Towards a Self-Tunable, Wide Frequency Bandwidth Vibration Energy Harvesting Device

2009 ◽  
Author(s):  
Vinod R. Challa ◽  
M. G. Prasad ◽  
Frank T. Fisher
Keyword(s):  
Energy Harvesting ◽  
Resonance Frequency ◽  
Power Output ◽  
Frequency Tuning ◽  
Cutoff Frequency ◽  
Peak Power Output ◽  
Vibration Energy ◽  
Frequency Bandwidth ◽  
Vibration Energy Harvesting ◽  
Ultra Low Power

Vibration energy harvesting is increasing in popularity due to potential applications such as powering wireless sensors and ultra low power devices. For efficient energy harvesting, matching the device frequency to the source frequency is a major design requirement. Since mechanical vibrations differ in characteristics (frequency and acceleration amplitude), it is difficult to design an individual energy harvesting device for every source. Recently, several groups have pursued techniques to tune the resonance frequency of the vibrating structure through active and passive methods. In this paper, work has been done to attain a self-tunable energy harvesting device, which utilizes a magnetic force resonance frequency tuning technique to tune the device. The device is successfully tuned with in a bandwidth of ± 27% of its untuned resonance frequency, considering root mean square of the peak power output as the cutoff for frequency bandwidth. Since the technique is semi-active, energy is only consumed to tune the resonance frequency and is not required to remain at that specific frequency. The device consists of a piezoelectric cantilever beam array which is displaced to the desired distance to induce magnetic stiffness and to match the source frequency using a DC motor. The device has a power output of approximately 0.7 mW to 1 mW in the designed cutoff frequency range. The amount of energy consumed by the actuator to displace the beam is approximately 3.5 W to 4.5 W, which requires approximately 150 minutes to reclaim the expended energy.

Design Considerations for Harvesting Vibration Energy at MEMS Scale: Review

2009 ◽  
Author(s):  
Vinod R. Challa ◽  
Frank T. Fisher
Keyword(s):  
Energy Harvesting ◽  
Low Power ◽  
Power Density ◽  
Wireless Sensors ◽  
Load Resistance ◽  
Peak Power Output ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Ultra Low Power ◽  
Design Considerations

Vibration based energy harvesting has wide potential applications in areas such as wireless sensors networks and ultra low power devices. While there have been various technologies through which vibration energy has been harvested, there is a considerable need to improve the power density of such devices. Recently, efforts have been made in developing MEMS scale devices as they would have increased power density and also provide ease of integration with wireless sensors and low power electronic devices. The aim of this paper is to present the generic and specific design considerations for vibration energy harvesting at the MEMS scale for electrostatic, electromagnetic and piezoelectric techniques. The effect of external load such as load resistance employed for peak power output on the total damping in the system is discussed. The typical MEMS scale vibrating structures such as cantilever beam, fixed-fixed beam and membrane are also presented.

A Vibration Energy Harvesting Structure, Tunable Over a Wide Frequency Range Using Minimal Actuation

2013 ◽  
Author(s):  
John Heit ◽  
David Christensen ◽  
Shad Roundy
Keyword(s):  
Energy Harvesting ◽  
Resonance Frequency ◽  
Frequency Tuning ◽  
Wide Frequency Range ◽  
Design Parameters ◽  
Vibration Energy ◽  
Test Results ◽  
Vibration Energy Harvesting ◽  
Frequency Tunability ◽  
Added Benefit

This paper introduces a novel vibration energy harvesting structure with a resonance frequency that is tunable over a large range using a simple compact mechanical adjustment that alters the structural stiffness. The frequency tuning requires minimal actuation that can be “turned off” while maintaining the new resonance frequency. Testing shows that the natural frequency can be adjusted from 32 Hz to 85 Hz. The structure is coupled with an electromagnetic transducer to generate power. Test results at varying excitation frequencies and amplitudes demonstrate tunable power generation over a very wide bandwidth. In addition to frequency tunability, the structure is a nonlinear softening spring, which provides the added benefit of a passively wider bandwidth for specific ranges of the design parameters.

scholarly journals A Theory for Energy-Optimized Operation of Self-Adaptive Vibration Energy Harvesting Systems with Passive Frequency Adjustment

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 44 ◽  
Author(s):  
Mario Mösch ◽  
Gerhard Fischerauer
Keyword(s):  
Energy Harvesting ◽  
Resonance Frequency ◽  
Optimal Operation ◽  
Energy Output ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Frequency Adjustment ◽  
Harvesting Systems ◽  
Self Adaptive

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.

