Experimental analysis of the effects of supercapacitor banks in a renewable DC microgrid

This paper presents a comprehensive experimental analysis about the influence of supercapacitor banks as energy storage system (ESS) in renewable energy sources-based (RES-based) microgrids with high voltage DC bus. The analysis includes a comparison between the microgrid performance supported by conventional ESS such as batteries (lead-acid and lithium-ion) and in hybridization with supercapacitors. For this purpose, the design, development, integration and testing of a supercapacitor bank connected to an existing RES-based microgrid is carried out. The results of the study demonstrate a smoothed dynamic response of the microgrid, more efficient and flexible power management, greater voltage stability, longer battery bank lifespan, and operational protection of equipment affected by current peaks. Of course, this is achieved if the microgrid control system is capable of optimize the operation of each element that makes up the ESS. The availability of more degrees of freedom in the ESS allows different control strategies to be configured in the microgrid, which, as will be seen, are completely conditioned according to the elements of the ESS that come into play.