Adaptive Super-Twisting Gains for Second-order Sliding-mode Control of Grid-connected Photovoltaic System under Voltage Sags

This study proposes adaptive fuzzy gain scheduling of super-twisting algorithm (AFGS-STA) based second-order sliding-mode control (SOSMC) scheme with a three-phase grid-connected photovoltaic system with unity power factor at different atmospheric conditions. The control of our system is tested under typical irradiation variations and fault grid condition. The maximum power point tracking control (MPPT) is based on adaptive fuzzy logic to control a switch of a boost converter. Adaptive fuzzy logic controllers provide attractive features such as fast response, good performance. We seek the achievement of three main control objectives: (i) the voltage reference must be designed so as to achieve maximum power point tracking (MPPT), (ii) the DC link voltage must be tightly regulated over a wide range voltage-reference variation, (iii) and the power factor correction (PFC) requirement must be satisfactorily realized. Some results and analysis are presented and discussed to prove simplicity and efficiency of the proposed controller. Then, it is formally demonstrated that the proposed controller actually meets the desired control objectives in term of Total Harmonic Distortion (THD) and power quality.