SMC Materials in Electrical Machine Prototypes

Abstract

In the last years, innovative magnetic materials have been studied and developed for the production of electrical machines, using both permanent magnets and soft magnetic parts. NdFeB bonded magnets have been adopted in place of ferrite magnets, whereas powder based Soft Magnetic Composites, in the form of Insulated Iron Powder Compounds have started substituting the traditional laminated sheets. The use of SMCs allows different advantages concerning traditionally laminated steels; focusing on the energetic aspects, SMCs have lower eddy currents losses and present lower specific losses at medium and high frequencies. While Radial Flux Machines (RFM) can be made both with laminated sheets or SMC powders, in Axial Flux Machines (AFM) the use of Powder Metallurgy allows to obtain the highest efficiency with a (relatively) easy production process, particularly in terms of designing and realizing new complex shapes. Different typologies of electrical machines, both RFM and AFM, have been evaluated in the research, using in-house made SMC components. Several prototypes have been prepared using different types of SMCs: organic and inorganic layers, commercial products and powders developed in the laboratory. Interesting results have been obtained, particularly in terms of efficiency, and a detailed comparison among the different products has been made.