Performance of differential power-processing submodule DC-DC converters in recovering inter-row shading losses

Large commercial photovoltaic systems suffer a regular and predictable energy loss due to both inter-row shading and reduced diffuse irradiance in tightly spaced arrays. This paper investigates the advantages of replacing bypass diodes with submodule-integrated DC-DC converters (subMICs) to mitigate these losses. Yearly simulations of commercial-scale PV systems were conducted considering two subMIC granularities and a range of row-to-row pitches given either a fixed array size or a fixed land area. Results show subMIC-enhanced systems can recover 35-48% of the total energy loss. In very tightly-spaced arrays, subMICS rated at 100% of maximum substring power can confer a 7% increase in annual energy output while power-limited subMICs rated at 30% or 15% of maximum substring power still provide a 6% or 3-4% increase, respectively.