Improved Maximum Power Point Tracking Algorithm for Step-Up/Down Partial Power Converters Operating Around Zero Partiality

This article presents a novel problem statement for photovoltaic (PV)-based partial power converter (PPC) around zero partiality or unity PPC gain. The idea of PPC is developed to reduce the power processed by the converter so that the overall efficiency can be increased. With efficient maximum power point tracking (MPPT) and PPC, the overall system efficiency can be enhanced significantly. However, the limited PPC controllability near zero partiality results in a significant reduction in the MPPT efficiency and overall system efficiency. This happens when the dc bus voltage lies between the maximum power voltage and open circuit voltage, and PPC operates around zero partiality. This proposes an improved MPPT algorithm that overcomes poor controllability near zero partiality and increases the overall system efficiency. The addressed problem and proposed solution are verified using an experimental porotype operating at 1.7 to 2.25 kW power.