High-efficiency and cost-minimization method of energy storage system with multi storage devices for grid connection

An energy storage system is integrated into a power-grid to compensate for the power fluctuation from renewable energy systems. This paper proposes a high-efficiency and low-cost energy storage system for the power-grid. The proposed system combines multi-energy storage devices such as a LaB and an EDLC for reducing the cost incurred by the system for the complete operation period. This paper also proposes a control method to improve the converter efficiency. The proposed method divides the amplitude of the compensation power reference into the LaB and the EDLC. A 10-kW prototype system has been designed and implemented to validate the proposed architecture and system performance. Experimental results demonstrate that the proposed control method effectively compensated for the power fluctuation from the renewable energy system. Simulation analysis confirms that the proposed system reduces the cost and losses in comparison with the conventional system.