Surface Eddy Current Loss Reduction in Additively Manufactured Permanent Magnet Rotor Active Parts

This paper describes the development process, 3D finite element analysis and resulting design guidelines for reducing eddy current effects on rotor surfaces of permanent magnet synchronous machines considering the three-dimensional freedom when designing parts to be made by additive manufacturing technologies. In a first step, a 3D finite element abstracted model, which optimally represents the rotor surface eddy current effects caused by higher spatial harmonics, is presented and discussed with regard to functionality and boundary conditions of the simulation data and the model itself. Today's metal additive manufacturing technologies allow the processing of soft magnetic ferro-silicon alloys. With respect to massive interior permanent magnet rotors, in the present paper, it will be used to groove the rotor surface in various manners. The impact of the particular rotor surface shapes on the flux path and the surface eddy current losses are evaluated and finally, the findings are used to develop specific design guidelines.