What you are trying to do sounds straightforward, but I don't think it is quite as easy as that. How do you convert an outdoors IV curve to STC if the outdoors condition isn't known accurately? How do you know the exact spectral power density of your outdoor sunlight? You seem to be in  Algeria, so you will be getting good sunlight, but how do you know the air mass exactly? Finally why do you want to convert the readings to STC? If you want to compare different PV arrays, just put them all next to each other and over the hours 11 am to 1 pm run IV plots on each in turn. That will give a good and useful comparison.

Thanks for your prompt response, I have five different PV module technologies in outdoor with I-V curve measurement and at noon hour I select the I-V curve for each PV module in clear sky day and each I-V curve is translated to STC and maximum power is extracted and divided to maximum power provided by manufacturer. I do this to show which technology perform more better in the location where the modules are installed.

Please find the attached figure below and give me your opinion and if it is possible an advice.

Thanks

Dear Sir;

Why do you need to translate I-V curves to STC ?. I mean why don't you compare these curves using different outdoor condictions which are the same for all PV Pannels ?.

Mr. Benslimane Tarak

Dear Tarak

Take a look at the PDF document attached with my answer to Sir Tony Maine, may be you will understand what I mean.

The I-V curves are from different technologies and are obtained for different outdoor conditions, I need to translate them to STC to see the seasonal trends of each technology.

Thanks

Theoretically yes, you can measure outdoor and transfer to STC with the formula from IEC60891. But it fits crystalline silicon cells best, you might need some more correction for other technologies.

However, practically  it is not easy to compare, because the measurement outdoor has huge uncertainty. First the temperature and irradiance  measurement has high uncertainty, and you can measure the ambient temperature, but you don't know exactly the cell temperature which you need for converting to STC.

And you also need cell parameters like temperature coefficient, but you don't know the exact value of each cell and the whole module, the parameters provided by the manufacturer is only for reference, sometimes far away from real value.

So it is difficult to compare power measured outdoor, but you can try to compare by the accumulated energy accumulation. If all the modules are at the same site, they will have the same irradiation and ambient temperature, and you can use electricity meter to measure the total energy generated during a certain time. This will help you compare the difference between technologies.

I am really looking forward to the comparison result in long term, especially the comparison between mono and multi cells which I can not find in the existing papers.

Dear Jay Lin ·

Thank you for your answer and advice.

Dear Nouar Aoun

Thanks for your advice

Jay Lin: "I am really looking forward to the comparison result in long term, especially the comparison between mono and multi cells which I can not find in the existing papers."

Such a comparison was/is made by the German PV magazine PHOTON. They run a laboratory for this and many other tasks. Unfortunately, their web pages are being reworked presently, and the new version isn't online yet, so one can only find some pages in the web archive (for example http://web.archive.org/web/20160109184211/http://www.photon.info/photon_laboratory_en.photon).

Dear Jay Lin

Please; find the following link to our paper about a comparison between five different PV modules in outdoor conditions :

Article Performance assessment of five different photovoltaic module...