IEC 60904-7-2019 pdf free.Photovoltaic devices – Part 7: Computation of the spectral mismatch correction for measurements of photovoltaic devices.
All integrals shall be performed in the entire spectral range where the respective quantitiesare not zero. The irradiance distribution shall be known over the entire combined spectralrange of sensitivity of the device under test and the reference PV device.
The spectral irradiance distributions and the spectral responsivities can be given on anabsolute or relative scale.
lf the relative test spectrum would be identical to relative reference spectrum，then theSMM is 1 and spectral mismatch corrections can be neglected,even if the spectralresponsivities of the devices differ. However, considering that the test spectrum as a physicalquantity has a measurement uncertainty assigned to it that is not zero， the SMM will still havea measurement uncertainty contribution different to zero.Thus，the SMM factor cannot beneglected when considering its measurement uncertainty contribution, though the value of thefactor is 1.
lf the relative spectral responsivity of the device under test would be identical to the relativespectral responsivity of the reference device,then the SMM is 1, even if the relative spectralirradiance distributions differ (perfectly matched reference device). Considering that bothspectral responsivities have a measurement uncertainty that is not zero，the SMM will stillhave a measurement uncertainty contribution different to zero.Thus, the SMM factor cannotbe neglected when considering its measurement uncertainty contribution,though the value ofthe factor is 1.
Due to the irregular shape of the reference and measured spectra,spectral responsivitiesshould be interpolated to the wavelength points of the spectral irradiance measurements, notvice versa.
Formula (3) is valid for single-junction devices,but may be used for multi-junction devices.For multi-junction devices, the calculation shall be performed for each junction in the device,using its spectral responsivity including the spectral filtering caused by the junctions abovethe junction under consideration.The test report should specify the spectral mismatch factorsand the relative current generation of the individual junctions. For multi-junction devices, referto lEC 60904-1-1 (1-V) and lEC 60904-8-1(SR).
The spectral responsivities used shall be valid at the level of target iradiance for which theSMM factor applies because for non-linear devices they may vary with the level of irradiance.IEC 60904-7 pdf download.