Synergetic simplified super-twisting algorithm control for stability enhancement of PV/BESS-based DC microgrid

To address the challenges of global warming and the greenhouse effect, extensive research has been dedicated to microgrids (MGs) powered by renewable energy sources (RESs). This paper presents an innovative control mechanism, the synergetic simplified super-twisting algorithm (SSSTA), designed specifically for a DC-MG incorporating a battery energy storage system (BESS), a solar photovoltaic (PV) unit, and DC loads. The PV system connects to a shared DC bus via a unidirectional DC-DC boost converter, optimized for maximum power point tracking from the PV generator. At the same time, the BESS is linked using a bidirectional DC-DC buck-boost converter to the same bus, aimed at maintaining supply-demand balance within the DC-MG through charging and discharging. The SSSTA is designed to regulate each power control unit in the MG. It ensures the desired voltage level at the common DC bus while tailoring energy allocation to meet load requirements. The study shows that SSSTA improves the performance and stability of DC-MG systems incorporating solar PV and batteries. By implementing SSSTA, the stability of the MG system is sustained even under varying load conditions, thereby minimizing the impact of disturbances such as fluctuations in load demand and solar irradiation. As a result, implementing this control strategy enhances the reliability and efficiency of MGs integrated with RESs, promoting broader adoption. Furthermore, to offer a clearer understanding of the proposed control approach, the results of the proportional-integral control are also presented. Simulation experiments in MATLAB confirm the effectiveness of the designed control mechanism.