Improved power quality of three-phase grid connected solar energy conversion system under grid voltages distortion and imbalances

Abstract

This paper proposes a control technique for improving power quality of a three-phase grid connected SECS (Solar Energy Conversion System) under grid voltage distortion and imbalances. SECS mainly extracts DC power from solar PV (Photovoltaic) array and converts it into AC power via a voltage source converter (VSC) and supplies it to grid and connected loads. This system functions on an incremental conductance (INC) driven MPPT (Maximum Power Point Tracking) algorithm along with unit vectors estimation via positive sequence voltages extraction and a neural network (NN) based least mean sixth (LM-Sixth) current control technique. The system aims to eliminate power quality issues and provides current conditioning while operating in coherence with a weak grid such as Indian grid which has poor power supply quality and voltages distortion and imbalances. The system provides functions of both SECS as well as shunt active power filter (SAPF) depending on the availability of sunlight. For validation of this system, experimental tests are carried out on a developed laboratory prototype and results are recorded for supporting the same.