The advent of soft magnetic composites (SMC) opens the arena for innovative electrical machine designs with three dimensional flux paths for mass production. The key to commercial success lies in interactive multi-disciplinary co-operation with parallel development activities. The SMC materials are based on iron powder particles with surface insulation for low eddy current loss. Insulated particles, such as those used for dust cores have existed for many years, however these low density products with permeability values of 150 to 200 and low saturation induction are better suited to high frequency applications. The thin inorganic insulation of the SMC materials allows heat treatment at 500°C, which results in a partial stress relief and permeabilities of 500 and above. High flux density requires high component density, which is achieved with high compressibility powders. The compressibility of the powder is dependent on the surface coating, which must be minimized. The SMC materials are suitable for large scale mass production of complex components with good tolerances, smooth surfaces, no secondary operations and no material waste. Electrical machines with two dimensional flux paths benefit from the use of laminated electrical steel as the anisotropic properties are put to advantage. Machines such as claw pole motors, transverse flux machines etc. have not achieved widespread industrial use, as these require a material with isotropic properties suitable for mass production. However SMC material data alone is insufficient as the sole aspect for design focus. A new design should incorporate all aspects of the new motor including windings, permanent magnets, reduction in the number of parts and simplification of assembly. It is first when all the advantages of concurrent engineering are applied that full commercial success can be achieved.
| Filename: | EPE Journal 14-1 - 6 - Jansson |
| Filesize: | 230.9 KB |
