Comparison of AC-Superconducting Multi-Phase Symmetric-Winding Topologies for Wind Power Generators with Passive PM Rotors

Abstract

In this paper, an AC superconducting multi-phase symmetric-winding machine is designed for a wind power generator to improve its performance and reduce losses, where four handpicked topological designs were explored and compared. In particular, it is found that using high-phase order of unique phasors further improves the performance. The iron losses are reduced, and the rippling behaviour is reduced due to the smoother airgap magnetic flux density. Furthermore, a higher LCM is achieved due to a better slot-pole combination for fractional slot concentrated windings without having space sub-harmonics. Nonetheless, it is shown that creating a smooth air gap magnetic flux density does not improve the AC hysteretic superconducting losses; thus, further analysis with another approach must be done. Moreover, it is found that the Meisner effect is present in the machine and is inversely proportional to the AC hysteretic superconducting losses. Finally, it shows that a 13-phase AC-superconducting machine can achieve a theoretical limit approaching 101.7017 Nm/kg for the torque-to-weight (TTW) ratio, outperforming a classic winding layouts.