Enhanced DC Voltage Based Grid-Forming Control for MMC-HVDC System Connecting Offshore Wind Farm

This paper proposes an enhanced grid-forming (GFM) control scheme for modular multilevel converter-based high-voltage direct current (MMC-HVDC) systems interfacing offshore wind farms. The proposed strategy adopts an improved DC voltage synchronization approach, which not only provides instantaneous active and reactive power support, but also achieves enhanced DC-link voltage regulation. To validate its control performance, PSCAD/EMTDC simulations are conducted using the actual parameters of the Borwin6 MMC-HVDC project. Simulation results demonstrate the scheme's effectiveness in delivering instantaneous grid support and maintaining system stability under various challenging conditions, including phase angle jumps, frequency variations, voltage dips, short-circuit ratio (SCR) changes and AC grid faults.