基于双极性驻极体的微振动能量采集器研究

发布时间：2018-05-06 03:28

本文选题：驻极体 + 双极性　；参考：《杭州电子科技大学》2017年硕士论文

【摘要】：随着微机电系统(MEMS)技术的快速发展,MEMS传感器被广泛的应用于大型桥梁或建筑的安全监控、动物跟踪、无线遥感监测等领域,并向低功耗、便携、自供能等方向发展。然而,相对滞后的微能源技术制约着MEMS传感器的发展。通过收集周围环境中的各种能源(如机械振动能、太阳能、热能等)实现自供能,构建“自驱动系统”,使得分布式的传感器能够无源、持续、免维护地运行成为当前研究的热点。基于驻极体的微振动能量采集器是自驱动系统微能源领域研究的一个重要方向。驻极体(electret)又名“永电体”,是一种能够长期储存空间电荷与偶极电荷并具有持久保持电极化强度的电介质材料。静电效应是其具有的基本物理效应。基于驻极体的微振动能量采集器正是利用其静电效应在驻极体与电极之间构建可变电容,通过外界激励改变电容量实现振动能向电能的转换。当前驻极体能量采集器的研究主要集中在驻极体材料性能与极化方法、微振动能采集方式、能量采集效率三个方面。在采集器的结构中,一般采用在驻极体材料一面镀电极的方式,没有利用驻极体材料正反两面呈现双极性的特点,因而能量转换效率较低。本文采用具有优异电荷存储性能的FEP/THV/FEP三明治型复合驻极体薄膜为对象,系统研究了该材料的双极性分布特性、以及电荷存储的稳定性和均匀性。在此基础上,提出了基于双极性驻极体的双间隙能量采集系统。通过对采集系统工作原理的理论分析,设计制备了非谐振式和谐振式两种振动能量采集器。通过对能量采集器输出特性的测量分析,研究了影响振动能量采集器输出功率的因素。所取得的主要结论如下:(1)通过高温热压工艺,将非极性材料FEP与极性材料THV复合,制备得到了三明治型复合膜材料FEP/THV/FEP;通过“电晕极化/热极化/电晕极化”的混合极化方法对复合膜进行注极,制备得到了双极性复合驻极体膜。经过200h的稳定性跟踪测试表明,驻极体薄膜呈现稳定的双极性特点,上下表面平均电位分别为-1230V和910V,表面电荷密度分别为σ1=-3.69mC/m2、σ2=2.74mC/m2。显示出了优异的电荷存储的稳定性。(2)通过自行搭建的二维表面电位分布测量平台,首次跟踪测试了三次极化后的三明治型复合膜材料FEP/THV/FEP表面电位分布的变化情况,得到了极化10.5h及200h后4cm×4cm面积样品的表面电位分布图。结果表明:极化10.5h时后,样品表面电位集中在核心区域,表面电位分布均匀,且保持较高的电位;存放200h后,样品表面电位向周围扩散,分布均匀。上下表面电场极性相反,电位变化规律相同。(3)设计了基于双极性驻极体的双空气间隙非谐振振动能量采集器。采集器中,双极性驻极体薄膜被放置在上下两电极中间,在上下电极与驻极体膜之间存在两层空气间隙,等效为两个可变电容串联。基于此结构,建立了数学理论模型,推导得到了输出电压和电流的表达式。得出了输出电压遵循正弦波特性、输出电流遵循余弦波特性的结论。(4)通过自行设计的测试平台,测试了基于双极性驻极体的双空气间隙非谐振振动能量采集器的输出特性,结果表明,输出波特性与理论推导一致,呈现交流波行为。输出行为经二极管整流后,交流输出信号负相位部分转换成正相位,并且振幅扩大,振动周期加倍。与单气隙采集器相比,在低频条件下,能量输出效率显著提高。对基于此能量采集结构设计制备的电子名片的测试表明,用手指单次触碰采集器就可点亮液晶屏幕(LCD),显示了良好的灵敏性。(5)采用在上下电极和驻极体膜之间嵌入微弹簧的方式,制备了谐振式能量采集器。通过对能量采集器的输出特性测量分析表明,输出电流、电压及功率在测量频率域30HZ~200HZ内呈现单峰对称分布,输出功率与振动幅度呈现正相关性;随驻极体膜表面电位的增大,最大输出功率增加,最佳振动频率向高频方向移动;随驻极体膜振动面积的增大,输出功率增加,最佳振动频率向低频方向移动;根据对振动驱动力与输出功率相关性实验结果的曲线拟合表明,随振动驱动力的增加,输出功率呈现类指数式增涨,当振动驱动力为0.5N时,输出功率为14.1μW,当F=2N时,输出功率高达11.12mW。由上述工作可得出,基于双极性驻极体的双气隙能量采集系统具有输出功率高、灵敏度好、制作简单等优点。本论文的工作,将会有力地促进驻极体能量采集器研究的发展,加快微振动能量采集器在“自驱动系统”中的应用进程。
[Abstract]:With the rapid development of microelectromechanical system (MEMS) technology, MEMS sensors are widely used in the safety monitoring of large bridges or buildings, animal tracking, wireless remote sensing monitoring and other fields, and are developing in the direction of low power, portable, and self supply. However, the relatively lagged micro energy source technology restricts the development of MEMS sensors. All kinds of energy in the environment (such as mechanical vibration energy, solar energy, heat energy, etc.) realize self supply and build a "self driving system", which makes the distributed sensor passive, continuous and maintenance free. The micro vibration energy collector based on electret is an important part of the research of the micro energy field of the self driving system. The electret (electret), also known as the "permanent electric body", is a dielectric material that can store space charge and dipole charge for a long time and maintain the electrode strength for a long time. The electrostatic effect is the basic physical effect. The micro vibration energy collector based on electret is using its electrostatic effect to construct between the electret and the electrode. At present, the research of the electret energy collector mainly focuses on the three aspects of the electret material performance and polarization method, the micro vibration energy acquisition mode and the energy acquisition efficiency. In the collector structure, the electret material is usually plated on the electret material. In a polar way, the energy conversion efficiency is low by using the positive and negative two sides of the electret material, so the energy conversion efficiency is low. In this paper, the FEP/THV/FEP sandwich composite electret film with excellent charge storage performance is used as the object. The bipolar distribution characteristics of the material and the stability and uniformity of the charge storage are systematically studied. On this basis, a dual gap energy acquisition system based on bipolar electret is proposed. Through the theoretical analysis of the working principle of the acquisition system, two kinds of non resonant and harmonious vibrational energy collector are designed and prepared. The output power of the vibration energy collector is studied by measuring and analyzing the output characteristics of the energy collector. The main conclusions are as follows: (1) the