Harmonic Compensation by Transformer-less Grid-tied PV inverter using Conservative Power Theory

The growing installations of low voltage PV systems on the distribution grid impose additional challenges on the PV inverter. Therefore, it is expected that the PV inverter would be more controllable to provide certain ancillary services with higher efficiency and better reliability. The possibility of using Conservative Power Theory (CPT) in the inverter current control to equip the inverter with multiple functionalities is explored in this paper. Inverter topology suitable for transformer-less grid-PV interface is considered in this work for higher efficiency and lesser cost. Elimination of ground leakage current into the grid is guaranteed due to the structure of the inverter considered. A power level of 200W is considered and the inverter control is modified incorporating CPT to generate suitable current reference. Detailed analysis and simulation results are presented in the paper.