Axial Type Switched Reluctance Motor of Soft Magnetic Composite

Abstract:
Recently, an increase in cost for magnetic materials has drawn attention to switch reluctance motors (SRMs), due to their operation principle without the need for rare-earth materials. It is object of research to overcome the known draw-backs of SRM irregular torque, noise emission and small tolerance to achieve the required small air gap. Especially the axial type SRM is discussed recently [1]-[5]. This design uses an axial flux through the air gap to generate the torque with the advantages e.g. to increase the air gap area and have plan parts surrounding the air gap, which alleviates to reach the small air gap tolerance. But these advantages are closely related to a complex geometry, which implies that rotor and stator cannot be built of laminated steel in an economic way. Soft magnetic composites (SMC) are interesting materials for these parts, since they allow freedom in shape and have a low electric conductivity. This paper presents an axial type SRM made of SMC. The dependency of flux linkage Ψ, excitation current I and motor angle α in case of various motor rotation speeds and current forms are experimentally analysed.