Changes to spectrum specification in upcoming IEC 60904-9 Ed.3

  • New classification class A+, tolerance ± 12.5 %.
  • Wavelength specification will cover 300 – 1200 nm to accommodate advances in cell and module technology (PERC, UV transparent EVA, etc.).
  • Wavelength ranges for spectral match will change. New ranges will have equal energy. Old ranges are 100 nm wide.
  • New parameters to assess quality of spectrum.
  • Spectral deviation SPD: difference in spectrum to AM 1.5G is compared wavelength-by-wavelength. SPD is the average deviation.
  • Spectral coverage SPC: the portion of wavelengths on the whole range (300 – 1200 nm) whose output is very small (< 10%) compared to AM 1.5G.
  • There will be no requirements on SPD and SPC in edition 3. The requirements will be given in future edition 4.
  • Standard will give assistance in calculating spectral match related uncertainty.

Spectral match of QuickSun 550CE is class A+ according to both editions of the standard IEC 60904-9.

The new parameters on spectrum quality are calculated on the left.

The graph shows spectral deviation is green (positive deviation) and red (negative deviation).

A typical 5 LED solar simulator spectrum is matched well for edition 2 of IEC 60904-9, but for the upcoming Ed.3 the match is poor. Also, spectral coverage is poor (marked with yellow), which increases measurement uncertainty considerably if spectral response of modules vary.