Comparative Study of Torque Analysis for Synchronous Permanent Magnet Coupling With Parallel and Halbach Magnetized Magnets Based on Analytical Field Calculations

This paper presents a comparative study of torque analysis for synchronous permanent magnet couplings (SPMCs) with parallel- and Halbach-magnetized magnets, using analytical field calculations. On the basis of the magnetic vector potential, we derived analytical solutions for the magnetic field produced by the interaction between the inner and outer PMs for the parallel- and Halbach-magnetized cases. Then, we calculated the magnetic torque using the derived solutions and Maxwell stress tensor. Our analytical results are verified using both 2-D and 3-D finite element analysis and experimental results. We found that SPMC with Halbach-magnetized magnets exhibit dominant pull-out torque than SPMC with parallel magnetized magnets.