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

The concept of partial power processing was developed to reduce the power processes by converter components to increase efficiency and power density. This paper investigates the behavior of partial power converter (PPC) applied to photovoltaic (PV) systems. This paper uses a series PPC to integrate a PV string into a DC bus. Extracting maximum power from PV string is problematic for PPC at near-zero partiality. At this point, the converter does not change its quadrant if needed, and the controller saturates. This leads to a loss of the maximum power point. This paper introduces a seamless maximum power point tracking method with enhanced performance near zero partiality. The proposed concept is verified through numerical simulations in PSIM.