A Wide Frequency Range Tunable Vibration Energy Harvesting Device Using Magnetically Induced Stiffness

Author(s):  
Vinod R. Challa ◽  
M. G. Prasad ◽  
Yong Shi ◽  
Frank Fisher

Although wireless sensors show extensive promise across a wide range of applications, one requirement necessary for widespread deployment is a suitable long-life power source. Self sustainable powering techniques allow for efficient use of these sensors, whose potential life is usually longer than that of the power sources. Vibration energy harvesting techniques offer to have the potential to be employed in powering these devices. The most important requirement of vibration energy harvesting devices is that they be in resonance to harvest energy efficiently. Most of the vibration energy harvesting devices built, irrespective of the mechanism involved, are based on a single resonance frequency, with the efficiency of these devices is very much limited to that specific frequency. In this paper, a frequency tunable mechanism is presented which allows the energy harvesting device to generate power over a wide range of frequencies. External magnetic forces have been used to induce additional stiffness which is variable depending on the distance between the magnets. This technique allowed us to tune the resonance frequencies to have +/− 20% of the original (untuned) resonant frequency. Further, the device can be tuned to higher and lower frequency with respect to the untuned resonance frequency by using attractive and repulsive magnetic forces, respectively. As a proof-of-concept, a piezoelectric cantilever-based energy harvesting device with a natural frequency of 26 Hz was fabricated whose resonance frequency was successfully tuned over a frequency range of 22 Hz to 32 Hz, enabling a continuous power output of 240 μW to 280 μW over the entire frequency range. The tuning mechanism can be employed to any vibrating structure.

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 44 ◽  
Author(s):  
Mario Mösch ◽  
Gerhard Fischerauer

Self-adaptive vibration energy harvesting systems vary their resonance frequency automatically to better exploit changing environmental conditions. The energy required for the adjustment is taken from the energy storage of the harvester module. The energy gained by an adjustment step has to exceed the energy expended on it to justify the adjustment. A smart self-adaptive system takes this into account and operates in a manner that maximizes the energy output. This paper presents a theory for the optimal operation of a vibration energy harvester with a passive resonance-frequency adjustment mechanism (one that only requires energy for the adjustment steps proper, but not during the hold phases between the steps). Several vibration scenarios are considered to derive a general guideline. It is shown that there exist conditions under which a narrowing of the adjustment bandwidth improves the system characteristics. The theory is applied to a self-adaptive energy harvesting system based on electromagnetic transduction with narrowband resonators. It is demonstrated that the novel optimum mode of operation increases the energy output by a factor of 3.6.


2015 ◽  
Vol 2015 (HiTEN) ◽  
pp. 000261-000265
Author(s):  
S T Riches ◽  
K Doyle ◽  
N Tebbit ◽  
Y Jia ◽  
A Seshia

Distributed electronics for improving the accuracy of sensing in harsh high temperature environments, such as aero-engine and down-well is a growing field, where reduced power input requirements in cabling and batteries is viewed a key enabler for accelerating the adoption of high temperature electronics. Although batteries are available that can operate up to 200°C, they offer limited life at high temperatures and are bulky, increasing the costs of deployment and maintenance. Cabling also adds weight and takes up space in limited access applications. Energy harvesting in-situ offers the opportunity to make a step change in the design of high temperature electronics modules and in expanding their possible range of applications; for example, in sensor systems for combustor and turbine monitoring in aero-engines. This paper covers an assessment of MEMS vibration energy harvesting technology for high temperature sensing applications. MEMS devices based on the principle of parametric resonance, using AlN on Silicon have been designed and fabricated, along with sourcing of high temperature components for rectification, impedance matching and energy storage. The MEMS devices have been packaged into ceramic chip carriers and measured for energy output from a random vibration profile representative of an aerospace application. The measured output from the MEMS vibration energy harvester is capable of providing sufficient power to be of interest for autonomous sensing applications. This paper reports on the performance of the MEMS vibration energy harvesting devices and their associated circuitry at room temperature and at temperatures of up to 150°C. The challenges remaining to develop robust energy harvesting devices that could be applied in aero-engine, down-well and other high temperature applications are described. This work has been carried out under the Innovate UK supported project HI-VIBE, in a collaboration between GE Aviation Systems – Newmarket and the University of Cambridge.


