scholarly journals A Piezo-Electromagnetic Coupling Multi-Directional Vibration Energy Harvester Based on Frequency Up-Conversion Technique

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 80 ◽  
Author(s):  
Ge Shi ◽  
Junfu Chen ◽  
Yansheng Peng ◽  
Mang Shi ◽  
Huakang Xia ◽  
...  
Keyword(s):  
Cantilever Beam ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Electromagnetic Coupling ◽  
Low Frequency ◽  
Human Motion ◽  
Vibration Energy ◽  
Cantilever Beams ◽  
Load Range ◽  
Vibration Energy Harvester

Harvesting vibration energy to power wearable devices has become a hot research topic, while the output power and conversion efficiency of a vibration energy harvester with a single electromechanical conversion mechanism is low and the working frequency band and load range are narrow. In this paper, a new structure of piezoelectric electromagnetic coupling up-conversion multi-directional vibration energy harvester is proposed. Four piezoelectric electromagnetic coupling cantilever beams are installed on the axis of the base along the circumferential direction. Piezoelectric plates are set on the surface of each cantilever beam to harvest energy. The permanent magnet on the beam is placed on the free end of the cantilever beam as a mass block. Four coils for collecting energy are arranged on the base under the permanent magnets on the cantilever beams. A bearing is installed on the central shaft of the base and a rotating mass block is arranged on the outer ring of the bearing. Four permanent magnets are arranged on the rotating mass block and their positions correspond to the permanent magnets on the cantilever beams. The piezoelectric cantilever is induced to vibrate at its natural frequency by the interaction between the magnet on cantilever and the magnets on the rotating mass block. It can collect the nonlinear impact vibration energy of low-frequency motion to meet the energy harvesting of human motion.

An enhanced performance of a horizontal diamagnetic levitation mechanism–based vibration energy harvester for low frequency applications

2016 ◽  
Vol 28 (5) ◽  
pp. 578-594 ◽  
Author(s):  
Sri Vikram Palagummi ◽  
Fuh-Gwo Yuan
Keyword(s):  
Figure Of Merit ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Performance Metrics ◽  
Low Frequency ◽  
Experimental System ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Diamagnetic Levitation

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.

An Electromagnetic Frequency Increased Vibration Energy Harvester

2011 ◽  
Vol 403-408 ◽  
pp. 4231-4234 ◽  
Author(s):  
Khalid Ashraf ◽  
Mohd Haris Md Khir ◽  
John Ojur Dennis
Keyword(s):  
Permanent Magnets ◽  
Energy Harvester ◽  
Proof Mass ◽  
Excitation Frequency ◽  
Average Power ◽  
Low Frequency ◽  
High Frequency Oscillation ◽  
Vibration Energy ◽  
Frequency Oscillation ◽  
Vibration Energy Harvester

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.

Analysis of the component forces of the nonlinear magnetic force in energy harvester

2020 ◽  
pp. 095440892094938
Author(s):  
Bing Chen ◽  
Xiaolei Tang
Keyword(s):  
Cantilever Beam ◽  
Magnetic Force ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Vertical Component ◽  
Energy Utilization ◽  
Vibration Energy ◽  
Utilization Rate ◽  
Vibration Energy Harvester ◽  
Force Calculation

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.

scholarly journals A Multi-Mode Broadband Vibration Energy Harvester Composed of Symmetrically Distributed U-Shaped Cantilever Beams

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 203
Author(s):  
Xiaohua Huang ◽  
Cheng Zhang ◽  
Keren Dai
Keyword(s):  
Energy Harvester ◽  
Low Frequency ◽  
Experimental Results ◽  
Vibration Energy ◽  
Cantilever Beams ◽  
Resonant Frequencies ◽  
Promising Alternative ◽  
Piezoelectric Energy ◽  
Straight Beam ◽  
Resonance Frequencies

