Novel Online Sensorless Dual-Axis Sun Tracker

In this study, a novel online sensorless dual-axis sun tracker regulated by the maximum power point tracking (MPPT) unit is proposed. The MPPT controller continuously calculates the maximum output power of the photovoltaic module/panel/array, and uses the altitude and azimuth angles deviations to find the sun direction where the greatest value of the maximum output power is extracted. Unlike all the other sensorless sun trackers that operate as open-loop systems, the proposed sun tracker is a closed-loop system, which uses the actual direction of the sun at any time to track the sun direction and this is the contribution of this study. The proposed sun tracker has the advantages of both sensor-based and sensorless dual-axis sun trackers, but it does not have their disadvantages. A photovoltaic system has been constructed, and it is experimentally verified that the proposed sun tracker finds the sun direction with the tracking error of only 0.11° which is less than the tracking errors of other both sensor-based and sensorless trackers. An increase of 28.8%-43.6% in the captured solar energy depending on the seasons is the main advantage of utilizing the proposed sun tracker.