Design, modeling and experimental investigation of a magnetically coupled flextensional rotation energy harvester

Energy can be harvested from rotational motion for powering wireless autonomous electronic devices. In this paper, a novel magnetically coupled flextensional rotation energy harvester (MF-REH) is designed, with the advantages of high equivalent piezoelectric constant and high reliability. The coupled dynamical model is developed to describe the electromechanical transition. Effects of design parameters on rotation energy harvesting are analyzed. Simulations and experiments are carried out to evaluate the performances of the harvesters with various configurations under different rotating speeds. The experimental results verify that the developed mathematical model can be used to accurately characterize the MF-REHs with various configurations, in different conditions under various excitation. The experimental results indicate more excitation magnets and smaller excitation distance can significantly increase the harvested energy. For the harvester with one magnetically coupled flextensional transducer and two rotating magnets which produce repulsive forces, the maximum instantaneous power is 3.1 mW and the average power is 0.22 mW at 1000 rpm.