Department of Materials, Cranfield University, Bedfordshire, UK.
IEEE Trans Ultrason Ferroelectr Freq Control. 2010;57(2):427-37. doi: 10.1109/TUFFC.2010.1423.
This paper presents a design study on the geometric parameters of a cantilever-based piezoelectric energy-harvesting devices (EHD), which harvest energy from motion (vibration), for the purpose of scavenging more energy from ambient vibration energy sources. The design study is based on the coupled piezoelectric-circuit finite element method (CPCFEM), previously presented by Dr. Zhu. This model can calculate the power output of piezoelectric EHDS directly connected to a load resistor and is used in this paper to obtain the following simulation results for variations in geometric parameters such as the beam length, width and thickness, and the mass length, width, and height: 1) the current flowing through and the voltage developed across the load resistor, 2) the power dissipated by the resistor and the corresponding vibrational displacement amplitude, and 3) the resonant frequency. By studying these results, straightforward design strategies that enable the generation of more power are obtained for each geometric parameter, and a physical understanding of how each parameter affects the output power is given. It is suggested that, in designing with the aim of generating more power, the following strategies be used: 1) for the beam, a shorter length, larger width, and lower ratio of piezoelectric layer thickness to total beam thickness are preferred in the case of a fixed mass; 2) for the mass, a shortened mass length and a higher mass height are preferred in the case of variation in the mass length and the mass height with mass width and mass value remain fixed, and a wider width and small mass height are preferred in the case of variation in mass width and height (mass length and value remain fixed; and 3) for the case of a fixed total length, a shorter beam length and longer mass length are preferred. With the design strategies, output powers from the device can reach above 1 to 2 mW/cm(3), much higher than the 200 microW/cm(3) currently achieved in the published literature. This is an encouraging prospect for enabling a wider range of applications of the EHDs. In addition, physical insights into how each parameter influences output power are also discussed in detail.
本文提出了一种基于悬臂式压电能量采集装置（EHD）的几何参数设计研究，该装置从运动（振动）中采集能量，旨在从环境振动能源中采集更多能量。设计研究基于朱博士之前提出的耦合压电电路有限元方法（CPCFEM）。该模型可以直接计算与负载电阻器相连的压电 EHDS 的功率输出，并在本文中用于获得以下几何参数变化的模拟结果：梁的长度、宽度和厚度，以及质量的长度、宽度和高度：1）流过负载电阻器的电流和电压，2）电阻器耗散的功率和相应的振动位移幅度，以及 3）谐振频率。通过研究这些结果，为每个几何参数获得了产生更多功率的直接设计策略，并给出了每个参数如何影响输出功率的物理理解。建议在设计时采用以下策略来产生更多的功率：1）对于梁，在固定质量的情况下，较短的长度、较大的宽度以及较低的压电层厚度与总梁厚度之比更有利；2）对于质量，在质量长度和质量高度变化的情况下，较短的质量长度和较高的质量高度更有利，而在质量宽度和高度变化的情况下（质量长度和质量值保持固定），较宽的宽度和较小的质量高度更有利，以及在质量宽度和高度（质量长度和值保持固定）变化的情况下，较宽的宽度和较小的质量高度更有利；3）对于固定总长度，较短的梁长度和较长的质量长度更有利。通过设计策略，设备的输出功率可以达到 1 到 2mW/cm³以上，远高于已发表文献中目前实现的 200μW/cm³。这为 EHD 的更广泛应用提供了令人鼓舞的前景。此外，还详细讨论了每个参数如何影响输出功率的物理见解。
