Examination to make eddy current loss density uniform in divided Nd-Fe-B magnets of a high torque density motor with axial-gap structure

An axial-gap motor with Nd-Fe-B magnets was examined by three-dimensional finite element analysis (3D-FEA) in order to achieve high torque density over 66.8 Nm/L under the constraint of a maximum current density of 12 A/mm2, and it was confirmed that the examined motor could satisfy these conditions. In this examination, suppressing eddy current loss occurring in these magnets by equally dividing a magnet constituting one pole toward radial direction was attempted. However, 3D-FEA results revealed that the eddy current loss density generated in each magnet which was equally divided was not uniform and had a large bias. So, this paper provides examination to make the eddy current loss density uniform in divided magnets by adjusting split width appropriately.