Thermal issues of solar irradiation sensor

Nowadays the importance of solar cells and R&D in this field is steadily increasing. The most important parameter of a solar cell is the generated power, which can be enhanced by use of solar tracking. For a correct determination of the tracking system´s efficiency an irradiation sensor is necessary, because the irradiation from the sun changes constantly. This sensor device is placed on the tracker´s frame and transfers the intensity data to a monitoring system. The sensor developed for irradiation measurement must have accuracy and a reliable construction under outdoor use conditions (between the temperature values of -20degC and 80degC). The sensor is based on a photoelectric cell, and incorporates a read out circuit for providing steady short circuit conditions for the cell as well as for signal amplification. Thermal tests (HTS, LTOL) were accomplished in a climate chamber in the temperature range of -20 to 80degC in steps of 10degC. To determine the fundamentals of the thermal dependence of the sensor cell spectral response measurements under varying temperatures were performed.