Abstract: In response to the problems of insufficient grid stability and frequent broadband oscillations in the construction of grid-forming optical storage systems in weak-grid scenarios, this paper proposes a multidimensional cooperative suppression technology. First, based on the analysis of the impedance-coupling mechanism, a virtual impedance reshaping algorithm is proposed to dynamically compensate for the grid's inductive impedance through real-time frequency-domain scanning. Second, a virtual synchronous generator (VSG) multi-timescale control architecture is designed to simulate the inertia characteristics of synchronous generators and enhance transient support capability. Meanwhile, a broadband oscillation online monitoring system is developed, combined with an improved Prony algorithm to achieve 2ms-level modal identification and adaptive suppression. Engineering applications show that in weak grids with SCR=1.2–1.5, the system's equivalent damping ratio increases by 260%, and the average annual oscillation events are reduced by 72.9%. The fault ride-through success rate improves from 67% to 96%, and the voltage fluctuation rate at the grid-connection point remains stable at 4.3%. After the application of this technology, the unplanned downtime losses of renewable energy stations decrease by ¥230 million per year, and the grid frequency compliance rate increases to 99.98%. The research results provide a replicable technical solution for improving the stability of weak grids with high-penetration renewable energy integration.