ABSTRACT

Through a snap-through process, the bistable vibration energy harvester (EH) could undergo large amplitude motion and yield a large energy output. But realizing the transitions between the stable states is a prerequisite for high power output of the bistable piezoelectric EH. To explore the conditions under which the harvester could switch from one stable state to the other, a bistable vibration EH based on PVDF film and its analytical model are investigated. The mechanisms responsible and the transitions of the harvester between the stable states are derived. The relationship between the PVDF axial compression distance, the mass of the proof mass, the excitation frequency and the critical switching force is obtained. The numerical simulation analysis of the bistable vibration EH is conducted. The effects of the different design parameters on the output performance of the EH are analyzed. The boundary conditions for the PVDF beam to realize the transitions between the stable states are obtained. A prototype of a bistable vibration EH was fabricated and measured. When the excitation frequency is 14 Hz, the mass of the proof mass is 12 g, the axial compression distance of the PVDF beam is 0.2 mm, the EH’s RMS output voltage value is 4.2 V with the load resistance of 1 MΩ. The maximum output power of 22.85 μW is obtained at the load resistance of 0.7 MΩ. It is found that the excitation frequency of implementing the transitions between the stable states increases with increasing the axial compression distance of the PVDF beam. The characteristic experimental results are contrasted with the simulation analysis results, which prove the validity of the presented model.

摘要

通过快速通过过程，双稳态振动能量收集器 (EH) 可以进行大振幅运动并产生大能量输出。但实现稳态之间的转换是双稳态压电 EH 高功率输出的先决条件。为了探索收割机从一种稳定状态切换到另一种稳定状态的条件，研究了基于 PVDF 薄膜的双稳态振动 EH 及其分析模型。导出负责机制和收割机在稳定状态之间的转换。得到PVDF轴向压缩距离、质量块质量、激励频率和临界开关力之间的关系。对双稳态振动EH进行了数值模拟分析。分析了不同设计参数对 EH 输出性能的影响。获得了 PVDF 梁实现稳态之间转变的边界条件。制造并测量了双稳态振动 EH 的原型。当激励频率为14 Hz，质量块质量为12 g，PVDF梁的轴向压缩距离为0.2 mm，EH的RMS输出电压值为4.2 V，负载电阻为1 MΩ。在负载电阻为 0.7 MΩ 时获得 22.85 μW 的最大输出功率。研究发现，随着PVDF梁轴向压缩距离的增加，实现稳态之间转变的激励频率增加。特征实验结果与仿真分析结果对比，