Eddy current loss calculation in rotor back iron for concentrated winding PM generator

Abstract

Permanent Magnet (PM) machines with concentrated windings can be advantageous due to possible automation in manufacturing process. However, a typical disadvantage of the concentrated winding machines is eddy current losses in the solid conductive parts. Eddy current losses occur because the air gap flux produced by the concentrated windings contains much more space harmonics compared to the distributed windings. In this paper an analytical and a finite element (FE) model of eddy current loss calculation in rotor back-iron are compared. It was concluded that the analytical method can be a first good guess to compare and select different topologies for detailed design. Analytical method is quick but has a lot of assumptions and thereby low accuracy for actual loss calculation. FE method is more accurate for calculating actual eddy current losses due to its ability to handle complex geometries and material non-linearities. A comparison of deviation of results has been presented.