Comparative study on Lyapunov-function-based control schemes for single-phase grid-connected voltage-source inverter with LCL filter


SEFA İ., ÖZDEMİR Ş., Komurcugil H., ALTIN N.

IET RENEWABLE POWER GENERATION, vol.11, no.11, pp.1473-1482, 2017 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 11 Issue: 11
  • Publication Date: 2017
  • Doi Number: 10.1049/iet-rpg.2016.0566
  • Journal Name: IET RENEWABLE POWER GENERATION
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.1473-1482
  • Keywords: invertors, voltage-source convertors, Lyapunov methods, LC circuits, closed loop systems, stability, capacitors, feedback, harmonic distortion, power harmonic filters, power grids, conventional Lyapunov-function based control scheme, single-phase grid connected voltage-source inverter, LCL filter, CLFBC scheme, inverter side current, asymptotic global stability, resonance damping, capacitor-voltage feedback scheme, grid-current feedback scheme, closed-loop pole system, total harmonic distortion, dynamic response, power 3, 3 kW, HYSTERESIS CURRENT CONTROL, CONTROL STRATEGY, CURRENT-FEEDBACK, DESIGN, DISTORTION, SYSTEMS, VSI

Abstract

This study deals with various Lyapunov-function-based control (LFBC) schemes proposed for a single-phase grid-connected voltage source inverter with LCL filter. Use of LCL filter causes resonance which may adversely affect the controller's stability. The conventional (CLFBC) scheme employing the inverter-side current guarantees the asymptotic global stability, but it is not able to damp the resonance. As a remedy to the poor resonance damping, the adoption of grid-current and capacitor-voltage feedback schemes have been investigated. Although the former offers a globally asymptotically stable system, it cannot improve the poor resonance damping. However, the CLFBC with capacitor-voltage feedback scheme not only preserves the global stability, but also improves the resonance damping substantially. The analytical equations of the closed-loop poles for each control scheme are provided which can be used to compute the pole positions and the damping ratio needed for a desired response. Furthermore, the effect of changing controller gains on the loci of closed-loop poles is also studied. Simulation and experimental results obtained from 3.3kW system demonstrate that the CLFBC with capacitor-voltage feedback scheme not only offers a global stability, but also leads to good quality sinusoidal grid current with reasonable total harmonic distortion and fast dynamic response.