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.