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Solar Modules

Working Group 4.53


In the solar module research group founded in 2018, calibration methods for the primary and secondary calibration of solar modules are currently being developed. Electrical properties such as the current-voltage characteristic, open-circuit voltage (Voc), short-circuit current (Isc) and maximum power point (Pmpp) of solar modules can be measured at standard test conditions (STC) on an LED-based steady-state solar simulator. The LED solar simulator can also be used in combination with a temperature test chamber to perform irradiance and temperature-dependent measurements in order to determine the power matrix of a PV module according to IEC 61853-1. By individual variation of the LED light, the spectral sensitivity at 18 different wavelengths between 370 nm and 1050 nm can be determined. The laboratory measurement is a secondary measurement, which is traced back to reference solar cells of the working group 4.52 solar cells.


Figure 1: LED-based steady-state solar simulator for PV modules. With a total of 18 different and individually tunable colors the solar spectrum can be simulated between 370 nm and 1100 nm.

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In addition to the laboratory measuring facility, several supplementary outdoor measuring facilities are currently being set up as part of research projects. These facilities will enable the measurement of wind dependence and angular dependence of PV modules in addition to the electrical parameters derived by the laboratory measuring facility. This soon offers our customers the possibility to have a complete PV module calibration according to the Energy Rating standard series IEC 61853. Furthermore, we are engaged in pre-normative research, e.g. on the shading of solar modules, we investigate the possibilities of utilizing laser light for a better characterization of our devices under test and we develop measurement methods for the precise characterization of solar simulators in order to realize the smallest measurement uncertainties possible. A large ongoing BMWi project includes the conversion of the existing solar simulator facility to a bifacial measurement operation with light sources on both sides and the setup of a measuring facility for the primary traceability of solar modules by outdoor measurements in sunlight.

Current Projects:

  • Metro-PV: 19ENG01 „Metrology for emerging PV applications” https://www.metro-pv.ptb.de
  • MetroKomPV: Setting up a Metrology Competence Center for the Precise Measurement and Validation of Standardized Yearly Yields of PV Systems
  • PV-Enerate: 16ENG02 „Advanced PV Energy Rating” https://www.pv-enerate.ptb.de


Figure 2: New building currently under construction for the working group solar modules. The building will bundle the outdoor facilities for a traceable calibration on solar radiation.

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Our portfolio will be established soon, we already are available for special calibrations of the module properties mentioned above as well as for bilateral comparisons.

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Head of Working Group
Dr. Stefan Riechelmann
Phone: +49 531 592-4149
Email: stefan.riechelmann(at)ptb.de


Physikalisch-Technische Bundesanstalt
Bundesallee 100
38116 Braunschweig

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