A new DC-DC buck-boost modified series forward converter for photovoltaic applications

In order to overcome the solar energy harvesting problem caused by photovoltaic (PV) panel mismatches, Distributed Maximum Power Point Tracking (DMPPT) architectures can be found in the literature. In these PV architectures, there is a DC-DC converter per PV panel, which has the function of operating the PV panel at its maximum power point (MPP). Other required specifications for the converters applied in DMPPT architectures are high efficiency, low cost and the capability to reduce and boost the output voltage regarding the input one. For high conversion efficiency and low cost, series connection converters have been presented in previous research. This kind of topologies improves the system efficiency due to a part of the power is directly transferred from the source to the load. However the solutions found in the literature are only able to boost the output voltage with regards to the input voltage. This paper proposes a new DC-DC buck-boost series connected converter. Its operating principle as well as its static characteristics are analyzed and validated through simulation results. Finally, a theoretical efficiency comparison analysis, between the proposed converter and the Non-Inverting Buck-Boost (NIBB) converter, is carried out in three different scenarios of study. In all the scenarios, the proposed converter provides higher efficiency than the NIBB converter.