Understanding the partial power processing concept: A case-study of buck-boost dc/dc series regulator

This paper discusses about the partial power processing concept applied to DC/DC converters, which has been presented in the literature as an option to be used on voltage regulators in several applications such as photovoltaic systems. The purpose of this paper is to elucidate the partial power processing concept and demonstrate that, opposing the sense created in the literature, the fact that a converter performs partial active power processing does not necessarily means that their efficiency and/or power density will be higher than that of a standard converter that processes full active power. It is shown that the performance of DC/DC converter depends not only on its active power, but also on nonactive power that flows inside the converter and the nonactive power drained from source and/or supplied to the load. To demonstrate it, the nonactive power is evaluated on a partial active power buck-boost converter and a new approach is proposed to quantify the total power handled by a DC/DC power converter. Experimental results are presented in order to confirm the analysis.