Analysis of Double-Star Modular Multilevel Topologies Applied in HVDC System for Grid Connection of Offshore Wind Power Plants

  • William Caires Silva Amorim
  • Dayane do Carmo Mendonça
  • Renata Oliveira de Sousa
  • Allan Fagner Cupertino
  • Heverton Augusto PereiraEmail author


Reducing costs related to passive elements and ensuring ability to handle short-circuit faults are essential for a reliable and cost-effective operation of modular multilevel converters (MMCs) in high-voltage direct current (HVDC) systems. HVDC systems have emerged in offshore wind power plants (OWPP), as an attractive solution to connect OWPP to the main ac system. To address these challenges, this paper carries out a benchmarking of double-star (DS) MMC topologies applied to OWPP. In this sense, comparisons among DS topologies of the DSCC (double-star chopper cell), DSBC (double-star bridge cell) and DSHyb (double-star hybrid) types are proposed. Quantitative analyses are performed, considering an OWPP of 100 MW. In the results, the topologies are compared for steady-state operation and active power dynamics. In addition, power losses and junction temperature through a one-year OWPP mission profile are analyzed. Due to dc fault tolerance and capacity to synthesize two times the converter output voltage in comparison with the DSCC, DSBC and DSHyb are best suited in HVDC systems. However, DSHyb stands out in terms of converter efficiency and capacitor energy storage. Thus, DSHyb proves to be a promising topology to connect OWPP to the ac system.


Double-star topologies Modular multilevel converter High-voltage direct current Offshore wind power plant 



This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG).


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© Brazilian Society for Automatics--SBA 2019

Authors and Affiliations

  1. 1.Graduate Program in Electrical EngineeringFederal Center for Technological Education of Minas GeraisBelo HorizonteBrazil
  2. 2.Department of Materials EngineeringFederal Center for Technological Education of Minas GeraisBelo HorizonteBrazil
  3. 3.Department of Electrical EngineeringUniversidade Federal de ViçosaViçosaBrazil

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