Analysis of Halbach magnet array and its application to linear motor

Abstract

Using Halbach magnet array, magnetic flux can be enhanced on one side (strong side) of the array while the flux cancelled on the other side (weak side). Inherently, rotor of rotary motor has infinite rotational length with respect to its rotation while mover of the linear motor has finite length with respect to mover’s translation. In this paper, we propose and validate a design method. By means of the method magnetic field can be calculated theoretically. General electrical motor without slotted yoke, therefore, can be designed analytically. Using the method, the linear motor with finite mover can be designed more accurately considering the flux leakage at both end of the mover. We introduce the method in designing the linear motor with Halbach magnet array. We also investigate the difference between conventional method that does not consider the finiteness and proposed one that considers it. Using the method, the magnetic field emanated from magnet can be obtained so accurately that actuating force characteristics of the motor can be predicted more precisely. So, the method is useful in designing the linear motor.