To address the problem of power fluctuations from wind and solar farms impacting the stability of power grids

a hybrid energy storage strategy is proposed considering the complementary characteristics of wind and solar energy to mitigate composite power fluctuations. The method is based on wind-solar power generation systems and utilizes the Savitzky-Golay (SG) filtering algorithm to separate grid-connected power from hybrid energy storage power while adhering to power fluctuation limits. Considering the effects of residual

a two-stage variational mode decomposition (VMD) is applied to the hybrid energy storage power

with VMD parameters determined by the improved Dung Beetle optimization (IDDBO). Meanwhile

the high-low frequency division points are determined by using mutual information entropy

and reconstruction is conducted to obtain the power of supercapacitors and batteries. Based on this strategy

the objective function is set to minimize the annual integrated cost of hybrid energy storage

with consideration of the constraints of the hybrid energy storage system to optimize storage capacity

and the approach is validated with typical daily operations. The results indicate that the proposed strategy can more accurately allocate energy storage components

harnessing the complementary advantages of different forms of energy storage. Additionally

it effectively smooths out grid-connected power fluctuations

thereby enhancing grid stability.