measurement solar panel requires a stable light source, which is closely related to the conditions of sunlight. Not only the intensity, but also the spectrum must also match the standard. An obvious option is to simply use the sun itself. In places where there are few clouds, this is a good solution 1, but there are still changes in atmospheric conditions that require correction to compare measurements over different periods. The spectrum also changes throughout the day, which further limits the time of testing.
The most common solution is to use an artificial light source that simulates the sun. An ideal lighting source should have the following characteristics:
- is less than 1% of spatial inhomogeneity. The total irradiance of
- changes less than 1% over time.
- filters a given reference spectrum so that its spectral mismatch error is less than 1%.
- These requirements are essential for achieving accuracy of better than 2%.
testers classified according to three criteria:
- spectrum matching
- irradiance inhomogeneity-space uniformity in illumination areas
- time instability-stability over time.
Deviation from air mass 1.5
(the deviation from AM1.5 causes the error of current (Isc))
It is difficult to create a light source that exactly matches the AM1.5 spectrum and has the necessary lighting intensity. There tends to be considerable differences between the light spectrum and the required AM1.5 spectrum. There are two ways to correct the difference between the AM1.5 spectrum and the actual spectrum of the solar simulator.
has the same spectrum corresponding calibration solar panel .
The method most internal testers take is to use calibration solar cell corresponding to the same spectrum as the battery under test. The light intensity of the tester is adjusted to match the Isc of the battery with the Isc measured by the external test lab. However, slight changes in cell processing (such as doping profile of emitters, changes in antireflective coatings) will result in corresponding spectral changes, requiring a new calibration standard.
Measure spectral response
Primary calibration lab uses light sources closer to standard, but there are still differences. To compensate for these differences, the calibration laboratory measures the spectral response of the device under test and then uses it to correct for the known differences between the spectra of the light source and the standard spectra. This correction is time-consuming and error-prone. In the early 1990s, analysis of test errors led to improvements in standards, while also reducing the efficiency of some records by 1% absolute value.
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