Super-twisting Sliding Mode Control for a Multifunctional Double Stage Grid-connected Photovoltaic System

Abstract

This paper proposes a super-twisting sliding mode control for a multifunctional system that includes a Photovoltaic (PV) system connected to the grid through the Active Power Filter (APF). The latter is implemented to improve the power quality in the grid side, and injecting the provided photovoltaic power into the grid. Sliding mode control is known as a pow- erful control with good performance in transient and steady-state conditions. In this work, a Super-Twisting Sliding Mode Control (ST-SMC) is applied to extract the maximum power from the PV source, correspond- ing to the irradiation level, as well as to the three- phase inverter-based-APF power control. For the sys- tem to inject the generated power from the PV source into the grid with respect to the international standards, fulfilling the active power filtering, synchronous refer- ence frame theory is used to generate the appropriate reference signals for harmonic and reactive power com- pensation. To test the multi-functionality of the sys- tem (PV-APF), this one is connected to a grid sup- plying nonlinear loads that absorb non-sinusoidal cur- rents. Through the simulation results, it has suc- cessfully achieved the multi-functionality of the pro- posed system under steady-state and dynamic condi- tions. The results also show the effectiveness and mod- eration of the proposed super-twisting sliding mode con- trol. Furthermore, a comparative study has been es- tablished over the conventional PI controller, showing the clear superiority of the proposed control in every aspect.