Comparative Study on Buck and Buck-Boost DC-DC Converters for MPP Tracking for Photovoltaic Power Systems

This research work addresses a comparative examination of the two basic non-isolated DC-DC converters that could be interfaced effectively for maximum power point tracking (MPPT) in photovoltaic (PV) systems via tracking algorithm of controlling the duty ratio of these converters. Examination of two famous DC-DC convertor topologies i.e. buck, and buck-boost converters has been performed here to scrutinize the behavior of converter behavior relating to changing atmospheric attributes, sequentially the deviation in the duty ratio (due to MPPT), and tracking efficiency. With the variant in the atmospheric conditions, the working value of resistance at the maximum power point (Rmpp) varies. In order to efficiently operate the system at the maximum power point, the MPPT algorithm must make the system work near to the value of Rmpp for the intermittent atmospheric pattern of varying insolation and temperature. The effectiveness of the MPPT algorithm can be scaled by this very obligation. The simulation study verifies that, although buck, and buck-boost converters are implemented as power converters for MPPT control, they are don't equally efficient. The consequence of diverse loads having values different to Rmpp on converter-side output is analyzed for the two important topologies, and it is inferred that the buck-boost converter topology most efficiently tracks the maximum power point (MPP) in case of varying temperature, insolation, and loading effect.