Grid connected photovoltaic topologies with current harmonic compensation

The aim of this paper is to discuss new alternatives for three-phase grid connected photovoltaic systems featuring harmonic compensation capability. The conventional and other five different topologies are presented and explained emphasizing the advantages and disadvantages in a scenario where current harmonic compensation is required. The topologies are based in the parallel operation of two grid-connected inverters. Each inverter is controlled in a different way to enhance the whole system dynamic providing a wide-band compensation. In addition, they are coupled in a combined topology in which one inverter is connected in a feedback loop and the other in a feedforward loop for harmonic compensation. Based on this characteristics, possible parallel operation situations of two inverters are investigated. Simulation results have been obtained for each topology under scrutiny to validate the theoretical considerations.