Large-Scale Design Optimization of an Axial-Flux Vernier Machine With Dual Stator and Spoke PM Rotor for EV In-Wheel Traction

Ali Mohammadi, Yaser Chulaee, Aaron M. Cramer, Ion G. Boldea, Dan M. Ionel

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

This article presents the optimization study targeting a specific drive cycle for a MAGNUS-type axial-flux permanent magnet vernier machine (AFPMVM). The proposed MAGNUS machine has a novel design with a dual-stator configuration, where only one stator is wound, with a high-polarity spoke permanent magnet (PM) rotor. The machine topology has a 3-D flux path, which necessitates the analysis of a large finite-element (FE) model. However, due to the computational complexity and time required for such a large FE model, a new approach was developed. This approach involves a computationally efficient FE analysis (CE-FEA) model combined with a single-point drive-cycle analysis and the differential evolution (DE) optimization algorithm. The targets of the optimization algorithm are derived by modeling the load operating cycle through a systematic k-means clustering method, identifying specific operating points representing high-energy zones within the drive cycle. The optimized design achieves a wide range of constant power operation, which is desirable for electric vehicle (EV) in-wheel traction. Experimental and numerical results demonstrate a higher torque density in the MAGNUS machine compared with commercially available EV traction motors. In addition, this article explores various flux-weakening methods for the MAGNUS machine, highlighting their respective benefits.

Original languageEnglish
Pages (from-to)2477-2488
Number of pages12
JournalIEEE Transactions on Transportation Electrification
Volume11
Issue number1
DOIs
StatePublished - 2025

Bibliographical note

Publisher Copyright:
© 2015 IEEE.

Funding

ACKNOWLEDGMENT This paper is based upon work supported by the National Science Foundation (NSF) under Award No. #1809876. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. The support of Ansys Inc., and University of Kentucky the L. Stanley Pigman Chair in Power endowment is also gratefully acknowledged. Special thanks are due to Mr. J. R. Hendershot of Motorsolver LLC, for his design contributions and the fabrication of the prototype motor.

FundersFunder number
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China1809876
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China

    Keywords

    • Axial-flux vernier machine
    • differential evolution (DE) optimization
    • drive cycle
    • electric vehicles (EVs)
    • finite-element analysis (FEA)
    • flux weakening
    • in-wheel traction
    • permanent magnet (PM) motor
    • spoke rotor

    ASJC Scopus subject areas

    • Automotive Engineering
    • Transportation
    • Energy Engineering and Power Technology
    • Electrical and Electronic Engineering

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