Partial Harmonic Current Compensation for Multifunctional Photovoltaic Inverters

Recent works have addressed the ancillary services provided by multifunctional photovoltaic inverters. This concept is based on the addition of extra functions to the conventional photovoltaic systems, such as harmonic current compensation of nonlinear loads and reactive power support. However, it is important to ensure that photovoltaic inverters work below the rated current peak. Therefore, this paper proposes two current dynamic saturation techniques to limit the current peak of multifunctional photovoltaic inverters during harmonic current compensation of nonlinear loads. One technique is based on a closed loop and other on an open loop. With this approach, the photovoltaic inverters are able to perform partial harmonic current compensation, i.e., it will only be allowed to compensate harmonic currents within their maximum current capacity. Mathematical models are developed to determine the parameters of the techniques. Comparisons in simulation and experimental environments show that both techniques provide improvements in the grid power quality at the same time as the inverter rated current capacity is respected.