Research On Wide-Band Nonlinear Piezoelectric Vibration Energy Harvester Coupled By Origami

Aiming at the energy supply of wireless sensor network,piezoelectric vibration energy conversion technique has been a research hotspot.Since the traditional linear piezoelectric vibration energy harvester has narrow energy conversion frequency band and low energy conversion,a wide band nonlinear dual piezoelectric cantilever energy harvester coupled by origami is proposed.Apart from using two piezoelectric cantilevered beams to broaden the working frequency band of the device,the nonlinear origami component is introduced into the upper and lower beams to realize the dynamic coupling of the two piezoelectric beams.When vibrating,the origami structure changes the stiffness,increases the nonlinearity of the system by dynamic folding,so as to further broaden the frequency band and increase the output power of system.Firstly,the structure of the proposed energy harvester is designed.Then,based on the Euler Bernoulli beam theory,Hamilton principle and the dynamic analysis of origami component,the electromechanical coupling dynamic model of two piezoelectric beam subsystems is established,and the approximate solutions of the output voltage and output power of each subsystem are obtained by harmonic balance method.The numerical simulation of each subsystem is implemented by Matlab,and the influences of excitation frequency and amplitude on the output voltage and power of the system are explored respectively.The results show that this energy harvester can significantly broaden the working frequency band and has a nonlinear characteristics of hardening stiffness.Via the simulated analysis of motion,it is further shown that the proposed energy harvester has strong nonlinear characteristics.Finally,the optimal coupling position is determined by analyzing the influence of the coupling position of origami component on the energy harvester,and the impedance matching of each subsystem is carried out respectively.Finally,an experimental test platform is built,a prototype and clamping device are also fabricated,and a series of experiments are carried out to verify the simulation results.The experimental results show that the working bandwidths of the two piezoelectric cantilever beams coupled by origami component are both effectively widened.At the same time,due to the introduction of origami component,the nonlinear characteristics of the structure are increased,which not only have the characteristics of harmonic compression and hardening stiffness,but also do chaotic and multiple periodic motion.The output voltage of two piezoelectric beam subsystems in different coupling positions is studied,and the best coupling position of origami element is determined.Finally,the impedance matching experiment is carried out to determine the external load when the two piezoelectric beam subsystems get the best output.The validity of simulation results and the electromechanical coupling model of two piezoelectric beam subsystems is validated.