A vibration-based energy harvester suitable for low-frequency, high-amplitude environments: Theoretical and experimental investigations

Abstract

This article presents theoretical and experimental investigations of a vibration-based energy harvester which is suitable to extract energy from low-frequency, high-amplitude environments. The proposed device consists of a rotating proof mass and eight piezoelectric bimorph beams. A magnet, mounted on the rotating pendulum, actuates the tips of the piezoelectric beams due to magnetic interaction. The free oscillations of the piezoelectric beam generate energy each time the pendulum passes over the beams. Based on energy principles, the nonlinear ordinary differential equations governing the electromechanical behavior of the system are derived and solved numerically. Using the proposed model, the effects of angular velocity of the rotating mass on the generated voltage are investigated. It is shown that the harvester with a relatively high angular velocity generates more voltage than the one with a low angular velocity. The performance of the proposed device in the attractive and the repulsive cases is compared to each other and it is concluded that the generated voltage of the attractive case is more than that of the repulsive case. The overall generated power of the harvester under harmonic external excitations is investigated for various amplitudes and frequencies. Using theoretical model, it is shown that the proposed device can be used for harvesting the out-of-plane vibrational energy. A model of the system has been devised and tested. The obtained experimental results show good qualitative agreements with the theoretical ones.