Design And Analysis Of Magnetostrictive Foot Vibration Energy Harvester

In recent years,with the rapid development of electronic engineering and communication technology,the power consumption of wireless sensor nodes in many wearable or portable devices is m W-level,which has been widely used in military,biomedical and other fields.The traditional chemical battery power supply method cannot meet the long-term power supply of the equipment and the inconvenience of equipment replacement.Therefore,the research of portable vibration energy harvester arises at the historic moment.Vibration energy exists everywhere in life,and humans also belong to vibration sources.In the process of walking and moving,people will produce vibration energy,which will be collected for the power supply of human microelectronic equipment,which is of great significance in the military and medical fields.At present,most collectors use piezoelectric materials,while magnetostrictive materials have the characteristics of stability and high energy conversion rate that are not affected by temperature.Therefore,in this paper,magnetostrictive materials are used as the core power generation materials.Aiming at the key difficulties of collectors in actual walking applications,the use of multi-stage force amplification mechanisms is determined as a feasible method to solve the problem.Design a new type of magnetostrictive foot vibration energy harvester,and study and analyze the working characteristics of the harvester through simulation and experiment.This paper firstly presents the domestic and foreign research status of vibration energy harvesters,and obtains the advantages of magnetostrictive vibration energy harvesters through comparison.At the same time,it explains the domestic and foreign development trend of collectors with force amplification mechanisms.Based on the magnetostrictive properties of the rod-shaped Terfenol-D,the mechanical-magnetic-electric coupling of the collector is explained and analyzed from a microscopic and mathematical point of view.Three kinds of force amplification mechanism are selected,and the principle of force amplification mechanism is elaborated in detail by using Euler Bernoulli equation and microlever principle.The structure type most suitable for vibration energy collector is selected through analysis.In addition,this paper uses the magnetostrictive inverse effect of the rod-shaped TerfenolD as the theoretical basis,and takes the multi-stage force amplification mechanism as the core mechanism of the device,and proposes a foot vibration energy harvester with a limited support mechanism.The structure,design details and working process of the proposed energy harvester are described in detail,and the force amplification ratio is modeled by the force analysis method and the element stiffness matrix method.Use Ansys workbench for parameter optimization and finite element simulation to obtain a force amplification ratio of 18.04.Finally,in order to verify the reliability of the designed device,the prototype and the built experimental platform are used to conduct experimental research on the characteristics of the device: when the N-N side magnet is installed,it has a significant impact on the power generation effect;The device is fully compressed and released in a complete process test,the device will generate a peak voltage of 397.5m V,and the voltage will change with the movement of the device in three stages;The voltage amplification ratio of 17.67 was obtained by comparing the voltage output with or without the amplifier;When the device is fully compressed and the load resistance is close to the internal resistance,the output power is as large as 3.33 m W;The actual walking experiment is carried out.Through the experiment,it can be concluded that the device’s force amplification ratio,safety and stability are in line with the design idea.