压电俘能器涡激振动俘能的建模与实验研究

Modeling and Experimental Study of Piezoelectric Energy Harvester under Vortex-Induced Vibration

针对微机电系统和传感器等低能耗电子产品的持续供能问题,提出了一种涡激振动式压电俘能器。该俘能器由压电悬臂梁和末端圆柱体组成,结构简单,可在较低水流流速下产生涡激共振,得到较大的能量输出。通过数学建模和实验测试的方法,研究了水流速度和外接电阻对压电俘能器振动和俘能的影响规律。实验结果表明:压电俘能器的振动频率随流速的增大而增大,振动幅值在涡激共振时最大,输出功率受流速和外接电阻两者影响,较小外接电阻适合较高流速,较大电阻适合较低流速,压电俘能器在涡激共振处可获得最大的能量输出,当外接电阻为0.5 MΩ、流速为0.41m/s时,实验测试得到了8.3μW的最大输出功率。数值分析结果与实验测试结果吻合较好,验证了数学模型的正确性。

A vortex-induced piezoelectric energy harvester（PEH）is proposed to meet the requirement of continuous energy supply for low energy-consumed electronic devices such as MEMS and sensors.The PEH is composed of a piezoelectric cantilever beam and a cylinder and has a simple mechanical structure.The PEH generates vortex-induced resonance at relatively low water velocities and obtains larger output powers.Effects of both the water velocity and the resistance on hydrodynamic response and energy harvesting ability of the PEH are investigated through mathematical modeling and experimental study.It is found that the vibration frequency increases as the velocity increases and the maximum vibration amplitude is found when the vortexinduced resonance appears.The Output power depends on both the water velocity and the resistance.More output power can be achieved through configurations of a smaller resistance with a higher velocity or a larger resistance with a lower velocity.The maximum output power is obtained with vortex-induced resonance.The maximum output power of 8.3μW is obtained in experimental study with 0.5 MΩand 0.41m/s.Furthermore,the results of numerical study are consistent with those of the experimental study well,and the validity of the mathematical model is verified.