动态多稳态压电风能俘能结构设计与实验验证

Design and Experimental Verification of Dynamic Multi-stable Piezoelectric Wind Energy Harvester

传统的线性颤振式风能俘能结构在变风速环境下转换效率不高.针对此问题,论文提出了一种动态多稳态颤振式压电俘能结构,可在较宽的风速范围内保持较高的电压输出.该结构在悬臂梁自由端有一矩形平板和一永磁体,并在梁自由端附近放置两个固定永磁体,磁铁间的磁吸力使结构具有两个静态稳定平衡位置和一个动态稳定平衡位置.为了验证所提出结构的优越性,加工了实验装置,开展了不同风速下风能转换效率的研究.发现当风速较小时,该结构具有双稳态特性;而当风速较大时,结构会出现新的稳定位置,变为三稳态系统.利用这种动态多稳态特性,可在很宽的风速范围内实现阱间跳跃并伴随高电压输出.实验结果表明,这种动态多稳态结构,当风速在2.0 m/s-7.5 m/s区间变化时,能够激发并保持阱间跳跃,甚至相干共振.因此,该结构可在宽风速阈环境下保障电能的高效输出.

The traditional flutter wind energy harvester is found to be inefficient for variable-speed wind.Aiming at solving this problem,this paper proposes a dynamic multi-stable flutter piezoelectric energy harvester capable of maintaining a high voltage output over a wide range of wind speeds.This structure consists of a cantilever with a rectangular flat plate and a tip magnet,a pair of fixed magnets and a piezoelectric patch.It owns two static and one dynamic equilibrium positions.To prove the harvester's superior performance,a prototype is fabricated.The validation experiments are carried out at different wind speeds.The results show that this harvester exhibits bi-stable characteristics at a low wind speed,and tri-stable characteristics at a high wind speed.For high-speed wind,an additional neutral equilibrium position emerges and becomes stable gradually.The results show that this harvester outperforms the traditional one over a wide range of wind speeds.It can execute snap-through and even coherent resonance at the wind speed varying from 2.0 m/s to 7.5 m/s,thus keeping a large output for the variable-speed wind.