Increasing the operable frequency range and improving the small acceleration amplitude harvesting performance of the piezoelectric energy harvesting devices is importance due to the wide frequency spectrum and large amplitude range of environmental vibrations. In this Letter, an improved piezoelectric energy harvester with frequency upconversion is proposed, which is comprised of a composite piezoelectric beam and a firing pin. In contrast to the conventional impact-based systems that mainly rely on beam vibrations to enhance harvesting performance, the proposed system employs a dual-impact strategy. In particular, an oblique impact-based harvesting phenomenon is observed, which has not been investigated in previous studies. A multilevel impact nonlinear coupled dynamic model is developed. The experimental results indicate that at an excitation acceleration amplitude of 0.15 g, the proposed system demonstrates a 482.9% increase in the output peak value and introduces dual-band frequency in comparison with the conventional structure. Additionally, the proposed coupled model is validated through adjustments to various load resistances. The highest output power is achieved at a load resistance of 210 kΩ, with the maximum average power reaching 3.96 mW and a power density of 1.59 mW/mm3g2 at an acceleration amplitude of 0.15 g, outperforming other piezoelectric energy harvesters.

中文翻译：

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改进的压电式能量收集器，具有双冲击策略，适用于较小的加速度幅度振动


由于环境振动的频谱范围宽、幅值范围大，增加压电能量收集器件的可操作频率范围和提高小加速度幅值收集性能非常重要。在这封信中，提出了一种改进的频率上变频压电能量收集器，它由复合压电束和撞针组成。与主要依靠光束振动来提高收获性能的传统基于冲击的系统相比，所提出的系统采用了双重冲击策略。特别是，观察到一种基于倾斜冲击的收获现象，这在以前的研究中没有进行过研究。建立了一种多级冲击非线性耦合动力学模型。实验结果表明，在0.15 g的激励加速度幅值下，与传统结构相比，所提出的系统输出峰值增加了482.9%，并引入了双频带频率。此外，通过调整各种负载电阻来验证所提出的耦合模型。在 210 kΩ 的负载电阻下可实现最高输出功率，最大平均功率达到 3.96 mW，在 0.15 g 的加速度幅度下，功率密度为 1.59 mW/mm3g2，性能优于其他压电式能量收集器。