Electromechanical Modeling of a PZT Disc-type Energy Harvester for Large Force Vibration

Using the piezoelectric (PZT) material to ha rvest electrical energy from the vibration environment has received growing attention over the last decade. Typically, the most commonly used configuration in PZT harvester is the rectangular cantilever beam because this structure makes straining of the material easily and fits for normal ambient vibrations. Unlike the cantilever beam structure, this paper focuses on the modelling problem of a PZT harvester in disc configuration which is appropriated for large force vibration conditions. A two-degree-of-freedom electromechanical model which considers both the mechanical part of the harvester and the electrical factors of the energy transmission circuit was built to estimate the harvested power across the external load. Also, the longitudinal mode of the PZT disc under force excitation was developed to fmd the internal force that is used to generate electrical power. The internal force will be used as the mechanical-to-electrical inter-medium to build the electromechanical model of the harvester. Exact closed-form expressions of the electromechanical model have been given and illustrated using numerical simulation.