Current improvement of a grid-connected photovoltaic system under unbalanced voltage conditions

This paper discusses the performance of a large-scale grid-connected photovoltaic system (GCPS) under unbalanced voltage sag conditions in the grid. By applying the droop control to address the low-voltage-ride-through (LVRT) capability, the output currents are no longer sinusoidal due to the oscillations produced in the current references. To deal with this problem a moving average filter (MAF) technique is proposed. Beside this application, there are other advantages of applying the MAF which are described in this paper. Selected simulation results using MATLAB/Simulink for a 1-MVA GCPS confirm the effectiveness of the proposed method.