Current Control Strategy for Reactive and Harmonic Compensation with Dynamic Saturation

The main objective of a photovoltaic (PV) inverter is inject the PV power into the grid. However, due to variations in solar irradiance, inverters have a current margin, which can be used in reactive power and harmonics compensation. This possibility, known as multifunctional operation, can be interesting in terms of power factor improvement and reduction of nonlinear loads impact at point of common couple (PCC). This work applies the instantaneous power theory in order to obtain the harmonic and reactive components of the load current. These components are used as references in the inverter control strategy. Simulation results show reduction in the grid distortion, with improvements in the power quality indexes. However, during multifunctional operation, inverters present a current limit that cannot be exceeded. Thus, this work introduces a dynamic saturation scheme for a multifunctional three-phase inverter. This strategy possibilities partial or total reactive and harmonic compensation without injection of low order harmonics.