An Effective Smooth Transition Control Strategy Using Droop-Based Synchronization for Parallel Inverters

Md Nayeem Arafat, Ali Elrayyah, Yilmaz Sozer

Research output: Contribution to journalArticle

45 Citations (Scopus)


This paper proposes a smooth transition control strategy for voltage-source inverters between stand-alone (SA) and grid-connected (GC) modes of operation. In both GC and SA modes of operation, the inverters use the droop control method to regulate the real power flow without the need of any external communication between them. One of the distributed energy sources working in the microgrid system is designated as a dispatch unit (DU) to facilitate interconnection with utility grid and achieve smooth transition between the modes of operations. During transition modes, this selected unit takes extra responsibility to ensure the continuous power delivery to the load. For smooth transition from GC to SA mode of operation, the DU compensates for the grid current immediately after the grid disconnection, and then, other units pick up this responsibility gradually through their individual droop controllers. The DU also adjusts its output power to synchronize the inverters with the grid during the transition from SA to GC mode. The simulation and experimental results, as well as the stability analysis, are provided to verify the effectiveness of the proposed control technique.

Original languageEnglish
Article number6954502
Pages (from-to)2443-2454
Number of pages12
JournalIEEE Transactions on Industry Applications
Issue number3
Publication statusPublished - 1 May 2015
Externally publishedYes



  • AC-DC power converters
  • microgrids
  • smooth transition control

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering

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