Comparative Study of Permanent Magnet Machines with Single-Sided and Dual-Sided Magnets

This paper presents a comparative study of permanent magnet machines (PMMs) with single-sided (SS) and dual-sided (DS) magnets, respectively. The SS-PMM employs homopolar PMs between either adjacent stator teeth or iron rotor poles, while the DS-PMM is geometrically characterized by PM arrangement on both rotor and stator sides. Different from the SS-PMM, the DS-PMM can operate based on a bidirectional field modulated effect, which enables the torque density improvement. The machine topologies and field modulated effect are firstly introduced. Then, the basic electromagnetic characteristics of three 12 slot/10 pole pairs PMMs with SS and DS magnet arrangements are comprehensively analyzed and compared by finite element analysis (FEA). Moreover, the torque quality of the PMMs with different pole pairs are investigated and compared to offer a general guideline of the feasible stator/rotor combination.