单磁耦合式压电振动俘能器的建模与试验

In order to achieve the recovery of high-reliability and wide-band vibration energy, a single magnetic-coupled piezoelectric vibration energy harvester is proposed. The dynamic equation of the energy harvester is established, and the effects of the horizontal coupling distance d, the vertical coupling distance h and the coupling angle α of the magnets on the potential energy are analyzed by using COMSOL simulation; a prototype is designed and fabricated, and experimental tests are carried out. The test results show that the potential energy curve of the energy harvester changes from a single potential well to a double potential well as the horizontal coupling distance d decreases, and there is an optimal horizontal coupling distance of the magnets (d = 11mm), which makes the well depth of the double potential well moderate, the natural frequency of the energy harvester decreases, and the effective frequency band widens; the increase of the vertical coupling distance h has a small impact on the effective frequency band, and when h≤2mm, the natural frequency is reduced compared with that without magnetic coupling (NMC); when only the coupling angle α is changed, there is an optimal parameter combination (d = 14mm, h = 6mm, α = 67.5°) that enables the energy harvester to obtain a lower natural frequency (16Hz) and a wider effective bandwidth (19.6Hz), which is 6Hz wider than the effective bandwidth without magnetic coupling, thus improving the power generation performance of the energy harvester.

为实现高可靠性及宽频带振动能量的回收,提出了一种单磁耦合式压电振动俘能器。建立了俘能器的动力学方程,采用COMSOL仿真分析了磁铁水平耦合距离d、竖直耦合距离h及耦合角α对势能的影响;设计制作了样机,并进行了试验测试。试验结果表明,俘能器的势能曲线随水平耦合距离d减小由单势阱变为双势阱,且存在较佳的磁铁水平耦合距离(d=11mm),使双势阱的阱深适中、俘能器的固有频率减小、有效频带变宽;竖直耦合距离h增大对有效频带的影响较小,h≤2mm时,相较于无磁耦合(NMC)降低了固有频率;仅改变耦合角α时,存在最佳参数组合(d=14mm、h=6mm、α=67.5°)使俘能器获得较低的固有频率(16Hz)和较宽的有效带宽(19.6Hz),较无磁耦合时的有效带宽拓宽了6Hz,进而提高了俘能器的发电性能。