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Abstract
Axial Flux Permanent Magnet (AFPM) machines are increasingly being studied for low-speed, direct-drive applications due to their compact structure and high torque output. This study proposes two novel dual-stator AFPM vernier machine topologies: a spoke-type rotor configuration and a back-to-back Halbach array rotor. Both designs employ dual outer stators with 12 double-layer concentrated windings, and high-polarity rotor configurations to enhance flux concentration. A three-dimensional finite element model, which was previously validated by a laboratory prototype motor was utilized to evaluate the electromagnetic characteristics of the proposed topologies. These characteristics include torque density, airgap flux distribution, and harmonic content. Comparative results show that under a current density of 35 A/mm2, the spoke-type topology achieves an efficiency of 85.2% and an average torque that is 13.5% higher than the double-stator single-rotor (DSSR) Halbach topology, which records 83.5% efficiency. Both topologies exhibit a torque ripple of 2%, highlighting consistent electromagnetic performance and smooth operation. Additionally, the spoke-type DSSR features an extended constant power operating range due to enhanced flux concentration. These findings confirm the spoke-type AFPM machine as a promising candidate for high-performance direct-drive systems, delivering improved electromagnetic torque, efficiency, and operational smoothness through strategic magnetic topology and flux profiling.
Document Type
Conference Proceeding
Publication Date
Fall 10-2025
Digital Object Identifier (DOI)
10.1109/ECCE58356.2025.11259657
Repository Citation
Mohammadi, Esmaeil; Mohammadi, Ali; Kondelaji, Mohammad Amin Jalali; Asef, Pedram; Boldea, Ion G.; and Ionel, Dan M., "High Torque Density Dual-stator Vernier Motors with Flux Concentrating Rotors" (2025). Electrical and Computer Engineering Graduate Research. 20.
https://uknowledge.uky.edu/ece_gradpub/20
Notes/Citation Information
Mohammadi, E., Mohammadi, A., Kondelaji, M. A., Asef, P., Boldea, I. G., and Ionel, D. M., "High Torque Density Dual-stator Vernier Motors with Flux Concentrating Rotors," Proceedings, IEEE Energy Conversion Congress & Expo (ECCE), Philadelphia, PA, doi: 10.1109/ECCE58356.2025.11259657, 7p (Oct 2025)