Strongly coupled piezoelectric energy harvesters: Optimised design with over 100 mW power, high durability and robustness for self-powered condition monitoring
Strongly coupled piezoelectric energy harvesters: Optimised design with over 100 mW power, high durability and robustness for self-powered condition monitoring
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DOI：
10.1016/j.enconman.2021.114129
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发表时间：
2021-06
影响因子：
10.4
通讯作者：
Yang Kuang;Z. Chew;John Dunville;J. Sibson;M. Zhu
中科院分区：
文献类型：
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作者：
Yang Kuang;Z. Chew;John Dunville;J. Sibson;M. Zhu
收集环境振动能量是实现自供电无线传感器的一种很有前途的方法。然而，迄今为止开发的大多数能量采集器都不适合实际应用，因为输出功率低，耐用性和稳健性差。为了克服这些挑战，本研究开发了一种强耦合压电堆叠能量收集器（PSEH），其设计不仅考虑了功率输出，还考虑了耐用性和稳健性。PSEH利用了优化的机械变压器的力放大能力和33模多层压电堆的高耦合系数来实现强耦合，从而产生高功率。为了提高压电材料的耐久性，对压电材料进行预压缩，以防止拉伸应力的发展，充分利用压电陶瓷的高抗压强度；机械变压器的最大动应力保持在材料疲劳极限的一半以下。采用板弹簧来引导PSEH的运动，防止不必要的振动，以提高鲁棒性。为了优化设计，开发了一个有限元模型，将设计参数直接与包括最大功率在内的全部性能矩阵联系起来。在实验室测试中，当以0.5 g， 157 Hz的频率驱动时，PSEH产生的最大平均功率为140 mW， 1mw带宽为72hz， 10mw带宽为24hz。在0.3 g， 157 Hz连续驱动7.9小时后，PSEH的性能没有下降。除了实验室测试外，还通过将PSEH安装在螺杆空气压缩机的两个位置进行了现场测试。现场试验表明，当空压机产生的加速度分别为0.125±0.012 g和0.259±0.004 g时，PSEH产生的平均功率分别为15.95±2.3 mW和43.19±1.52 mW。
Harvesting ambient vibration energy is a promising method to realise self-powered wireless sensors. However, most of the energy harvesters developed to date are not suitable for real-world applications because of low power output and/or poor durability and robustness. To overcome these challenges, this work develops a strongly coupled piezoelectric stack energy harvester (PSEH) with design considerations not just on the power output but also on the durability and robustness. The PSEH took advantages of the force amplification capability of an optimised mechanical transformer and the high coupling coefficient of a 33-mode multilayer piezoelectric stack to achieve strong coupling and therefore high-power generation. To increase the durability, the piezoelectric stack was pre-compressed to prevent the development of tensile stress, to exploit the high compressive strength of piezoelectric ceramics; the maximum dynamic stress in the mechanical transformer was kept below half of the material’s fatigue limit. Plate springs were used to guide the motion of the PSEH and prevent undesired vibration to enhance robustness. A finite element model was developed for design optimisation, which links the design parameters directly to the full performance matrix including maximum power generation. When actuated at 0.5 g, 157 Hz in the lab tests, the PSEH produced a maximum average power of 140 mW with a 1-mW-bandwidth of 72 Hz and 10-mW-bandwidth of 24 Hz. The PSEH showed no performance degradation after continuously actuated at 0.3 g, 157 Hz for 7.9 h. In addition to the lab tests, on-site tests were performed by installing the PSEH in two locations of a screw air compressor. On-site tests showed that the PSEH was able to produce average power of 15.95 ± 2.3 mW and 43.19 ± 1.52 mW when the acceleration produced by the air compressor was 0.125 ± 0.012 g and 0.259 ± 0.004 g, respectively.