A Sigmoid Least Mean Fourth based Control Scheme for a Single-Stage Grid-Tied PV System

In a single-stage grid-tied PV system, the Voltage Source Inverter (VSI) performs the task of MPPT along with delivery of high quality power to the grid. However, the presence of non-linear loads gives rise to Power Quality (PQ) issues in the distribution network. Therefore, it is necessary to develop a suitable control scheme for efficient functioning of the VSI. In this work, a Sigmoid Least Mean Fourth (SLMF) based control technique is discussed for a single-stage grid-tied PV system. The sigmoidal based adaptive algorithms embeds the conventional cost function into the sigmoidal framework to obtain improved performance by exploiting the saturation characteristics of the non-linear sigmoid function. The performance of the proposed SLMF based control scheme is simulated in MATLAB/Simulink under dynamic changes in load and environmental conditions and is compared with its conventional counterpart in terms of oscillation in weights and Total Harmonic Distortion (THD) of grid current.