MAGNETIZATION, GEOMETRY, AND SEGMENTATION ANALYSIS OF NESTED HALBACH CYLINDERS FOR OPTIMIZING THE INTERACTIVE TORQUE

Cylindrical permanent magnets with a Halbach magnetization are used for a variety of applications. Nesting two such cylinders concentrically and rotating one with respect to the other generates a passive torque, which could be harnessed to counterbalance a payload attached to the rotating magnet. In this paper, we analyze the effects of critical magnetic and geometrical parameters of the nested Halbach cylinders on the generated interactive torques by using electromechanical simulation software. Specifically, the effects of the dipolar and multipolar Halbach magnetization patterns, cylinder geometric parameters, and cylinder segmentation are of major interest in this study. The results show that the optimal Halbach magnetization pattern is one where the exterior cylinder has an internal magnetic field while the interior cylinder has an external magnetic field. The simulation observes changes in the magnitude of the interactive torque for modifications in the radial width ratio, thickness-to-width ratio, and thickness ratio of the cylinders. To maximize the torque, the airgap between the cylinders should be as minimal as possible. Outer cylinders that are segmented into eight or more discrete arc shapes could reliably approximate the torque produced by the ideal continuous magnetization. Moreover, the study shows that the interactive torque of a segmented outer cylinder could approach the ideal maximum torque produced by a continuous magnetic cylinder. It is anticipated that the outcome of this study is beneficial for the optimal design of nested Halbach cylinders for gravity compensation.