AC Iron Loss Investigation with Consideration of a DC Bias Magnetisation in Non-Grain Oriented Electrical Steel Sheets

This work deals with the characterisation and modelling of AC iron losses, of non grain oriented (NO) soft magnetic steel sheets, under the presence of a DC bias magnetisation. Such DC fields occur in multiple electrical motor topologies, e.g., permanent magnet synchronous machines (PMSM), and lead to increased local iron losses, and therefore a greater demagnetisation risk of permanent magnets in use. Hence, this loss increase needs to be accounted for. In this paper numerous NO steel sheet samples are characterised and the influence of multiple parameters affecting losses is discussed. Furthermore, loss modelling approaches are presented and evaluated regarding their applicability in electric machine design.