A simple solar simulator with highly stable controlled irradiance for solar panel characterization

A solar simulator suitable for universities’ lab was designed and developed using a quartz tungsten halogen lamp as its light source, an alternating current phase-cut dimmer, a light intensity meter, and an ATMega328p microcontroller with a computer and a liquid crystal display. Noting that the quartz tungsten halogen lamp suffers bulb overheating and long-term degradation that leads to the decrease in its light intensity, a control mechanism was applied. The control mechanism employed a proportional–integral–differential action with Some-Overshoot Ziegler–Nichols tuning rule. It was shown that the control mechanism works well in stabilizing the quartz tungsten halogen lamp irradiance between 273 and 1182 W/m2. The developed solar simulator was then tested to obtain I-V (current–voltage) characteristics of 3 W peak and 5 W peak commercial solar panels (GH Solar, GH5P-9). Based on the gained I-V characteristics, it was shown that the obtained characteristics of the commercial solar panels are in the range of the characteristics provided by the manufacturer’s data sheets. The developed quartz tungsten halogen lamp-based solar cell simulator can therefore be used to characterize solar cells.

TM-30–15 and CIE-CRI-Ra: Investigation of Сolour Rendering of White PC LEDs

The colour rendering properties of 21 phosphor converted LED light sources (pc LED) with different Rf and Rg values as in the Fidelity Index and Gamut Index of the TM­30–15 have been investigated. Scenarios illuminated by pc LEDs, a fluorescent lamp (FL) and a tungsten halogen lamp (THL) were presented to 34 subjects. An assortment of coloured objects was arranged identically in two adjoining booths and participants rated the test scenarios in comparison with the reference illuminant (THL). For colour quality, both indexes are reflected in the observer’s ratings. The Fidelity Index strongly correlates with the colour difference and colour shift perceived; the Gamut Index with the subjects’ ratings of the colour saturation. Participants found the best match with the fluorescent lamp (Rf = 80/ Rg = 100) to be the pc LEDs with Rf = 75/ Rg = 105 and Rf = 80/ Rg = 105.