Power Quality Enhancement of Grid-Connected Solar Photovoltaic System Using LCL Filter

This paper provides a detailed analysis of the double stage grid connected solar photo voltaic (GCPV) system with a robust control mechanism and improved power quality. This system employs a dc-dc boost converter which changes variable dc voltage to a steady dc voltage. A power electronic voltage source inverter (VSI) is employed to convert steady dc voltage to the ac voltage. Harmonics can adversely affect the power quality if they are not eliminated in the PV system. So an efficient passive LCL filter is employed at the utility grid to reduce the harmonics. The systematic LCL filter design is presented in this paper. The LCL filter designed in this research reduces the grid voltage THD from 0.59 to 0.08 percent, grid output current THD from 10.71 to 1.17 percent and the inverter current THD is reduced from 10.70 to 4.9 percent. Thus the power quality is enhanced by almost ten times when compared to the system without filter unit.