Abstract: The existing HFO active suppression methods have shortcomings such as deteriorating the dynamic performance of flexible HVDC system and poor adaptability to the changing grid conditions. In this paper, a dynamic performance-friendly high-frequency self-stabilization control method is proposed, which can completely eliminate the high-frequency negative resistance of a modular multilevel converter (MMC) and have strong adaptability to different gird conditions, basically not affecting the dynamic performance of the flexible HVDC system. First, the MMC high-frequency impedance model including sequence separation, sequence current decoupling control, phase-locked loop (PLL) and etc., is established in the stationary frame, and the additional resistance effect of PLL on MMC high-frequency impedance model is found by comparing with the traditional simplified high-frequency impedance model. Furthermore, the influence of operating points and PLL control parameters on the additional resistance effect of PLL is analyzed. Then, the basic principle of the proposed high-frequency self-stabilization control method is introduced, and the parameter design method is also presented. Besides, by establishing the dynamic response model and transient current model of the flexible HVDC system, the advantages of the proposed method in dynamic performance are analyzed. Finally, simulations are carried out to validate the efficacy of the proposed method in different grid conditions and the negligible influence on the dynamic performance of flexible HVDC systems.