Conventional string inverters (SINV) can outperform module-level power electronics (MLPE) in partially shaded PV generators, according to the latest insights. IEA-PVPS report.
The technical report, “Performance of partially shaded PV generators powered by optimized power electronics 2024”, describes the current challenges of partial shading in PV systems and evaluates the latest technological innovation for optimizing energy performance under such conditions.
IEA-PVPS said that inhomogeneous shading on PV generators leads to disproportionately high losses. It was explained that a combination of optimized module placement, the use of shade-tolerant modules and optimized power electronics can help maximize the performance of partially shaded installations.
It said the use of shade-tolerant PV modules, which typically have four or more bypass diodes instead of three, is necessary. A greater number of bypass diodes per module makes it possible to selectively bypass less efficient parts of the modules, leading to an increase in module yield. It added that the first manufacturers are starting to bring such modules to the market.
The report stated that SINV produces the highest yields under weak to medium shade, such as light obstructions from a chimney or module. This applies when shade does not cover more than one-tenth of a module in the string at any one time during the six hours around noon.
IEA-PVPS said commercial PV software tools most improve theirs Component efficiency data and calculations for the operating points of each optimizer based on each solar cell within a module, so PV planners can provide customers with the most optimal PV design under partial shade conditions.
The report also highlighted ongoing research aimed at reducing PV shadow effects, including developing advanced power electronics for individual solar cells and optimizing single-axis mechanical tracking systems for large-scale PV installations on uneven terrain.
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