Piezoelectric Energy Harvesting from Nonlinear Vibrations of Rotating System: Theoretical and Experimental Studies

Energy harvesting has received considerable attention in the last two decades. Piezoelectric energy harvesting has been widely used in this field. This study investigates energy harvesting from vibration of two beams in a rotating piezoelectric nonlinear system. The presence of two factors, the nonlinear spring and the nonlinear strain, causes the system to be nonlinear, and consequently, it is possible to harvest energy over a wider range of frequencies. The coupled nonlinear differential equations of the system are derived using Lagrange electromechanical equations. Then, the approximate analytical solution of the multiple scales method and also the numerical solution of the equations using the Runge–Kutta method have been obtained. The resulting voltage and power are presented as a function of the rotating frequency, physical, and geometric parameters of the system. It is shown that the results of the perturbation solution are near to the numerical solution. Moreover, an experiment has been done on the constructed model to verify the theoretical results. The test results showed that the maximum difference between the power values in practice and theoretical results was less than 8%. Power in the range of 20–288.05 µW is produced in the frequency range of 1–3.1 Hz, which is more than the power required for wireless data transmission systems. Also the nonlinear energy harvester is superior to the linear type due to produce of more power in a wider bandwidth. The maximum efficiency of the real sample is 88%, and its output power density is 1.47–23.49 µW/cm³ in the frequency range of 0.75–3.1 Hz.