Two-Port Up/Down DC-DC Converter for Two-Dimensional Maximum Power Point Tracking of Differential Diffusion Charge Redistribution Solar Panel

Maximum power point tracking (MPPT) is one of the main challenges in solar photovoltaic systems, especially under partial shading conditions in which solar panels do not receive uniform solar irradiance. The diffusion charge redistribution (DCR) technique is an approach which uses the intrinsic diffusion capacitance of solar cells together with semiconductor switches to balance the voltage among the cells. Using this technique enables us to apply MPPT with cell-level granularity using a single module-level converter. The differential DCR (dDCR) structure is a modification to the conventional DCR structure to enable differential power processing, which leads to low insertion loss because only the mismatch power is processed by every switch. The dDCR architecture has two outputs and needs a two-port converter. This paper examines a two-port up/down dc-dc converter which is capable of doing two-dimensional MPPT of dDCR solar panels. An emulator is also presented to replicate the averaged behavior of dDCR solar panels for evaluating the converter. Prototypes of the converter and the emulator were built and a coordinate ascent method was used as the two-dimensional MPPT algorithm; the capability of the converter to do two-dimensional MPPT of dDCR solar panels was demonstrated.