Intrinsic-Capacitance-based Differential Power Processing for Photovoltaic Modules

Partial shading reduces energy production and affects the lifetime of the overall PV system. To mitigate the mismatch effects caused by partial shading, several PV cell- or sub-panel-level techniques employing power electronics have been proposed in the literature, where discrete passive components, e.g., inductors and capacitors, are also used. In this paper, a differential power processing (DPP) technique, which utilizes only the intrinsic capacitance of solar cells, is introduced for small-scale PV applications. The developed DPP topology mitigates the mismatch effects by operating all PV cells at or near to their corresponding maximum power points (MPPs) even under mismatch conditions. The analysis of the topology and its comparison with the frequently used series- and series-parallel (SP)-connected techniques, are presented to validate its efficacy and operational capabilities, through simulation results. Moreover, a prototype is built to verify the topology. The experimental results confirm the elimination of multiple power peaks under mismatch along with maintaining the same voltages across the PV panels.