A Ferrite Based Carbon Reinforced Composite Wrapped IPM Rotor Design for High-Speed Traction Applications

This paper presents the design and analysis of a novel high-speed, multi-layer ferrite-based interior permanent magnet motor (HSFR) incorporating a reinforced carbon composite (RCC) rotor. While ferrite-based IPMs offer a cost-effective alternative to rare-earth (RE) magnet motors for traction applications, their mechanical limitations at high speeds necessitate innovative design approaches. Traditional central ribs, often employed to enhance rotor stability, compromise electromagnetic performance. Consequently, removing the ribs and introducing a retention sleeve around the rotor is a feasible choice until it offers a good-fit between electromagnetic and mechanical performances. However, this technique has been limitedly studied for ferrite magnets, which is mechanically weaker than RE ones. To address this, the RCC is strategically integrated in circumferential (sleeve) and radial (rib) directions to optimize rotor strength. Additionally, a six-phase winding configuration is implemented to augment torque output, compensating for the inherent lower magnetic energy density of ferrite magnets. A 4kW rated, maximum 30,000rpm, six-phase ferrite-based IPM with an RCC-wrapped internal permanent magnet motor (6PF-CCW-IPM) is developed through analytical optimization and finite element analysis (FEA). Performance comparisons with equivalent reference design validate the effectiveness of the proposed design in achieving high-speed operation while maintaining competitive power density