Energetic Performance Analysis of Soft Magnetic Materials for High Efficiency Electric Motors

Electrical machines efficiency is a key issue for the reduction of the absorbed electrical power in the industry sector with consequent benefit on pollutant emissions. For this reason, the accurate evaluation of power losses assumes a significant role during the design stage of electric motors. Among the different loss sources, iron losses represent one of the most difficult contribution to be evaluated as they depend on the non-linear soft magnetic material characteristics. Electrical engineers as well as Finite Element Software dedicated to electrical machine analyses, usually recur to the energetic model that represents the total iron losses through three main contributions: hysteresis, eddy current and excess losses. Nevertheless, this approach relies on some empirical coefficients that are not provided by the material producers. This paper reports the analytical procedure for the empirical coefficients computation starting from the data reported in the material datasheet. On the basis of this procedure, the paper discusses the energetic performance of different silicon iron materials suitable for electric motors. In particular, the analysis considers silicon iron magnetic steels having different quality and different lamination thickness, reporting the empirical coefficients suitable for the computation of the hysteresis, eddy current and excess loss contributions.