Controller saturation nonlinearity in doubly fed induction generator-based wind turbines under unbalanced grid conditions

Zhen Li, Siu Chung Wong, Chi Kong Tse, Xiangdong Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


Doubly fed induction generator (DFIG) is widely used in wind energy generation systems due to its cost-effective, partially rated back-to-back power converters, variable rotor speed operation, and maximum wind power capture. The conventional design assumes balanced grid voltage and utilizes power protection for the power converters. The DFIG wind turbine is naturally one of the major components in distributed generations of the smart grid system. However, newly developed smart grid system is rich in unbalanced loads. This paper summarizes the limiter settings of controllers and explores the nonlinear behaviors of the DFIG-based wind power generation system with unbalanced loads. The generator rotor speed and an unbalanced load resistance are chosen as variation parameters. An emerging low-frequency linear-modulated oscillation at line second harmonic frequency with DC drifting is identified on the DC link voltage of the back-to-back power converters. In terms of second harmonic and the usually reported hazardous low-frequency oscillation, the saturation nonlinearity and over-modulation of the back-to-back power converter and its power flow are investigated and analyzed. The built-in detailed model of the DFIG wind energy generation system in Matlab with SimPowerSystems library is used in this study.
Original languageEnglish
Pages (from-to)1602-1619
Number of pages18
JournalInternational Journal of Circuit Theory and Applications
Issue number8
Publication statusPublished - 1 Aug 2016


  • controller saturation
  • doubly fed induction generator
  • nonlinearity
  • over-modulation
  • unbalanced loads

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


Dive into the research topics of 'Controller saturation nonlinearity in doubly fed induction generator-based wind turbines under unbalanced grid conditions'. Together they form a unique fingerprint.

Cite this