横向电磁式振动能量采集器的设计与制作

Design and fabrication of transverse electromagnetic vibration energy harvester

基于微机电系统(MEMS)设计了一种结构新颖的横向电磁式振动能量采集器,用于把周围环境中振动的机械能转化为电能。该能量采集器主要由两块长方形永磁体、螺旋铜线圈、质量块-弹性梁振动系统及衬底等构成。选用有限元分析软件对器件结构参数进行了仿真分析与优化,并利用电镀技术制作螺旋铜线圈,KOH湿法腐蚀和深反应离子刻蚀(DRIE)技术制作质量块-弹性梁振动系统,然后与永磁体一起组成了体积大约为100mm3的能量采集器样机。对制作好的电磁式振动能量采集器样机的振动特性测试表明:质量块-弹性梁振动系统的一阶固有频率为241Hz;在频率为241Hz、加速度为2.8ms-2的外界振动激励下,负载两端产生的交流电压峰峰值为9.2mV。另外调节质量块和弹性梁的参数,还可以得到不同固有频率的能量采集器。该能量采集器实现了从机械能到电能的转化,对无线传感器件的发展和应用很有意义。

A transverse electromagnetic vibration energy harvester based on Micro-electro-mechanical System（MEMS） was designed to convert the vibration mechanical energy around our environments to electrical powers. It mainly consisted of two vertically polarized rectangle permanent magnets, a mass- spring vibration system with a copper coil and a substrate. The structure parameters of system were analyzed and optimized by Finite Element Analysis （FEA）, and a harvester prototype was fabricated. During the fabrication of the harvester, electroplating technology was employed to fabricate a spiral copper coil, KOH wet etching and Deep Reaction Ion Etching（DRIE） technology were employed to fabricate mass-spring vibration system, then the harvester prototype was formed together with perma- nent magnets. The volume of the harvester was about 100 mm3. The test results for vibration charac- teristics show that the natural frequency of the mass-spring vibration system is 241 Hz. The electro-magnetic vibration energy harvester can generate a peak-peak voltage of 9.2 mV at an external acceler- ation of 2.8 ms-2 and frequency of 241 Hz. Furthermore, by adjusting the parameters of mass-spring vibration system, the harvester with different natural frequencies can obtained. The havester can con- vert the mechanical energy to the electrical energy and have significance for the clevelopment and ap- plication of the wireless sensor devices.