A Novel Linear-Rotary Permanent-Magnet Actuator Using Interlaced Poles

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

Research output: Journal article publicationJournal articleAcademic researchpeer-review

16 Citations (Scopus)


� 2015 IEEE. This paper proposes a novel linear-rotary permanent-magnet actuator (LRPMA) with interlaced poles, which has the merit of using only 50% of the neodymium-iron-boron permanent magnets when compared with those used in traditional Halbach structure. By assuming the stator is slotless, the magnetic field distribution of the LRPMA is initially analyzed using the magnetic scalar potential in the Cartesian coordinate system. A method for calculating the relative permeance by Schwarz-Christoffel transformation (SCT) is subsequently deduced to analyze the magnetic field in detail and predict the cogging force/torque of LRPMA very accurately. The analytical linear cogging force and rotary cogging torque are derived and verified for the design optimization of the actuator. The 3-D finite-element method is used to verify the correctness and effectiveness of the proposed SCT.
Original languageEnglish
Article number7131551
JournalIEEE Transactions on Magnetics
Issue number11
Publication statusPublished - 1 Nov 2015


  • Air-gap magnetic field
  • interlaced poles
  • linear cogging force
  • linear-rotary permanent-magnet actuator (LRPMA)
  • rotary cogging torque
  • Schwarz-Christoffel transformation (SCT)

ASJC Scopus subject areas

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


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