Design and analysis of a new axial-field magnetic variable gear using pole-changing permanent magnets

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Original languageEnglish
Pages (from-to)23-32
Journal / PublicationProgress in Electromagnetics Research
Publication statusPublished - 2015
Externally publishedYes


This paper presents a new non-rare-earth axial-field magnetic variable gear (MVG). By real-time changing the numbers of permanent magnet (PM) pole-pairs in the input and output rotors, the gear ratio becomes controllable. The key is to propose a new stationary ring integrated with magnetizing windings in such a way that various PM pieces can be independently magnetized to form different pole-pair numbers. After introducing the unique features of the non-rare-earth PM material aluminum-nickel-cobalt (AlNiCo), the proposed topology and design principle are discussed. By using finite element analysis, the electromagnetic performances of the proposed MVG under different gear ratios are analyzed. In particular, the corresponding torque transmission capability is assessed, and the influence caused by the introduction of the magnetizing windings is discussed. Hence, the validity of the proposed MVG can be verified.