A novel coreless contra-rotating axial-flux machine for wind power applications

TL;DR: In this paper, a coreless bidirectional axial-flux-modulation machine for direct-drive contra-rotating wind power generation is presented, where dual rotors rotate in opposite directions and all permanent magnets with the same polarity are alternatively located with salient poles in rotors.

Abstract: This paper presents a novel coreless bidirectional axial-flux-modulation machine for direct-drive contra-rotating wind power generation. Different with the conventional axial flux wind generators, in the proposed machine, dual rotors rotate in the opposite directions and all permanent magnets (PM) with the same polarity are alternatively located with salient poles in rotors. With the bidirectional flux modulation effect, a high-speed rotating magnetic flux harmonic is produced in the air gap and interacts with the coreless windings to produce electricity. With this design, the induced frequency is enhanced and machine volume can be reduced. In addition, the coreless structure can reduce the iron loss. The electromagnetic performance of the proposed machine is analyzed by finite element method (FEM).