A Generic 3-D Analytical Model of Permanent Magnet Eddy-Current Couplings Using a Magnetic Vector Potential Formulation

Abstract

In this article, a new and general three-dimensional (3-D) analytical frame for evaluating the performance characteristics of the permanent magnet (PM) eddy-current coupling is presented using a magnetic vector potential formulation. Based on the 3-D Cartesian coordinate system, the actual coupling geometry is equated to a linear structure by applying the mean radius (for cylindrical conductor and PM rotors) and the equivalent cuboid (for PMs of various shapes) assumptions. The torque contribution from the overhangs of conductor back iron and the effects of PM and air gap thicknesses are all taken into considered. A verification process is implemented and it is shown that, in any case, the proposed 3-D analytical model can yield the results very close to those obtained by both the 3-D finite-element analysis and experimental measurement.