Iron loss prediction considering the rotational field and flux density harmonics in IPMSM and SynRM

Although good precision has been realised in iron loss calculation for static electrical apparatus, such as transformers, difficulties have been encountered in the case of rotating machines. Due to complex structures, varying flux distributions, rotational field and flux density harmonics, less satisfactory results are achieved for the prediction of iron loss in rotating machines. The influence of the rotational field as well as flux density harmonics on the iron loss calculation based on finite element method are considered in this paper. To account for the effect of additional iron losses due to the appearance of rotational flux density vectors and harmonics, revisions to the conventional method are made to reduce the prediction error. Calculations and experiments have been carried out on two interior permanent magnet synchronous motors with different kinds of winding and a synchronous reluctance motor. Experimental results have verified that improved precision of iron loss calculation can be achieved by using the proposed method.