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Control of grid-following inverters under unbalanced grid conditions

Zarei, S. F ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1109/TEC.2019.2945699
  3. Publisher: Institute of Electrical and Electronics Engineers Inc , 2020
  4. Abstract:
  5. This paper proposes a new control scheme to eliminate the 3rd harmonic in the output currents of grid-following inverters under unbalanced grid conditions. Unbalanced grids adversely affect the performance of grid-following inverters due to the oscillations appearing on the DC-link voltage with a frequency twice the line frequency. The paper is based on instantaneous active reactive control (IARC) technique due to its advantages over other existing methods. However, the presence of severe asymmetrical 3rd harmonic distortions in the inverter output currents is the main challenge with IARC method, which impairs the power quality requirements. This paper enhances the IARC scheme by proposing a 3rd harmonic elimination approach by adopting a current reference generation method using the symmetric sequence components concept. Furthermore, the proposed scheme complies with the grid code requirements by injecting the requested reactive current. Finally, the proposed approach is evaluated by theoretical and simulation analysis and validated experimentally using a hardware setup. © 2019 IEEE
  6. Keywords:
  7. Asymmetrical short circuit faults ; DC-link voltage control ; Grid-following inverters ; Instantaneous active reactive control ; Output currents 3rd harmonics ; Harmonic analysis ; DC link voltage control ; Output current ; Reactive control ; Short-circuit fault ; Unbalanced grid conditions ; Electric inverters
  8. Source: IEEE Transactions on Energy Conversion ; Volume 35, Issue 1 , 2020 , Pages 184-192
  9. URL: https://ieeexplore.ieee.org/document/8859288