Sub/Super-synchronous oscillation phenomena may occur in a modular multi-level converter-based high-voltage direct current (MMC-HVDC) transmission system due to the complex control coupling between the wind farm and the MMC. In order to reveal the interaction between the control loops of the wind farm and the MMC converter station

and to clarify the interaction mechanism and design constraints of the control loops of the VSC-HVDC transmission system for the wind farm. Firstly

the MMC-HVDC sequence impedance model is established. Next

the matching relationship between the wind farm and the MMC-HVDC control loop is investigated

and the results indicate a significant stability boundary exists between the bandwidths of the MMC voltage loop and the wind farm phase-locked loop. On this basis

the explicit mathematical relationship between controller parameter interaction and the Nyquist stability determination equation is analyzed

and the coupling influence law and parameter design boundary of the control loop of the VSC-HVDC transmission system for the wind farm in the sub/super-synchronous frequency band are clarified. On this basis

an impedance remodeling control strategy based on the MMC converter station is proposed. It completely decouples the wind farm and MMC converter station

expands the range of control parameters

and improves the stability of the interactive system. Finally

the theoretical analysis and experimental verification of the impedance reshaping method are completed on RT-LAB control hardware-in-the-loop platform.