A Low-Voltage Ride-Through Control Strategy for Three-Phase Grid-Connected PV Systems

Ehsan Afshari, Babak Farhangi, Yongheng Yang, Shahrokh Farhangi

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

19 Citations (Scopus)


This paper proposes a novel control strategy for the two-stage three-phase Photovoltaic (PV) systems to improve the operation under unbalanced grid faults. In case that a three-phase power converter operates under unbalanced grid voltage faults, power related issues, including injected currents, active and reactive power can be negatively affected. In grid-connected systems, the unbalanced faults may lead to Double Grid Frequency (DGF) oscillations of active and/or reactive power or injection of non-sinusoidal three-phase currents. The DGF oscillations of the injected active power can cause similar variations in the dc-link voltage of conventional two-stage PV inverters. In such systems with an electrolytic capacitor in the dc-link, the oscillations of the dc-link voltage with DGF can deteriorate the capacitor lifetime, and thus the entire system. The proposed Low-Voltage Ride-Through (LVRT) control strategy benefits from a reference current generation method, which can eliminate the oscillations at the dc-link and in the active power during unbalanced voltage dips. In addition, a reliable current limiting method is introduced, which can efficiently prevent overcurrent failure under grid faults. Performance of the proposed LVRT strategy is verified on a 2-kW system by simulations under unbalanced voltage dips.
Original languageEnglish
Title of host publicationProceedings of the 2017 IEEE Power and Energy Conference at Illinois (PECI)
Number of pages6
PublisherIEEE Press
Publication dateFeb 2017
ISBN (Print)978-1-5090-5550-0
Publication statusPublished - Feb 2017
Event2017 IEEE Power and Energy Conference at Illinois (PECI) - Champaign, United States
Duration: 23 Feb 201724 Feb 2017


Conference2017 IEEE Power and Energy Conference at Illinois (PECI)
Country/TerritoryUnited States


  • Current limitation
  • Dc-link voltage oscillations
  • Low-Voltage Ride-Through (LVRT)
  • PV systems
  • Two-stage converters
  • Unbalanced faults


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