Design of SynRM and PMaSynRM using a common industrial stator platform: a new design methodology for transition from industrial applications to electric vehicles

This study presents a design methodology for synchronous reluctance (SynRM) and permanent magnet-assisted synchronous reluctance motors (PMaSynRM), developed through rotor lamination optimizations without altering the existing stator platform. This approach enables the realization of different motor types using a common stator, eliminating the need for additional tooling costs in the production line. It is based on the principle of "Efficiency Class Upgrade with Minimum Die Cost", whereby the existing tooling infrastructure is preserved, and higher-efficiency motors are prototyped at low cost through topological modifications in the rotor design. Using a multi-objective genetic algorithm (MOGA), rotor designs were optimized to achieve Pareto-optimal solutions among conflicting targets such as torque production, efficiency, magnet volume, and torque ripple. The electromagnetic performance of rotor geometries was assessed via 2D finite element analysis (FEA), providing flux distribution, torque profiles, and efficiency curves. A reference IE2-class induction motor (IM) was used as the baseline, upon which SynRM and PMaSynRM models were designed using the same stator. These three motor types were comparatively analyzed, along with a dimensional-level comparison against the IE4 version of the same motor. Throughout the process, the stator geometry, slot structure, and winding features remained unchanged, ensuring design novelty through rotor-side innovations. The results demonstrate the electromagnetic potential and structural compatibility of SynRM and PMaSynRM configurations with the existing stator. The proposed method offers a scalable and cost-effective solution for manufacturers aiming to adopt high-efficiency motor technologies, paving a transition path from industrial motors to electric vehicle (EV) applications via a unified stator platform. This study is limited to an IE2-class, frame-90, four-pole squirrel-cage IM stator reference; applying the methodology to other frame sizes and pole counts requires re-parameterization. From a practical standpoint, redesigning only the rotor eliminates stator/winding tooling costs, enabling efficiency-class upgrades and making the approach suitable for rapid industrial adoption. From a social perspective, higher efficiency and reduced dependence on rare-earth materials contribute to energy savings and supply-chain sustainability.