Research on MMC-HVDC start-up control strategy for grid-connected wind power

Abstract

In recent years, flexible DC transmission has developed rapidly, and offshore wind power DC grid connection projects are using modular multilevel converters, which will become the main grid connection method for large wind farms. However, most of the research on MMC-HVDC uses two-terminal power systems, whose control strategies must be different from two-terminal active systems, and more research is needed on the application of MMC-HVDC in the field of wind power grid connection. Based on this paper the equivalent mathematical model of a wind farm is studied, the flexible DC startup process of the wind farm is analysed and the proposed MMC controlled rectifier charging strategy is validated by simulation.