Practical Strategy for Improving Harmonics and Power Factor Using a Three-Phase Rooftop Photovoltaic Inverter

New strategies are required to mitigate the adverse effects of nonlinear loads on the electric grid. The high cost of devising such strategies often necessitates the use of existing equipment, specifically the power electronic (PE) equipment from grid-tied renewable energy systems. Among these PE equipment options, photovoltaic (PV) inverters have gained attention for power quality improvement purposes since they typically operate for only a few hours a day at their nominal power. Given their extra capacity, PV inverters are a suitable candidate for power quality enhancement. Rooftop PV inverters are commonly used for residential and commercial facilities where local nonlinear loads are distributed. However, the point of common coupling (PCC) is typically far from the inverter, without any communication infrastructure to send information to the inverter. In this study, a low-cost and reliable power line carrier (PLC) communication approach is used to transfer the data of grid current harmonics and reactive power demand through the power line to the PV inverter. Additionally, a comprehensive algorithm is proposed to partially or completely compensate the low-order harmonics and reactive power without exceeding the available inverter capacity. This strategy is validated through both simulation studies using MATLAB-Simulink and experimental tests.