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This paper presents a new robust super-twisting sliding mode control (STSMC) strategy for a standalone hybrid renewable energy system (HRES). A voltage source inverter (VSI) is used to connect these sources to alternative current (AC) loads at constant voltage and frequency. The effectiveness of the proposed control strategy is evaluated and tested under different scenarios of climate and load conditions, such as variations in wind speed, temperature, and irradiation, irregularity of the load power demand, unbalanced load, and nonlinear load. The performance of the STSMC controller is finally compared with the classical proportional-integral (PI) controller and with the first-order sliding mode controller (FOSMC) using a Matlab/Simulink environment. The simulation results show that the robustness and the stability of the whole system are widely improved using STSMC rather than other classical approaches. [ABSTRACT FROM AUTHOR]

This study presents a design and an implementation of a robust Maximum Power Point Tracking (MPPT) for a stand-alone photovoltaic (PV) system with battery storage. A new control scheme is applied for the boost converter based on the combination of the adaptive perturb and observe fuzzy logic controller (P&O-FLC) MPPT technique and the backstepping sliding mode control (BS-SMC) approach. The MPPT controller design was used to accurately track the PV operating point to its maximum power point (MPP) under changing climatic conditions. The presented MPPT based on the P&O-FLC technique generates the reference PV voltage and then a cascade control loop type, based on the BS-SMC approach is used. The aims of this approach are applied to regulate the inductor current and then the PV voltage to its reference values. In order to reduce system costs and complexity, a high gain observer (HGO) was designed, based on the model of the PV system, to estimate online the real value of the boost converter's inductor current. The performance and the robustness of the BS-SMC approach are evaluated using a comparative simulation with a conventional proportional integral (PI) controller implemented in the MATLAB/Simulink environment. The obtained results demonstrate that the proposed approach not only provides a near-perfect tracking performance (dynamic response, overshoot, steady-state error), but also offers greater robustness and stability than the conventional PI controller. Experimental results fitted with dSPACE software reveal that the PV module could reach the MPP and achieve the performance and robustness of the designed BS-SMC MPPT controller. [ABSTRACT FROM AUTHOR]