Parameter Optimization of a Vibration-Based Energy Harvester With an RL Electric Circuit

2007 ◽  
Author(s):  
Jamil M. Renno ◽  
Mohammed F. Daqaq ◽  
Justin R. Farmer ◽  
Daniel J. Inman
Keyword(s):  
Energy Harvester ◽  
Damping Ratio ◽  
Real Life ◽  
Electric Circuit ◽  
Operating Conditions ◽  
Constitutive Law ◽  
Energy Harvesters ◽  
Small Deflection ◽  
Piezoceramic Element ◽  
Quantitative Manner

An alternative circuit to improve the performance of a vibration-based energy harvester is proposed. The harvesting device considered consists of a piezoceramic element operating in the {33} direction. In normal operating conditions, piezoceramics experience small deflection and hence the small signal linear constitutive law of piezoelectricity is adopted for the scope of this work. Typically, vibration-based energy harvesters are designed to operate at the resonance or antiresonance frequencies. This condition might be tolerable in many cases, but is often difficult to realize in real-life applications. In this work, the authors propose adding an inductor to the harvesting circuit. It is shown that the addition of this simple electric element modifies the performance remarkably in a qualitative and quantitative manner. The maximum power values obtained at the resonance and antiresonance frequencies can be achieved at any frequency ratio if optimal electric elements are used. This allows for harvesting a constant optimal power everywhere in the frequency domain. Further investigation reveals the existence of a singularity at low damping ratios (below a bifurcation damping ratio). In that case, the optimization scheme yields a negative value for the optimal inductance between the resonance and antiresonance frequencies. However, this singularity is not experienced at a high damping ratio (beyond a bifurcation damping ratio). Moreover, for high damping ratios, it is shown that the proposed circuit is superior to a circuit that does not deploy an inductor.

scholarly journals A Comparison of Methods to Measure the Coupling Coefficient of Electromagnetic Vibration Energy Harvesters

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 826 ◽  
Author(s):  
Mario Mösch ◽  
Gerhard Fischerauer
Keyword(s):  
Coupling Coefficient ◽  
Energy Harvester ◽  
Electromagnetic Coupling ◽  
Electric Circuit ◽  
Open Circuit ◽  
Measurement Methods ◽  
Vibration Energy ◽  
Simulation Data ◽  
Average Deviation ◽  
Energy Harvesters

Vibration energy harvesters transform environmental vibration energy into usable electrical energy. The transformation is only possible because of a coupling between the mechanical part of the energy harvester and the electric circuit. This paper compares several measurement methods to determine the electromagnetic coupling coefficient. These methods are applied to various implementations of an energy harvester and the results are compared with one another and with simulation data by analyzing the magnetic flux. The average deviation between the measurement methods and the simulation data in our study was 5%. This good agreement validates the methods. Based on this, we recommend determination of the coupling coefficient and the optimum load resistance for maximum power harvesting on the basis of simulations and the open circuit method, because this procedure leads to the shortest measurement times.

Equivalent impedance and power analysis of monostable piezoelectric energy harvesters

2020 ◽  
Vol 31 (14) ◽  
pp. 1697-1715
Author(s):  
Chunbo Lan ◽  
Yabin Liao ◽  
Guobiao Hu ◽  
Lihua Tang
Keyword(s):  
Equivalent Circuit ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Performance Enhancement ◽  
Damping Ratio ◽  
Power Performance ◽  
Closed Form Solutions ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Power Limit

Nonlinearity has been successfully introduced into piezoelectric energy harvesting for power performance enhancement and bandwidth enlargement. While a great deal of emphasis has been placed by researchers on the structural design and broadband effect, this article is motivated to investigate the maximum power of a representative type of nonlinear piezoelectric energy harvesters, that is, monostable piezoelectric energy harvester. An equivalent circuit is proposed to analytically study and explain system behaviors. The effect of nonlinearity is modeled as a nonlinear stiffness element mechanically and a nonlinear capacitive element electrically. Facilitated by the equivalent circuit, closed-form solutions of power limit and critical electromechanical coupling, that is, minimum coupling to reach the power limit, of monostable piezoelectric energy harvesters are obtained, which are used for a clear explanation of the system behavior. Several important conclusions have been drawn from the analytical analysis and validated by numerical simulations. First, given the same level of external excitation, the monostable piezoelectric energy harvester and its linear counterpart are subjected to the same power limit. Second, while the critical coupling of linear piezoelectric energy harvesters depends on the mechanical damping ratio only, it also depends on the vibration excitation and magnetic field for monostable piezoelectric energy harvesters, which can be used to adjust the power performance of the system.

