| With the rapid development of radio communication and MEMS,low-power micro-devices such as wireless sensor network nodes and microprocessors have a good development prospect,but the energy supply problem of these micro-devices has been one of the bottlenecks of its development.It is well known that the current use of micro devices is mainly battery powered,but since these devices are often used in occasions where the environment is harsh or difficult to disassemble,it is very difficult to replace the battery.Environmental vibration is a form of vibration energy that exists widely in nature.Converting vibrations in the environment into electrical energy can provide a solution to the problem of power supply for micro devices.With the continuous exploration of research on giant magnetostrictive materials,energy harvesting technology based on giant magnetostrictive materials has attracted the attention of scholars and experts from all walks of life.Based on the giant magnetostrictive material,the output characteristics and energy harvesting technology of the magnetostrictive cantilever vibration collecting device are studied.Firstly,the magnetostrictive inverse effect is taken as the theoretical basis,the research status of magnetostrictive energy harvesting technology and the vibration characteristics of two kinds of giant magnetostrictive materials are analyzed and compared and the flake Fe-Ga alloy is selected as the vibration source material of the vibration collecting device.Based on the mass-spring-damping model of the cantilever beam structure,the output voltage model of the cantilever type energy harvesting device is established,and the output power characteristics of the external load resistance of the collecting device are theoretically analyzed.In addition,the bending vibration of the magnetostrictive cantilever beam is analyzed,and the vibration differential equation of the free end excitation and pedestal excitation of the cantilever beam is obtained.The static analysis and modal analysis of the magnetostrictive cantilever beam structure are carried out.The bending and modal characteristics of the cantilever beam structure are analyzed by finite element software,and the influence of the size of Fe-Ga alloy material on the natural frequency of the cantilever beam is analyzed.In addition,the motion characteristics of the cantilever beam when the inertia block is installed at the free end are also analyzed.Then,a energy storage circuit is designed,which includes:rectifier circuit,voltage regulation circuit and energy storage management circuit,and each circuit was designed and analyzed separately.The energy storage characteristics of supercapacitors and lithium batteries were analyzed.The supercapacitors were used for temporary energy storage,and lithium batteries were used as the final energy storage components.Finally,a prototype of the experimental device was fabricated,and the output characteristics of the Fe-Ga alloy cantilever type collecting device and the charging performance of the energy storage circuit for lithium battery were experimented respectively.The experimental results show that the cantilever type collecting device has a maximum output power of 116?w when connected to a 47?load resistor,and the corresponding power density is 271?W/cm~3.In the experiment of the energy storage circuit,when the voltage generated by the collecting device at the 67 Hz frequency and the 9.4 m/s~2acceleration passes through the rectifying circuit,and charging of the supercapacitor C5 is started.When the voltage of C5 is higher than 0.9V,the voltage regulation circuit and energy storage management circuit start to work,providing power to the lithium battery.When the C5voltage is lower than 0.9V,the circuit stops working. |
PDF Full Text Request