Loss analysis of energy-storage system with multiple storage devices for grid connection

Energy storage system is used in power-grid to compensate for the power fluctuation caused by renewable energy systems. This paper presents loss-analysis results of power converter utilized for the energy-storage systems. The system has multiple energy storage devices such as a LaB and an EDLC. This paper discusses two methods to distribute the compensation power reference to each device. Conventional method is that the compensation power reference is divided by frequency filter. Proposed method is that the compensation power reference is divided by amplitude limiter. This paper designs and implements a prototype system to validate the performances of the control method. Experimental results demonstrate that the proposed control method effectively compensated for the power fluctuation caused by the renewable energy system. This paper uses FRR (Fluctuation Reduction Rate) in order to evaluate the compensation ability of the system.