Series-Parallel Connection of Low-Voltage Sources for Integration of Galvanically Isolated Energy Storage Systems

Abstract

This work explores the Series-Parallel Connection of a Low Voltage Supercapacitor Module to obtain a Hybrid Energy Storage System for grid support applications. The Hybrid System is formed by the Supercapacitor Module itself, intended to ensure fast performance upon peak power requirements, together with a battery that provides the energy requirements. In the full system, the front end converter and the load interfacing converter share a common DC link. The battery is connected to the DC link by means of a Full-Bridge Current- Source bidirectional DC-DC converter. The Supercapacitor Module is connected to the system using a Series-Parallel Configuration, which overcomes the main problems that arise with the most common topologies found in the literature. The full operation of the system has been demonstrated theoretically and by simulations. A demonstration of such connection is shown experimentally, in a converter operating at reduced power levels, in order to validate the feasibility of the system. Conclusions show how this scheme can be used in Hybrid Storage Systems.