Reliable Power Exchange in Energy Storage Systems using Multiport Bidirectional SEPIC-Luo Converter with PI Control Strategy

The main objective of this study is to develop a high-efficiency bidirectional DC-DC converter capable of ensuring reliable power exchange within Energy Storage Systems (ESS) and improving the lifespan of series-connected batteries through precise management of charging and discharging processes. The proposed work aims to achieve stable voltage-current regulation and effective battery protection under varying load and supply conditions. To accomplish these objectives, a Multiport Bidirectional Single Ended Primary Inductor Converter (SEPIC)-Luo Converter (MB-SLC) is designed, which operate efficiently in both boost and buck modes. In addition, a cascaded Proportional-Integral (PI) control architecture is implemented for regulating the voltage, the current, and the State of Charge (SOC) with high precision. The proposed converter and control performance are validated through MATLAB/Simulink simulations conducted under diverse operating scenarios. The results demonstrate smooth voltage and current profiles, rapid transient response, accurate SOC tracking, reduced ripple levels, and high conversion efficiency of 96% in step-up mode and 95.7% in step-down mode. These outcomes confirm the ability of the proposed system to maintain reliable power exchange while minimizing stress on the battery. The significance of the obtained results lies in their contribution to enhancing battery protection, extending operational lifespan, and providing a robust solution for renewable energy-integrated ESS. By combining advanced converter topology with cascaded PI control, the study offers a practical and scalable approach to improving energy storage reliability, efficiency, and sustainability.