Equivalent Circuit Modelling for Unimorph and Bimorph Piezoelectric Energy Harvester

Piezoelectricity is a growing area of energy harvesting research. Piezoelectric energy harvester (PEH) generally use cantilever structures in unimorph and bimorph configuration. These harvester sense the mechanical vibration and convert them into usable electric energy. In this work, an analytical model displaying the characteristics of PEH with resonant frequency, tip deflections and output power have been determined. Analytical model is in close agreement with the FEM simulation model having an error of about 5%. In order to bridge the gap between FEM simulation and energy harvesting circuitry an equivalent electrical model for the energy harvester is developed. Resonant frequency determined from the equivalent model is 87.12 Hz, whereas from FEM model and analytical model are 90.56 Hz and 93.32 Hz respectively.