【作者】 于斌；

【导师】 张宇峰；

【作者基本信息】 哈尔滨工业大学 ， 集成电路工程（专业学位）， 2019， 硕士

【摘要】 近些年,无线传感技术因为环境适应性强、功耗较小、独立且持久的优点被广泛的应用到了各个不同的领域,但是传统电池供电时间短、必须经常更换等问题限制了该技术的发展。能量收集技术是解决这个问题的好办法。光能、海洋能、温差能、振动能等资源是日常生活中常见的能量,但是振动能因为其不受环境所限的优点,被广泛应用到各种设备中。振动能量收集器主要有三种形式,分别是压电式、电磁式和静电式。压电式能量收集器具有输出电压比较大、能量密度高、容易与MEMS集成、环境适应性强的优点,对本课题来说是十分合适的选择。针对环境中低频振动的能量不方便收集的缺点,本文考虑将低频驱动作为研究重点。本课题的设计包含有两个特征频率不同的悬臂梁结构,其中长梁为普通悬臂梁,特征频率比较低,起驱动的作用;而短梁是压电悬臂梁,特征频率比较高,负责收集驱动引起的振动能量;永磁体作为悬臂梁的质量块,将这两个特征频率差别很大的悬臂梁通过磁场耦合为一个整体。外界振动能量通过长梁收集,经过磁场传递到压电悬臂梁,从而产生电流的输出,在此过程中也完成了从低频振动到高频的转化。压电悬臂梁是整个系统的核心结构,通过特征频率分析找到最佳尺寸来适合环境的振动频率;通过频率分析电阻和加速度对输出功率的影响,找到最合适的负载电阻和加速度参数。在对长梁和短梁建模仿真以及磁场耦合后,需要对系统整体结构仿真。通过对整体结构的几何模型、电势分布、输出电压瞬态特性、磁力瞬态特性、磁通密度模变化进行仿真,得到一系列性能参数。最后通过制作低频驱动悬臂梁式振动能量收集器的实物、设计后端的能量收集电路、搭建振动台测试系统等一系列措施,进行了能量采集器的物理测试,并通过与仿真结果的比较验证了建模仿真的正确性。对压电悬臂梁来说,在91.5Hz的振动频率、负载电阻为18.1kΩ、加速度为1g时输出功率达到最大值1.67mW;对整个系统结构来说,实现了频率的提升,信号输入频率为2Hz时,输出信号的频率为91.5Hz,功率为0.71mW。更多还原

【Abstract】 In recent years,wireless sensing technology has been widely used in various fields due to its strong environmental adaptability,low power consumption,and independence and durability.However,the problem that the traditional battery power supply time is short and must be replaced frequently limits the development of this technology.Energy harvesting technology is a good way to solve this problem.Light energy,ocean energy,temperature difference energy,vibration energy and other energy are common in daily life,but vibration energy is widely used in various equipment because it is not limited by the environment.There are three main types of vibration energy harvesters,namely piezoelectric,electromagnetic and electrostatic.Piezoelectric energy harvesters have the advantages of large output voltage,high energy density,easy integration with MEMS,and strong environmental adaptability,which is a very suitable choice for this topic.In view of the inconvenience of low-frequency vibration energy collection in the environment,this paper considers low-frequency drive as the research focus.The design of this subject contains two cantilever beam structures with different characteristic frequencies.The long beam is an ordinary cantilever beam,the characteristic frequency is relatively low,and it plays the role of driving;while the short beam is a piezoelectric cantilever beam,the characteristic frequency is relatively high,and it is responsible for collecting the vibration energy caused by the driving;the permanent magnet is used as the mass of the cantilever beam,The two cantilever beams with widely different characteristic frequencies are coupled as a whole by a magnetic field.The external vibration energy is collected by the long beam and transmitted to the piezoelectric cantilever beam through the magnetic field,thereby generating the output of electric energy.The conversion from low frequency vibration to high frequency is also completed in this process.The piezoelectric cantilever is the core structure of the whole system.It finds the optimal size by characteristic frequency analysis and is suitable for the vibration frequency of the environment.Through the analysis of the influence of the resistance and acceleration on the output power,the most suitable load resistance and acceleration parameters are found.After long beam and short beam modeling and simulation,magnetic field coupling,the overall structure of the system needs to be simulated.A series of performance parameters are obtained by simulating the geometric model of the overall structure,potential distribution,output voltage transient characteristics,magnetic transient characteristics,and flux density mode changes.Finally,through the production of low-frequency driving cantilever vibration energy harvester,designing the subsequent energy harvesting circuit,building a vibration table test system and other measures,the physical test of the energy harvester was carried out,and verified by comparison with the simulation results.The correctness of the modeling simulation.For the piezoelectric cantilever beam,the output power reaches a maximum value of 1.67 mW at a vibration frequency of91.5Hz,a load resistance of 18.1kΩ,and an acceleration of 1g.For the entire system structure,the frequency is increased,and the signal input frequency is At 2 Hz,the output signal has a frequency of 91.5 Hz and an output power of 0.71 mW.更多还原