To address the challenge of insufficient active support capability in wind-solar integrated systems under weak grid conditions
this study proposes an active support strategy based on a dual-adaptive cooperative optimization scheme for grid-forming energy storage systems. The proposed method aims to enhance the system’s dynamic support performance. A small-signal model of the virtual synchronous generator(VSG) is developed to derive the boundary conditions of the inertia constant and damping coefficient that satisfy the design requirements for system damping ratio and phase margin. Combined with the frequency regulation characteristics of VSG
differentiated interval gain adjustment coefficients are developed to achieve precise control tailored to various operating conditions
thereby further enhancing the system’s dynamic response capability. In addition
an adaptive weighted coefficient model predictive control method when frequency deviation and rate of frequency change are taken as inputs is introduced to further enhance the frequency regulation capability of grid-forming energy storage systems while reducing the control cost. Finally
a wind-photovoltaic- storage integrated simulation model is established
and the active support performance is validated under weak grid conditions with different short-circuit ratios. The dual adaptive collaborative optimization method can be adopted to effectively improve the output performance of grid-forming energy storage
lower the frequency offset
and effectively modify the frequency fluctuation of the system.