A High-Speed Rare-Earth Free IPM with Carbon Composite Wrapped Rotor

This paper presents a novel high-speed, six-phase, rare-earth-free interior permanent magnet synchronous machine (6P-REF-IPSM) for electrified transportation applications. Motivated by the scarcity and supply chain disruption of the rare-earth (RE) magnets, this work presents a rare-earth-free (REF) machine design. State-of-the-art offers solutions for Carbon sleeves and REF machines. However, it’s effectiveness toward high temperature, power density, and speed has been limitedly investigated until recently, despite it could provide considerable benefit for traction motors. Thus, this paper proposes a new approach to Carbon composite sleeve design for a rotor. This has been uniquely done in a radial and axial (Carbon rib) direction, offering superior dynamic performance in high-speed operations. The equivalent mechanical stress (EMS) model of the rotor has been evaluated to verify the advantages of carbon composite integration. A low power of 4kW, 32000rpm 6P-REF-IPSM has been designed through a time-stepping finite element analysis (FEA). Its performance has been comparatively studied over a conventional RE-based motor to verify its effectiveness.