DC-Link Loop Bandwidth Selection Strategy for Grid-Connected Inverters Considering Power Quality Requirements

Seyed Fariborz Zarei, Hossein Mokhtari, Mohammad Amin Ghasemi, Saeed Peyghami, Pooya Davari, Frede Blaabjerg

Research output: Contribution to journalJournal article

Abstract

DC-link voltage and output current control loops are two cascaded loops in the control structure of grid-connected inverters. A high DC-link voltage loop bandwidth (DCL-BW) provides more disturbance rejection capability for the control loop and is preferred from control system perspective. However, for stability issues, this BW is limited and must be sufficiently less than that of the current control loop. This paper shows that the DCL-BW must be limited by another factor, which is the harmonic content of the DC-link, and can be even more restrictive than the limit specified by the current control loop. Violating this limit degrades the inverter performance. Even low values of harmonics on the DC-link voltage can result in significant harmonic distortion in the inverter output currents. This paper analytically investigates the relationship between the DCL-BW and the output current waveform quality. Correspondingly, a supplementary DCL-BW selection criterion is proposed based on the harmonic contents of the DC-link voltage and the inverter nominal rating. Finally, to validate the conducted analysis, experimental and simulation results are provided
Original languageEnglish
JournalInternational Journal of Electrical Power & Energy Systems
Volume119
ISSN0142-0615
DOIs
Publication statusPublished - 2020

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Keywords

  • DC-link voltage control loop bandwidth
  • DC-link voltage harmonics
  • grid-connected inverter
  • output currents quality

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