Optimisation and Application of Kinetic Piezoelectric Energy Harvesters Aimed at Powering Autonomous Sensors

Piezoelectric energy harvesters, characterised by design simplicity, robustness, high energy density and conversion efficiency, as well as scalability, are a viable choice for transducing ubiquitous kinetic energy in a reliable and stable electrical energy source aimed at powering IoT and other prospective applications of autonomous sensors. The performances of this class of harvesting devices can be considerably enhanced by optimising their design configurations. An overview of several optimised piezoelectric harvesters' designs, with the respective modelling and experimental validation procedures, is provided in this work. In this regard, special attention is dedicated to innovative topologies of the considered devices, as well as to excitation mechanisms leading to considerably ameliorated output power levels. Possible applications in wearables for biomedical applications, structural health monitoring in aircraft, open-field applications (either for environmental monitoring of river flows or rainfall-actuated devices), as well as in automobile tyre pressure monitoring, are given as elaborated examples of conceivable sensing nodes. A basic overview of the aspects related to the conforming power management electronics and an outlook on future research directions are also given.