Jackson Nathan
Center for High Technology Materials & Mechanical Engineering Department, University of New Mexico, Albuquerque, NM 87106, USA.
Micromachines (Basel). 2020 May 15;11(5):500. doi: 10.3390/mi11050500.
Increasing the power density and bandwidth are two major challenges associated with microelectromechanical systems (MEMS)-based vibration energy harvesting devices. Devices implementing magnetic forces have been used to create nonlinear vibration structures and have demonstrated limited success at widening the bandwidth. However, monolithic integration of a magnetic proof mass and optimizing the magnet configuration have been challenging tasks to date. This paper investigates three different magnetic configurations and their effects on bandwidth and power generation using attractive and repulsive magnetic forces. A piezoMEMS device was developed to harvest vibration energy, while monolithically integrating a thick embedded permanent magnet (NdFeB) film. The results demonstrated that repulsive forces increased the bandwidth for in-plane and out-of-plane magnetic configurations from <1 to >7 Hz bandwidths. In addition, by using attractive forces between the magnets, the power density increased while decreasing the bandwidth. Combining these forces into a single device resulted in increased power and increased bandwidth. The devices created in this paper focused on low acceleration values (<0.1 g) and low-frequency applications.
提高功率密度和带宽是与基于微机电系统（MEMS）的振动能量采集装置相关的两个主要挑战。采用磁力的装置已被用于创建非线性振动结构，并且在拓宽带宽方面取得了有限的成功。然而，迄今为止，磁质量块的单片集成以及磁体配置的优化一直是具有挑战性的任务。本文研究了三种不同的磁体配置，以及吸引力和排斥力对带宽和发电的影响。开发了一种压电MEMS装置来采集振动能量，同时单片集成了一层厚的嵌入式永磁体（钕铁硼）薄膜。结果表明，排斥力使面内和面外磁体配置的带宽从小于1Hz增加到大于7Hz。此外，通过利用磁体之间的吸引力，功率密度增加，同时带宽减小。将这些力组合到单个装置中可提高功率并增加带宽。本文所制造的装置专注于低加速度值（<0.1g）和低频应用。
