Detection of incipient stator winding faults in PMSMs with single-layer fractional slot concentrated windings

•An online stator incipient fault detection technique is proposed.•DC variations in the voltage are used to detect high resistance winding faults.•The presence of an incipient winding fault shifts the voltage (vd,vqvd,vq) to the right.•Temperature monitoring improves accuracy of the proposed online technique.

Permanent magnet synchronous machines designed with single-layer fractional slot concentrated windings are inherently fault tolerant; however, this does not eliminate the occurrence of winding failures. The ability to detect pending failures during operation provides added reliability. In this paper, an online fault detection technique is developed for high resistance inter-turn winding faults. It is shown through analysis, simulation and experiment that variations are present in the DC reference voltages prior to the presence of a short-circuit.