Rare Earth Materials Reduction in a Hypercar Propulsion System

Low-usage and rare earth free high-performance machines are in high demand, pushed by increasing costs and supply issues of rare earth materials. High torque density and high efficiency are key requirements in traction field. The challenge is designing propulsion systems which achieve such objectives while pursuing a global optimization logic in costs. This paper fits into this context by proposing a solution in which the same interior permanent magnet motor design is used for a four-wheel drive of a hypercar. A proper adaptation in axial length and magnets arrangement of the rear axle motor makes it suitable for the front axle requirements. Electromagnetic finite element analyses are performed to test different solutions with and without ferrite magnets. Torque, torque ripple, base speed, efficiency and rare earth reduction are the outputs under investigation. The best configurations are further studied via finite element structural analyses, as well as they are subjected to vibrational considerations. Different eligible solutions are found out with good performance while achieving a reduction in rare earth usage by 45.5%.