Vibration Energy Harvesting System Research Articles

Time‐Delayed Feedback Control in the Multiple Attractors Wind‐Induced Vibration Energy Harvesting System

This paper proposes a time‐delayed feedback control to improve collection performance of the multiple attractors wind‐induced vibration energy harvester system. By employing a conversion mechanism for decoupling the electromechanical equations and the stochastic averaging method, the roles of the time‐delayed feedback and the system parameters have been systematically examined. In the deterministic case, the time delay can control efficiently the birhythmic properties; thus one can realize a dividing line in the parameter plane that separates the space into two subspaces of generically distinct nature. Further, it is exclusively demonstrated that implementing time‐delayed feedback control serves as a very simple but highly efficient scheme to increase the harvested energy from vibrations in presence of noise disturbances. Additionally, the time constant ratio and coupling coefficients can also be properly tuned to optimize power generation.

Examination of vibration energy harvesting system by translation type bistable vibration

Examination of vibration energy harvesting system by translation type bistable vibration

Electrical power management and optimization with nonlinear energy harvesting structures

In recent years, great advances in understanding the opportunities for nonlinear vibration energy harvesting systems have been achieved giving attention to either the structural or electrical subsystems. Yet, a notable disconnect appears in the knowledge on optimal means to integrate nonlinear energy harvesting structures with effective nonlinear rectifying and power management circuits for practical applications. Motivated to fill this knowledge gap, this research employs impedance principles to investigate power optimization strategies for a nonlinear vibration energy harvester interfaced with a bridge rectifier and a buck-boost converter. The frequency and amplitude dependence of the internal impedance of the harvester structure challenges the conventional impedance matching concepts. Instead, a system-level optimization strategy is established and validated through simulations and experiments. Through careful studies, the means to optimize the electrical power with partial information of the electrical load is revealed and verified in comparison to the full analysis. These results suggest that future study and implementation of optimal nonlinear energy harvesting systems may find effective guidance through power flow concepts built on linear theories despite the presence of nonlinearities in structures and circuits.

Dual serial vortex-induced energy harvesting system for enhanced energy harvesting

This paper presents a novel dual serial vortex-induced vibration energy harvesting system for enhanced energy harvesting. It consists of two identical cantilever-based piezoelectric vortex-induced vibration energy harvesters, which are successively installed in one plane (which is paralleled with the wind flow direction) of the wind tunnel. The Lattice Boltzmann method is employed to predict the strength of vortex-induced vibrations and the pressure distribution around the circular cylinders of the harvesters. The numerical results qualitatively explain the influence of the space distance on the energy harvesting performance of the presented system. Experimental results verify the numerical analysis and demonstrate a higher energy harvesting efficiency of the presented system over its traditional single harvester. In detail, experimental results indicate that the effective wind speed range and the output power area of a coupled harvester in the presented system can be as many as 2.67 times and 6.79 times of that of the traditional single harvester, respectively.

Feasibility of vibration energy harvesting powered wireless tracking of falcons in flight

The use of wireless tagging of birds has been widely used for monitoring or tracking purposes. This include over 10 thousand wireless tracking devices currently used by the UK falconers alone. However, due to the concern of not burdening the birds with a heavy battery, the existing lightweight telemetry tracking systems can only last for days, if not hours. Falcons can have top flight speeds in excess of a hundred miles an hour, which makes it a near impossible task to track a missing falcon after the battery has been depleted. This paper investigates the feasibility of incorporating a piezoelectric vibration energy harvesting system to act as a secondary power source for the wireless tracking of falcons. The ultimate aim is to both extend the primary battery life and enable periodic burst transmissions of telemetry after the depletion of the primary battery. The presented tracking and harvesting system is lightweight and has been field trialled on a gyrfalcon at the Chester Cathedral Falconry.

