ECN publication
Outdoor characterization of three PV architectures under clear and shaded conditions
Published by: Publication date:
ECN Solar Energy 22-9-2014
ECN report number: Document type:
ECN-M--14-078 Conference Paper
Number of pages: Full text:
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Building Integrated and Building Applied Photovoltaic (BIPV, BAPV) systems often suffer from low performance due to partial shading. New system architectures have been proposed to optimize the energy yield. The common approach of these new architectures is to track the Maximum Power Point (MPP) of every solar module individually. Three independent PV systems were installed in Eindhoven, a reference string inverter system, a power optimizer (PO) system and a micro inverter system. We designed a sophisticated monitoring system that allows for a detailed comparison of the three PV systems. We calculated system and component efficiencies and found a good agreement with data sheets provided by the manufacturers. Additionally, we analyzed the performance ratio for DC and AC of the systems for different weather types based on the clearness index. A pole shading covering 1 to 2% of the total system surface has been used to evaluate system performance under a specific type of partial shading. Module Level Power Electronics (MLPE) are capable of increasing the Performance Ratio (PR) up to 35% under certain partial shading conditions. However, the string inverter system outperformed MLPE under unshaded operation conditions.

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