Author(s):  
Ziheng Zhu ◽  
Lin Xu ◽  
Mohamed A. A. Abdelkareem ◽  
Junyi Zou ◽  
Jia Mi

Abstract With the recent energy crisis, the new energy harvesting technologies have become one of the hot spots in engineering academic research and industrial applications. By its wide range of application fields, vibration energy harvesting technologies have been gradually developed and utilized in which an efficient and stable harvester technology is one of the recent key problems. In order to improve energy harvesting efficiency and reduce energy loss caused by motor inertial commutation, many mechanical structures or hydraulic structures that convert reciprocating vibration energy into single direction rotation of motor are proposed. Although these methods can improve energy harvesting efficiency, they can have negative effects in some cases, especially in the case of vibration energy harvesting from human beings. This paper proposes a vibration harvesting mechanism with mechanical rectification filter function applied to backpack. The prototype model of the system was established in SolidWorks and imported into ADAMS. Thereafter, dynamic analyses of mechanical rectification filtering characteristics and meshing characteristics of one-way clutch were simulated in ADAMS. Based on ADAMS, parametric design analysis and its influence on the mechanical rectification characteristics were investigated. The simulation results were validated by bench test results. Simulation results is done by ADAMS and the results match well with bench test results.


2021 ◽  
Vol 8 ◽  
Author(s):  
Huaxia Deng ◽  
Zizheng Zhao ◽  
Chong Jiao ◽  
Jingchang Ye ◽  
Shiyu Zhao ◽  
...  

There are a lot of vibrational energies, which are low frequency, multidirectional, and broadband, in the nature. This creates difficulties for devices that aim at harvesting vibration energy. Here, we present a liquid-metal-based freestanding triboelectric generator (LM-FTG) for vibration energy harvesting. In this device, the fluidity of liquid is used to increase sensitivity to vibration for better low-frequency response and multidirectional vibration energy harvesting capability. The freestanding power generation mode is able to increase power generation stability. Experiments show that the bandwidth of LM-FTG can almost cover the entire sweep frequency range, and a 10 μF capacitor can be charged to 6.46 V at 7.5 Hz in 60 s by LM-FTG. In particular, 100 LEDs are illuminated in the low-frequency environmental experiment successfully. The proposed LM-FTG can work in low frequency with large working bandwidth, which provides an effective method for energy harvesting of low-frequency and multidirectional vibrations.


Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 500 ◽  
Author(s):  
Nathan Jackson

Increasing the power density and bandwidth are two major challenges associated with microelectromechanical systems (MEMS)-based vibration energy harvesting devices. Devices implementing magnetic forces have been used to create nonlinear vibration structures and have demonstrated limited success at widening the bandwidth. However, monolithic integration of a magnetic proof mass and optimizing the magnet configuration have been challenging tasks to date. This paper investigates three different magnetic configurations and their effects on bandwidth and power generation using attractive and repulsive magnetic forces. A piezoMEMS device was developed to harvest vibration energy, while monolithically integrating a thick embedded permanent magnet (NdFeB) film. The results demonstrated that repulsive forces increased the bandwidth for in-plane and out-of-plane magnetic configurations from <1 to >7 Hz bandwidths. In addition, by using attractive forces between the magnets, the power density increased while decreasing the bandwidth. Combining these forces into a single device resulted in increased power and increased bandwidth. The devices created in this paper focused on low acceleration values (<0.1 g) and low-frequency applications.


2017 ◽  
Vol 29 (7) ◽  
pp. 1333-1347 ◽  
Author(s):  
Dominik Gedeon ◽  
Stefan J Rupitsch

We present a system simulation approach for piezoelectric vibration energy harvesting devices. Accurate modeling of the electromechanical structure is achieved by the finite element method. For consideration of power electronic circuits as a means of energy extraction, the finite element model is iteratively coupled to electric circuits via Simulink. The high computational cost of conventional finite element calculations is overcome by a specialized modal truncation method for general linear piezoelectric structures. In doing so, the simulation approach allows efficient prediction of mechanical quantities (e.g. displacements, stresses) as well as electric potentials in the continuum under the influence of arbitrary electrical circuits. Several examples are studied to validate the truncation approach against analytical models and full finite element models. The applicability of the method is demonstrated for a piezoelectric vibration energy harvester in conjunction with a power electronic circuit.


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