Tracking the apparent movement of the sun with high precision is crucial in dual-axis tracking systems for solar concentration applications. It is important to develop control strategies to reduce losses by solar radiation displacement (drift) on the receiver and improve the solar concentration system. In concentrated photovoltaics, a high-precision tracking control is required to keep the concentration point. This paper compares open-loop and closed-loop solar tracking control strategies to solve drift problems and correct azimuth and elevation angles in a non-image reflective FRESNEL solar concentrator. The open-loop strategy consists of a programming code to calculate the apparent sun position, sending command signals to the actuator systems in azimuth and elevation tracker axes. In the open-loop strategy, the actual position of the sun is not verified. A closed-loop strategy with a visual monitoring device is proposed here to detect the sun’s position in real time. This can be simultaneously compared with a fixed reference to evaluate drift through time, calculate the generated error, and send feedback signals to correct azimuth and elevation angles. With this configuration, displacement containment of the solar point concentration projection was ±0.00215 m in the azimuth direction and ±0.0027 m in the elevation direction on the receiver.

This paper presents the results of the electrical evaluation of a triple-junction solar cell obtained under two different lighting concentration systems: one using a solar simulator with an ellipsoid concentrator and the other using a parabolic concentrator solar furnace, both providing different concentration levels, from 220 to 670 suns inside of a surface of 1 × 1 cm², which correspond to the triple-union solar cell area. A characterization system using an automatized XY table was designed to put the solar cell at different position from the concentration systems, allowing the sample under study to be positioned in the center of the light beam where the concentrated radiative flux is most uniform. It was found that for the solar cell under study, using the solar simulator, the electric efficiency (η) behavior has a trend to reduce when the radiative flux concentration increases from 265 to 670 suns with a (η) values of 32.1% and 22.4%, respectively; while using the solar furnace, the η was around 30%. For the solar furnace, efficiency was around 30% in almost all concentration levels.