Harmonic Analysis of Electromagnetic Torque in Brushless Direct Current Motors


This study has aimed at establishing and analyzing the causes that produce oscillations of electromagnetic torque developed by brushless direct current motor. The study opportunity is given by the progresses obtained in command and power electronics, which made this motor performant from technical and economic viewpoint. The
specialty literature reveals that important torque oscillations occur in this motor in a complete rotation. That is why, this study and the simulations presented here emphasize
that there are five classes of slots relatively to the torque magnitude developed and the fact that all the slots are active, that meaning that the average torque developed occurs
in the rotation direction. The harmonic analysis reveals that the torque distortion, within the five classes of slots, is variable between 51.03% and 97.63%. The torques computed
for the slots classes are between the minimum limit of 0.029 Nm and the maximum one of 0.077 Nm. The low speed torque oscillations can be reduced with a high inertia moment,
a speed reaction loop and a performant control system. The importance of the research theme is justified by what we have presented before and is a subject of major interest for engineering.