Control method for three-phase grid-connected inverter PV system employing unity power factor (UPF) strategy in microgrid

Microgrids (mgs) are developing owing to the rapidly growing distributed power generation systems. The mg controls the flexibility of the network to ensure the requirements of reliability and power quality are satisfied. A typical mg normally consists of dispersed generation resources, which are connected by power electronic inverters, storages, and non-linear loads. This study deals with a compensation control method of a photovoltaic grid-connected inverter using unity power factor (upf) strategy in mg. In this case, the proposed control method can provide output currents without distortion and with the upf. Further, it is able to increase the inverter output current to approximately 19 times of the value obtained conventionally. The proposed control method can be applied to three-phase grid interfaced converters such as dg inverters and can also be easily integrated into the conventional control scheme without installation of extra hardware. A theoretical analysis is presented and the performance of the proposed control method for a grid-connected inverter in a mg is evaluated through simulation results

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