Design and implementation of a low-cost dual-axes autonomous solar tracker

The use of fossil fuels and the greenhouse gases emission is a growing concern of the international community. For this reason, the research and development of alternative sources are forcing down the costs associated with renewable energy sources. Photovoltaic energy production is the best example of these exponential growing rates at the last years. However, the output power provided through the photovoltaic conversion process depends on solar irradiation, and the daily and seasonal movements directly affect the intensity of radiation received in the solar collectors. In order to optimize the energy production, this paper describes the development of a low-cost, dual axes solar tracker (DAST) with low power consumption. The work encompasses the design, construction, assembly of the entire mechanical structure, electrical systems and devices and the elaboration of the control logic responsible for all the movement of the module to search the position of maximum solar irradiation. The tracking is designed through the use of LDR sensors responsible for providing the input signal to a microcontroller. The PV panel rotates automatically based on the sun irradiance during the day while at night, the panel remains in a horizontal position to protect the mechanical structure against inclement weather. The proposed system also has a development of a 12V battery charging system used for module movement and as a power source for electronic devices. Results show that a system with the designed DAST can reduce in 8% the payback of a single PV installation when compared with a fixed structure, taking in account the solar irradiance available in the region of Serra Gaúcha in South Brazil.