Enhanced Vibration Energy-Harvesting Using Inerter-Based Two-Degree-of-Freedom System

2018 ◽  
Author(s):  
Mingyi Liu ◽  
Wei-Che Tai ◽  
Lei Zuo
Keyword(s):  
Energy Harvesting ◽  
Degree Of Freedom ◽  
Power Stroke ◽  
Specific Power ◽  
Vibration Energy ◽  
Frequency Bandwidth ◽  
Vibration Energy Harvesting ◽  
Sdof System ◽  
Harvesting Systems ◽  
Two Degree Of Freedom

In rotational electromagnetic generator based vibration energy-harvesting systems, the generator rotor is an inerter. From analysis, it is found that the inerter decreases system frequency bandwidth in single-degree-of-freedom (SDOF) energy-harvesting systems. The maximum electric power output of a SDOF system is limited by mechanical damping and maximum stroke that allowed. Two-degree-of-freedom (2DOF) energy-harvesting systems was proposed in recent years and has been shown to have the potential to have better power, power/stroke ratio, and frequency bandwidth performance compared with SDOF systems. However, extra mass has to be added in most of the case. In this paper, a new design of inerter-based-2DOF energy-harvesting system was proposed by adding a spring in series with the inerter in SDOF system. No extra mass is added compared with its counterpart SDOF system. Optimal specific power at limited stroke were obtained by tuning system parameters, which includes resonance frequency ratio, spring ratio, mass ratio, and damping ratio. The contribution of each parameter to system performance was analyzed. The results show that the proposed inerter-based-2DOF system has better performance compared with the SDOF system. The inerter-based-2DOF can have larger specific power and larger power/stroke ratio over a wider frequency bandwidth. Simulation also show that improved performance not only obtained with sinusoidal excitation with constant displacement amplitude, but also with sinusoidal excitation with constant force amplitude.

Investigating the Feasibility of Tuning the Natural Frequency of an Electromagnetically-Transduced Energy Harvester Using Passively-Controlled Inductance

2014 ◽  
Author(s):  
Brennan E. Yamamoto ◽  
A. Zachary Trimble
Keyword(s):  
Energy Harvesting ◽  
Natural Frequency ◽  
Energy Harvester ◽  
Frequency Tuning ◽  
Excitation Frequency ◽  
Energy Output ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Mechanical Spring ◽  
Energy Harvesting System

As the required power for wireless, low-power sensor systems continues to decrease, the feasibility of a fully self-sustaining, onboard power supply, has increased interest in the field of vibration energy harvesting — where ambient kinetic energy is scavenged from the surrounding environment. Current literature has produced a number of harvesting techniques and transduction methods; however, they are all fundamentally similar in that, the harmonic excitation frequency must fall within the resonant bandwidth frequency of the harvesting mechanism to maintain acceptable energy output. The purpose of this research is to investigate the potential for natural frequency tuning by means of passive electrical components, that is, using an imposed electrical inductance to adjust the equivalent stiffness, and resulting resonant frequency of a vibration energy harvester. In past literature, it was concluded that an “active” frequency tuning mechanism would be infeasible, as the power required by an equivalent “stiffening transducer” would require more power to maintain the system at resonance, than the system would actually produce as a result of maintaining resonance, i.e., a net energy loss (Roundy and Zhang 2005). It is believed that the model used in this conclusion can be improved by directly modeling changes in system stiffness as an equivalent mechanical spring, instead of an external inertial loading. Due to the conservative nature of the harmonic spring, the compliance of a harvesting mechanism can be theoretically altered without energy losses, whether the actuation is applied using “active” or “passive” means. This revised model departs from the traditional, base excitation model in most vibration energy harvesting systems, and includes additional stiffness, and damping elements, representative of induced mechanical spring, and related losses. We can validate the feasibility of this technique, if it can be shown that the natural frequency of an energy harvester can be altered, and still maintain energy output similar to its “untuned” natural frequency. If feasible, this tuning method would provide a viable alternative to other bandwidth-increasing techniques in literature, e.g., wideband harvesting, bandwidth normalizing, high-damping, etc. In this research, a change in natural frequency of the experimental energy harvesting system of 0.5 Hz was demonstrated, indicating that adjusting the natural frequency of a vibration energy harvesting system is possible; however, there are many new challenges associated with the revised energy harvesting model, related to the new introduced losses to the system, as well as impedance matching between the mechanical and electrical domains. Further research is required to better quantitatively characterize the relationship between natural frequency shift, and imposed electrical inductance.

