Flexible multilayer MEMS coils and their application in energy harvesters  

作　　者：ZHANG Jie HOU XiaoJuan QIAN Shuo BI XiaoXue HU DongXu LIU JianJun GENG WenPing MU JiLiang HE Jian CHOU XiuJian 

机构地区：[1]Science and Technology on Electronic Test and Measurement Laboratory,North University of China,Taiyuan 030051,China [2]School of Software,North University of China,Taiyuan 030051,China

出　　处：《Science China(Technological Sciences)》2024年第4期1282-1293,共12页中国科学（技术科学英文版）

基　　金：supported by the National Key R&D Program of China(Grant No.2019YFE0120300);the National Natural Science Foundation of China(Grant Nos.62171414,52175554,&52205608);the Fundamental Research Program of Shanxi Province(Grant Nos.20210302123059 and 20210302124610)。

摘　　要：Electromagnetic vibration energy harvesters are promising for the power supply of wireless sensor nodes,small electronic devices,and wearable electronics.Conventional electromagnetic harvesters usually increase output by increasing the size of coils and magnets,limiting the improvement of energy conversion efficiency and power density.In this study,multilayer microelectromechanical system(MEMS)coils were prepared using flexible electronics,and their high integration performance in arbitrary space was utilized to greatly improve the utilization of the space magnetic field by the electromagnetic harvester.The core magnet of the generator was magnetically balanced to achieve levitation,which improved the sensitivity and reduced fatigue damage compared with traditional spring structures.The wound coils on the top and bottom of the magnet and the flexible coils on the sides worked together to improve the energy efficiency and output of the devices.The output performance of the device with different number distributions was simulated using mathematical models to obtain the optimal structural parameters.The results show that by introducing flexible multilayer MEMS coils on the side surface of the energy harvester,the open-circuit voltage of the energy generators increased from 7 to 10 V by more than 43%.Flexible multilayer MEMS coils can enhance energy conversion rates and possess compact dimensions,making them suitable for integration onto complex surfaces.After the vibration energy harvesting system testing,the maximum peak power of the harvester was 7.1 m W at an acceleration of1 g and a resonant frequency of 11 Hz with a resistor of 3.5 kΩinternal resistance.Moreover,a 470μF capacitor can be charged to 3.5 V within 10 s to drive a hygrothermograph to work for more than 80 s and can supply a light bulb continuously.This strategy shows the great potential of vibration-energy-driven electromagnetic generators for powering small electronics in limited spaces.

关 键 词：electromagnetic harvester mechanical energy harvesting multilayer MEMS coils magnetic levitation overall space magnetic field flexible planar coils 

分 类 号：TM619[电气工程—电力系统及自动化]