Comparison of PR controller and damped PR controller for grid current control of LCL filter based grid-tied inverter under frequency variation and grid distortion

Voltage Source Inverters (VSIs) are essential component for integration of renewable energy sources into utility grid or microgrid. Most of the utility grid regulation standards demand high quality sinusoidal current regulation by these inverters with renewable sources, which necessitates the use of LCL filters at the output of VSIs. Different load conditions and other factors influence grid conditions, such as voltage profile, harmonic distortion and frequency variation. The scope of this paper include comparison of effects on grid current of LCL filter based inverter while using PR controller and damped PR controller under distorted grid voltage and frequency variation conditions. The effects are analyzed through simulation studies in MATLAB/PLECS and real time simulation studies are carried out in Typhoon HIL environment.