Simulation And Experimental Study Of A Coupled Double-beam Nonlinear Piezoelectric Energy Harvester

With the development of wireless sensor,many problems of its traditional chemical battery energy supply mode are gradually exposed.In order to solve this problem,many experts and scholars turn their attention to other energy supply methods,including solar cell power,wind power,vibration energy power and so on.Vibration energy exists widely in the environment,and piezoelectric vibration energy harvest device has been widely concerned because of its high energy density and easy integration.The vibration in the environment often has the characteristics of wide frequency band and randomness.Only when the excitation acceleration level reaches a certain level can the traditional bistable system achieve broadband energy capture performance.To solve this problem,a novel piezoelectric energy harvester is proposed.The main work is as follows:1.A nonlinear piezoelectric energy harvester with coupled double beams is proposed.Based on the lumped parameter model of linear system and bistable system,the mathematical model of the nonlinear piezoelectric energy harvester with coupled double beams is established.Based on the theory of mechanical vibration and piezoelectric field,the electromechanical coupling equation of the nonlinear piezoelectric energy harvester with coupled double beams is derived.2.Analysis is carried out by MATLAB.The amplitude frequency response of traditional bistable system and the nonlinear system with coupled double beams are studied respectively.The energy harvest characteristics of the system under different coupling spring stiffness are studied,and the law of the energy capture characteristics changing with the stiffness is obtained.3.The nonlinear piezoelectric energy harvester with coupled double beams is experimentally studied.Firstly,the experimental device is built to test the energy harvest performance of the traditional bistable system and the nonlinear piezoelectric energy harvester with coupled double beams,and the output voltages at different frequencies are obtained.By changing the coupling spring stiffness of the nonlinear piezoelectric energy harvester with coupled double beams,the output voltages of the system under different stiffness are measured.The experimental results show that the coupled double beam structure can reduce the potential well of bistable system,and realize high-energy inter well oscillation under 0.3g acceleration excitation,while the traditional bistable structure can realize high-energy inter well oscillation only under 0.6g acceleration excitation.Under the same excitation level,the working bandwidth of the coupled double beam structure is broadened by 140%.