Solar Photovoltaic Array Fed Unified Power Quality Conditioner System Enabling Alleviation of Asymmetrical Voltage Sag

A modified generalized integrator (GI) is presented for controlling a single stage topology of solar photovoltaic (PV) array tied unified power quality conditioner (SSSPVA-UPQC) system. This control is used to estimate the positive sequence fundamental components of unbalance grid voltages, and it effectively suppresses the DC bias from the input signal as well as mitigate asymmetrical voltages sag/swell. The series active power filter (APF) of the SSSPVA-UPQC system compensates all kinds of voltage related power quality (PQ) issues viz. symmetrical/ asymmetrical grid voltages variations and protects the sensitive loads. The shunt APF of the SSSPVA-UPQC system compensates for PQ issues like imbalanced loads, harmonics, power factor improvement etc. along with providing active power to the system from the solar PV array. The Simulink model for SSSPVA-UPQC system is developed in MATLAB/Simulink, for various PQ issues mitigation such as symmetrical/asymmetrical grid voltages swell, sag, imbalanced loads, solar insolation variation etc. Test results validate the efficiency and effectiveness of the presented control on a laboratory prototype.