Comparative Evaluation of Rotor Segmentation Strategies for Eddy-Current Loss Reduction in Additively Manufactured Multi-Material Synchronous Reluctance Rotors

Abstract

Eddy-current losses remain a significant parasitic issue affecting the efficiency and thermal stability of electric machines. This paper provides a comparative three-dimensional transient finite-element (FE) analysis of different additively manufactured and hybrid rotor geometries. The study investigates induced current density, Joule-loss distribution, and magnetic flux behaviour under identical load conditions. Flux-density contour maps are used to identify local saturation zones and to evaluate how hybrid magnetic–non-magnetic interfaces influence field concentration and eddy-current suppression. Magnetic alloys such as FeCo form primary flux paths, while stainless steel 316L is strategically embedded to interrupt large flux loops and reduce edge-saturation hotspots.The inclusion of high-resistivity regions promotes a more uniform flux distribution and greatly reduces localized fieldintensification. Optimised hybrid structures achieve up to 70% lower total eddy-current losses and a 60% reduction in peak current density compared to solid rotors, demonstrating the effectiveness of conductivity zoning in advancing next generation synchronous reluctance machine design.