Sun Feng, Dong Runhong, Zhou Ran, Xu Fangchao, Mei Xutao
School of Mechanical Engineering, Shenyang University of Technology, Shenyang 110870, China.
Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
Micromachines (Basel). 2022 Jun 12;13(6):936. doi: 10.3390/mi13060936.
With the rapid development of Internet of Things (IoT) and the popularity of wireless sensors, using internal permanent or rechargeable batteries as a power source will face a higher maintenance workload. Therefore, self-powered wireless sensors through environmental energy harvesting are becoming an important development trend. Among the many studies of energy harvesting, the research on rotational energy harvesting still has many shortcomings, such as rarely working effectively under low-frequency rotational motion or working in a narrow frequency band. In this article, a rotational magnetic couple piezoelectric energy harvester is proposed. Under the low-frequency excitation (<10 Hz) condition, the harvester can convert low-frequency rotational into high-frequency vibrational of the piezoelectric beam by frequency up-conversion, effectively increasing the working bandwidth (0.5−16 Hz) and improving the efficiency of low-speed rotational energy harvesting. In addition, when the excitation frequency is too high (>16 Hz), it can solve the condition that the piezoelectric beam cannot respond in time by frequency down-conversion. Therefore, the energy harvester still has a certain degree of energy harvesting ability (18−22 Hz and 29−31 Hz) under high-frequency conditions. Meanwhile, corresponding theoretical analyses and experimental verifications were carried out to investigate the dynamic characteristics of the harvester with different excitation and installation directions. The experimental results illustrate that the proposed energy harvester has a wider working bandwidth benefiting from the frequency up-conversion mechanism and frequency down-conversion mechanism. In addition, the forward beam will have a wider bandwidth than the inverse beam due to the softening effect. In addition, the maximum powers of the forward and inverse beams at 310 rpm (15.5 Hz) are 93.8 μW and 58.5 μW, respectively. The maximum powers of the two beams at 420 rpm (21 Hz) reached 177 μW and 85.2 μW, respectively. The self-powered requirement of micromechanical systems can be achieved. Furthermore, this study provides the theoretical and experimental basis for rotational energy harvesting.
随着物联网（IoT）的快速发展和无线传感器的普及，使用内置的永久性或可充电电池作为电源将面临更高的维护工作量。因此，通过环境能量收集实现自供电的无线传感器正成为一个重要的发展趋势。在众多能量收集研究中，旋转能量收集的研究仍存在许多不足，例如在低频旋转运动下很少能有效工作或在狭窄的频带内工作。本文提出了一种旋转磁耦合压电能量收集器。在低频激励（<10 Hz）条件下，该收集器可通过频率上转换将低频旋转转换为压电梁的高频振动，有效增加工作带宽（0.5−16 Hz）并提高低速旋转能量收集的效率。此外，当激励频率过高（>16 Hz）时，它可以通过频率下转换解决压电梁无法及时响应的情况。因此，该能量收集器在高频条件下仍具有一定程度的能量收集能力（18−22 Hz和29−31 Hz）。同时，进行了相应的理论分析和实验验证，以研究不同激励和安装方向下收集器的动态特性。实验结果表明，所提出的能量收集器得益于频率上转换机制和频率下转换机制，具有更宽的工作带宽。此外，由于软化效应，正向梁的带宽将比反向梁更宽。此外，正向和反向梁在310 rpm（15.5 Hz）时的最大功率分别为93.8 μW和58.5 μW。两根梁在420 rpm（21 Hz）时的最大功率分别达到177 μW和85.2 μW。可以实现微机械系统的自供电要求。此外，本研究为旋转能量收集提供了理论和实验依据。
