conditions, is investigated using voltage and current signature analysis. The spectral fault signature is identified through 2D finite element analysis, and then confirmed by laboratory experimental tests.