This folder contains original measurement data described and available in "K. Lappalainen, H. Kalliojärvi, M. Talvi and M. Piliougine. (2026). Photovoltaic module current–voltage curve data from OptimalPV project. Zenodo. https://doi.org/10.5281/zenodo.20472706.".
The data is licensed under CC Attribution 4.0 International.

The datasets of a NAPS NP190GK PV module are from the Tampere University Photovoltaic Power Research Plant located in Tampere, Finland. Current–voltage curves were measured once a second by a tracer where parallel-connected IGBTs act as a variable load. Each curve contains 4000 pairs of current and voltage values. The current and voltage values were measured by a Tektronix TCP312A current probe with a Tektronix TCPA300 current probe ampliﬁer and a LeCroy AP031 differential voltage probe, respectively. Irradiance was measured with a Kipp & Zonen SP Lite2 pyranometer mounted at the same 157° azimuth angle from north to east and 45° tilt angle as the PV module. Back-sheet temperature of the PV module was measured by a Pt100 temperature sensor attached to the back-sheet of the PV module. More information about the measurement system is provided in the following article:
-D. Torres Lobera, A. Mäki, J. Huusari, K. Lappalainen, T. Suntio and S. Valkealahti. Operation of TUT solar PV power station research plant under partial shading caused by snow and buildings. International Journal of Photoenergy 2013 (2013) 837310. DOI:10.1155/2013/837310.

The datasets of an ISOFOTON I-53 PV module, an ISOFOTON ISF-145 PV module and a Kyocera KD140GH-2PU PV module are from the University of Malaga, Spain. Irradiance was measured with a Kipp & Zonen CMP2 pyranometer mounted at the same azimuth and tilt angle as the PV module. Back-sheet temperature of the PV module was measured by a Pt100 temperature sensor attached to the back-sheet of the PV module. More information about the measurement system is provided in the following article:
-M. Piliougine, J. Carretero, L. Mora-Lopez and M. Sidrach-de Cardona. Experimental system for current–voltage curve measurement of photovoltaic modules under outdoor conditions. Progress in Photovoltaics: Research and Applications 19 (2011) 591–602. DOI:10.1002/pip.1073.

Each dataset is presented as a separate file, the name of the file indicating the PV module, the date of the measurement, the number of curves measured and, if applicable, the size of an additional series resistance.
The datasets are as follows:
-ISOFOTON_I-53_2017-06-29_90curves: This file contains 90 current–voltage curves of an ISOFOTON I-53 monocrystalline silicon PV module measured on 29.6.2017. Time intervals between consecutive measurements were from 6 to 13 s and measured irradiance was from 989 to 996 W/m^2.
-ISOFOTON_ISF-145_2014-06-11_20curves: This file contains 20 current–voltage curves of an ISOFOTON ISF-145 monocrystalline silicon PV module measured on 11.6.2014. Time intervals between consecutive measurements were from 8 to 10 s and measured irradiance was from 1018 to 1026 W/m^2.
-ISOFOTON_ISF-145_2014-06-14_150curves: This file contains 150 current–voltage curves of an ISOFOTON ISF-145 monocrystalline silicon PV module measured on 14.6.2014. Time intervals between consecutive measurements were from 8 to 11 s and measured irradiance was from 844 to 902 W/m^2.
-KYOCERA_KD140GH-2PU_2015-02-06_100curves: This file contains 100 current–voltage curves of a Kyocera KD140GH-2PU polycrystalline silicon PV module measured on 6.2.2015. Time intervals between consecutive measurements were from 11 to 14 s and measured irradiance was from 861 to 916 W/m^2.
-NAPS_NP190GK_2023-08-09_100curves_022Ohm: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 9.8.2023 with an additional series resistance of 0.22 Ohm. The curves are not consecutive. Measured irradiance was from 800 to 1000 W/m^2.
-NAPS_NP190GK_2023-08-10_100curves_022Ohm: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 10.8.2023 with an additional series resistance of 0.22 Ohm. The curves are not consecutive. Measured irradiance was from 900 to 999 W/m^2.
-NAPS_NP190GK_2023-08-14_100curves_047Ohm: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 14.8.2023 with an additional series resistance of 0.47 Ohm. The curves are not consecutive. Measured irradiance was from 900 to 1000 W/m^2.
-NAPS_NP190GK_2023-08-16_100curves_069Ohm: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 16.8.2023 with an additional series resistance of 0.69 Ohm. The curves are not consecutive. Measured irradiance was from 901 to 995 W/m^2.
-NAPS_NP190GK_2023-08-23_100curves_147Ohm: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 23.8.2023 with an additional series resistance of 1.47 Ohm. The curves are not consecutive. Measured irradiance was from 902 to 999 W/m^2.
-NAPS_NP190GK_2023-08-26_100curves: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 26.8.2023. The curves are not consecutive. Measured irradiance was from 922 to 991 W/m^2.
-NAPS_NP190GK_2023-08-26_100curves_2: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 26.8.2023. The curves are consecutive, measured once a second. Measured irradiance was from 959 to 989 W/m^2.
-NAPS_NP190GK_2023-08-26_100curves_3: This file contains 100 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 26.8.2023. The curves are consecutive, measured once a second. Measured irradiance was from 677 to 693 W/m^2.
-NAPS_NP190GK_2023-08-26_300curves: This file contains 300 current–voltage curves of a NAPS NP190GK polycrystalline silicon PV module measured on 26.8.2023. The curves are consecutive, measured once a second. Measured irradiance was from 228 to 991 W/m^2.

Each file includes the following variables:
-Time: Time stamps of the measurements (UTC+2) as given by the measurement devices
-Current: Current (A)
-Voltage: Voltage (V)
-Irradiance: Irradiance (W/m^2)
-Temperature: Back-sheet temperature of the PV module (degree Celsius)