An improved coaxial magnetic gear using flux focusing

This paper presents a new topology of the coaxial magnetic gear (CMG) in which the permanent magnets (PMs) in the outer rotor are magnetized in tangential direction, hence offering the flux-focusing effect. By using the 2D finite element method, the influence of the main design parameters on the maximum pull-out torque of the proposed magnetic gear is investigated. Also, a quantitative comparison between the proposed topology and the conventional surface-mounted CMG employing radially-magnetized PMs (CMGRM) has been performed and the analysis results indicate that the torque transmission capability of the proposed one can be significantly improved.