Voltage support control strategy of grid-connected inverter system under unbalanced grid faults to meet fault ride through requirements

Çelik D., Meral M. E.

IET GENERATION TRANSMISSION & DISTRIBUTION, vol.14, no.16, pp.3198-3210, 2020 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 16
  • Publication Date: 2020
  • Doi Number: 10.1049/iet-gtd.2019.1206
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Applied Science & Technology Source, Business Source Elite, Business Source Premier, Communication Abstracts, Compendex, Computer & Applied Sciences, Environment Index, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.3198-3210
  • Keywords: distributed power generation, power generation faults, reactive power, invertors, power grids, voltage control, power generation control, grid-connected inverter system, unbalanced grid faults, fault ride, GCI, main interface, modern power units, distributed energy resources, electric vehicles, high voltage direct-current transmission systems, novel voltage support control strategy, unbalanced grid fault conditions, regulating phase voltages magnitude, pre-defined safety limits, positive sequence, negative sequence voltages, active-reactive power oscillations, DC-link voltage oscillations, active power oscillations, adjustable control, third-order current harmonic component, resistive-inductive grid impedance model, grid support, active powers, reactive powers, utility grid, DISTRIBUTED GENERATION INVERTERS, POWER-CONTROL STRATEGIES, THROUGH STRATEGY, CONTROL SCHEME, PV INVERTERS, CAPABILITY, LIMITATION, MANAGEMENT, CONVERTER, MAXIMIZE
  • Van Yüzüncü Yıl University Affiliated: Yes


Grid-connected inverter (GCI) has become the main interface for integrating modern power units, such as distributed energy resources, electric vehicles, microgrids and high voltage direct-current transmission systems. To proceed in this direction, this study presents a novel voltage support control strategy to enhance the reliability and stability of the GCI during unbalanced grid fault conditions. The proposed control strategy simultaneously achieves multiple objectives during grid faults; regulating phase voltages magnitude within pre-defined safety limits, increasing the difference between positive sequence (PS) and negative sequence (NS) voltages, eliminating both active-reactive power oscillations and the DC-link voltage oscillations. Reducing active power oscillations ensure an adjustable control for the DC-link voltage oscillations which result in third-order current harmonic component at the grid side. One of the main contributions to previous studies, reference for reactive power is computed online based on resistive-inductive grid impedance model and reference voltage sequences for the grid support. Another important contribution to existing studies is to supply both the active and reactive powers to the utility grid and load. Detailed mathematical analyses are performed to theoretically describe the behaviour of the proposed control strategy. A comprehensive set of results is presented to confirm the theoretical solutions.