Theory of Proportional Solenoids and Magnetic Force Calculation Using COMSOL Multiphysics
Proportional solenoids are well-known and used in a wide range of applications today. This paper is about methods of influencing the characteristic force-stroke-curves of magnetic actuators by means of different pole geometries. The conical design of the stator pole which is mostly used to accomplish proportional solenoids is analyzed by both a simple analytic reluctance model and a FEM model created with the AC/DC module of COMSOL Multiphysics.
Furthermore, three different approaches of magnetic force calculation in COMSOL MULTIPHYSICS are introduced showing their advantages and disadvantages. The three methods are Maxwell Stress Tensor (COMSOL default method), Maxwell Tensile Force and the method of virtual displacement.