Intelligent Energy Storage System for Standalone PV Systems: Optimizing Battery Performance with Ultra capacitors

Abstract

This paper introduces the concept of a intelligent energy storage system (IESS) due to the limitations of heterogeneous energy storage systems in providing reliable, long-term power to dynamic loads. Dynamic loads, such as induction or DC motors, draw large currents during start-up, leading to accelerated aging of battery storage systems. By integrating an ultra capacitor with battery blocks, the sudden energy demands of these loads can be met, preventing excessive strain on the batteries. The study proposes an experimental approach to explore the advantages of a IESS that combines an ultra capacitor with a battery, storing energy generated from a stand-alone photovoltaic (PV) system. The performance of this hybrid system is tested under three different load conditions, and the results are verified. A prototype setup, including a PV module, converter, control unit, and load, is developed to compare the input and output voltage and current of the inverter, both with and without ultra capacitor batteries. Results show that, battery performance is optimized and the noted reduction  in the drain rate is approximatly 22% with the use of the ultracapacitor. Increasing the ultra capacitor's capacity could further reduce battery drain significantly.