Complex modal analysis and coupled electromechanical simulation of energy harvesting piezoelectric laminated beams

In this paper, coupled electromechanical behavior of a vibrational energy harvesting system composed of a unimorph piezoelectric laminated beam with a large attached tip mass is investigated. To achieve this goal, first the electromechanically coupled partial differential equations governing the lateral displacement and output voltage of the harvester are extracted through exploiting the Hamilton’s principle. Considering vibration damping due to mechanical to electrical energy conversion, a complex modal analysis is performed to extract the complex eigenfrequencies and eigenfunctions of the system. Furthermore, an exact analytical solution is presented for the system response to the harmonic base excitations, including output voltage and harvested power. To validate the analytical results, at the next step a finite element simulation is conducted through ABAQUS software. To perform a fully-coupled analysis which brings into account the effect of harvesting circuit, user subroutine User-defined Amplitude (UAMP) is utilized to calculate the voltage–current relation and impose the correct electrical charge on the electrodes in each step by monitoring the output voltage of the system at previous time increments. Results of both analytical and numerical simulations are compared for a Micro-Electro-Mechanical Systems (MEMS) harvester as a case study, where a very good agreement is observed between them.

Improving low-frequency piezoelectric energy harvesting performance with novel X-structured harvesters

Vibration energy harvesting systems via an X-structure coupled with piezoelectric patches of special arrangements are investigated in this study. Two piezoelectric harvesters are specially installed on the X-shaped structure to explore potential benefits that the X-shaped structure could provide, and each piezoelectric pad has two layers composed of a polyvinyl chloride base patch and a micro-fibre composite patch. The theoretical analysis and experiment results indicate that the energy harvesting performance of the proposed novel arrangements of the piezoelectric harvesters can be enhanced especially in low-frequency range (below 10 Hz), compared with conventional cantilevered piezoelectric harvesters. More and higher energy harvesting peaks can be created and the effective harvesting frequency band can be obviously enlarged by expanding it to low-frequency range with the proposed methods. The X-structure-based generators can enable piezoelectric materials to harvest power from low-frequency vibration sources due to its advantages in designable equivalent nonlinear stiffness, which can be easily tuned by adjusting the key structural parameters. The design and results would provide an innovative solution and insight for smart piezoelectric materials to improve the energy harvesting efficiency in the low-frequency range including small-scale ocean wave power harvesting, human motion power and animal kinetic power harvesting, etc.

A Dimensionless Parameter Analysis of a Cylindrical Tube Electromagnetic Vibration Energy Harvester and Its Oscillator Nonlinearity Effect

This paper investigates a single degree of freedom oscillator in a cylindrical tube vibration energy harvester which is applicable in a low-frequency range. A duffing-type nonlinear dynamic differential equation of the oscillator was developed for the nonlinear analysis and solved by using the harmonic balance method in order to widen energy harvesting frequency bandwidth. The exploitation of nonlinear spring force interactions of the oscillator to enhance the generator’s performance is also presented in this paper. The dimensionless harvested power formula of the nonlinear mass-spring-damper system was derived, and a parameter study was conducted for the design optimization of the harvester. The main contribution of this paper is to establish a dimensionless performance analysis method of a nonlinear electromagnetic vibration energy harvester system and to disclose the effects of the parameters and nonlinearity of the system on the harvesting performance.

A tunable nonlinear vibrational energy harvesting system with scissor-like structure

Vibrational energy harvesting systems with linear electromechanical generators have been largely studied, due to their simple structures and convenience in application. However, the ambient vibration characteristics such as random, time-varying or low-frequency properties make the linear electromagnetic devices cannot be excited at their resonances, which will greatly affect the energy harvesting efficiency. Some attempts to improve the efficiency of a vibration energy harvesting system involve both expand the operating bandwidth and enlarging the magnitude of power output. To this end, a scissor-like energy harvesting system with equivalent nonlinear damping and linear stiffness has been developed in this study. It has been shown that, due to the beneficial nonlinear damping effects provided by the scissor-like structure, the proposed system can greatly improve the vibration energy harvesting performance in terms of the magnitude of power output and energy harvesting bandwidth. On the other hand, the structure parameters of the proposed system can be modified to achieve more significant energy harvesting performance. Moreover, to achieve tunable resonant frequency of the energy harvesting system, the scissor-like structure has been updated by attaching a new lever-type system. In this way, the energy harvesting performance can be improved by tuning the proposed system according to the properties of the surrounding vibration sources. In this paper, both harmonic and random excitations have been adopted to verify the performance of the proposed energy harvesting system.