sandwich composite membrane material FEP/THV/FEP was prepared by compounding the non polar material FEP and the polar material THV through the high temperature hot pressing process, and the bipolar composite electret was prepared by the mixed polarization method of "corona polarization / thermal polarization / corona polarization". The stability tracking test of the 200H shows that the electret film shows a stable bipolar characteristic, the average potential of the upper and lower surfaces is -1230V and 910V, the surface charge density is respectively Sigma 1=-3.69mC/m2, and the sigma 2=2.74mC/m2. shows excellent stability of the charge storage. (2) the two-dimensional surface potential distribution is measured by self constructed flat surface. The surface potential distribution of the sandwich composite membrane material FEP/THV/FEP after three polarizations was measured for the first time. The surface potential distribution map of the area samples of 4cm x 4cm after polarization 10.5h and 200H was obtained. The results showed that the surface potential of the sample was concentrated in the core area after polarization 10.5h and 200H, and the surface potential distribution was uniform and maintained. High potential, after storage of 200H, the surface potential of the sample diffuses around and distributes evenly. The electric field polarity is opposite to the upper and lower surface, and the potential change law is the same. (3) a double air gap non resonant vibratory energy collector based on bipolar electret is designed. The bipolar electret film is placed in the middle and down of the two electrodes in the collector. There are two layers of air gap between the pole and the electret film, which is equivalent to two variable capacitance series. Based on this structure, a mathematical model is established and the expression of the output voltage and current is derived. The conclusion is drawn that the output voltage follows the characteristic of the sine wave and the output current follows the Yu Xianbo characteristic. (4) through the self designed test platform, The output characteristics of the dual air gap non resonant vibration energy collector based on the bipolar electret are tested. The results show that the output wave characteristic is consistent with the theoretical deduction and presents the behavior of the AC wave. After the diode rectifier, the negative phase part of the AC output signal is converted into positive phase, and the amplitude of the amplitude is enlarged and the vibration period doubles. The energy output efficiency of the air gap collector is significantly increased in low frequency conditions. The test of the electronic card based on the design of this energy acquisition structure shows that the finger single touch collector can light the liquid crystal screen (LCD), showing good sensitivity. (5) the use of a square spring between the upper and lower electrodes and the electret film is used. The output characteristics of the energy collector show that the output current, the voltage and the power show a single peak symmetry distribution in the measurement frequency domain 30HZ~200HZ, and the output power and the amplitude of the vibration show a positive correlation; with the increase of the surface potential of the electret film, the maximum output power is increased and the optimum vibration is obtained. With the increase of the vibration area of the electret film, the output power increases and the optimum vibration frequency moves to the low frequency direction. According to the curve fitting of the experimental results of the vibration driving force and the output power, the output power presents an exponential increase with the increase of the vibration driving force, when the vibration driving force is 0.5N When the output power is 14.1 u W, when F=2N, the output power is up to 11.12mW. by the above work, the dual air gap energy acquisition system based on bipolar electret has the advantages of high output power, good sensitivity and simple fabrication. The work of this paper will effectively promote the development of the electret energy collector research and accelerate the micro vibration kinetic energy. The application process of volume harvester in self driving system.

【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM619

【参考文献】