Analysis of magnet layout in circumferential and axial direction for halbach PM arrays

Permanent magnet (PM) array has great influence on flux field distribution of motor. A Halbach PM array is used in the motor of this paper, which not only increases the thrust output, but also decreases the mover mass. A new analytical model for magnetic flux density in circumferential direction is proposed in this paper based on equivalent surface current method, which could solve the flux density of X and Y component conveniently. The magnetic flux density in axial direction is formulated based on equivalent circuit method. These two methods are both simple and convenient to analyze air-gap flux density in different directions. Both finite element methods (FEM) and experimental results validate the analytical models. This study is useful for quick analysis and design optimization of PM array in motor.