Design and experimental investigation of a magnetically coupled vibration energy harvester using two inverted piezoelectric cantilever beams for rotational motion

As the low-power wireless sensor components and the development of micro electromechanical systems, long-term supply of components is a major obstacle of their development. One of solutions to this problem is based on the environmental energy collection of piezoelectric vibration energy harvesting. Currently, frequency band of piezoelectric vibration energy harvester is narrow and the frequency is high, which is not fit for the vibration energy acquisition in the natural environment. A piezoelectric vibration energy harvester with lower working frequency and broader band is designed and a test system to analyze the harvester is presented in this paper. The traditional mass is replaced by a permanent magnet in this paper, While other two permanent magnets are also placed on the upper and above of the piezoelectric cantilever. Experiments showed, under the 0.5g acceleration, compared with the traditional non-magnetic piezoelectric vibration energy harvesting, a piezoelectric cantilever (length 40mm, width 8mm, thickness 0.8mm) has a peak-peak voltage of 32.4V, effectively enlarges working frequency band from 67HZ-105HZ to 63HZ-108HZ.

Download Full-text

A Self-Sufficient and Frequency Tunable Piezoelectric Vibration Energy Harvester

Journal of Vibration and Acoustics ◽

10.1115/1.4034775 ◽

2016 ◽

Vol 139 (1) ◽

Cited By ~ 15

Author(s):

Cevat Volkan Karadag ◽

Nezih Topaloglu

Keyword(s):

Energy Demand ◽

Energy Harvester ◽

Electrical Power ◽

Control Unit ◽

Ambient Vibration ◽

Vibration Energy ◽

Vibration Energy Harvester ◽

Piezoelectric Cantilever ◽

Wide Range ◽

Piezoelectric Vibration

In this paper, a novel smart vibration energy harvester (VEH) is presented. The harvester automatically adjusts its natural frequency to stay in resonance with ambient vibration. The proposed harvester consists of two piezoelectric cantilever beams, a tiny piezomotor with a movable mass attached to one of the beams, a control unit, and electronics. Thanks to its self-locking feature, the piezomotor does not require energy to fix its movable part, resulting in an improvement in overall energy demand. The operation of the system is optimized in order to maximize the energy efficiency. At each predefined interval, the control unit wakes up, calculates the phase difference between two beams, and if necessary, actuates the piezomotor to move its mass in the appropriate direction. It is shown that the proposed tuning algorithm successfully increases the fractional bandwidth of the harvester from 4% to 10%. The system is able to deliver 83.4% of the total harvested power into usable electrical power, while the piezomotor uses only 2.4% of the harvested power. The presented efficient, autotunable, and self-sufficient harvester is built using off-the-shelf components and it can be easily modified for wide range of applications.

Download Full-text

A Curled Piezoelectric Cantilever for Two Dimensional Vibration Energy Harvesting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.811.469 ◽

2013 ◽

Vol 811 ◽

pp. 469-473

Author(s):

Xue Feng He ◽

Yao Qing Cheng ◽

Jun Gao ◽

You Zhu

Keyword(s):

Energy Harvester ◽

Proof Mass ◽

Ambient Vibration ◽

Vibration Energy ◽

Two Dimensional ◽

Vibration Energy Harvesting ◽

Vibration Direction ◽

Vibration Energy Harvester ◽

Piezoelectric Cantilever ◽

Scavenging Efficiency

To harvest ambient vibration energy of different directions, a micromachined vibration energy harvester which can harvest two-dimensional vibration energy was proposed. The harvester is composed of a curled piezoelectric cantilever, a proof mass and the substrate. One end of the cantilever is fixed onto the substrate and the other end is connected with a proof mass. It is the residual stress of micromachining processes that causes the cantilever to curl. A proof-of-concept prototype of the two-dimensional vibration energy harvester was assembled and tested to evaluate the performance. Experimental results show that the vibration direction with the highest energy scavenging efficiency changed with the frequency of the ambient vibration. The vibration energy of any direction in the neutral plane of the curled cantilever can be harvested by using the first two natural vibration modes of the prototype.

Download Full-text