Numerical analysis of permanent-magnet motor performance considering rotor movement

Abstract

The paper presents a numerical analysis of a permanent-magnet brushless motor. The goal of the research was to estimate and reduce the torque ripple of a motor under research. The rotor movement was also taken into account in order to consider all the prime causes for torque ripple production. Therefore, two different types of analysis were carried out. The first approach was based on a transient analysis of a two-dimensional (2-D) planar finite-element model coupled to a voltage-fed electric circuit. The second approach was based on a static analysis of 2-D and three-dimensional models where stator current waveforms were calculated separately by a circuit model. Both analyses enable a comprehensive study of the electric machine's performance under arbitrary load conditions considering the effects of the time-varying electrical variables as well as those due to rotor movement. An analysis was done of differently constructed varieties of motor model and different source voltage waveforms. Numerical results were verified by measurements in the laboratory.