Integral backstepping-ILC controller for suppressing circulating currents in parallel-connected photovoltaic inverters

In big solar plants where the use of a single inverter is neither economically or technically feasible, parallel linked photovoltaic inverters are necessary. For parallel-connected operation, the most significant issue is that even a slight variation in the output voltages of particular in-verters results flow of circulating currents. A high level of circulation current causes inverter power losses to increase, which lowers the system's overall performance by decreasing its effi-ciency. In this paper, a novel simple and effective controller for parallel-connected inverters is proposed to ovoid the circulating currents among the inverters. Convergence efficiency and low computational cost of the suggested controller based on integral backstepping method are the primary motivations of this work. The simulation and experimental findings show that the sug-gested control system achieves the required power quality and reduces circulation current under various loading situations.