Influence of the potential barrier switching frequency on the effectiveness of energy harvesting

Abstract

Dynamical systems for kinetic energy harvesting have recently been designed that use nonlinear mechanical resonators and corresponding transducers to create electrical output. Nonlinearities are important for providing a broadband input frequency efficiency, which is necessary to ensure that the output voltage is at a satisfactory level in the case of a variable ambient vibration source. In this paper, we analyze the dynamics of such a system with the additional possibility of a switching potential barrier in the nonlinear resonator. In order to improve the effectiveness of the energy harvester, we numerically test the possibility of using abrupt changes in the system parameters. We analyze the voltage output for various frequencies of both the harmonic excitations and the potential barrier switching. In a range that includes low and high switching frequencies of potentials, the periodic solutions dominate in the bifurcation diagrams. With regard to the large switching frequency, the effective values of the voltage at the piezoelectric electrodes are significantly reduced. The highest effective values of the voltage that are induced at the piezoelectric electrodes are observed when the chaotic solutions appear due to their specific ability to pass the potential barrier for relatively small excitation. The results also show that mechanical damping with high-enough magnitudes minimize the influence of the transient states caused by the switching potentials.