Injection-Based Self-Sensing of Rotor Displacement in Combined Winding Bearingless Motors

Nathan P. Petersen, Eric L. Severson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper investigates rotor displacement self-sensing (sensorless) algorithms for surface permanent magnet bearingless motors (SPMBMs). The techniques are derived for and applied to multi-phase combined (single) windings where each phase contributes to both torque and force production. First, a non-linear analytic model based on modified winding function theory is presented for the SPMBM which includes the effects of time-varying rotor displacements and rotor rotation. Then, the state-of-the-art high-frequency (HF) injection methods for rotor displacement self-sensing are reviewed and applied to the model. It is shown that these methods apply well at low motor loading, but do not extend to the full-load/high-speed region where bearingless motors are desired to operate. Analytical equations are derived which predict the maximum load and rotational speed permissible for state-of-art self-sensing methods. An improved method is proposed for current component frequency separation which can effectively isolate the HF response. Simulations validate the analytically-predicted motor load limitations and the proposed algorithm. Realistic HF injection self-sensing is simulated for a SPMBM at 90 kRPM with 10 kW of mechanical output power. The results herein motivate displacement self-sensing as a practical alternative to physical gap sensors.

Original languageEnglish (US)
Title of host publication2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages4874-4881
Number of pages8
ISBN (Electronic)9798350316445
DOIs
StatePublished - 2023
Externally publishedYes
Event2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023 - Nashville, United States
Duration: Oct 29 2023Nov 2 2023

Publication series

Name2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023

Conference

Conference2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023
Country/TerritoryUnited States
CityNashville
Period10/29/2311/2/23

Bibliographical note

Publisher Copyright:
© 2023 IEEE.

Keywords

  • combined windings
  • high-frequency injection
  • rotor displacement
  • self-sensing

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