Assessing the Effect of Geometric Error on the Performance of Magnetic Gears

This paper presents and compares different methods for assessing the effect of planar geometric errors on the performance of magnetic gears using both Finite Element Analysis (FEA)and analytical techniques. In FEA, small geometrical deviations lead to the generation of different forms of the mesh, even when mesh size and type are constant. However, to accurately assess the effect of small deviations on performance, the influence of the specific mesh form must be negligible. Different torque calculation methods, along with different mesh parameters, have been used to obtain specific mesh form independence and hence accuracy in results. It is observed that both Maxwell's stress tensor and virtual work methods are computationally inefficient and, if many studies are to be conducted, FEA becomes impractical. Analytical solutions of magnetic potential offer a computationally efficient and accurate alternative for assessing magnetic gears under certain assumptions. This could allow the sensitivity of a magnetic gear's performance to be assessed with respect to manufacturing error, enabling the designer to appropriately specify tolerances and manufacturing processes.