Dynamics Modeling And Analysis Of Cantilever Magnetostrictive Vibration Energy Harvester With Nonlinear Magnetic Force

Magnetostrictive Vibration Energy Harvester?MVEH?has the advantages of high electromechanical conversion efficiency,low impedance,wide working range and no ageing.It has broad application prospects in the low power of wireless sensor networks,MEMS and implantable medical devices.In order to broaden the harvest bandwidth of device and reduce its frequency,the cantilever MVEH with nonlinear magnetic is studied deeply in this paper.1.Dynamic modeling is performed on the MVEH with nonlinear magnetic force.The magnetic model is deduced.Based on the magnetic model,the principle of dynamic balance,the nonlinear constitutive model of magnetostrictive material and the Faraday's law of electromagnetic induction,the electromechanical coupling dynamics model of cantilever MVEH with nonlinear magnetic force was established.Based on the model and the Routh-Hurwitz stability criterion and the dynamic model,the bifurcated value and the curve of potentional energy of the device is determined.2.Based on the finite element method,the design and analysis of nonlinear magnetic cantilever MVEH are designed and analyzed.First,the size of the magnet in the device with the basic structure is determined.The finite element calculation results show that the bias magnetic field is unevenly distributed under the influence of the applied magnet.Therefore,an improved structure scheme of the device is proposed.The results of finite element calculation show that the device with improved structure has a relatively small change of bias magnetic field when the magnet distance d from the bifurcation value d_bifif to an infinite value,and distribution more evenly.In addition,the magnetic force,potential energy function and open-circuit voltage of the device are calculated and analyzed,and finally the structural parameters of the device are determined.3.Based on the established electromechanical coupling dynamics model and the determined structural parameters,the dynamic simulation of the device is analyzed.The numerical results and experimental results show that the proposed model is correct and effective.On this basis,the output response under monostatic and bistable state of the device under harmonic excitation is analyzed and compared,which shows that the acquisition frequency decreases and the acquisition bandwidth has been greatly improved in the bistable state.Finally,the output characteristics of the device under random vibration excitation are calculated and analyzed.The results show that the cantilever MVEH with nonlinear magnetic force exhibits a wider acquisition bandwidth and stronger output capability in the random vibration environment than the traditional cantilever MVEH.By means of device dynamics modeling,design,numerical calculation and analysis,the cantilever MVEH with nonlinear magnetic is studied deeply in this paper.The physical model established in this paper is demonstrated.The research conclusion are of great guiding significance for the overall output performance prediction,structure design,control and usage of this device.