通过侧向条增加压电振动能量采集器的机电耦合
Increase of the electromechanical coupling of piezoelectric vibration harvesters through lateral bars
- Université Savoie Mont-Blanc（萨瓦蒙布朗克大学）
- Université de Bordeaux, CNRS, Bordeaux INP, IMS（波尔多大学、法国国家科学研究中心、波尔多国立理工学院、IMS研究所）
- Université Grenoble Alpes, CEA, LETI, MINATEC（格勒诺布尔阿尔卑斯大学、法国原子能和替代能源委员会、电子信息技术实验室、微电子技术中心）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过添加侧向条最小化横向应变，提高压电悬臂梁的机电耦合系数，实验显示耦合系数提升30%，带宽提升32%，实现高性能无铅振动能量采集器。
AI中文摘要：
为提升振动能量采集器的性能，必须最大化压电器件的机电耦合系数 k${}^2$。这能够实现足够的采集功率以及通过电学方法调谐共振频率的能力。尽管大量文献涉及压电悬臂梁的优化，但优化范围通常受限于材料的横向耦合系数 k31${}^2$。本工作提出了一种创新解决方案，以扩展优化范围并提高压电悬臂梁的耦合系数。这是通过使用侧向条最小化梁中的横向应变，从而最大化等效材料耦合系数来实现的。该创新的理论基础通过利用压电材料的本构方程得以展示。通过基于有限元方法的仿真，展示并研究了添加侧向条以提高耦合系数的益处。最后，使用集成无铅 KNaNbO3 (KNN) 压电材料的铝制悬臂梁原型实现了概念验证。该原型在 0.1 m/s${}^2$ 的振动下以可变电阻负载进行测试。结果表明，通过将八根钢条固定到悬臂梁上，耦合系数增加了 30%，相对频率带宽在电阻调谐共振频率下增加了 32%。所设计的原型是一种高性能的无铅振动能量采集器。它在共振时产生最大功率 49.9 μW，其归一化功率密度等于 16.5 mW/G${}^2$/cm${}^3$。其相对频率带宽等于 3.1%。
英文摘要：
To enhance the performance of vibration energy harvesters, it is essential to maximise the electromechanical coupling coefficient k${}^2$ of piezoelectric devices. This enables sufficient harvested power and tuning capability of the resonant frequency through electrical methods. While much literature treats the optimisation of piezoelectric cantilevers, the optimisation range is usually limited by the transverse coupling coefficient k31${}^2$ of the material. This work introduces an innovative solution to extend the optimisation range and increase the coupling coefficient of piezoelectric cantilevers. This is achieved by minimising lateral strain in the beam using lateral bars to maximise the equivalent material coupling coefficient. The theoretical basis of this innovation is demonstrated through the exploitation of the constitutive equations of piezoelectric materials. The interest of the addition of lateral bars to increase the coupling coefficient is demonstrated and studied with simulations based on the finite elements method. Finally, a proof of concept is realised using a aluminum cantilever prototype integrating a lead-free KNaNbO3 (KNN) piezoelectric material. It is tested under vibration at 0.1 m/s${}^2$ with variable resistive loads. The results show that the coupling coefficient increases by 30% and the relative frequency bandwidth by 32% with resistive tuning of the resonant frequency, by fixing eight steel bars to the cantilever. The designed prototype is a highly performant leadfree vibration energy harvester. It produces a maximum power of 49.9 $μ$W at resonance, and its normalised power density is equal to 16.5 mW/G${}^2$/cm${}^3$. Its relative frequency bandwidth is equal to 3.1%.
