Enhanced Control Approach for PV Hybrid Energy Storage System With Supercapacitors Using Fuzzy MPPT Technique and Optimally Tuned Fractional Controllers

Abstract

Hybrid energy storage systems (HESS) comprising supercapacitors and batteries in photovoltaic (PV) applications ensure overall system performance by compensating for their mutual drawbacks. However, the reliability of the PV-based HESS against frequent load variation and irregular solar irradiance demands a robust power management scheme (PMS) and associated control strategies. This paper presents an enhanced DC voltage stabilization control strategy for robust PMS for the PV-based HESS. The proposed control approach ensures stable DC link voltage regulation, improving the overall efficiency and thus reliability of the overall system. A comprehensive analysis of the system dynamics and control objectives is conducted under different operating conditions, leading to the development of a combined tilt-integral (TI) and fractional proportional-integral (FOPI)-based controller. The controller parameters are estimated using the particle swarm optimization (PSO) technique and a gradient-free Nelder–Mead simplex search (NMSS) algorithm for optimizing the time-domain parameters. Thereafter, the dynamic performance of the presented PMS is investigated through extensive experimentation analyzed in terms of various parameters. The investigation suggests that the proposed control scheme outperforms the conventional control approach by a significant margin of 60.81% and 40.42% in steady-state error and peak overshoot, respectively. Also, the state of charge (SOC) consumption of the battery is reduced by 8.46%, thus increasing the overall lifespan of the energy storage system. Therefore, the proposed control strategy offers a viable solution for ensuring stable and efficient operation of PV-based energy storage systems, contributing to the advancement of renewable energy integration and grid resilience.