Research On Multi-frequency Vibration Energy Harvester Based On Ferrofluid

There is a variety of low frequency vibration energy in nature,such as human motion energy,wave energy,wind energy and so on.The low frequency vibration energy is huge and considerable.Collect and pick up the low frequency vibration energy can not only relieve the pressure of traditional energy consumption,but also be used to supply the energy required by micro low-power electronic devices.At present,the electromagnetic energy acquisition device is used in the efficient acquisition process of low frequency vibration energy,which mainly relies on the magnetic inertial mass block to pick up and convert the vibration energy.However,the inertia block in the common electromagnetic energy harvesting device has too much damping in the process of responding to vibration,which makes its low frequency micro-vibration response performance poor;At present,the wide frequency range of low frequency vibration makes it impossible for the single-frequency vibration energy collector to collect energy efficiently.Therefore,a multi-frequency vibration energy collector based on ferrofluid is proposed in this paper.By taking advantage of the suspension characteristics of ferrofluid,the permanent magnet mass block is suspended to avoid the solid-solid friction between the permanent magnet mass block and the wall surface,and the vibration response performance of the inertial mass block is enhanced;The multi-frequency vibration energy acquisition module is adopted to widen the frequency range of energy acquisition and improve the efficiency of energy acquisition.In this paper,through theoretical and simulation analysis,experimental research to carry out the research on ferrofluid multi-frequency vibration energy collector,the main work of this paper is as follows:(1)The basic theory of ferrofluid vibration energy acquisition device is studied.Bernoulli equation of ferrofluid and second-order suspension force equation of ferrofluid are analyzed theoretically.The collecting power of electromagnetic vibration energy is deduced theoretically,it is found that the output power of the acquisition device is the maximum when the resonance and the ratio of the electromagnetic damping ratio to the mechanical damping ratio are equal.(2)The structure design and theoretical model parameter analysis of the ferrofluid plane vibration energy collecting unit are carried out.A single degree of freedom vibration mechanics model was established for the low-frequency micro-vibration pickup module.The stiffness and damping in the equivalent model of plane vibration energy acquisition unit are analyzed,and the factors affecting the stiffness and damping are studied experimentally.(3)The ferrofluid multi-frequency vibration energy collector is studied theoretically,and the structure design and simulation analysis are carried out.The interaction degree of the actuators in the upper and lower single-degree-of-freedom systems is simulated,and the overall structural parameters are finally determined.(4)The power characteristics of multi-frequency vibration energy collector under low frequency vibration are studied experimentally.The cantilever beam vibration is used as the vibration source to simulate the low frequency vibration of the acquisition device,The output power and power density of the energy acquisition device under different low frequency(1Hz～2Hz)vibration sources were studied experimentally.According to the movement form of human body,the power characteristics of the energy collection device are studied experimentally.The experiment shows that the maximum volume power density of the collection device is 529.9 m W/cm~3与 438.1m W/cm~3,and the maximum mass power density is 0.7111 m W/kg 与 0.5879 m W/kg,respectively,when the human body is walking and jogging.There are 57 pictures,19 tables,70 references in this paper.