Projeto e implementação de um conversor elevador de tensão alimentado em corrente com acoplamento magnético aplicado em sistemas fotovoltaicos

Abstract

This paper proposes the design of an Active-Clamped Current-Fed Half- Bridge converter (ACCFHB) with magnetic-coupling, operating in open loop for photovoltaic applications with high voltage gain. Initially the characteristics of the boost converter and its deviations are shown, consequently the interleaved boost converter is presented, pointing out its advantages and disadvantages. Next, the analysis of the Current-Fed Half-Bridge Converter (CFHB) is made, and its physical implementation is realized, with the intent to verify the effects caused by the leakage inductance of the transformer over the circuit functioning. The main effects are the voltage spikes over the semiconductor switches, that can surpass the supported limits causing permanent damage. In front of that, snubber auxiliary circuits are inserted in order to minimize theese effects. Lastly, the power stages of the ACCFHB converter are shown in order to realize its design, and with that, the prototype was build in order to obtain the experimental results that are compared with the theory. The main results obtained can be cited as: high voltage gain, physical size reduction of the converter by means of coupled inductors, an efficiency increase, reduction of the effects caused by the leakage inductance, and a clamped voltage over the switches.