Estudo comparativo de sistemas fotovoltaicos trifásicos de simples e duplo estágio operando com condicionamento ativo de potência

Abstract

This work presents a comparative study involving four different topologies of three-phase grid-connected photovoltaic systems for single and double stages, which are implemmented in three-phase four-wire electrical systems. Simultaneously, these topologies are designed to operate as shunt active power filter performing the active conditioning, suppressing load harmonic currents and compensating reactive power. The first topology, named in this work PV-FAPP-1E-C, is implemmented using three single phase full-bridge inverters sharing a common DC-bus voltage, thus it involves a single stage of energy conversion. The second, PV-FAPP-2E-C, is implemented in a similar way to the previous topology, but now the DC-DC stage, by a boost converter, is included resulting in a double stage system. The third topology, called PV-FAPP-1E-I, also uses three single-phase full-bridge inverters, but each inverter is connected to an independent DC-bus voltage, so this topology involves a single stage of energy conversion. Finally, the PV-FAPP-2E-I topology presents a double stage, similar to the PV-FAPP-2E-C topology, but each inverter has an independent DC-bus voltage. All topologies employ the independent control strategy meaning that a three-phase four-wire system can be treated as three single-phase systems, so the currents of each phase can be controlled individually. To ensure that photovoltaic systems operate at their maximum power point, the MPPT P&O algorithm is employed, while the reference currents are obtained through the algorithm based on the synchronous reference frame. The performances of the topologies are evaluated through computational simulations. In addition, a comparative analysis among the topologies is presented considering the aspects of performance, yield and cost. Thus, through this analysis, it is possible to determine which of the four topologies is most indicated in terms of cost and applicability.