Implementation of demodulation-SOGI control algorithm for improving the power quality

This study presents a robust estimation control technique of single stage grid connected solar PV (Photovoltaic) energy conversion system with distribution static synchronous compensator (DSTATCOM) capabilities. The estimated perturb and observe (EPO) based maximum power point tracking (MPPT) algorithm is used to obtain crest power from solar PV array under varying atmospheric conditions. The proposed topology is connected to the grid and also provides the power factor correction and harmonics elimination. This control algorithm contains of a DF (Differential Filter) and QSG-SOGI (Quadrature Signal generator-Second Order generalized Integrator) and it is used to extract the fundamental component of loads current for generating the reference currents. In this control algorithm, a frequency domain analysis is used for DF to extract the fundamental frequency from the instantaneous phase angle using the demodulation method. The main advantage of this control is no interdependent loop, frequency calculation, the tuning process is easy because of using demodulation method. To validate the control algorithm, tests are performed on a developed prototype in the laboratory for various operating conditions.