Design of Reduced and Rare-Earth-Free PM-assisted SynRMs for Electric Vehicles to Overcome Electromagnetic-Structural Challenges

Reducing the ownership cost and global emissions in the transportation sector are major factors for targeting low-cost, highly efficient, and more sustainable traction electric motors. While commercially-available rare-earth magnets, such as NdFeB, can help achieve widespread electrification due to their extremely high magnetic energy product, the uncertainty of their global availability has created substantial supply chain concerns for automotive suppliers and OEMs. Given their price volatility, alternative solutions are desired with lower market risk and improved sustainability. Using the Hyundai IONIQ 5 rear motor with NdFeB magnets as a baseline, this paper proposes the effective design of reduced and rare-earth-free permanent magnet-assisted synchronous reluctance motors while accounting for electromagnetic and structural challenges. Different design variants are analyzed in terms of their multiphysics tradeoffs as well as their overall technoeconomic impact on the electric vehicle.