A robust control approach to smooth output power of wind units using Hybrid Storage Systems considering state of charge

Output power smoothing of wind units is one of the attractive topics in renewable energies. This paper presents a novel method to control Hybrid Storage Systems (HSSs) for smoothing the output power of wind units. HSS consists of a lead-acid battery and an Electric Double-Layer Capacitor (EDLC), each one equipped with a DC/DC converter, connected to the grid through a DC/AC converter. Proposed control scheme applies mode switching strategy, in which different operation modes are carefully designed under different HSS status. This method takes the state of charge (SoC) of both battery and EDLC into consideration. Performance of the proposed control method is investigated using simulations in MATLAB-Simulink. Results show robustness and effectiveness of the proposed control method.