Evaluation of the Output Load Effect on a Piezoelectric Energy Harvester

This paper presents the study of a vibration energy harvesting system using piezoelectric generator coupled to a cantilever beam when subjected to output loads with different electrical characteristics. The proposed analysis is based on the system frequency response under two scenarios at the output of the piezoelectric energy harvester: a purely resistive load and a full-wave rectifier before the load. A prototype capable of varying the amplitude and frequency of the input mechanical stimulus was constructed in order to evaluate the energy harvester. Then system identification techniques were employed to determine how the resonance frequency and output power are affected by the load. Experimental results showed that depending on the load there is significant change on the operating point at which the maximum power transfer occurs.

Stochastic averaging for bistable vibration energy harvesting system

Vibration energy harvesting technique provides the possibility of the development of self-sustaining microelectronic components. The bistable energy harvesting devices have higher efficiency than the traditional mono-stable devices and deserve further investigation. In this manuscript, a novel stochastic averaging procedure is established to evaluate the stationary random response of bistable energy harvester to additive and multiplicative white noises. An equivalent nonlinear system associated with the original coupling system is first derived by integrating the circuit equation and adopting the assumption of generalized harmonic functions of sample responses. The stationary probability density for mechanical energy of the equivalent nonlinear system is then derived through the stochastic averaging technique. The mean-square mechanical responses, the mean-square voltage and the mean output power are obtained analytically. Finally, the influences of crucial parameters, such as excitation intensity, coupling factor, time constant ratio etc., on mean-square voltage and mean output power are discussed in detail which may provide some guidance for structural design for maximizing output power.

Theoretical modeling and experimental validation of a torsional piezoelectric vibration energy harvesting system

Vibration energy harvesting has been extensively studied in recent years to explore a continuous power source for sensor networks and low-power electronics. Torsional vibration widely exists in mechanical engineering; however, it has not yet been well exploited for energy harvesting. This paper presents a theoretical model and an experimental validation of a torsional vibration energy harvesting system comprised of a shaft and a shear mode piezoelectric transducer. The piezoelectric transducer position on the surface of the shaft is parameterized by two variables that are optimized to obtain the maximum power output. The piezoelectric transducer can work in d15 mode (pure shear mode), coupled mode of d31 and d33, and coupled mode of d33, d31 and d15, respectively, when attached at different angles. Approximate expressions of voltage and power are derived from the theoretical model, which gave predictions in good agreement with analytical solutions. Physical interpretations on the implicit relationship between the power output and the position parameters of the piezoelectric transducer is given based on the derived approximate expression. The optimal position and angle of the piezoelectric transducer is determined, in which case, the transducer works in the coupled mode of d15, d31 and d33.

Circuit implementation of a piezoelectric buckled beam and its response under fractional components considerations

In this paper, an analog testing circuit and determinist averaging method for a vibration energy harvesting system with fractional derivative and nonlinear damping under a sinusoidal vibration source is proposed in order to predict the system response and its stability. The objective of this paper is to show that there is a possibility to make a pre-experimental design of the structure by using analog circuit and discussing the performance of a system with fractional derivative. Bifurcation diagram, poincare maps and power spectral density are provided to deeply characterize the dynamic of the system. These results are corroborated by using 0–1 test. By using the Melnikov method, we find the necessary condition for which homoclinic bifurcation occurs. Understanding and predicting this bifurcation is very judicious in the energy harvesting field because it may lead to different types of motion in the perturbed system. The appearance of chaotic vibrations increases the frequency’s bandwidth of the harvester thereby, allowing to harvest more energy. The pre-experimental investigation is carried out through appropriate software electronic circuit (Multisim®). The corresponding electronic circuit is designed exhibiting transient to chaos in accord with numerical simulations. The impact of fractional derivatives is presented upon the power generated by the system. In addition, by combining the harmonic force and a random excitation, the stochastic resonance appears, giving rise to large amplitude of vibration and consequently, enhancing the performance of the system. The results obtained in this work show the interest of using the electronic circuit to make the experiment analysis of the physical structure and also, the effects of the use of piezoelectric material exhibiting fractional properties in this research field.