Impulsively-Excited Bistable Energy Harvester Combined With Electromagnetic Mechanism

2018 ◽  
Author(s):  
Shitong Fang ◽  
Wei-Hsin Liao
Keyword(s):  
Energy Harvester ◽  
Damping Ratio ◽  
High Amplitude ◽  
High Energy ◽  
Living Environment ◽  
Energy Output ◽  
Energy Harvesters ◽  
Hybrid Configuration ◽  
Promising Source ◽  
Bistable Energy Harvester

Impulsive energy provides a promising source for energy harvesting techniques due to their high amplitude and abundance in a living environment. The sensitivity to excitation of bistable energy harvesters makes them feasible for impulsive-type events. In this paper, a novel impulsively-excited bistable energy harvester with rotary structure and plectrum is proposed to achieve plucking-based frequency up-conversion. The input excitation is converted to plucking force on the bistable energy harvester, so as to help it go into the high-energy orbit. The piezoelectric and electromagnetic transduction mechanisms are combined by incorporating a coil to the structure in order to overcome the increase of damping introduced by the bistable configuration. As a result, high-energy output and broadband performance could be realized. Impact mechanics is employed to develop a comprehensive model, which could be used to analyze the nonlinear dynamics and predict the system responses under various plucking velocities and overlap lengths. Numerical simulation shows that the bistable energy harvester could experience large-amplitude oscillation under impulsive excitation and the hybrid configuration outperforms the standalone ones under high damping ratio and low coupling coefficient. The proposed design is targeted to be applied on the turnstile gates of the subway station. Less human effort would be needed when passengers pass the turnstile gate due to the snap-through motion of bistability.

scholarly journals Buckled MEMS Beams for Energy Harvesting from Low Frequency Vibrations

Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Ruize Xu ◽  
Haluk Akay ◽  
Sang-Gook Kim
Keyword(s):  
Residual Stress ◽  
Energy Harvester ◽  
Low Frequency ◽  
Operating Conditions ◽  
Operating Frequency ◽  
Vibration Energy ◽  
Vibration Source ◽  
Beam Structure ◽  
Energy Harvesters ◽  
Frequency Window

Vibration energy harvesters based on the resonance of the beam structure work effectively only when the operating frequency window of the beam resonance matches with the available vibration source. None of the resonating MEMS structures can operate with low frequency, low amplitude, and unpredictable ambient vibrations since the resonant frequency goes up very high as the structure gets smaller. Bistable buckled beam energy harvester is therefore developed for lowering the operating frequency window below 100Hz for the first time at the MEMS scale. This design does not rely on the resonance of the MEMS structure but operates with the large snapping motion of the beam at very low frequencies when input energy overcomes an energy threshold. A fully functional piezoelectric MEMS energy harvester is designed, monolithically fabricated, and tested. An electromechanical lumped parameter model is developed to analyze the nonlinear dynamics and to guide the design of the nonlinear oscillator based energy harvester. Multilayer beam structure with residual stress induced buckling is achieved through the progressive residual stress control of the deposition processes along the fabrication steps. Surface profile of the released device shows bistable buckling of 200μm which matches well with the amount of buckling designed. Dynamic testing demonstrates the energy harvester operates with 50% bandwidth under 70Hz at 0.5g input, operating conditions that have not been demonstrated by MEMS vibration energy harvesters before.

scholarly journals An Effect of Coupling Factor on the Power Output for Electromagnetic Vibration Energy Harvester

2021 ◽  
Vol 10 (1) ◽  
pp. 5
Author(s):  
Tunde Isaiah Toluwaloju ◽  
Chung Ket Thein ◽  
Dunant Halim
Keyword(s):  
Flux Density ◽  
Energy Harvester ◽  
Damping Ratio ◽  
Real Life ◽  
Analytical Framework ◽  
Vibration Energy ◽  
Coupling Constant ◽  
Power Module ◽  
Vibration Energy Harvester ◽  
Electromagnetic Vibration

Sensors are devices that measures a change in physical stimulus by converting it into an electronic signal which can be read by a designated instrument. To overcome the real-life challenges associated with powering a sensor using conventional batteries and chargers, this work focuses on formulating analytical framework for designing an ecofriendly, cheap, almost zero retrofit implication (except on damage) power module for sensors using an electromagnetic vibration energy harvester. This principle relies on the electromagnetic transduction whose harvested voltage/power is formulated from Faraday law of electromagnetic induction. An electromagnetic parameter that determines the degree of transduction is the coupling constant. The value of coupling constant must be accurately set during harvester design because it directly determines harvester damping ratio and the power available for the sensor. All parameters used to compute the coupling except the flux density are constant. In this work, we focus on formulating a set of analytical equations that could effectively determine the harvester’s optimum magnetic flux parameter to be used in computing the optimum coupling constant, the electromagnetic damping ratio, and the harvested power at resonant. This work concludes that the degree of coupling for the determined optimum flux density increases with an increased load resistance and hence larger harvested power is available to power the sensor.

