Conversor estático para geração fotovoltaica com rastreamento de máxima potência

Abstract

A power extraction system for photovoltaic panels, that is, a DC-DC converter operating together with the Maximum Power Point Tracking (MPPT) algorithm, is studied in this work. The characteristic curve of a photovoltaic module presents a single Maximum Power Point (MPP), which varies according the climatic conditions of operation. When a load is connected to the panel output, an operating point is established, but only under specific conditions this point will coincide with the MPP. Through tracking systems it is possible to identify and induce the panel to operate in MPP, varying the impedance of the converter, which occurs by controlling the output voltage or current of the panel. To achieve this goal, the operating characteristics of photovoltaic panels are studied and modeled, to identify how the climatic variables interfere in energy generation. Subsequently, the boost converter is analyzed and designed using the mean state space modeling, thus obtaining steady-state operation characteristics and transfer functions. Then, auxiliary circuits for activation, supply, signal conditioning and protection are designed. Finally, the simulations of the system in open and closed loop and in MPPT operation are presented. The tests to verify the system operation were carried out under controlled conditions, through the emulation of the photovoltaic panel. The implemented system was able to operate under varied climatic conditions, with the percentages of extracted power consistent with the algorithm used.