Irreversible demagnetization analysis of permanent magnet materials in a novel flux reversal linear-rotary permanent magnet actuator

Kaikai Guo, Shuhua Fang, Yang Zhang, Hui Yang, Heyun Lin, Siu Lau Ho, Ningjun Feng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

13 Citations (Scopus)


This paper proposes a novel flux reversal linear-rotary permanent magnet actuator (FR-LRPMA) with permanent magnets (PMs) mounted on the stator surface. The proposed FR-LRPMA uses only 50% of the PM materials when compared with that of the topology with four-PM poles in a conventional stator pole actuator. The FR-LRPMA provides a pathway for the magnetic field, which is generated by currents in the armature winding, resulting in substantial reduction in the possibility of irreversible demagnetization of the PMs to increase its torque density. According to the physics of PM demagnetization, a simplified fitting analytical expression, which considers the angular velocity, current, temperature, and PM thickness, is derived to determine the least work point of the PM. The torque prediction using the proposed algorithm at different currents agrees well with the values calculated using a finite-element method. It also confirms that the novel topology has a larger torque density.
Original languageEnglish
Article number7381667
JournalIEEE Transactions on Magnetics
Issue number7
Publication statusPublished - 1 Jul 2016


  • Finite element method
  • flux reversal
  • irreversible demagnetization
  • linear-rotary permanent magnet actuator
  • torque density

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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