Anna_Sweden Posted September 16, 2016 Share Posted September 16, 2016 I am writing a guide about shadings on PV-systems, hence I am really interested in the “Module layout” with the possibility to view I/V-curves.I have created a string with six 200 W modules, 60 cells, 3 bypass-diodes, connected in series to an inverter with one MPPT. I have also created a really near shading which, most of the day, is almost covering the lowest row in three of the modules. This should result in two MPPs: one with the three shaded modules included and one without them when the bypass-diodes are taking over. This is not the case. Instead I get various results during the day, even though the shadow is almost completely constant, for example:11.45: full production, 1 MPP.12.00: 2 MPPs - one with a really low current and one with approximatly half the full voltage. 12.15: full production, 1 MPP.I think the result at 12 is the correct one, the others are not. Why is this the case? Can I do anything about it?Anna Link to comment Share on other sites More sharing options...
André Mermoud Posted September 18, 2016 Share Posted September 18, 2016 I don't see well your configuration, the shading objects and the disposition of the modules. I find rather strange that you have a shade at 12:00 and no shade at 11:45 or 12:15: please have a look on the shade drawings. Perhaps you have a rather thin shading object, and the shades don't affect the corners of the submodules, which are taken as reference for the shading evaluation in the Module Layout part. Link to comment Share on other sites More sharing options...
Anna_Sweden Posted September 19, 2016 Author Share Posted September 19, 2016 Thanks for your quick reply! I did not realize I can attach images, but maybe that will make it easier to understand.11.45:11.45 Shadow 12.00: Link to comment Share on other sites More sharing options...
Anna_Sweden Posted September 19, 2016 Author Share Posted September 19, 2016 12.00: 12.15: Link to comment Share on other sites More sharing options...
Anna_Sweden Posted September 19, 2016 Author Share Posted September 19, 2016 So you see the shadow is almost constant but the IV-curve is varying a lot. This is continuing all day, not just around noon.Do you know why?Is there anywhere I can read about the IV-curve algorithm to understand it better? I am really curious about your sentence "the shades don't affect the corners of the submodules, which are taken as reference for the shading evaluation in the Module Layout part".Anna Link to comment Share on other sites More sharing options...
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