多稳态压电俘能系统的力电耦合机理研究

Piezoelectric vibration energy harvesting belongs to green energy, and it aims to solve the challenging issue of the energy supply for wireless sensors and small embedded devices. The multi-stable piezoelectric energy harvester is one of most recent nonlinear harvesters and owns excellent energy harvesting performance. In order to improve the energy harvesting efficiency, mechanical-electrical coupling mechanism among the external circuit, the host structure and piezoelectric transducer of the harvester will be investigated. Firstly, a complete dynamic model of the multi-stable piezoelectric energy harvester under environmental excitations will be established to obtain the theoretical solutions and dynamic responses. Secondly, the multi-freedom model of the host structure, the piezoelectric transducer and the external circuit will be deduced and analyzed to reveal the mechanical-electrical coupling mechanism and its influence on nonlinear characteristics of the harvester. Finally, the optimization design method for the multi-stable piezoelectric energy harvester to maximize its energy harvesting efficiency will be presented. With thoroughly theoretical, experimental and optimization study on the mechanical-electrical coupling mechanism of multi-stable piezoelectric energy harvesters, the project will play a significant role in developing and improving nonlinear energy harvesting techniques, which will also be helpful in stimulating the interdisciplinary research between mechanics and electricity.

压电振动能量俘获属于绿色能源，旨在解决无线传感器、嵌入式微型机电设备的持续供电问题。多稳态压电俘能系统具备优异的能量俘获特性，为提高其能量俘获效率，本项目以弄清多稳态压电俘能系统的外接电路与宿结构和压电换能器之间的力电耦合机理，以发展能量俘获效率最大化的多稳态压电俘能系统的优化设计方法为目的，建立多稳态压电俘能结构的动力学模型，进行理论分析，得到环境激励下俘能结构的动力学响应和理论解；设计高效的外接电路，对宿结构、压电换能器与外接电路组成的多自由度系统进行数学建模，分析力电耦合关系及其对俘能系统的非线性振动特性的影响机制；发展能量俘获效率最大化的多稳态压电俘能系统的优化设计方法。通过对多稳态压电俘能系统的力电耦合机理问题的分析、实验与优化研究，对发展和完善非线性振动能量俘获技术，促进力学和电学的学科交叉具有重要意义。

随着传感器技术、电子技术、材料科学与技术等领域的快速发展，大量微型化、低功耗无线传感器和嵌入式设备已经应用到各种结构、设备、周围环境甚至人体，对结构健康监测、灾难性事故预防以及人体健康监测等均起着关键作用。压电振动能量俘获旨在解决这些低功耗设备的持续供电问题，其中多稳态压电俘能系统具有优异的能量俘获特性和丰富的动力学现象，得到了国内外学者的广泛关注。为了提高能量俘获效率，本项目主要开展了三个方面研究工作：（1）多稳态压电俘能系统的结构设计、动力学建模及理论分析；（2）外接电路、宿结构和压电换能器之间的力电耦合机理研究;（3）多稳态压电俘能系统的参数分析和优化设计。.研究发现在旋转环境中离心效应对多稳态能量俘获系统可以起到调频作用，进而可以跟环境旋转频率相匹配。此外，当环境振动较弱时，可以设计具有更多平衡点数量的多稳态能量俘获系统；当环境振动很强时，可以设计具有更少平衡点数量的多稳态能量俘获系统。外接电路（一种同步电荷提取电路）对多稳态能量俘获结构产生明显的电阻作用，进而影响了后者的动力学响应（包括工作频带和输出电压幅值），应充分考虑。最后，研究发现多稳态能量俘获系统对环境激励的不确定性高度敏感，而对系统参数具有一定的鲁棒性（即机械制造和装配带来的微小误差对系统影响较小）。因此，在未来优化设计中应充分考虑应用环境激励的不确定性。本项目的研究成果对振动能量俘获领域的未来发展具有参考和借鉴作用，对实现在线智能健康监测及物联网的发展起着促进作用。