Modified grid-forming converter control for black-start and grid-synchronization applications

Abdulrahman Alassi, Khaled Ahmed, Agusti Egea-Alvarez, Colin Foote

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

12 Citations (Scopus)
49 Downloads (Pure)


The increasing grid integration of converter- based generation and distributed resources is necessitating a review to the classical synchronous generators dominant network models, and to equip converters with the necessary control capabilities such as inertia emulation and black-start to carry on the required ancillary services provision. This paper proposes a modified grid-forming converter control technique based on virtual synchronous machine (VSM). The modified controller uses a ramping voltage reference to achieve soft transformer energization and eliminate high-magnitude inrush current that can traditionally exceed converters rating. Grid-synchronizing functionality is added to the VSM controller to achieve smooth transition from black-start to grid-connected mode while maintaining grid-forming operation. This is achieved by gradually adjusting the power loop reference through a dedicated synchronizing controller, which is disconnected once grid-connection is achieved. A MATLAB/ Simulink case study is presented to illustrate the controller performance with a 40 MVA simulated converter. The results demonstrate successful black-start sequence execution, starting by soft transformer energization, followed by a block load pickup and grid-synchronization. The sequence is achieved with minimal transformer inrush current, and with seamless transition to the grid-connected operating mode.
Original languageEnglish
Title of host publication2021 56th International Universities Power Engineering Conference (UPEC)
Place of PublicationPiscataway, NJ
Number of pages5
ISBN (Electronic)9781665443890
ISBN (Print)9781665443906
Publication statusPublished - 30 Sept 2021
Event56th International Universities Power Engineering Conference, UPEC 2021 - Virtual, Middlesbrough, United Kingdom
Duration: 31 Aug 20213 Sept 2021


Conference56th International Universities Power Engineering Conference, UPEC 2021
Country/TerritoryUnited Kingdom
CityVirtual, Middlesbrough


  • power engineering
  • matched filters
  • software packages
  • emulation
  • transformers
  • synchronous generators
  • synchronization


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