Machu Zdenek, Rubes Ondrej, Sevecek Oldrich, Hadas Zdenek
Laboratory of Energy Harvesting, Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, Brno University of Technology, 616 69 Brno, Czech Republic.
Institute of Physics, Czech Academy of Sciences, 182 21 Prague, Czech Republic.
Sensors (Basel). 2021 Oct 12;21(20):6759. doi: 10.3390/s21206759.
This paper deals with analytical modelling of piezoelectric energy harvesting systems for generating useful electricity from ambient vibrations and comparing the usefulness of materials commonly used in designing such harvesters for energy harvesting applications. The kinetic energy harvesters have the potential to be used as an autonomous source of energy for wireless applications. Here in this paper, the considered energy harvesting device is designed as a piezoelectric cantilever beam with different piezoelectric materials in both bimorph and unimorph configurations. For both these configurations a single degree-of-freedom model of a kinematically excited cantilever with a full and partial electrode length respecting the dimensions of added tip mass is derived. The analytical model is based on Euler-Bernoulli beam theory and its output is successfully verified with available experimental results of piezoelectric energy harvesters in three different configurations. The electrical output of the derived model for the three different materials (PZT-5A, PZZN-PLZT and PVDF) and design configurations is in accordance with lab measurements which are presented in the paper. Therefore, this model can be used for predicting the amount of harvested power in a particular vibratory environment. Finally, the derived analytical model was used to compare the energy harvesting effectiveness of the three considered materials for both simple harmonic excitation and random vibrations of the corresponding harvesters. The comparison revealed that both PZT-5A and PZZN-PLZT are an excellent choice for energy harvesting purposes thanks to high electrical power output, whereas PVDF should be used only for sensing applications due to low harvested electrical power output.
本文研究了压电能量收集系统的分析模型，该系统用于从环境振动中产生有用的电力，并比较了在设计此类用于能量收集应用的收集器时常用材料的实用性。动能收集器有潜力用作无线应用的自主能源。在本文中，所考虑的能量收集装置被设计为一个压电悬臂梁，在双压电晶片和单压电晶片配置中使用不同的压电材料。对于这两种配置，推导了一个运动激励悬臂梁的单自由度模型，该模型考虑了完整和部分电极长度，并考虑了附加尖端质量的尺寸。该分析模型基于欧拉-伯努利梁理论，其输出结果与三种不同配置的压电能量收集器的现有实验结果成功验证。针对三种不同材料（PZT-5A、PZZN-PLZT和PVDF）以及设计配置所推导模型的电输出与本文中给出的实验室测量结果一致。因此，该模型可用于预测特定振动环境下的收集功率。最后，利用所推导的分析模型比较了三种考虑材料在相应收集器的简谐激励和随机振动下的能量收集效率。比较结果表明，由于高电输出功率，PZT-5A和PZZN-PLZT都是能量收集的优秀选择，而PVDF由于低收集电输出功率仅应用于传感应用。
