Diseño de un generador piezoeléctrico de 5W

Abstract

Currently, despite the advancement in the field of renewable energies, a dependency on current weather conditions still exists, leading to some uncertainty when ensuring the continuity of energy supply. Therefore, other sources of renewable energy independent of weather conditions have been sought, and among these the generation through piezoelectricity have been of great interest. While it is a method that has great potential, it is not being used because of the low amount of energy production, resulting at the same a low efficiency of harvesting with the conventional methods. Therefore in this study it is considered three different types of rectifiers, choosing the most efficient to recollect and store the energy generated by the piezoelectric in a battery. Method The first step on this project was the selection of the piezoelectric. For this purpose there was a force Vs voltage test, where the piezoelectric, which had a better voltage generated vs force applied ratio, was selected and modeled. Then a theoretical efficiency analysis was done for the three rectifiers, where the most efficient was selected. Afterwards a battery charger system was designed and simulated. Finally a prototype was made, using as a mechanical base the tile designed by the university. After the prototype was tested, measures of voltage generated vs force were done. Results Of the piezoelectrics analyzed, the biggest piezoelectric was chosen because it had the best ratio of power to voltage generated. Initially, it was planned to connect all the piezoelectics in series, to increase the voltage, decrease the parasitic capacitance thus increasing the efficiency, but with the tests performed it was determined that it was better to implement a rectifier for each piezoelectric due to its distribution in the tile. Within the efficiency study performed, it was found that the full bridge rectifier was the most efficient and simplest, when collecting energy generated by the piezoelectric tile. It was observed that at the output of the rectifier, an average current of 20mA is delivered to the battery with several fluctuations. Conclusions Although the designed generator cannot generate 5W with a single footfall, with the constant flow of pedestrians it can generate that amount of energy, which requires 725 steps, or the equivalent of 725 pedestrians walking on the tile.