为了解决跟/构网混联风电场经柔性直流送出系统中因系统传输容量提升及构网型风机容量占比降低引发的振荡问题，建立了系统整体的状态空间模型，基于该模型采用根轨迹法与模态分析方法，识别了在不同工况下导致系统振荡的主导参与因子。分析结果表明，系统振荡主要受构网型风机和柔性直流换流站电压外环相关变量的影响。在此基础上提出了一种在构网型风机与柔直换流站的电压外环中引入虚拟阻抗的控制策略，以改善系统的阻抗特性，抑制振荡现象。通过根轨迹分析进一步确定了虚拟阻抗参数的合理设置范围。最后，通过仿真验证了所提出虚拟阻抗控制方法能够有效提升系统运行性能，证明了所提策略的可行性和有效性。

In order to address the oscillation issues induced by the increase in system transmission capacity and the reduction of grid-forming wind turbine capacity share in grid-forming and grid-following hybrid wind farms delivered via VSC DC transmission systems, a overall state-space model of the system is established. Based on this model, root locus and modal analysis methods are employed to identify the dominant contributing factors to system oscillations under different operating conditions. The analysis results indicate that system oscillations are mainly influenced by the control variables associated with the voltage outer loops of the grid-forming wind turbines and the VSC DC converter stations. On this basis, a control strategy introducing virtual impedance into the voltage outer loops of the grid-forming wind turbines and the VSC DC converter stations is proposed to improve the system impedance characteristics and suppress oscillations. Furthermore, the feasible parameter range for the virtual impedance is determined through root locus analysis. Finally, simulation results validate that the proposed virtual impedance control method can effectively enhance system performance, thereby confirming the feasibility and effectiveness of the proposed strategy.