A piezoelectric energy harvester based on magnetic coupling effect

2017 ◽  
Vol 110 (16) ◽  
pp. 163905 ◽  
Author(s):  
Hai Wang ◽  
Feng Hu ◽  
Ke Wang ◽  
Yan Liu ◽  
Wei Zhao

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3101
Author(s):  
Xiaobiao Shan ◽  
Haigang Tian ◽  
Han Cao ◽  
Tao Xie

This paper proposes a novel and efficient energy harvester (EH) system, for capturing simultaneously flutter and vortex-induced vibration. There exists a coupling effect between flexible spring energy harvester (FSEH) and cantilever beam energy harvester (CBEH) in aerodynamic response and output characteristic. Many prototypes of the harvester were manufactured to explore the coupling effect in a wind tunnel. The experimental results demonstrate that FSEH is mainly subjected to flutter-induced vibration and CBEH undergoes vortex-induced vibration. Disturbance of FSEH first takes place, a limited oscillation cycle then occurs, and chaos ultimately happens as airflow velocity increase. Root mean square voltages are more than 11 V for FSEH at beyond 10.52 m/s, which shows the better output performance over the existing harvesters. Vibration response and output voltage of various harvesters are mutually enhanced with each other. An enhancing ratio for FSEH-130-25 is up to 69.6% over FSEH-130-0, while the enhancing ratio for CBEH-130-30 is 198.3% compared to CBEH-0-30. Field application testing manifests that discharging time to power the pedometer is almost twice as long as the charging one for FSEH-130-25 at 14.48 m/s. The current research offers a suggestive guidance for promoting future practical application in micro airfoil aircrafts.


2015 ◽  
Vol 117 (14) ◽  
pp. 144502 ◽  
Author(s):  
Jinchi Han ◽  
Jun Hu ◽  
Zhongxu Wang ◽  
Shan X. Wang ◽  
Jinliang He

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Fengxia Wang

Abstract In this work, a parametric model for a frequency-up-conversion piezoelectric energy harvester (PEH) was developed based on the Galerkin method. The PEH is composed of a piezoelectric bimorph and a stopper, which was subjected to a harmonic excitation. Although backward coupling results in a structure dynamic damping, models with neglected backward coupling were often adopted to estimate the output power of a piezoelectric energy harvester. The purpose of this work is to examine the effect of backward coupling on the dynamic response and the output power generation for a frequency-up-conversion PEH. With the same base excitations, we compared the dynamics and output energies of two cases: (1) neglecting the backward coupling effect (BCE) in the model and (2) including the BCE in the model. To obtain the optimum gap with maximum output power, we studied the relationship between the output power and the gap of the steady-state solutions. From the analytical results, it was found that the BCE can be neglected as long as there is no impact or the output power is small. However, once impacts get involved, the piezoelectric backward effect dominates the total damping due to small mechanical damping which is true for most PEH. The backward coupling will significantly diminish both the vibration and output power. Therefore, if the BCE is neglected in an impact-driven frequency-up-conversion PEH, the simplified model will exaggerate the output power.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jianjun Liu ◽  
Xianghua Chen ◽  
Yujie Chen ◽  
Hong Zuo ◽  
Qun Li

Piezoelectric cantilever beams, which have simple structures and excellent mechanical/electrical coupling characteristics, are widely applied in energy harvesting. When the piezoelectric cantilever beam is in a wind field, we should consider not only the influence of the wind field on piezoelectric beam but also the electromechanical coupling effect on it. In this paper, we design and test a wind-induced flag-swing piezoelectric energy harvester (PEH). The piezoelectric cantilever beam may vibrate in the wind field by affixing a flexible ribbon to the free end as the windward structure. To fulfill the goal of producing electricity, the flexible ribbon can swing the piezoelectric cantilever in a wind-induced unstable condition. The experimental findings demonstrate that the flag-swing PEH performs well in energy harvesting when the wind field is excited. When the wind speed is 15 m/s, the peak-to-peak output AC voltage may reach 13.88 V. In addition, the voltage at both ends of the closed-loop circuit’s external resistance is examined. The maximum electric power of the PEH may reach 43.4 μW with an external resistance of 650 kΩ. After passing through the AC-DC conversion circuit, the flag-swing PEH has a steady DC voltage output of 1.67 V. The proposed energy harvester transforms wind energy from a wind farm into electrical energy for supply to low-power electronic devices, allowing for the creation and use of green energy to efficiently address the issue of inadequate energy.


Author(s):  
Fengxia Wang ◽  
Saeed Onsorynezhad

Abstract This paper developed an analytical model for a frequency-up-conversion piezoelectric energy harvester (PEH) composed of a piezoelectric bimorph and a stopper as shown in Fig.1. The whole system was subjected to a harmonic excitation. A bimodal approach was adopted to animate the beam stopper reaction. When the tip of the bimorph vibrates in free space or impacts with the stopper, a cantilever beam function was adopted. On the other hand, if the tip of the bimorph sticks with the stopper, a clamped-pinned beam function was applied to model the piezoelectric bimorph. To exam the effect of backward mechanical-electric coupling on power output, the dynamics and output energies are compared for two cases: 1) neglecting the backward mechanical-electric coupling effect in the model; 2) including the backward mechanical-electric coupling effect in the model. To obtain maximum output energy, the steady-state analytical solutions were studied to obtain the optimum gap between the piezoelectric beam and the stopper. From the results, we found that if the beam impacts and/or sticks with the stopper, the PEH model without the backward mechanical-electric coupling will exaggerate the output energy.


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