To address the issues of the wideband oscillation risks faced by grid-forming converters when they are integrated into complex power grids

as well as the limitations of existing damping control methods that rely on prior parameter information and have difficulty in achieving adaptive mitigation

we propose a wideband oscillation mitigation strategy based on adaptive impedance reshaping. First

a wideband impedance model of the grid-forming modular multilevel converter (MMC) is established

and the negative damping mechanism responsible for system oscillation instability is revealed. Second

a cascaded second-order generalized integrator with frequency-locked loop (SOGI-FLL) is introduced to achieve fast extraction of wideband oscillation features. Furthermore

by combining a dual-mode startup strategy with two-stage impedance identification

an adaptive tuning method for virtual impedance parameters is proposed. Without requiring accurate knowledge of the external grid topology and parameters

the proposed method can be adopted to determine the system damping requirement in real time based on known converter impedance characteristics and dynamically adjust the virtual impedance parameters

thereby achieving adaptive reshaping of the MMC terminal impedance. Finally

time-domain simulations validate the effectiveness of the proposed strategy under different oscillation scenarios.