The symmetrical differential Buck-Boost DC-DC converter with partial power processing applied to photovoltaic systems

This paper presents the symmetric differential Buck-Boost converter, obtained from the differential connection between two Buck-Boost converters. The topology is characterized by presenting low-voltage ripple, partial power processing, ability to provide intermediate voltage gains (1 < M < 10) and design simplicity. In this configuration, the output voltage is composed of the sum of the input voltage and the output voltages of both converters differentially connected. The topology description along with its main equations and waveforms in continuous conduction mode with phase-shift modulation are presented in this paper. Moreover, a mathematical analysis that demonstrates its capability of performing with partial power processing and a comparative analysis with similar topologies are also presented. In addition, experimental results extracted from a prototype are presented and discussed. Because the proposed converter is applied to photovoltaic energy processing, it is validated in open loop and as maximum power point tracker, in which the obtained CEC efficiency is 97.8%.