South Korean Engineers Advance Lower-Cost Electric Motor Design That Reduces Dependence on Rare Earth Magnets

Highlights

• Researchers at Chungnam National University developed an optimized Permanent Magnet Assisted Synchronous Reluctance Motor using low-cost ferrite magnets instead of rare earth materials.
• The fluid-shaped rotor design, modeled using Joukowski transformation mathematics, improved mechanical stiffness, reduced torque ripple, and boosted power factor simultaneously.
• The study is simulation-based and requires further real-world validation before commercial adoption is feasible.
• Rare earth magnets remain essential for high-performance EVs, aerospace, and defense applications, but alternative designs are expanding into cost-sensitive segments.
• Global automaker suppliers are quietly pursuing incremental alternative motor innovations, signaling a diversifying rather than replacing trend in the motor market.

Study suggests new motor design could improve durability while relying on lower-cost, non-rare-earth permanent magnets.

Researchers led by Su-Min Kim, PhD (opens in a new tab), of the Department of Electrical Engineering at Chungnam National University, working with colleagues from Chungnam State University and Changwon National University including Jang Young Choi, PhD (opens in a new tab), have developed an optimized design for a Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM) that improves mechanical strength while maintaining strong electrical performance. Instead of relying on expensive rare earth permanent magnets used in conventional electric motors, the team's design uses lower-cost non-rare-earth magnets combined with sophisticated rotor geometry and computer optimization. While this is an engineering design study—not a commercial product—it represents another incremental step toward reducing industry dependence on rare earth permanent magnets in selected applications.

Why This Matters

Permanent Magnet Synchronous Motors (opens in a new tab) (PMSMs) power everything from electric vehicles to industrial equipment because they are compact, efficient, and powerful. However, they typically depend on powerful rare earth magnets such as neodymium and dysprosium, materials whose supply chains remain heavily concentrated in China.

The Korean researchers explored an alternative motor architecture called the PMa-SynRM, which combines magnetic assistance with reluctance motor technology. Although these motors generally produce less performance than premium rare earth motors, they can substantially reduce material costs and supply chain risk.

How the Researchers Improved the Design

The team compared two rotor designs—a conventional segmented rotor and a more advanced "fluid-shaped" rotor modeled using aerodynamic mathematics known as the Joukowski transformation. They then used finite element modeling and optimization algorithms to analyze how rotor geometry affected torque, efficiency, vibration, and mechanical stiffness.

The study found that adjusting key rotor design parameters—particularly the angle of the first magnet layer—could simultaneously improve stiffness, reduce torque ripple, and improve power factor. In practical terms, the optimized design could produce a motor that is more durable and reliable while using inexpensive ferrite permanent magnets instead of rare earth materials.

What It Means for Rare Earth Markets

This study does not suggest that rare earth permanent magnets are becoming obsolete. High-performance electric vehicles, aerospace systems, defense platforms, robotics, and many advanced industrial applications will continue to require the superior magnetic performance of rare earth magnets for the foreseeable future.

Instead, the research reflects a broader global trend: engineers are seeking ways to reserve rare earth magnets for applications where they are truly indispensable while developing lower-cost alternatives for less demanding uses.

Study Limitations

The work remains an engineering optimization study based primarily on simulation and modeling. The researchers did not report long-term commercial testing, manufacturing costs, large-scale production data, or real-world durability under industrial operating conditions. Significant engineering validation would still be required before widespread commercial adoption.

The Bottom Line

For Rare Earth Exchanges®, this study reinforces an important reality often overlooked in critical minerals discussions. Innovation is occurring on both sides of the equation. While governments race to secure rare earth supply chains, engineers are simultaneously working to reduce dependence on those materials where technically feasible. The likely future is not one technology replacing another, but a more diversified motor market where rare earth magnets remain essential for the highest-performance applications while alternative designs expand into cost-sensitive segments.

Note that Rare Earth Exchanges has conducted numerous surveys of the automobile supply chain, finding that major suppliers are investigating alternative designs and other innovations. While none are openly touting a replacement of rare earth-based magnets, they are looking to achieve incremental value breakthroughs over the next several years.

Citation: Kim, S.-M., Jung, W.-S., Nguyen, M.-D., Hoang, D.-T., You, D.-J., Shin, K.-H., & Choi, J.-Y. Optimal Design of Permanent Magnet Assisted Synchronous Reluctance Motor Considering Mechanical Stiffness. Chungnam National University; Chungnam State University; Changwon National University.