Investigation Effect of Magnet Skew on Thrust Force in Linear Brushless Direct Current Motor with FEM

Abstract

This study is concerned with the reduction of ripple in the thrust force produced in a linear Brushless Direct Current Motor (BLDC). To reduce the ripples in the generated thrust force, different methods such as structural solutions are applied both in the control part and in the production phase of the motor. In this study, skew application, which is one of the mechanical methods, is proposed. For this reason, the changes in the thrust force of a BLDC motor with a surface magnet-placed translator are investigated by applying different levels of skew to the magnets. First, a 3D solid model of the motor was created. A pole on the translator of the linear BLDC motor is composed of 3 equal magnet groups. For each skew level, the magnets were shifted 3 mm independently of each other and the thrust force values were examined. For this process, a 3D magnetostatic analysis of the linear BLDC motor was performed. The results obtained show that the skewing process applied to the magnets reduces the ripples in the thrust curve up to a certain point, after which no significant improvement in the ripple is observed, while the average force value decreases significantly.