Analysis of Electromagnetic Performance of Halbach PM Brushless Machines Having Mixed Grade and Unequal Height of Magnets

This paper proposes a permanent magnet machine having mixed high-cost NdFeB and low-cost ferrite magnets with modular unequal magnet height poles, i.e., the modular Hat- and T-type magnet poles, together with optimized Halbach magnetization. The investigation shows that the modular T-type magnet poles with mixed magnet grade and unequal side-magnet height exhibit significant potential to achieve low torque ripple, relatively large electromagnetic torque, and high magnet usage efficiency simultaneously.