Optimal Sizing of Battery-Ultracapacitor Hybrid Energy Storage Device in a Standalone Photovoltaic System

In standalone renewable energy systems, it is most essential to deploy energy storage devices to compensate for the intermittent and random output power generation. Since the last few years, hybrid energy storage devices (HESDs) composed of two or more energy storage technologies are being adopted in these power systems. In this paper, a standalone photovoltaic system with battery-ultracapacitor HESD has been considered for case study. A suitable problem formulation with the necessary objective function and constraints has been developed for the system. A variant of one of the popular meta-heuristic techniques, particle swarm optimization (PSO) has been used to address the optimization problem. The simulation results along with the convergence characteristics of the algorithm have been presented. It is observed that the proposed technique can produce comparable results.