Control strategy of Grid-Connected PV Inverters in Microgrid with Nonlinear Operating Conditions

This paper proposes a current control strategy for a Photovoltaic (PV) system in three-phase three-wire grid-connected microgrids under unbalanced and nonlinear load conditions. The proposed control strategy comprise of a multi-loop control technique to provide balanced output current, multi-resonant harmonic compensator to reduce the Total Harmonic Distortion (THD) and a droop-based control scheme to achieve accurate power sharing. Additionally, the current THDs were reduced from above 17.51% to lower than 3% with the proposed control strategy under nonlinear load conditions. The effectiveness of the proposed control strategy was proven via simulation using MATLAB/Simulink.