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This paper studies innovative application of sliding mode control (SMC) for a Hybrid Renewable Energy System (HRES) in grid-connected and autonomous modes of operation. The considered HRES includes a photovoltaic (PV), wind turbine (WT) based on a Permanent Magnet Synchronous Generator (PMSG). The PV generator is coupled to the common DC bus via a DC/DC converter. The latter is controlled by an MPPT algorithm based on the Adaptive Perturbation and Observation Algorithm Method (APOAM) to search the optimum working of this source. A SMC is utilized to manage the PV voltage to achieve the Maximum Power Point (MPP) by altering the obligation duty cycle. The battery interfaced by a bidirectional buck-boost DC/DC converter can be charged or discharged depending on the production situation. On the one hand, the wind turbine conversion chain is equipped with a PMSG and a rectifier controlled to regulate the operating point of the wind turbine to its optimum value. During a Stand-Alone Mode (SAM) operation, the Voltage Source Converter (VSC) was used for controlling the output voltage in terms of amplitude and frequency delivered to the AC load. However, in Grid-Connected Mode (GCM) operation, the VSC was adapted to control the electrical parameters of the grid. To better appreciate the advantages of the proposed SMC approach, we have proposed a series of comparative tests with the conventional PI control in the operating modes GC and SA and under different scenarios. The proposed control strategy has undeniable advantages in terms of control performance and very low total harmonic distortion THD value compared with the conventional PI control. Finally, It is concluded that the proposed approach improves the quality and provides a stable operation of the HRES.

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]