Engineering Performance Without Compromise: How To Minimize Rare Earth Use in E-Machines

Permanent magnet synchronous machines are at the heart of efficient electric drives, but their performance often relies on heavy rare earth elements (HREs) like dysprosium (Dy) and terbium (Tb). These materials help magnets maintain their strength at high temperatures – but they’re expensive, environmentally problematic to source, and tied to volatile supply chains."Light rare earth elements like neodymium (Nd) are more common and more stable in supply. So our goal is to design motors that can avoid HREs altogether – without compromising performance," Knorr explains.

SEG Automotive’s approach relies on a combination of innovative mechanical design and advanced simulation capabilities:

1.Thermal Management
Efficient oil cooling systems for both rotor and stator – including oil-guided hollow shafts – allow the magnets to stay below critical temperature thresholds (e.g., <120°C), enabling the use of magnet grades that don’t require HRE additives.

2. Failure-Mode Robustness
By reducing the demagnetizing currents that would occur during failure scenarios, the team minimizes the risk of permanent damage to the magnets – even without HRE reinforcement.

3.Flux Optimization
Lowering the required magnetic flux density and offsetting this with increased machine length (where installation space allows) helps maintain torque output with more accessible materials.

All of this is achieved through precise simulation workflows powered by SEG Automotive’s in-house high-performance computing cluster – ensuring results that are both fast and reliable.

Validation from extensive prototype testing helps refine the models further.

Simulation-Driven Innovation

A key differentiator for SEG Automotive is its use of Multi-Objective Optimization (MOO) – a simulation-driven methodology that balances trade-offs like torque, efficiency, thermal limits, and cost. By iteratively adjusting design parameters, the team can fine-tune machines for specific applications, while keeping rare earth content as low as possible.

Additionally, SEG Automotive has developed proprietary models that factor in so-called Pulse Width Modulation (PWM) induced magnet losses – a critical consideration for accurate thermal prediction and magnet selection.