Modeling and experiment of piecewise linear hybrid vibration energy harvester

WANG Hao-yu, YANG Huan, PENG Li-ping, LIU De-yang
(School of Mechanical Engineering, Hohai University, Changzhou 213000, China)

Abstract: Aiming at the problems of narrow working bandwidth and low output power of traditional energy harvesters,vibration energy harvester with multiple energy conversionsand nonlinear technology were researched. The free ends of multiple piezoelectric cantilever beamsonproposedenergy harvester were connectedto the coil oscillator for obtaining multiple energy conversion methods. And a segmented linear spring was introducedin system to expand the bandwidth. After analyzing the geometric characteristics of energy harvester, the device was simplified into a fixed supportguide beam. Based on Euler-Bernoulli beam theory,a RayleighRitz approximate distributed parameter model was established. By using equivalent parameters, a lumped parameter electromechanical coupling model was established. The research results show that the theoretical simulationis in good agreement with the experiment. The introduction of a non-linear spring will generate a sub-resonant peak on the right side of the resonance peak, which expands the bandwidth.At the same time, the output voltage increases monotonically with the increase of the load. As the resistance of the load increases, the power gradually increases to a certain maximum value and then decreases, and the maximum output achieves 27.6 mW/g2.

Key words: vibration energy harvester; piezoelectric-electromagnetic; piecewise linear; electromechanical coupling modeling