Photovoltaic Power System with Ancillary Service Capability Based on Instantaneous Power

In this paper, a photovoltaic system connected to the grid with the capability of providing ancillary service of harmonic compensation based on the instantaneous power theory is studied. For this, the control strategy uses the inverter, that interfaces the PV with the grid, to operate injecting the power from the PV and additionally functioning as an active power filter. One of the advantages of the proposed strategy is that the compensation is performed without the need of detection of the harmonic components present in the current and a phase locked loop, which reduces the computational effort. Other advantages of this method are a simple algorithm, good dynamic response and a low number of sensors. For implementation the measured grid power is used as control variable. The control is based on the power balance between the grid and the inverter, and is carried out in αβ coordinated system. A perturb and observe (P&O) algorithm is used for maximum power tracking, along with a control algorithm for dc bus voltage. To validate the study, results were obtained in three different scenarios.