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1、 硕士学位论文硕士学位论文 流体耦合压电俘能器的研究 RESEARCH ON FLUID-COUPLED PIEZOELECTRIC ENERGY HARVESTER （学术型） 范兆凯范兆凯 哈尔滨工业大学哈尔滨工业大学 2013 年年 7 月月 国内图书分类号：TM619 学校代码：10213 国际图书分类号：621.3 密级：公开 工学工学硕士硕士学学位论文位论文 流体耦合压电俘能器的研究 （学术型） 硕 士 研 究 生 ： 范兆凯 导 师 ： 陈维山 教授 申请学位 ： 工学硕士 学科 ： 机械电子工程 所 在 单 位 ： 机电工程学院 答 辩 日 期 ： 2013 年 7 月 授予学
2、位单位 ： 哈尔滨工业大学 Classified Index: TM619 U.D.C: 621.3 Dissertation for the Master Degree in Engineering RESEARCH ON FLUID-COUPLED PIEZOELECTRIC ENERGY HARVESTER (Academic) Candidate： Fan Zhaokai Supervisor： Prof. Chen Weishan Academic Degree Applied for： Master of Engineering Speciality： Mechatronics E
3、ngineering Affiliation： School of Mechatronics Engineering Date of Defence： July, 2013 Degree-Conferring-Institution： Harbin Institute of Technology 哈尔滨工业大学工学硕士学位论文 - I - 摘 要 随着微电子技术和无线电技术的飞速发展，无线传感器已经在多个领域广泛应用，在能量供给方式上仍以传统的化学电池为主。由于化学电池存在的问题日益突出，如生命周期短，需要定期更换或者再充电，体积大，回收困难、污染环境等，因此寻求新型的能量供给方式尤为必要。基
4、于压电效应的压电发电方式能够将环境的振动能转换为电能，能够产生较高电压，可以直接为电子器件供能，且结构简单，易于加工制作，便于集成化和微型化，能适应于条件比较恶劣的环境中，因此压电发电技术逐渐成为研究热点。当压电发电装置的谐振频率与外界激励频率相近达到谐振状态时俘能效果较好，但是一般环境频率并不固定，因此通过对结构进行适当设计使其谐振频率随着外界激励频率值的改变而改变就变得尤为重要。本文提出一种利用液体对压电振子进行固有频率调节的方法，根据没入液体深度的不同而改变俘能器的谐振频率，实现在一定的宽频范围内实现良好的俘能效果。 首先， 建立了悬臂梁压电俘能器的振动模型， 分析对俘能功率有影响的参数
5、。分别建立在空气中和液体中时压电俘能器固有频率的理论公式，并将空气中固有频率与完全没入液体中固有频率之差作为液体对俘能器的频率调节范围，对影响频率调节范围的不同参数进行了数值分析。 接着对俘能器在空气和液体的情况进行 ANSYS 有限元仿真分析。 对俘能器在空气和液体中的情况进行模态分析，得到不同没入深度比的情况下的固有频率，并对数值分析结果进行验证。对空气和液体情况下俘能器的俘能特性进行仿真分析，主要分析不同没入深度比的情况下俘能器的开路特性，内阻抗特性，最优功率，带宽和品质因数等，并对结构参数对发电能力的影响进行分析。 最后通过建立实验装置对理论分析和仿真分析结果进行验证。通过不同没入深度
6、比的情况下下的谐振频率对数值结果和仿真结果进行验证，研究了不同参数对频率调节范围的影响，通过示波器记录停止激振后的衰减曲线对阻尼比进行计算，与仿真分析相同，研究不同没入深度比情况下的俘能特性，并分析验证不同的结构参数对俘能器压电发电能力的影响。 关键词：压电俘能器；流体耦合；悬臂梁；固有频率；有限元仿真；附加质量 哈尔滨工业大学工学硕士学位论文 - II - Abstract With the rapid development of microelectronics technology and wireless technology, wireless sensors are widely
7、 used in many application areas. The mostly used in energy supplication are traditional chemical batteries. As the problems of chemical battery are increasingly prominent, such as short lifetime, requires periodic replacement, large volume, difficult in recycling, environmental pollution, etc, its p
8、articularly essential to pursue new method of energy supplication. Piezoelectric power generation, based on piezoelectric effect and can convert kinetic energy to electric energy, is becoming a research hotspot for the reasons as follows: it can produce a higher voltage, can directly supply energy t
9、o electronic devices, has simple structure which is easy in manufacturing, integration and miniaturization, and can adapt to relatively harsh environment. The convention effectiveness is better when the resonance is achieved as the resonance frequency of the piezoelectric power generating device is
10、close to the external excitation frequency. However, the frequency of the environment is not fixed generally, so it becomes particularly important designing the structure appropriately to change its resonant frequency to match the changing-frequencies of the environment. This paper presents a method
11、 of changing the natural frequency of the piezoelectric energy harvester by changing the immersing depth ratio of in liquid. In that way, good results are achieved in certain broad frequency ranges. Firstly, the vibration model of piezoelectric cantilever beam is established, the parameters of influ
12、encing generation power are analysised. The natural frequency of piezoelectric energy harvester in vacuum and fluid are separately built. Treat the difference between the two frequencies as frequency adjusting range, different parameters influencing the frequency adjusting range are investigated usi
13、ng numerical method. Then the simulation analysis of piezoelectric energy harvester in the 2 different kinds of medium is performed using the finite element analysis software ANSYS. The modal analysis is conducted and natural frequencies are obtained of different situation in depth ratio. Comparison
14、 is made between the simulation and the numerical results to verifying the theoretical analysis. The energy harvesting properties of different depth ratio are simulated mainly including the following aspects: open-circuit characteristic, internal impedance characteristic, optimal power, bandwidth an
15、d quality factor, etc. The influence of structural parameters on power generation capacity is also investigated. Finally, the experimental system is established to validate the theoretical and the simulation results. The resonant frequencies of different depth ratio are obtained and verification is
16、made between experimental results, theoretical and the simulation results. The attenuation curve is recorded right after excitation through oscilloscope, and the 哈尔滨工业大学工学硕士学位论文 - III - damping ration of different cases are calculated. As with the simulation analysis, the energy harvesting properties are obtained. And the influence of structural parameters on power generatio
