Koretska O. Models and tools for building energy-efficient IoT devices based on piezoceramic transducers

The dissertation research is devoted to solving the actual scientific and practical problem of increasing the energy efficiency of IoT devices by developing models and tools for building energy efficient IoT devices based on piezoceramic transducers. A conducted analysis of existing models and tools for building IoT devices with power from autonomous voltage sources found their main shortcomings and ways to further improve. It is shown that the use of piezoceramic transducers as sources of additional power is a promising direction for further development. The main ways of increasing the energy efficiency of IoT devices based on piezoceramic transducers are identified. An improved analytical description of the parameters of piezoelectric ceramics, taking into account the orientation effects of domains in piezoceramics, made it possible to determine the shapes of bimorph piezoelectric elements, their electrodes, and the necessary mechanical voltage to increase the output power of IoT devices based on piezoceramic transducers. Developed and investigated functional models of cantilever bimorph domaindissipative piezotransducers allowed to calculate the linear dimensions of piezoelectric elements, as well as metal and cantilever plates to obtain the maximum output signal of the piezotransducer, and therefore, an increase in the operating time of the IoT device when it is self-powered. The developed mathematical model of the functioning of IoT devices in conditions of limited power supply allows determining the possibility and time of autonomous operation of such devices using the piezotransducers developed in operation. An experimental study of the developed IoT device samples based on the console domain-dissipative asymmetric bimorph piezoceramic transducers proposed in the work showed that the positions obtained in the work allow extending the battery operating time of the IoT devices up to 10%, making it possible to transfer signal information during an emergency event, and also reduce the cost of IoT devices by up to 15%. Two designs of IoT devices have been developed and patented on the example of piezo-magnetic tachometers, in which the theoretical concepts proposed in the work are implemented. The practical value of the work is to expand the scientific and technical base for designing IoT devices based on piezoceramic transducers and to bring the obtained scientific results in specific models and IoT devices, implemented, in particular, during the development of IoT Smart Toys by the Cubomania startup and in the educational process of two universities: Petro Mohyla Black Sea National University (Nikolaev) and at The Bogdan Khmelnitsky National University of Cherkasy.