Strongly coupled piezoelectric energy harvesters: Finite element modelling and experimental validation
Strongly coupled piezoelectric energy harvesters: Finite element modelling and experimental validation
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强耦合压电能量收集器：有限元建模与实验验证
DOI：
10.1016/j.enconman.2020.112855
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发表时间：
2020-06-01
影响因子：
10.4
通讯作者：
Zhu, Meiling
中科院分区：
文献类型：
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作者：
Kuang, Yang;Chew, Zheng Jun;Zhu, Meiling
压电能量采集器 (PEH) 通常连接到与其内部电容 CPT 的阻抗相匹配的负载电阻 RL，以表征传感器设计和优化期间的发电特性。对于在谐振附近工作的强耦合 PEH，这种简单的 RC 匹配方法低估了功率输出，并且无法表征双功率峰值，但仍然经常在仿真和实验中使用。本研究分析了PEH的内部阻抗网络和功率输出特性。基于分析，首次开发了强耦合PEH的有限元模型（FEM），并将其应用于预应力压电堆能量收集器（PSEH）。首先进行平稳分析来模拟 PSEH 的预应力状态。然后，FEM 分析了预应力 PSEH 的内部阻抗，将其用作模拟电力输出的最佳负载电阻。实验验证了PSEH的模拟内阻抗和电功率输出，吻合良好。开发的 FEM 精确预测了强耦合 PSEH 的电功率输出，包括两个相同的功率峰值，该强耦合 PSEH 在谐振附近和外部谐振下运行。相比之下，采用传统 RC 匹配的 FEM 仅显示一个功率峰值，并且明显低估了谐振附近的功率输出，尽管它在谐振外仍然有效。开发的 FEM 还能够预测静态预应力和耦合效率品质因数对 PSEH 的影响。发现耦合效率品质因数可以增加功率输出。
Piezoelectric energy harvesters (PEHs) are usually connected to a load resistor RL matching to the impedance of their internal capacitance CPT to characterise the power generation during transducer design and optimisation. For strongly-coupled PEHs operating near resonance, this simple RC matching method underestimates the power output and fails to characterise the dual power peaks but is still often used in both simulation and experiment. This study analysed the internal impedance network and the power output characteristics of PEHs. Based on the analysis, a finite element model (FEM) for strongly coupled PEHs was developed for the first time and applied to a pre-stressed piezoelectric stack energy harvester (PSEH). A stationary analysis was first performed to simulate the pre-stressed state of the PSEH. The FEM then analysed the internal impedance of the pre-stressed PSEH, which was used as the optimal load resistance to simulate the electric power output. The simulated internal impedance and electric power output of the PSEH were validated by the experiment with good agreement. The FEM developed precisely predicted the electric power output, including the two identical power peaks, of the strongly coupled PSEH operating near resonance and outside resonance. In contrast, the FEM with the traditional RC matching showed only one power peak and significantly underestimated the power output near resonance, although it was still valid outside resonance. The developed FEM was also able to predict the effects of the static pre-stress and coupling efficiency figure of merit on the PSEH. The coupling efficiency figure of merit was found to increase the power output.