Hybrid Energy Storage Strategy Based on Parameter Optimized Variational Mode Decomposition

To smooth the output of wind power generation the power-type energy storage elements and energy-type energy storage elements are usually combined into a hybrid energy storage system (HESS) and connected to the wind power system. To improve both flexibility and economy of HESS, the control strategy of HESS based on parameter optimized variational mode decomposition (VMD) was researched. Firstly, the particle swarm optimization (PSO) algorithm was utilized to determine the optimal combination of the values of decomposition mode number K and the secondary penalty factor α in the VMD algorithm. Secondly, the values of K and α were preset to reasonably distribute the unbalanced power signal between battery and super-capacitor by VMD. Finally, the fuzzy control was adopted to optimize the state of charge (SOC) of the hybrid energy storage system. Simulation results show that by use of the proposed control strategy the reasonable power distribution between energy storage elements can be realized, the fluctuation of wind power output can be effectively suppressed and the SOC of the hybrid energy storage system can be stabilized in a certain interval to make the long-term secure operation of the hybrid energy storage system come true.