scholarly journals Study on Parameterization of Vortex-Induced Vibration Energy Harvester in Agricultural Environment

2020 ◽  
Vol 2 (4) ◽  
pp. 511-522
Author(s):  
Zhangyi Liao ◽  
Anping Xiong ◽  
Renxin Liu
Keyword(s):  
Energy Harvesting ◽  
Energy Harvester ◽  
Damping Ratio ◽  
Large Mass ◽  
Maximum Efficiency ◽  
Mass Ratio ◽  
Vibration Energy Harvester ◽  
Vortex Induced Vibration ◽  
Agricultural Environment ◽  
Energy Harvesters

In many special agricultural environments, many wireless sensors have a problem of power supply selection. Energy harvesting in the agricultural environment based on vortex-induced vibration (VIV) has the potential to solve the problem. In this paper, an energy harvester based on the VIV is designed in an agricultural environment. Relevant parameters of the harvester are studied with wind tunnel experiment to improve the efficiency of energy conversation. The results show that: (i) For large mass ratio, m*≫1, and the same mass ratio m*, the smaller the damping ratio ζ, the larger the normalized amplitude A*, the larger the maximum efficiency η of VIV energy harvesting; (ii) m*≫1, and under a certain range of Reynolds numbers, the smaller the mass-damping parameter m*ζ, the larger the normalized amplitude A*, the larger the maximum and average efficiency η of VIV energy harvesting. (iii) m*≫1, the larger the mass ratio m*, the larger the range of resonance; the normalized frequency f*≃1, the stable VIV locked state appears. The research results can provide references for the design of VIV energy harvesters in agricultural environments.

scholarly journals Modeling of a Real-Life Industrial Reactor for Hydrogenation of Benzene Process

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 412
Author(s):  
Mirosław K. Szukiewicz ◽  
Krzysztof Kaczmarski
Keyword(s):  
Catalyst Activity ◽  
Real Life ◽  
Operating Conditions ◽  
Reactor Operation ◽  
Reactor Model ◽  
High Scale ◽  
Industrial Reactor ◽  
Knowledge Based ◽  
Operation Conditions ◽  
Insight Into

A dynamic model of the hydrogenation of benzene to cyclohexane reaction in a real-life industrial reactor is elaborated. Transformations of the model leading to satisfactory results are presented and discussed. Operating conditions accepted in the simulations are identical to those observed in the chemical plant. Under those conditions, some components of the reaction mixture vanish, and the diffusion coefficients of the components vary along the reactor (they are strongly concentration-dependent). We came up with a final reactor model predicting with reasonable accuracy the reaction mixture’s outlet composition and temperature profile throughout the process. Additionally, the model enables the anticipation of catalyst activity and the remaining deactivated catalyst lifetime. Conclusions concerning reactor operation conditions resulting from the simulations are presented as well. Since the model provides deep insight into the process of simulating, it allows us to make knowledge-based decisions. It should be pointed out that improvements in the process run, related to operating conditions, or catalyst application, or both on account of the high scale of the process and its expected growth, will remarkably influence both the profits and environmental protection.

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

scholarly journals Load Resistance Optimization of a Broadband Bistable Piezoelectric Energy Harvester for Primary Harmonic and Subharmonic Behaviors

2021 ◽  
Vol 13 (5) ◽  
pp. 2865 ◽  
Author(s):  
Sungryong Bae ◽  
Pilkee Kim
Keyword(s):  
Energy Harvester ◽  
Load Resistance ◽  
Oscillation Period ◽  
Ambient Vibration ◽  
Ambient Vibrations ◽  
Frequency Dependency ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Optimal Load ◽  
Bistable Energy Harvester

In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the interwell motions, and evaluated. The analytical results are in excellent agreement with the numerical ones. A parametric study shows that the optimal load resistance depended on the forcing frequency, but not the intensity of the ambient vibration. Additionally, it was found that the optimal resistance for the period-3T interwell motion tended to be approximately three times larger than that for the period-1T interwell motion, which means that the optimal resistance was directly affected by the oscillation frequency (or oscillation period) of the motion rather than the forcing frequency. For broadband energy harvesting applications, the subharmonic interwell motion is also useful, in addition to the primary harmonic interwell motion. In designing such piezoelectric bistable energy harvesters, the frequency dependency of the optimal load resistance should be considered properly depending on ambient vibrations.

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