An enhanced tunable rotational energy harvester with variable stiffness system for low-frequency vibration

Author(s):  
Seon-Jun Jang ◽  
In-Ho Kim ◽  
Kyoungwoo Park ◽  
Hyung-Jo Jung

An enhanced tunable rotational energy harvester for low-frequency vibration is proposed. It consists of a rotational vibrating system and a translating proof mass suspended by wire. The active tuning of the resonant frequency is implemented using the serial connection control of spiral springs, which is named here as a variable stiffness system. The concept, design, and implementation for the proposed device are presented. The numerical simulation and the vertical shaker test are performed, respectively, and the results showed that the proposed energy harvester could effectively generate the electricity under the low-frequency vibration and readily change its natural frequency as well.

2011 ◽  
Vol 99 (13) ◽  
pp. 134102 ◽  
Author(s):  
Seon-Jun Jang ◽  
In-Ho Kim ◽  
Hyung-Jo Jung ◽  
Yoon-Pyo Lee

2013 ◽  
Vol 475-476 ◽  
pp. 1624-1628
Author(s):  
Hasnizah Aris ◽  
David Fitrio ◽  
Jack Singh

The development and utilization of different structural materials, optimization of the cantilever geometry and power harvesting circuit are the most commonly methods used to increase the power density of MEMS energy harvester. This paper discusses the cantilever geometry optimization process of low power and low frequency of bimorph MEMS energy harvester. Three piezoelectric materials, ZnO, AlN and PZT are deposited on top and bottom of the cantilever Si substrate. This study focuses on the optimization of the cantilevers length, width, substrate thickness and PZe thickness in order to achieve lower than 600 Hz of resonant frequency. The harvested power for this work is in the range of 0.02 ~ 194.49 nW.


Author(s):  
Jui-Ta Chien ◽  
Yung-Hsing Fu ◽  
Chao-Ting Chen ◽  
Shun-Chiu Lin ◽  
Yi-Chung Shu ◽  
...  

This paper proposes a broadband rotational energy harvesting setup by using micro piezoelectric energy harvester (PEH). When driven in different rotating speed, the PEH can output relatively high power which exhibits the phenomenon of frequency up-conversion transforming the low frequency of rotation into the high frequency of resonant vibration. It aims to power self-powered devices used in the applications, like smart tires, smart bearings, and health monitoring sensors on rotational machines. Through the excitation of the rotary magnetic repulsion, the cantilever beam presents periodically damped oscillation. Under the rotational excitation, the maximum output voltage and power of PEH with optimal impedance is 28.2 Vpp and 663 μW, respectively. The output performance of the same energy harvester driven in ordinary vibrational based excitation is compared with rotational oscillation under open circuit condition. The maximum output voltage under 2.5g acceleration level of vibration is 27.54 Vpp while the peak output voltage of 36.5 Vpp in rotational excitation (in 265 rpm).


2019 ◽  
Vol 115 (6) ◽  
pp. 063901 ◽  
Author(s):  
Bin Yang ◽  
Zhiran Yi ◽  
Gang Tang ◽  
Jingquan Liu

2018 ◽  
Vol 18 (3) ◽  
pp. 920-933 ◽  
Author(s):  
Suyoung Yang ◽  
Sung-Youb Jung ◽  
Kiyoung Kim ◽  
Peipei Liu ◽  
Sangmin Lee ◽  
...  

In this study, a tunable electromagnetic energy harvesting system, consisting of an energy harvester and energy harvesting circuits, is developed for harnessing energy from low-frequency vibration (below 10 Hz) of a bridge, and the harvesting system is integrated with a wireless fatigue crack detection sensor. The uniqueness of the proposed energy harvesting system includes that (1) the resonance frequencies of the proposed energy harvester can be readily tuned to the resonance frequencies of a host structure, (2) an improved energy harvesting efficiency compared to other electromagnetic energy harvesters is achieved in low-frequency and vibration, and (3) high-efficiency energy harvesting circuits for rectification are developed. Furthermore, the developed energy harvesting system is integrated with an on-site wireless sensor deployed on Yeongjong Grand Bridge in South Korea for online fatigue crack detection. To the best knowledge of the authors, this is the very first study where a series of low-frequency vibration energy harvesting, rectification, and battery charging processes are demonstrated under a real field condition. The field test conducted on Yeongjong Grand Bridge, where fatigue cracks have become of a great concern, shows that the proposed energy harvester can generate a peak voltage of 2.27 V and a root mean square voltage of 0.21 V from 0.18-m/s2 root mean square acceleration at 3.05 Hz. It is estimated the proposed energy harvesting system can harness around 67.90 J for 3 weeks and an average power of 37.42 µW. The battery life of the wireless sensor is expected to extend from 1.5 to 2.2 years. The proposed energy harvesting circuits, composed of the AC–DC and boost-up converters, exhibit up to 50% battery charging efficiency when the voltage generated by the proposed energy harvester is 200 mV or higher. The proposed boost-up converter has a 100 times wider input power range than a conventional boost-up converter with a similar efficiency.


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