Influence of soft magnetic materials on the design and performance of tubular permanent magnet machines

This paper investigates the influence of the choice of soft magnetic material on the performance of a tubular permanent magnet machine, and quantifies the relative merits of silicon iron laminations and soft magnetic composites (SMCs). The machine is equipped with a modular stator winding and employs a quasi-Halbach magnetized moving-magnet armature. It is shown that, despite its poorer space utilization, a machine whose stator is fabricated from silicon iron laminations has the highest force capability, efficiency and power factor. A machine with a SMC stator, on the other hand, has potential advantages in terms of ease of manufacture and lower cost.