Design of Electronic Control of PV Tracking Independent of Weather Forecast

With over 28 Terawatt-hours of annual electricity produced globally, only 2% is generated by photovoltaics (PV). Solar tracking is one of the most efficient methods to increase the amount of clean energy produced by PV panels. It was shown in experimental studies that the solar day could become 30% longer, i.e., 30% more solar energy collected daily, if proper single-axis (or dual-axis) tracking systems are installed. However, many commercial systems are controlled by input from local weather forecasts, which rarely take the specific location of a solar farm into account. Thus, usage of pyranometers positioned close to solar farms produce accurate solar irradiance information, despite their delayed response and drawbacks with predicting solar production. In the current study we describe the design and operation of a miniature, low cost, electronic system which tracks the sun and instantly prescribes the optimal orientation of PV panels [1] for any local weather. The system consists of two stepper motors, where each carry three small photodetectors connected to its shaft. The total sensitivity of sensors covers the entire spectrum of silicon solar cells. Stepper motors control the movement of optical sensors scanning the skies in the vertical (elevation) and horizontal (azimuth) directions. The programmable microcontroller stores information of complete elevation and azimuthal scans. The algorithm then predicts the amount of power that could be generated by large PV panels, if their orientation replicates positions of motor shafts. Experimental testing of the novel system supports our method of efficient sun tracking.