Research On Piezo-electromagnetic Hybrid Energy Harvester Based On Wind-induced Vibration

In recent years,the development and utilization of environmental vibration energy has attracted extensive attention of researchers in industry and academia.The forms of vibration energy in the environment mainly include wind energy,tidal energy and mechanical vibration energy(vehicles,infrastructure equipment,household appliances,etc.).Wind energy is widely distributed,green,clean,renewable,which is an ideal form of energy.Many scholars are doing research on vibration energy harvesting and conversion: through some small equipment,using energy conversion mechanism,environmental vibration energy is captured and converted into electric energy.This technology can realize the continuous and stable independent energy supply of electronic energy consuming equipment,so as to solve the disadvantages of traditional energy sources(electronics,batteries,etc.)such as limited reserves,instability,easy to pollute the environment,and reduce the cost of equipment maintenance and the burden of social development.At present,the research on single energy harvester mechanism is the main one,while the research on multi energy harvester mechanism is less.The power supply type of the energy harvester is single and the adaptability to the environment is low.The research mainly explores the influence of structural parameters and load resistance on its output characteristics.In addition,there are vibration sources in the environment with two or more discrete vibration frequencies.However,most of the studies ignore the influence of external environmental factors,such as wind speed,multi frequency vibration,impact and so on,which is difficult to truly reflect the energy output performance of the energy harvester in the natural environment.In this paper,based on the wind-induced vibration of piezoelectric electromagnetic composite energy harvester as the research object,a nonlinear energy harvester and a multi frequency energy harvester are proposed.Considering the piezoelectric and electromagnetic dual energy conversion mechanism,wind-induced vibration and harmonic vibration dual excitation source,nonlinear magnetic coupling,according to the theoretical knowledge of hydrodynamics,piezoelectricity,elasticity and material mechanics,the total kinetic energy,total potential energy and virtual work of the energy harvester system are calculated.The approximate distributed parameter coupling mathematical model of the energy harvester system is established by using Lagrange equation and Rayleigh Ritz reduction method,and the solution program is written by using MATLAB Software platform.In this paper,the influence of cylinder mass,magnet spacing,spring elastic coefficient,external impedance on the power generation performance of the energy harvester is simulated and analyzed by MATLAB.The results show that the piezoelectric electromagnetic nonlinear energy harvester based on wind-induced vibration can obtain higher output power by reasonably arranging the cylinder diameter,cylinder mass,cantilever length and other parameters within a certain range;the resonance frequency of the energy harvester system can be adjusted by adjusting the magnet spacing to match the vibration source frequency,and enhance its ability to adapt to the natural environment.The multi frequency energy harvester system can obtain higher power generation performance under the double excitation of wind-induced vibration and harmonic vibration,but the electromagnetic energy harvesting part is less affected by the wind speed;the harmonic frequency of the system can be adjusted by adjusting the cylinder mass,magnet mass,spring elastic coefficient and magnet spacing,which can collect the energy of continuous vibration frequency within a certain range,and can also collect two separators Energy dispersing vibration frequency.In order to verify the correctness of the mathematical model in this paper,the small direct current wind tunnel test platform and excitation test platform used in the experiment are built,and the energy harvester test prototype is made.The physical experiment is carried out by using data acquisition equipment,and the experimental results are processed by relevant software.The comparison analysis shows that the experimental results are consistent with the simulation results,which verifies the correctness of the mathematical model.