Broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums

Author(s):  
Qiang Yan ◽  
Xianzhi Dai ◽  
Zhang Zhang ◽  
Lijun Wang ◽  
Yong Wang

Abstract A broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums is proposed in this paper. The harvester is mainly composed of a magnetoelectric transducer and a rotary pendulum fixed with four permanent magnets. In order to improve the working bandwidth of the harvester, two pairs of permanent magnets are added in the middle of the rotary pendulum by using magnetic nonlinearity. The mechanical - magnetic - electrical analytical model of the harvester is established, and the theoretical value obtained by the model is basically consistent with the experimental value. The results show that the harvester has a strong nonlinearity through the magnetic force. When the acceleration is 0.4 g, some typical testing results are as follows: the resonant frequency is 19 Hz, maximum peak-peak voltage is 94.1 V, half power bandwidth is 15.8 Hz, center frequency is 26.9 Hz, and the ratio of half power bandwidth to the center frequency is 58.73 %.

Author(s):  
Bing Chen ◽  
Xiaolei Tang

In the piezoelectric vibration energy harvester, permanent magnets are often used to generate nonlinear applied magnetics force to improve the energy utilization rate of the system, the modeling analysis and accurate calculation of the force between magnets in the system is a difficult problem in the study of nonlinear bistable vibration energy harvesting. During the deformation of the cantilever beam, the direct force of the permanent magnet block can be divided into horizontal and vertical component forces. In most existing literatures analyzing such problems, the magnetizing current method magnetic force calculation model of double-stabilized electric beam mainly considers the influence of vertical magnetic force on the system of cantilever beam, and it is considered that the horizontal component of magnetic force has little influence on the vibration response of cantilever beam, but there is no detailed proof and elaboration of this problem. In this paper, the magnetic force, the effect of magnetic force on natural frequency and magnetic potential energy are calculated and simulated from three aspects. Through the comparison of results, it is proved that the effect of the horizontal magnetic force on the whole nonlinear piezoelectric beam vibration energy harvester can be ignored.


2016 ◽  
Vol 28 (5) ◽  
pp. 578-594 ◽  
Author(s):  
Sri Vikram Palagummi ◽  
Fuh-Gwo Yuan

This article identifies and studies key parameters that characterize a horizontal diamagnetic levitation mechanism–based low frequency vibration energy harvester with the aim of enhancing performance metrics such as efficiency and volume figure of merit. The horizontal diamagnetic levitation mechanism comprises three permanent magnets and two diamagnetic plates. Two of the magnets, lifting magnets, are placed co-axially at a distance such that each attracts a centrally located magnet, floating magnet, to balance its weight. This floating magnet is flanked closely by two diamagnetic plates which stabilize the levitation in the axial direction. The influence of the geometry of the floating magnet, the lifting magnet, and the diamagnetic plate is parametrically studied to quantify their effects on the size, stability of the levitation mechanism, and the resonant frequency of the floating magnet. For vibration energy harvesting using the horizontal diamagnetic levitation mechanism, a coil geometry and eddy current damping are critically discussed. Based on the analysis, an efficient experimental system is setup which showed a softening frequency response with an average system efficiency of 25.8% and a volume figure of merit of 0.23% when excited at a root mean square acceleration of 0.0546 m/s2 and at a frequency of 1.9 Hz.


2011 ◽  
Vol 403-408 ◽  
pp. 4231-4234 ◽  
Author(s):  
Khalid Ashraf ◽  
Mohd Haris Md Khir ◽  
John Ojur Dennis

This paper presents an impact-based frequency increased electromagnetic vibration energy harvester to scavenge energy in a low frequency environment. To realize the novel impact based frequency up-conversion mechanism, a coil has been elastically anchored with a platform on which four permanent magnets are arranged in such a way that a strong closed magnetic flux path, linking the coil, is formed. The proposed scavenger has two dynamics of motion. The first phase is a low frequency oscillation to absorb energy from ambient vibration during which both the coil and magnet act as proof mass and move collectively. The increased proof mass ensures maximization of absorbed energy. After crossing a certain clearance, the platform containing magnetic setup rigidly and supporting the coil elastically, collides with a rigid stopper and bounces back. As a result of this mechanical impact a high frequency oscillation is setup in the coil relative to the magnets during which energy is transferred to electrical domain by electromagnetic induction. A macro-prototype has been build to prove the proposed concept. Initial test results show that the proposed harvester generates a peak voltage of 1 volt across a load of 220 Ω at an excitation frequency of 5 Hz which corresponds to a peak power of 4.5 mW and average power of 660 µW.


Author(s):  
Jianyong Zuo ◽  
Jie Yu ◽  
Cheng Liu ◽  
Yihao Gu ◽  
Lei Zuo ◽  
...  

Abstract Railroad vibration energy harvester has been researched and developed to harness the energy from the vibration of railway track when the trains pass. The vibrational energy could be transformed into electrical energy using mechanical motion rectification (MMR) mechanism and then further be used to power trackside equipment including sensors and some smart electrical devices. In order to test the performance of the MMR railroad energy harvesting system, a series of infield tests were conducted with a self-developed distributed measurement system in Railroad Test Lab at Tongji University. A 10V peak voltage was achieved with 8 Ohms external resistive load at the train speed of 30 km/h, which was consistent with the result of in-lab bench tests. In addition, some experience of design and installation for the motioned based energy harvesting system was gained, which can provide some references for the future improvement of railroad energy harvesting systems.


Fluids ◽  
2021 ◽  
Vol 6 (8) ◽  
pp. 295
Author(s):  
Nadish Anand ◽  
Richard Gould

Ferrofluid sloshing vibration energy harvesters use ferrofluid sloshing movement as a moving magnet between a fixed coil to induce current and, in turn, harvest energy from external excitations. A symmetric ferrofluid sloshing vibration energy harvester configuration is introduced in this study which utilizes four external, symmetrically placed, permanent magnets to magnetize a ferrofluid inside a tank. An external sinusoidal excitation of amplitude 1 m/s2 is imparted, and the whole system is studied numerically using a level-set method to track the sharp interface between ferrofluid and air. The system is studied for two significant length scales of 0.1 m and 0.05 m while varying the four external magnets’ polarity arrangements. All of the system configuration dimensions are parametrized with the length scale to keep the system configuration invariant with the length scale. Finally, a frequency sweep is performed, encompassing the structure’s first modal frequency and impedance matching to obtain the system’s energy harvesting characteristics.


2013 ◽  
Vol 103 (24) ◽  
pp. 243903 ◽  
Author(s):  
Jin Yang ◽  
Yumei Wen ◽  
Ping Li ◽  
Xihai Yue ◽  
Qiangmo Yu ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document