Analytical modeling of a vertically distributed winding configuration for Fault Tolerant Permanent Magnet Machines to suppress inter-turn short circuit current limiting

This paper presents an analytical model to evaluate the inter-turn short-circuit current in a Fault Tolerant Permanent Magnet Synchronous Machine (FT-PMSM) for different winding configurations. By evaluating slot-leakage and air-gap fluxes, the inductance of both healthy and faulty parts of the phase winding, as well as the mutual inductance between them, can be determined for any position and number of the shorted turns. Using these inductances, the short-circuit current is determined. The proposed model is verified with finite-element analysis and validated experimentally. It will be shown that the magnitude of an inter-turn short-circuit current depends on both the number of shorted turns and their position in the slot. A new concentrated winding configuration with vertical plate conductors in the slot is proposed. The measured short-circuit inductance shows that this winding can inherently limit the short-circuit current and reduce its dependence on the position within the slot.