Novel non-flat photovoltaic module geometries and implications to power conversion

Emerging photovoltaic (PV) technologies have enabled the creation of intentionally non-flat PV modules for energy generation. Doing so however has significant implications to the power electronics since these cells are not coplanar by design. Non-uniform insolation from cell-to-cell gives rise to non-uniform current density which limits the ability to series-connect these cells without bypass diode or other ways to shunt current, well known in the maximum power tracking literature to limit energy harvest. This paper presents a modeling approach to determine and quantify the variations in generation of energy due to intentionally non-flat PV geometries. This in turn will enable the power electronics circuitry to be optimized to harvest maximum energy from PV pixel elements - clusters of cells with similar operating characteristics and thus able to be interconnected in series/parallel combination. This paper systematically compares different geometries with the same two-dimensional projection “footprint” for energy harvest throughout the day. The results show that for the same footprint a semi-cylindrical surface harvest more energy over a typical day than a flat plate. These results have broad application to a variety of energy scavenging scenarios in which either total energy harvested needs to be maximized or unusual geometries for the PV active surfaces are required, including building-integrated PV. This paper serves as a first step towards analyzing the potential gain in energy harvest the implication the design of the power electronics circuits and control algorithms.

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