Rotor position tracking control for low speed operation of direct-drive PMSM servo system

Feifei Bu, Fuqiang Xuan, Zhida Yang, Yu Gao, Zihao Pan, Michele Degano, Chris Gerada

Research output: Journal PublicationArticlepeer-review

19 Citations (Scopus)


In this article, a rotor position tracking control (RPTC) strategy is proposed to effectively reduce the speed fluctuation for a direct-drive permanent magnet synchronous motor servo system operating at a low speed with different torque disturbances. In this article, considering the derivative relationship between the rotor position and speed, a speed command is converted to a real-time rotor position trajectory, and then a position-current two-loop control with the RPTC controller is proposed based on the internal model method to smoothly track the rotor position. In addition, the parameter design of the RPTC controller from the perspectives of robust stability and antidisturbance capability is investigated as well. The comparative simulation and experimental results demonstrate that, at a low speed, the proposed RPTC strategy has a good speed performance for both periodic and nonperiodic torque disturbances. Moreover, it enjoys a simple implementation for not requiring the precise speed feedback and specific torque disturbance information.

Original languageEnglish
Article number9174919
Pages (from-to)1129-1139
Number of pages11
JournalIEEE/ASME Transactions on Mechatronics
Issue number2
Publication statusPublished - Apr 2021


  • Direct-drive servo system
  • Low speed
  • Permanent magnet synchronous machine (PMSM)
  • Rotor position tracking control (RPTC)
  • Torque disturbance

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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