Control strategy of wind power smooth grid connection based on adaptive VMD and hybrid energy storage

Abstract

In nature, the variation of wind speed is characterized by randomness, fluctuation, and intermittence. In order to suppress the power fluctuation caused by wind speed changes in the process of wind turbine grid connection, a wind power smooth grid-connected control strategy based on the adaptive variational modal decomposition algorithm and the hybrid energy storage system is proposed. For the problem that the selection of variational modal decomposition parameters is subjective and experiential, which leads to the poor signal decomposition reduction degree, the sparrow search algorithm is proposed to optimize variational modal decomposition to realize the adaptive selection of key variational modal decomposition parameters k and α. First, the reference power of the hybrid energy storage system conforming to the grid-connected power fluctuation standard is obtained by the adaptive moving average algorithm. Then, adaptive variational modal decomposition of the reference power was performed to obtain a set of inherent modal functional components, and the low frequency and high frequency components of the modal components were allocated for lithium batteries and the supercapacitor, respectively. Finally, Matlab/Simulink was used to simulate and compare with the control strategy of low-pass filtering. The results show that the proposed algorithm realizes the selection of adaptive decomposition parameters of variational modal decomposition, solves the lag and frequency aliasing problems existing in power distribution of the low-pass filtering algorithm, and realizes the high reduction solution of reference power. The fluctuation of wind power connected to the grid is effectively suppressed.