旋转式自调频振动能量收集器的频率自匹配机理研究

One of the main research tasks of vibration energy harvester（VEH）is to solve the frequency mismatch between the working frequency of the VEH and the ambient excitation frequency. For this scientific issue, this proposal aims to study the mechanism of frequency self-matching which is achieved by adjusting the resonant frequency of piezoelectric vibration energy harvester (PVEH) with its own centrifugal force. In this proposal: ① The mechanism of frequency self-matching achieved by a novel method of frequency self-adjusting is researched — the resonant frequency of PVEH is adjusted by changing both the mass center position of the tip mass on the beam and the area moment of inertia of the beam simultaneously using its own centrifugal force. Then the theoretical model of the resonant frequency self-matching PVEH is established; ②A novel structure of resonant frequency self-matching PVEH is proposed —this proposed PVEH consists of a main beam whose area moment of inertia is related to the length of the beam, an auxiliary beam only whose tensile stiffness is not zero and a mass which is constrained to slide in the longitudinal direction of the main beam. The influence law of the area moment of inertia of the main beam and the mass center position of the tip mass on both the frequency matching range and output performance of the PVEH is mainly studied, and then the optimization design method of the resonant frequency self-matching of PVEH is developed. ③A prototype of resonant frequency self-matching PVEH to verify the correctness of the proposed frequency self-matching method is developed and power output of the developed prototype can meet the requirements of tire pressure monitoring system in the tire speed range of 40-160km/h. This study is of great significance for enriching the frequency matching methods of the VEH and promoting practical applications of the VEH.

解决振动能量收集器（VEH）的工作频率与环境激励频率不匹配的问题是VEH的主要研究任务之一。本项目围绕此科学问题，拟开展利用自身离心力调节VEH共振频率实现频率自匹配的机理研究。具体研究内容为：①研究利用离心力同时改变质量块质心在悬臂梁上的位置和悬臂梁的截面惯性矩调节压电VEH（PVEH）共振频率实现频率自匹配的机理，建立频率自匹配的PVEH理论模型；②提出由截面惯性矩与梁长有关的主梁、只有拉伸刚度不为零的副梁和约束在主梁长度方向滑动的质量块构成的频率自匹配PVEH新结构，重点研究悬臂梁截面惯性矩、质量块质心位置对PVEH频率匹配范围和输出性能的影响规律，发展频率自匹配PVEH优化设计方法；③研制出在轮胎转速为40~160km/h范围内输出电能都能满足胎压监测系统需求的频率自匹配PVEH原理样机，验证频率自匹配方法的正确性。本研究对于丰富VEH频率匹配方法、推动VEH应用具有重要意义。

将环境中的动能转化为电能为微电子设备供电的能量收集技术是近年来的研究热点，其主要的挑战是解决振动能量收集器（VEH）谐振频率与环境激励频率不匹配的矛盾。本项目针对该科学技术问题，开展了旋转式自调频振动能量收集器的频率自匹配机理研究。研究了转动激励下VEH实现频率自匹配的机理，提出了通过刚柔耦合效应调频和离心力改变悬臂梁有效长度调频共同作用实现频率自匹配的方法；提出了同时实现刚柔耦合和离心力改变悬臂梁长度的自调频VEH新结构，并建立了考虑刚柔耦合效应的VEH理论模型；分析了调频质量块、附加质量块等关键结构参数对VEH频率匹配范围和输出性能的影响规律，根据面向胎压监测系统应用环境特点，完成了自调频VEH结构设计；研制出了自调频VEH样机，搭建了转动测试平台，完成了样机的性能测试与分析。研制的样机转速最大匹配范围为580-890RPM，对应输出电压峰峰值最大可达56.8V，最大输出功率为1.24mW，验证了项目提出的频率自匹配方法的有效性。本项目的实施丰富了VEH频率自匹配的方法，为推动VEH的实用化提供了理论和技术支撑。