Performance Analysis of HTS Armature Axial Flux Magnetic Field Modulation Direct Drive Wind Generator

Axial flux electrical machine has higher power density than the radial flux electrical machine, showing a promising application in the field of offshore wind power generation. However, the conventional copper armature winding will suffer from severe joule loss when improving the electrical loading, resulting in that the further improvement of the power density of axial flux electrical machine is limited. In order to overcome the limitation of the electrical loading improvement of the copper armature winding, this paper uses the high-temperature superconducting (HTS) armature winding instead of the conventional copper armature winding, proposes an HTS armature axial flux magnetic field modulation direct-drive wind generator (HTSAAFFM-DDG). In this paper, the topology and operational principle of the proposed HTSAAFFM-DDG is clearly demonstrated. Meanwhile, the electromagnetic performances are carefully analyzed, including airgap magnetic field, basic electromagnetic characteristics, and AC loss analysis of the HTS armature winding. The research results show that the torque density of the proposed HTS armature axial flux machine can be 24% higher than that of the copper armature axial flux machine with the same size and topology. Besides, the superconducting (SC) shielding layer used in the proposed HTSAAFFM-DDG exhibits an excellent inhibition effect on the PM excited field, and can reduce the AC loss of the armature winding obviously.