Implementation of Passive Damping Technique in LCL Filter for Three-Phase Grid Connected Inverter

In current scenario, conventional non-renewable sources of energy like coal, uranium, diesel etc. are depleting day by day because of their limited availability in nature. And our demand for electricity is increasing year by year. Therefore, there is need to shift our usage at renewable sources of energy that can meet our increasing load demand and are environmentally friendly. Three phase grid connected inverter is used as an interface between DG sources like solar and grid. Filter acts as interfacing element between them. Design of filter is crucial because stability of power system largely depends on it. LCL filter being a third order filter provides better attenuation of inverter switching harmonics than L and LC filter. LCL filter is having many advantages but there is a possibility of resonance of LCL filter with the grid. This may cause stability problems in power system. Passive damping techniques is proposed in this paper to reduce resonance peak at resonant frequency. Simulations results are shown to verify the performance of passive damping technique used.