A MEMS Piezoelectric Cantilever Beam Array for Vibration Energy Harvesting

2013 ◽  
Vol 562-565 ◽  
pp. 1052-1057 ◽  
Author(s):  
Xing Qiang Zhao ◽  
Zhi Yu Wen ◽  
Li Cheng Deng ◽  
Guo Xi Luo ◽  
Zheng Guo Shang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Resonance Frequency ◽  
Cantilever Beam ◽  
Maximum Output Power ◽  
Vibration Energy ◽  
Cmos Process ◽  
Maximum Output ◽  
Vibration Energy Harvesting ◽  
Beam Array ◽  
Piezoelectric Cantilever

A micro piezoelectric cantilever beam array is designed for vibration energy harvesting. A single degree of freedom analytical model is developed to predict the properties of the device and is verified by finite element method. The piezoelectric material Aluminum Nitride was chosen for the compatibility with the CMOS process. The devices consisting of 5 piezoelectric cantilever beams and one proof mass were fabricated using micromachining technology. The resonance frequency, voltage and power were tested at excitation acceleration of 5.0 g. The maximum output power of the device is 9.13 μW at the resonance frequency of 1315 Hz when piezoelectric beams are connected in parallel.

On the stochastic dynamics of a nonlinear vibration energy harvester driven by Lévy flight excitations

2018 ◽  
Vol 30 (5) ◽  
pp. 945-967
Author(s):  
SUBRAMANIAN RAMAKRISHNAN ◽  
CONNOR EDLUND ◽  
COLLIN LAMBRECHT
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Stochastic Dynamics ◽  
Nonequilibrium Dynamics ◽  
Vibration Energy ◽  
Small Scale ◽  
Lévy Flight ◽  
Coupling Coefficients ◽  
Vibration Energy Harvesting ◽  
Levy Flight

Vibration energy harvesting aims to harness the energy of ambient random vibrations for power generation, particularly in small-scale devices. Typically, stochastic excitation driving the harvester is modelled as a Brownian process and the dynamics are studied in the equilibrium state. However, non-Brownian excitations are of interest, particularly in the nonequilibrium regime of the dynamics. In this work we study the nonequilibrium dynamics of a generic piezoelectric harvester driven by Brownian as well as (non-Brownian) Lévy flight excitation, both in the linear and the Duffing regimes. Both the monostable and the bistable cases of the Duffing regime are studied. The first set of results demonstrate that Lévy flight excitation results in higher expectation values of harvested power. In particular, it is shown that increasing the noise intensity leads to a significant increase in power output. It is also shown that a linearly coupled array of nonlinear harvesters yields improved power output for tailored values of coupling coefficients. The second set of results show that Lévy flight excitation fundamentally alters the bifurcation characteristics of the dynamics. Together, the results underscore the importance of non-Brownian excitation characterised by Lévy flight in vibration energy harvesting, both from a theoretical viewpoint and from the perspective of practical applications.

Sign in / Sign up

Export Citation Format

Share Document