Vibration energy harvesting has attracted considerable attention because of its application prospects for charging or powering micro-electro-mechanical system. Abundant hydrokinetic energy of water at low velocity is contained in the fluid environment, such as rivers and oceans, which are widely existing in nature. In this paper, a flow-induced piezoelectric vibration energy harvester (PVEH) with magnetic force enhancement, which is integrated by piezoelectric beam, circular cylinder bluff body and magnets, is proposed and experimental investigated. It could transfer the hydrokinetic energy, both the vortex-induced vibration and magnetic force excitation underwater, into electricity. First, the frequency sweep experiment of the piezoelectric cantilever beam is carried out to determine the resonance frequency where the effect of magnetic force on the vibration characteristic is obtained. Furthermore, the flow-induced vibration experiment platform is setup and the energy harvesting performance of the PVEH is investigated in detail. The effects of the magnet property, flow velocity and the magnetic poles distance on the vibration frequency and the acquisition voltage are demonstrated and discussed. The results show that it could improve the harvesting performance by introducing magnetic force. It has advantages in higher output voltage for the flow-induced PVEH, especially in low velocity water flow, when the flow velocity is 0.35 m/s, the PVEH under attractive magnetic force with magnetic distance of 20 mm scavenges the higher acquisition voltage of 5.2 V, which is increased by 225% than the PVEH with non-magnetic. The results can be applied to guide further fabrication process and optimized design of the proposed flow-induced PVEH underwater with low flow velocity.

振动能量收集由于对微机电系统充电或供电的应用前景而备受关注。在自然界中广泛存在的河流和海洋等流体环境中，含有大量低速的水动能。本文提出了一种由压电梁，圆柱钝体和磁体结合而成的具有磁力增强作用的流致压电振动能量采集器（PVEH），并进行了实验研究。它可以将涡流引起的振动和水下磁力激发的流体动能转化为电能。第一，进行压电悬臂梁的扫频实验以确定共振频率，在共振频率下可获得磁力对振动特性的影响。此外，建立了流致振动实验平台，并详细研究了PVEH的能量收集性能。演示并讨论了磁体性能，流速和磁极距离对振动频率和采集电压的影响。结果表明，通过引入磁力可以提高收割性能。对于流速引起的PVEH，它具有较高的输出电压的优势，尤其是在流速为0.35 m / s的低速水流中，在具有20 mm磁距的有吸引力的磁力下，PVEH清除了5.2 V的较高采集电压，该电压比非磁性PVEH增大了225％。研究结果可用于指导低流速水下引水PVEH的进一步制造工艺和优化设计。