The Mitigation of Eddy-Current Losses in Ferromagnetic Samples Produced by Laser Powder Bed Fusion

Abstract

We study the use of topology optimization in the design of low-loss ferromagnetic core structures for additively manufactured electrical machines. The test case was a simple toroid core with a primary and a secondary winding. A 2D axisymmetric finite element method model was implemented for the toroid, and the core topology was optimized for minimum losses and maximum secondary flux linkage. The optimized core was then modified for additive manufacturing, and test samples were built via laser powder bed fusion. The B-H characteristics and losses of the core were measured in several operation points. The losses were compared against an additively manufactured solid core, a laminated core, and an additively manufactured core with evenly placed air gaps (i.e., grooves). The results show that the losses in the topology-optimized core are on the same level as the losses in the laminated core and considerably smaller than those in the solid core, which is a considerable improvement to previous published works.

Keywords

• Eddy currents
• magnetic cores
• optimization
• soft magnetic materials
• three-dimensional printing