Experimental and FEM verification of cogging forces of a permanent magnet linear motor with a discontinuous magnet track

Permanent magnet track linear motor drives offer a cost-effective motion control solution in numerous industrial manufacturing processes, covering a wide range of material handling and conveyor applications. To further reduce the initial costs of a permanent magnet track linear motor drive system, discontinuous magnet tracks can be considered. However, in a discontinuous magnet track, the armature has to face regions with and without permanent magnets, thereby resulting in edge crossings, where the armature is only partly overlapping with the permanent magnets. As a result, both the cogging force and electromechanical forces cause high disturbances at the edge crossings, having a major impact on the performance of the motion controllers. In this paper, disturbances of a nonsalient permanent magnet linear motor with a discontinuous magnet track are studied. An experimental test setup for the estimation of disturbance forces at the edge is presented. The behavior of the estimated disturbance forces at the edge crossings is also evaluated by a FEM model and compared with the experimental results.