Design And Experimental Study Of Energy Harvester Based On Flexural Piezoelectric Beam

With the development of technology and economy,the demand for energy is increasing and the problem of energy shortage has seriously affected the future sustainable development of mankind.How to harvest energy is becoming an important topic in contemporary energy research.In the natural environment,wind energy has a wide distribution and has good research prospects in energy regeneration.In this paper,an energy harvesting device based on a flexural piezoelectric beam is developed to provide an idea for solving the problem of power supply for micropower electronic devices.The device has the characteristics of sustainable power supply,large frequency domain bandwidth range and high energy harvesting efficiency.Firstly,the dynamics model of the energy harvester is established.The wind energy harvesting module is designed according to the flow characteristics of the wind,and the dynamics model of the fan is established;the magnetomechanical model of the interaction force between the magnets is established according to the magnetic dipole theory;the dynamics relationship between the rotating hub magnet and the magnet at the head of the flexural beam is established by studying the working process of the energy harvester;the energy transfer module is designed according to the energy transfer path;based on the positive piezoelectric effect and the flexural principle,the Based on the positive piezoelectric effect and the principle of flexure,the energy conversion module of the flexural piezoelectric beam is designed,and the dynamics model of the flexural beam is established.Based on the above kinetic model,the dimensionless differential equations of the flexural beam are derived.Next,the structure of the energy harvester is designed.Based on the structural parameters,modal analysis of the energy harvester is carried out to investigate the influence of the length,thickness and arch height of the flexural piezoelectric beam on the first-order modal values;based on the modal simulation results,harmonic response analysis is further carried out to investigate the optimum frequency domain bandwidth.Frequency-voltage curves were plotted to investigate the effects of length,thickness and arch height of the flexural piezoelectric beam on the energy output performance respectively.The results show that the length has little effect on the first-order mode and frequency-voltage curve;the larger the thickness,the larger the first-order mode of the piezoelectric buckling beam;the larger the arch height,the smaller the first-order mode of the piezoelectric buckling beam;by adjusting the thickness and arch height,the bandwidth of the frequency-voltage curve can be shifted significantly;the peak voltage is not sensitive to the above three parameters.Finally,to verify the theoretical analysis and simulation results.The effect of the operating parameters(fan speed,magnetic pitch and the length,thickness and arch height of the flexural beam)on the energy harvesting performance is experimentally investigated.The experimental results show that: the bandwidth of the energy harvester can be made to fall within the operating frequency range by varying the parameters of the flexural beam;the best power generation effect is achieved under the condition that the magnetic spacing between the rotating magnet and the magnet at the head of the flexural beam is 3mm and the magnets are installed in opposite directions;the maximum voltage of 4.6V can be generated at a fan speed of 400r/min,which is equivalent to three dry cells in series and meets the power supply requirements of micro-power electronic devices.