压电式宽带振动能量高效采集系统设计基础研究

The development of self-powered MEMS and wireless sensor networks for industry and intelligent systems has attracted considerable attention in the research field during the last decade. Because of the fast developments of very-large-scale integration systems have significantly reduced the power requirements of micro-electronic components to the range of tens to hundreds of microwatts, it is possible to harvest environmental energy as the power supply instead of using batteries. Vibration energy harvesting using piezoelectric materials has become the most popular energy harvesting technique, which has a good potential to generate adequate power. However, there is a limitation for the conventional beam-shaped harvester designs in real applications due to their limited bandwidth in each single mode and the higher modes are far away from the first mode. In order to overcome this limitation, the essential objective of this project is to enhance the broadband performance of harvesters for multi-modal structures. The main tasks of this project are summarised as follows: .(1) Design and optimize novel linear multi-modal harvesters; develop analytical models and determine the optimal parameters to maximize the effective bandwidth of the multi-modal harvesters..(2) Investigate how nonlinearities can affect the vibration energy distributions and power output performances of the multi-modal harvesters; enhance the non-resonance performance by optimizing the nonlinearities. .(3) Study the effects of configurations and material properties of the piezoelectric layers on electro-mechanical coupling of harvesters; develop a system without anti-resonance between two adjacent modes by optimizing the configurations of the piezoelectric layers..(4) Once the harvesters are designed and optimized for real applications using the broadband techniques, investigate the effective bandwidth and power output performance of multi-modal harvesters when rectifier circuits are connected..Based on the study of the four aspects, the multi-modal harvesters can achieve good broadband performance, which have close resonance frequencies and relatively large power output in multiple modes while non-resonance performance are also significantly enhanced.

压电振动能量采集装置具有功率密度较高、环境干扰小、易于微型化等优点，是未来有望替代电池而应用于微机电系统和无源无线传感器的新能源技术。但是，受单个共振峰带宽限制，传统采集装置对环境中宽频、低频振动能量的采集很不充分。本项目针对现有宽频带技术存在的不足，提出了改进思路并将进行以下研究：1）探索多模态结构下压电耦合动力学特性以及宽频带特征，提出多模态结构优化设计方法，确定不同模态数量下的最优结构参数，实现带宽最优化；2）探索多模态结构的非线性振动在频带间的响应特征，设计引入有益非线性振动进一步优化宽频带性能；3）探索压电元件结构参数和材料特性对机电耦合的影响，针对高阶模态下电耦合特性优化多模态间非谐振区域性能；4）针对环境振源设计优化宽带采集装置，并探索采集电路对采集性能的影响。通过上述研究，掌握采集装置在多模态下的频响特征和宽频带优化设计方法，为压电振动能量采集技术成熟化奠定理论基础。