Airgap Search Coil Based Identification of PM Synchronous Motor Defects

Muhammad Saad Rafaq, Hyeonjun Lee, Yonghyun Park, Sang Bin Lee, Marcos Orviz Zapico, Daniel Fernandez, David Diaz-Reigosa, Fernando Briz

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Online detection of rotor and load faults in permanent magnet synchronous motors (PMSM) based on spectrum analysis of current or vibration is not capable of identifying the root cause of the fault, since all faults produce identical fault signatures. The sensitivity of fault detection also depends on the motor and controller design making fault detection unreliable. In addition, operation under variable frequency and load limits the effectiveness of spectrum analysis based methods. In this article, airgap flux monitoring is investigated as an alternative for providing reliable identification of rotor and load faults in PMSMs. Based on the analysis of airgap flux under partial and uniform demagnetization, dynamic eccentricity, and load unbalance, an airgap search coil voltage based method for detection and classification of the faults is proposed. The claims made in the article are verified through experimental testing on an IPMSM under emulated fault conditions along with a comparison to vibration and current spectra-based detection. It is shown that the proposed method provides reliable online identification of the faults for cases where conventional spectrum analysis based methods fail.

Original languageEnglish
Pages (from-to)6551-6560
Number of pages10
JournalIEEE Transactions on Industrial Electronics
Issue number7
Publication statusPublished - 2022 Jul 1

Bibliographical note

Publisher Copyright:
© 1982-2012 IEEE.


  • Airgap flux
  • Demagnetization
  • Eccentricity
  • Fault diagnosis
  • Load unbalance
  • Permanent magnet synchronous motors
  • Search coil

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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