CONTROL STRATEGY FOR A CURRENT-SOURCE BOOST-BUCK CONVERTER FOR PV SYSTEMS

DANIEL WESTERMAN SPIER; GERMÁN G. OGGIER; SÉRGIO AUGUSTO OLIVEIRA DA SILVA

Congreso; 14th Brazilian Power Electronics Conference (COBEP); 2017

In this paper a single phase two-stage grid-tied photovoltaic (PV) system is presented. The first stage is composed of a DC-DC boost-buck converter, which has current source characteristics for both input and output, while the second stage consists of a DC-AC converter tied to the grid. The mathematical model is obtained and validated for different operating conditions. Using the referred model, the transfer functions can be obtained and are used for designing the controllers. Simulation results of a 3.5 kW PV system validate the control strategy, regardless of the solar irradiation conditions, such that undesirable behaviors due to transitory oscillations of the input current and DC-bus capacitor voltage are avoided. In addition, the results show low total harmonic distortion of the current injected into the grid and unit power factor.