Design of PI Controller Together with Active Damping for Grid-Tied LCL-Filter Systems Using Disturbance-Observer-Based Control Approach

Rachid Errouissi, Ahmed Al-Durra

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

The main advantage of the LCL filter in grid-tied converters is its ability to achieve a better harmonic mitigation in comparison with L filter. A proportional-integral (PI) regulator can be considered as a good candidate for controlling the LCL-filter system, as it is more convenient for real-time implementation. However, PI controller is not capable of stabilizing the grid-tied LCL -filter system when the resonance frequency of the LCL network is below a certain value that mainly depends on the sampling frequency. Such a problem can be overcome by adding an active damping (AD) to the PI controller. This paper presents the design, implementation, and performance testing of a stable PI current controller for a grid-tied inverter using LCL filter. The design process is based on combining feedback linearization (FBL) technique with a disturbance-observer-based control (DOBC). It turns out that the composite controller, consisting of FBL and DOBC, reduces to a PI current controller associated with a linear state-feedback control that plays the role of an AD. In addition, an antiwindup compensator arises naturally into the controller when considering the limits on the control input. An important feature of the proposed PI current controller is its ability to retain the nominal transient response achieved with state-feedback control even in the presence of model uncertainty and external disturbances. The proposed controller was verified through simulation and experimental tests. The results demonstrated the ability of the controller to provide good transient and steady-state performances.

Original languageBritish English
Pages (from-to)3820-3831
Number of pages12
JournalIEEE Transactions on Industry Applications
Volume54
Issue number4
DOIs
StatePublished - 1 Jul 2018

Keywords

  • Active damping
  • anti-windup scheme
  • disturbance observer
  • feedback-linearization
  • grid-tied inverter
  • LCL filter
  • PI controller
  • renewable energy

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