A 3D multidirectional piezoelectric energy harvester using rope-driven mechanism for low frequency and ultralow intensity vibration environment

Abstract

Though numerous piezoelectric vibration energy harvesters (PVEHs) have been designed and investigated to provide power supply for wireless sensors or wearable devices, it remains a challenge for traditional PVEHs to work effectively in an environment of low frequency, low acceleration and multidirectional vibrations. This work presents a PVEH using a low-frequency energy-capturing resonant system formed by a rolling ball in a hemispherical shell and driven by a rope. Due to the symmetry of the sphere, the ball can be excited at multiple directions in 3D space, and the piezoelectric beam can be pulled by the ball through a rope in multiple directions. Thus, the efficient multidirectional energy harvesting under low frequency (< 10 Hz) and ultralow intensity (< 0.1 g) vibrations could be realized. A mass-spring-damper equivalent model was built to understand the operation mechanism of the proposed PVEH. The results show that the proposed PVEH has a potential to collect energy in any direction in 3D space, and could achieve a good angle bandwidth with 360° for φ and 240° for β under the excitation of a = 0.04 g, f = 6.8 Hz with the acceleration defined in the spherical coordinate system. The developed PVEH can generate 6.5 μW under a low-intensity excitation (0.03 g), and the normalized power density can reach 22.63 μW/(cm3g2Hz). Moreover, the minimum start-up acceleration analysis of the proposed PVEH indicates that the PVEH can capture multidirectional energy from vibrations as low as 0.01 g. In addition, both simulation and experimental study on rope redundancy and ball mass show that they can be used to adjust the device performance easily without structure re-fabrication. Overall, this study demonstrates a new mechanism that could effectively harvest low frequency, ultralow intensity and multidirectional vibration

Design and experimental investigation of a positive feedback magnetic-coupled piezoelectric energy harvester

“…Each method of energy harvesting possesses its own advantages and disadvantages; however, the piezoelectric vibration energy harvester stands out due to its simplistic structure, high output energy density, and ease in achieving structural miniaturization. Consequently, it exhibits a broader range of applications [14][15][16].…”

Design and Experimental Investigation of an Ultra-Low Frequency, Low-Intensity, and Multidirectional Piezoelectric Energy Harvester with Liquid as the Energy-Capture Medium

“…Wang et al [ 14 ] developed a cross-coupled dual-beam structure that comprised two sets of three beams joined crosswise and a circular cylinder bluff-body attached to the free end of the bottom beam, which reduced the resonance frequency of the device to 12.23 Hz and enabled the device to harvest multidirectional wind energy in a two-dimensional (2D) plane. Zhang et al [ 15 ] proposed a tridirectional piezoelectric energy harvester composed of the main beam, a rolling ball, and a hemispherical shell, and it achieved a normalized power density of 22.63 µW/(cm 3 g 2 Hz) under the action of 3D multidirectional external excitation at a low frequency (7.6 Hz) and low intensity (0.03 g).…”

Multidirectional Piezoelectric Vibration Energy Harvester Based on Cam Rotor Mechanism

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