Torque transfer efficiency estimation of the magnetic gear considering eddy current loss

Magnetic gear which is capable of non-contact transfer torque has replaced mechanical gear and has advantages of high-efficiency and improved reliability. However, the magnetic gear has eddy current loss due to magnets unlike the mechanical gear. In addition, the magnetic gear has ferromagnetic pole pieces between two rotors. When kinds of steel use stainless (SUS) materials which have high strength is used to support these ferromagnetic pole pieces, the eddy current loss is generated through those materials. The eddy current loss becomes a main cause of decrease of torque transfer efficiency. Therefore, in a design process, investigating and analyzing the eddy current loss are very important. In this paper, the eddy current loss of the magnets and the pole pieces supporter is calculated using a non-linear finite element method (FEM) based on 3-D numerical analysis and the effect of eddy current loss on the torque transfer efficiency is analyzed. Furthermore, the reliability of this paper ensures by comparison the torque transfer efficiency of numerical analysis and the experiment.