Abstract The goal of this paper is to present a comparative study on the principal features and scaling properties of time-harmonic vibration energy harvesting with electromagnetic and piezoelectric reactive transducers. The study is organised around two prototype reactive harvesters having one end connected to ground. The two harvesters are composed respectively by a coil-magnet and a composite piezoelectric beam characterised by similar dimensions, weights and fundamental natural frequencies. The work is based on equivalent lumped parameter models and energy formulations for the two harvesters. The study shows that, to maximise the power harvesting, the electromagnetic and piezoelectric transducers should be connected respectively to a resistive load and to a resistive-reactive load. In this case, the spectra of the harvested power per unit base acceleration falls proportionally to the inverse of frequency squared and the spectra of the energy harvesting efficiency remains constant with frequency. The scaling study shows that the normalised harvested power density for the electromagnetic harvester grows proportionally to the square of dimension whereas that for the piezoelectric harvester does not vary with dimension. In parallel, the efficiency to absorb vibration energy of the electromagnetic harvester scales following a distinctive S-type law, which reaches the maximum of 0.5 for large transducers. Instead, the efficiency of the piezoelectric transducer is constant and limited to a maximum of 0.5, apart for large transducers where it drops for large scales.

中文翻译：

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用反应电磁和压电换能器收集振动能量的分析和标度研究

摘要 本文的目的是对电磁和压电反应换能器时谐振动能量收集的主要特征和标度特性进行比较研究。该研究围绕两个原型反应式收集器进行组织，其一端接地。两个采集器分别由一个线圈磁铁和一个复合压电梁组成，其特点是尺寸、重量和基本固有频率相似。这项工作基于两个收集器的等效集总参数模型和能量公式。研究表明，为了最大限度地收集能量，电磁和压电换能器应分别连接到电阻负载和电阻-电抗负载。在这种情况下，每单位基础加速度收集的功率谱与频率平方的倒数成比例下降，并且能量收集效率的谱随频率保持恒定。缩放研究表明，电磁采集器的归一化采集功率密度与尺寸的平方成比例增长，而压电采集器的归一化采集功率密度不随尺寸变化。同时，电磁采集器吸收振动能量的效率遵循独特的 S 型定律，对于大型换能器，该定律达到最大值 0.5。相反，压电换能器的效率是恒定的，并且限制为最大值 0.5，除了大型换能器在大规模时会下降。