Studying the principles of converting acoustic waves into electric current and prototyping an acoustic transducer panel, p.1
Students Name: Pylat Markiian Olehovych
Qualification Level: master (ESP)
Speciality: Telecommunications and Radio Engineering
Institute: Institute of Telecommunications, Radioelectronics and Electronic Engineering
Mode of Study: full
Academic Year: 2022-2023 н.р.
Language of Defence: ukrainian
Abstract: In this master’s thesis, the conversion of acoustic energy into electricity based on the piezoelectric effect was studied. The piezoelectric effect is the occurrence of electric charges (piezoelectricity) on the faces of some crystals when they are deformed (direct piezoelectric effect), or vice versa - the occurrence of deformation of these crystals due to the action of an electric field (inverse piezoelectric effect). The direct piezoelectric effect is the phenomenon of dielectric polarization under mechanical stress, i.e., an electric field is generated during deformation. The inverse piezoelectric effect is the process of deformation of a piezoelectric due to the influence of an external electric field. The piezoelectric effect is used in acoustoelectronics to create sources of ultrasonic waves, sound emitters and receivers, in microphones, resonators, i.e. in cases where it is necessary to convert mechanical vibrations into electrical ones or vice versa. In addition, in medicine, the piezoelectric effect is used in sensors for measuring heart rate, and in vibrometers - devices for measuring vibrations. The piezoelectric effect was experimentally discovered by brothers Pierre and Jacques Curie in 1880 in crystalline quartz, which still remains one of the best piezoelectrics due to its low energy losses. A model of a piezoelectric generator has been created that is capable of absorbing acoustic waves and generating an electric current based on the direct piezoelectric effect. The acoustic panel itself should consist of such generators. The existing types of acoustic energy conversion and their features were also analyzed. A structural-functional diagram of the conversion of acoustic energy into mechanical energy, and subsequently into electrical energy, was drawn up. Using the capabilities of the COMSOL Multiphysics modeling package, we performed a 6 simulation, which determined that in the idle mode at a frequency of 750 Hz, we can theoretically obtain up to 1.81 V of voltage. The modeled product was tested using different piezoelectric elements. Different voltage values were obtained at different frequencies: the highest voltage value was obtained at frequencies of 500-750 Hz - from 0.97 to 1.81 V. After comparing the results, the element with the highest voltage was chosen. The study can be useful as a new way to generate electricity from a source that has not yet been fully explored and is to some extent a novelty. Noise and sound is a constant component in many places on our planet, and it can be used to power low- consumption appliances or illuminate streets, for example. In addition, the economic feasibility of this study was calculated, its cost, the economic effect in the field of research, and the overall economic effect were calculated. At the end of each section, conclusions are presented. The paper concludes with a general conclusion analyzing the research work conducted and further proposals in this area. In total, the report consists of: 76 pages, 25 figures, 27 references. Keywords: acoustic waves, piezoelectric effect, sound, noise, energy, transducer, generator, acoustic panel, energy source, forward piezoelectric effect, reverse piezoelectric effect, acousto-optics, piezoelectric transducer, piezoelectricians, microelectromechanical systems (MEMS)