High efficiency DC-DC autotransformer forward-flyback converter for DMPPT architectures in solar plants

Distributed Maximum Power Point Tracking (DMPPT) architectures are one of the most promising solutions to overcome the drawbacks associated to mismatching phenomena in photovoltaic (PV) applications. In these PV architectures, there is a DC-DC converter dedicated to perform the Maximum Power Point Tracking (MPPT) for each PV panel. In order to have the greatest flexibility, the converter needs to have the ability of voltage step-up and step-down. Other desired specifications for the converters applied in DMPPT architectures are high efficiency and low cost. This paper proposes a new DCDC converter topology for PV applications. Its operating principle, as well as its static characteristics, is analyzed. Moreover, a theoretical efficiency comparison analysis, between the proposed converter and the Non-Inverting Buck-Boost (NIBB) converter, is carried out for a 100 kW solar plant. Three different scenarios are studied, according to different mismatching conditions. In all the scenarios, the proposed converter provides higher efficiency than the NIBB converter.