Numerical modelling of the rotor movement in a permanent‐magnet stepper motor

Abstract

This study deals with predicting the dynamic behaviour of the rotor in a claw‐poled, permanent‐magnet (PM) stepper motor. The finite element method (FEM) model of a prototype stepper is used to calculate the magnetic forces on the rotor, where the PM is modelled with an altered geometry approach. This altered geometry helps achieving a realistic magnetic flux density profile and direct PM material property input. The obtained forces are used in the following analysis as the excitation, to simulate the rotor's rotational and also axial movements with the help of proposed system of equations. To validate the introduced modelling approach, a measurement of the rotational and axial movement was performed on a motor with the same geometry and material properties. The results of the simulated movement are in good agreement with the experimental data for the tested motor.