Control of Grid Connected Inverter system for sinusoidal current injection with improved performance

This paper presents a control strategy for a three-phase Grid Connected Inverter (GCI) under abnormal conditions of the grid like voltage sag, line to ground fault and presence of harmonics. This technique intends to overcome the hitches faced by the conventional controller working under abnormal conditions of the grid. The control strategy adopted here counterbalances the distortions in grid voltage by injecting sinusoidal current into the grid. In addition to this, active and reactive power control during the step changes of the load has also been studied. In order to study the dynamic performance of the system, the models are simulated and the results are analyzed. Simulation results exhibits improved performance under grid disturbances and the studied system is modeled and simulated in the MATLAB/Simulink environment.