Control Energy and Performance in Hybridized energy storage systems based on Lithium-ion and supercapacitor in isolated DC-Microgrids

Nanogrids and Microgrids use decentralized power systems because they are cheaper, simpler, faster, and smaller. Smart infrastructures need reliable power control and energy management to maintain power exchange and supply voltage. This paper examines a photovoltaic (PV) system with a Lithium-ion (Li-ion) battery and a supercapacitor (SC) in a DC-coupled configuration with a single DC Bus to supply DC loads. The control structure comprises dual-closed loops with low-pass-filtering for the hybridized energy storage system (HESS). The paper assists in selecting bus voltage regulators and battery current trackers. Classical, high-order nonlinear, and optimal quadratic controllers are compared for performance evaluation. HESS control experienced pulsing and random PV outputs. Statistical key performance metrics (KPMs) validated the proposed system. Super-Twisting-Sliding-Mode-Control (STSMC) is effective for DC Bus voltage regulation and recovery, despite its slow transient convergence. Despite higher overshoots, the Linear-Quadratuque Regulator-with-Integral-Action (LQRI) performed well with battery current tracking. Despite slow response and high overshoot, PI was competitive. Finally, LQRI and STSMC controllers perform better when combined.