A robust super twisting sliding mode controller for optimal grid synchronization of photovoltaic system

The grid connected photovoltaic system (GCPVS) faces several difficulties due to their intermittent natures such as solar irradiance variations, grid voltage distortions and unbalanced load distributions. These complications interrupt the functioning of power system to attain maximum probable power output. Therefore, to address these problems, this article proposes a robust super twisting sliding mode-incremental conductance-instantaneous power theory (STSM-IC-IPT) based control mechanism for 3-phase GCPVS. The super twisting sliding mode (STSM) controller is introduced to reduce the difference between actual inverter current and reference inverter current of GCPVS when it is subject to various uncertainties and nonlinearities. The modified incremental conductance (IC) maximizes the solar power output generated from the photovoltaic panels. In addition, the instantaneous power theory (IPT) is applied to enhance the active power and reactive power transmission between grid-connected PV systems. The proposed STSM-IC-IPT method is examined under two different experimental procedures namely simulation setup and experimental setup. The efficiency of the proposed STSM-IC-IPT control mechanism is evaluated by comparing its performance with existing ASMC-IC-IPT control scheme. The experimental results illustrate that the proposed STSM-IC-IPT control mechanism achieves superior performance efficiency under dynamic loading, steady and transient conditions.