Using the piezoelectric effect to harvest energy from surrounding vibrations is a promising alternative solution for powering small electronic devices such as wireless sensors and portable devices. A conventional piezoelectric energy harvester (PEH) can only efficiently collect energy within a small range around the resonance frequency. To realize broadband vibration energy harvesting, the idea of multiple-degrees-of-freedom (DOF) PEH to realize multiple resonant frequencies within a certain range has been recently proposed and some preliminary research has validated its feasibility. Therefore, this paper proposed a multi-DOF wideband PEH based on the frequency interval shortening mechanism to realize five resonance frequencies close enough to each other. The PEH consists of five tip masses, two U-shaped cantilever beams and a straight beam, and tuning of the resonance frequencies is realized by specific parameter design. The electrical characteristics of the PEH are analyzed by simulation and experiment, validating that the PEH can effectively expand the operating bandwidth and collect vibration energy in the low frequency. Experimental results show that the PEH has five low-frequency resonant frequencies, which are 13, 15, 18, 21 and 24 Hz; under the action of 0.5 g acceleration, the maximum output power is 52.2, 49.4, 61.3, 39.2 and 32.1 μW, respectively. In view of the difference between the simulation and the experimental results, this paper conducted an error analysis and revealed that the material parameters and parasitic capacitance are important factors that affect the simulation results. Based on the analysis, the simulation is improved for better agreement with experiments.

scholarly journals Theoretical and Experimental Studies on MEMS Variable Cross-Section Cantilever Beam Based Piezoelectric Vibration Energy Harvester

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 772
Author(s):  
Xianming He ◽  
Dongxiao Li ◽  
Hong Zhou ◽  
Xindan Hui ◽  
Xiaojing Mu
Keyword(s):  
Power Density ◽  
Cantilever Beam ◽  
Cross Section ◽  
Energy Harvester ◽  
Variable Cross Section ◽  
Vibration Energy ◽  
Variable Cross ◽  
Vibration Energy Harvester ◽  
Piezoelectric Vibration Energy Harvester ◽  
Piezoelectric Vibration

The piezoelectric vibration energy harvester (PVEH) based on the variable cross-section cantilever beam (VCSCB) structure has the advantages of uniform axial strain distribution and high output power density, so it has become a research hotspot of the PVEH. However, its electromechanical model needs to be further studied. In this paper, the bidirectional coupled distributed parameter electromechanical model of the MEMS VCSCB based PVEH is constructed, analytically solved, and verified, which laid an important theoretical foundation for structural design and optimization, performance improvement, and output prediction of the PVEH. Based on the constructed model, the output performances of five kinds of VCSCB based PVEHs with different cross-sectional shapes were compared and analyzed. The results show that the PVEH with the concave quadratic beam shape has the best output due to the uniform surface stress distribution. Additionally, the influence of the main structural parameters of the MEMS trapezoidal cantilever beam (TCB) based PVEH on the output performance of the device is theoretically analyzed. Finally, a prototype of the Aluminum Nitride (AlN) TCB based PVEH is designed and developed. The peak open-circuit voltage and normalized power density of the device can reach 5.64 V and 742 μW/cm3/g2, which is in good agreement with the theoretical model value. The prototype has wide application prospects in the power supply of the wireless sensor network node such as the structural health monitoring system and the Internet of Things.

A Novel Broadband Vibration Energy Harvester

2014 ◽  
Vol 644-650 ◽  
pp. 3560-3563
Author(s):  
Yu Liu ◽  
Xiao Yan He ◽  
Shen Liu ◽  
Ying Wu ◽  
Yi Ou
Keyword(s):  
Resonance Frequency ◽  
Energy Harvester ◽  
Engineering Application ◽  
Low Frequency ◽  
Structure Design ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Collector Efficiency ◽  
Energy Acquisition ◽  
Mode Energy

A single resonance frequency is the main factor of limiting vibration energy collector efficiency. In this paper, the multi degree of freedom oscillation adjusting bandwidth scheme is reported, designing a kind of new broadband vibration energy harvester, which has multi-mode energy acquisition, multi freedom vibration and broadband characteristics. Firstly, Broadband energy collector structure design. Secondly, Combining with the main vibration form, using the ANSYS carried out a detailed analysis of its working model. Finally, designing the prototype and doing some experimental verification, the results show that the designed energy collector with low frequency and wideband energy acquisition performance, the frequency domain of energy collection is 57.6 to 69.45HZ ,which break through the bottleneck of traditional single resonance frequency of energy acquisition, has a high value of theory and engineering application.

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