Improving IV curve measurement accuracy of high-efficiency PV modules using extrapolation based on a dual load capacitor scanning method

Oražem, Jonas Aleksander (author), Topič, Marko (author), Jankovec, Marko (author)

With continuous progress in photovoltaic (PV) technology, the conversion efficiency of commercial PV modules is steadily increasing well above 20 %, even exceeding 24 %. Such high-efficiency (HE) PV modules typically exhibit long free-carrier lifetimes, resulting in high diffusion capacitances. For routine field testing, technicians rely on fast, affordable and portable IV curve scanners, which typically employ the load capacitor scanning method. When applied to HE PV modules with high internal capacitance, this method frequently leads to IV curve distortion, resulting in a significant underestimation of the measured maximum power point (MPP). In this paper, we propose a novel extrapolation technique that corrects the distortion of the measured IV curve through two consecutive IV scans using two different load capacitors. The extrapolation algorithm uses a dynamic electrical model of the whole system, including the PV module and the measurement setup, to compensate for the effect of the PV module’s capacitance on the acquired IV curve shape. It extracts two free parameters related to series resistance and the lifetime of the minority carriers that give the best match between the two extrapolated IV curves. We validated the method on four different state-of-the-art HE PV modules (HIT, TOPCon, IBC, and PERC), reliably reducing the MPP error from the initial up to 4 % to less than 1 %.

• Language: English
• Keywords: difussion capacitance, dynamic modelling, high-efficiency PV modules, IV curve extrapolation, load capacitor IV scanning method, measurement accuracy
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 214960-214970
• Numbering: Vol. 13
• PID: 20.500.12556/RUL-177847
• UDC: 621.38
• ISSN on article: 2169-3536
• DOI: 10.1109/ACCESS.2025.3645420
• COBISS.SI-ID: 262738179
• Publication date in RUL: 09.01.2026

Record is a part of a journal

• Title: IEEE access
• Publisher: Institute of Electrical and Electronics Engineers
• ISSN: 2169-3536
• COBISS.SI-ID: 519839513

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: difuzijska kapacitivnost, dinamično modeliranje, visokoučinkoviti PV moduli, ekstrapolacija IU krivulje, metoda IU skeniranja z bremenskim kondenzatorjem, merilna negotovost

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0415
• Name: Fotovoltaika in elektronika