Flexible harmonic current compensation strategy applied in single and three-phase photovoltaic inverters

Non-linear loads connected to power system have increased considerably in the recent decades. Traditional generation based on hydro and thermal power plants cannot mitigate harmonic currents. However, due to the increased connection of photovoltaic into the power system, its power electronic converter can be used to perform ancillary services such as harmonic current compensation. This work presents a dynamic method based on the Second Order Generalized Integrator coupled with a phase locked loop structure to detect and compensate the most predominant harmonic current components from the power system. It is also presented an extension to detect multiple harmonics, according to the amplitude. Technical issues related with the harmonic current compensation strategy, and its implementation for both single and three-phase PV inverters are explored to demonstrate the functionality and efficiency of the method. The results show the harmonic current compensation being compensated by a PV inverter. Finally, a losses analysis were performed in the LCL filter. The magnetic and damping resistor losses are more impacted due to high harmonic current compensation.