Variable Step-size LMS Filter for Power Quality Enhancement using Grid Supportive Photovoltaic System

The emergence of semiconductor technology and applications related to switching devices have caused many problems related to power quality (PQ) such as harmonics, voltage fluctuations and power oscillations. In order to overcome these issues, inverter is connected at distribution end alongside photovoltaic source at DC-bus to enhance the PQ and active power submission to utility grid. The accuracy and performance of grid connected PV systems are depending on performance of control structure. This paper presents, an adaptive algorithm based on variable step size least mean square (VSS-LMS) has been proposed for controlling the distributed static compensator (DSTATCOM). In this structure a new parameter according to the error-based autocorrelation function has been introduced to vary the step size for weight updating process. This adjustment not only maintains the immunity against the external disturbances but also controls the misadjustment and convergence time independently. In the overall control structure, the independent weight of the three phases distorted current have been estimated for further generation of reference current signals. The proposed control methodology is simulated in MATLAB/Simulink and tested using real-time simulator. The simulation results under various practical scenarios such as unbalanced loading, sudden loading, harmonic penetration etc. presents the superior performance of proposed methodology.