Harmonic current reduction control for grid-connected PV generation systems

Integration of renewable energy sources (RES) with significant capacity, including photovoltaic (PV) generation systems, into the grid is expected within ten years. Such RESs bring to the grid not only their benefits but also some technical problems, as increase of harmonic currents. Compliance with the technical requirements for harmonic current is necessary for successful increase of RES capacity. A scheme to reduce harmonic current for grid-connected PV generation systems was developed. This control scheme effectively reduced harmonic current in the grid current of the PV generation system caused by voltage distortions at the grid. Experiments using a prototype of the power conditioning system (PCS) showed its validity. 400-kW PCSs with the control scheme have been installed and have been in service since the end of 2009.