Analysis of the Use of Supercapacitors and Batteries as Energy Storage Elements for Off-Grid Hybrid Photovoltaic Inverters

Using batteries and supercapacitors as hybrid energy storage systems (HESS) is advantageous due to the flexibility between the high energy density of batteries and the high power density of supercapacitors. Additionally, the intermittent generation of renewables, such as photovoltaic systems (PV), offers a promising application for these HESS. This paper proposes an off-grid hybrid photovoltaic converter with Li-Ion batteries and supercapacitors as storage elements. It includes all converters' modeling and controller design. Also, a rule-based management system is described. Simulation results, based on hardware-in-the-loop, were employed to pre-validate the proposed power management. Tests across different scenarios evaluated the advantages of integrating supercapacitors in this application. The outcomes show that supercapacitors serve as an energy buffer for batteries, frequently encountering power fluctuations due to PV generation, potentially extending their lifespan.