An impact-engaged two-degrees-of-freedom piezoelectric energy harvester for wideband operation

In order to achieve broadband energy harvesting, this paper proposes a two-degree-of-freedom piezoelectric energy harvesting system with stoppers. The synergy of the multi-modal technique and the nonlinearity feature benefits the wideband energy harvesting. First, the mechanism of the proposed system is described and the electromechanical model is developed. Subsequently, investigations of the effect of the presence of stoppers on the energy harvesting performance are carried out and compared to a linear 2-DOF counterpart. The impact-induced nonlinear dynamics is characterized by two parameters: the stopper distance and the stopper stiffness. A parametric study is performed to investigate the influence of these two parameters on the voltage output in terms of bandwidth and magnitude. Finally, to reconcile the demands of both operating bandwidth and the amplitude of output voltage, optimized stopper distance and stiffness have been recommended. (C) 2017 The Authors. Published by Elsevier Ltd.