High-Performance Rare-Earth Magnet-Free Synchronous Reluctance Machine for Electric Vehicle Propulsion Systems

A high-performance rare-earth-free electric motor is developed for electric vehicle propulsion, using a ferrite-assisted synchronous reluctance machine (SynRM) design. The proposed motor combines several innovative features: a multi-layer flux-barrier rotor optimized for maximum reluctance torque and low ripple, an amorphous alloy core to significantly reduce iron losses, and a carbon fiber rotor sleeve to ensure mechanical integrity at 25,000rpm. Finite element analysis (FEA) validates that a four-layer flux-barrier rotor offers the best trade-off between torque output and torque ripple. The amorphous alloy core reduces core losses by ∼ 90% compared to conventional silicon steel. A 0.9 mm carbon-fiber retaining sleeve safely contains the rotor at high speed, enabling operation up to 25,000 rpm. Comparative results show the optimized ferrite-assisted SynRM achieves comparable peak efficiency to a benchmark Toyota Prius 2010 interior permanent-magnet motor (IPMSM) while reducing material costs by ∼ 28%. The ferrite-SynRM also achieves a broader highefficiency range at high speeds, demonstrating its potential as a sustainable and cost-effective alternative to rare-earth magnet motors in EVs.