The Research Of Sound Energy Harvesters Based On Helmholtz Resonator And Acoustic Metamaterial

As part of the renewable energy sources that meet environmental standards,sound energy,once converted into electrical energy,can be used to power low-power devices.Given that in the flow of the abundance of sound energy in our environment,the density of the production of this type of energy remains low and the techniques of recovery and conversion also pose problems for better performance.Thus,this study proposes two solutions to improve the recovery and conversion of sound energy into electrical energy.A study has been made on the acoustic energy harvester based on the Helmholtz resonator.Firstly,a Helmholtz resonator with a conical cavity,a piezoelectric plate,permanent magnets,and a coil were designed under Solid Works,this structure can be used to harvest the acoustic energy both by the piezoelectric plate and coil.After that,the effect of two structures with different parameters was compared,throughout the different simulations we have these results as follows: the two models of conical cavity Helmholtz collectors have a resonance frequency of 1634 Hz and 1745 Hz under a pressure of 1 Pa(90d B)and a sound pressure of 192 d B SPL and 189 d B SPL inside their respective conical cavity.Then,always by using different methods of calculus,we get as results of the conversion devices into electricity,namely the piezoelectric plate and the permanent magnets respectively provided a power of 22 m W,48 m W and 18 m W,36 m W.A study has been made on the acoustic energy harvester based on the acoustic metamaterial.Firstly,the sound enlarges effect of acoustic metamaterial with cylindrical,triangle,and square unit cells were compared.It indicated that the acoustic metamaterial with cylindrical unit cell has a bandwidth of 595 Hz to 756 Hz,with a width of 161 Hz,the acoustic metamaterial with triangle unit cell has a bandwidth of 555 Hz to 700 Hz,with a width of 145 Hz,and the acoustic metamaterial with square unit cell has a bandwidth of from 584 Hz to 748 Hz with a width of164 Hz.Then,considering the requirement of a broad band,the acoustic metamaterial plate with a square unit cell was constructed;the simulation result indicates that the energy can be focused on the center of the acoustic metamaterial plate,and we can harvester the acoustic energy in this area.