Loss Analysis of Permanent-Magnet Synchronous Machines Considering In-plane Eddy Current in Electrical Steel Sheets

The quantification of the stray load losses such as the in-plane eddy-current loss in electrical steel sheets, and circulating-current loss in the armature windings is important in order to develop rotating machines with high efficiency. We investigate the losses caused by the in-plane eddy current in the stator cores of permanent-magnet synchronous machines by using three-dimensional finite element method. The influences of the coil-end structure, skew structure, and carrier harmonics of a pulse-width-modulated inverter on the in-plane eddy-current loss in the stator core are described. The circulating-current loss in the parallel connected armature windings is analyzed by using two-dimensional finite element method. The accuracy of the analyses is confirmed by the comparison with experimental results.