The effects of the electro-mechanical coupling and Halbach magnet pattern on energy harvesting performance of a two degree of freedom electromagnetic vibration energy harvester

This paper studies a two degree of freedom electromagnetic vibration energy harvesting system with a magnet arrangement of the Halbach array. A theoretical analysis and computational simulation of the system were established through frequency response analysis and time domain integration of the system motion equations using the Matlab Simulink software. The results of the theoretical analysis and simulation models were compared with the results of a series of experiments, verifying the analysis approach.

Analysis of cantilevered piezoelectric harvester with different proof mass geometry for low frequency vibrations

To improve the performance of the vibration energy harvesting system based on piezoelectric cantilever beam, it is proposed to alter the shape and dimension of proof mass and the beam. Four cases namely cantilever with rectangular proof mass, cantilever with T, arc T shape proof mass and tapered cantilever with arc T shape proof mass are considered in this paper. Numerical simulations have been carried out for all the structures by maintaining the volume of the structure as constant. From the results it is observed that the trapezoidal beam with arc shape proof mass generates high output voltage for a given applied force compared to the other structures due to the increased bending moment produced near fixed end by the arced proof mass and uniform strain distribution produced by tapered section.

The effects of the electro-mechanical coupling and Halbach magnet pattern on energy harvesting performance of a two degree of freedom electromagnetic vibration energy harvester

This paper studies a two degree of freedom electromagnetic vibration energy harvesting system with a magnet arrangement of the Halbach array. A theoretical analysis and computational simulation of the system were established through frequency response analysis and time domain integration of the system motion equations using the Matlab Simulink software. The results of the theoretical analysis and simulation models were compared with the results of a series of experiments, verifying the analysis approach.

Energy harvesting from passing train as source of energy for autonomous trackside objects

This paper deals with an energy harvesting review and analysis of an ambient mechanical energy on a trackside during a passing of a train. Trains provide very high level of vibration and deformation which could be converted into useful electricity. Due to maintenance and safety reasons a rail trackside includes sensing systems and number of sensor nodes is increased for modern transportation. Recent development of modern communication and ultra-low power electronics allows to use energy harvesting systems as autonomous source of electrical energy for these trackside objects. Main aim of this paper is model-based design of proposed vibration energy harvesting systems inside sleeper and predict harvested power during the train passing. Measurements of passing train is used as input for simulation models and harvested power is calculated. This simulation of proposed energy harvesting device is very useful for future design.

Bandwidth Widening of Piezoelectric Cantilever Beam Arrays by Mass-Tip Tuning for Low-Frequency Vibration Energy Harvesting

Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs). The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power.

Charging power optimization for nonlinear vibration energy harvesting systems subjected to arbitrary, persistent base excitations

The vibrations of mechanical systems and structures are often a combination of periodic and random motions. Emerging interest to exploit nonlinearities in vibration energy harvesting systems for charging microelectronics may be challenged by such reality due to the potential to transition between favorable and unfavorable dynamic regimes for DC power delivery. Therefore, a need exists to devise an optimization method whereby charging power from nonlinear energy harvesters remains maximized when excitation conditions are neither purely harmonic nor purely random, which have been the attention of past research. This study meets the need by building from an analytical approach that characterizes the dynamic response of nonlinear energy harvesting platforms subjected to combined harmonic and stochastic base accelerations. Here, analytical expressions are formulated and validated to optimize charging power while the influences of the relative proportions of excitation types are concurrently assessed. It is found that about a 2 times deviation in optimal resistive loads can reduce the charging power by 20% when the system is more prominently driven by harmonic base accelerations, whereas a greater proportion of stochastic excitation results in a 11% reduction in power for the same resistance deviation. In addition, the results reveal that when the frequency of a predominantly harmonic excitation deviates by 50% from optimal conditions the charging power reduces by 70%, whereas the same frequency deviation for a more stochastically dominated excitation reduce total DC power by only 20%. These results underscore the need for maximizing direct current power delivery for nonlinear energy harvesting systems in practical operating environments.

Probabilistic response analysis of nonlinear vibration energy harvesting system driven by Gaussian colored noise

A new quasi-conservative stochastic averaging method is proposed to analyze the Probabilistic response of nonlinear vibration energy harvesting (VEH) system driven by exponentially correlated Gaussian colored noise. By introducing a method combining a transformation and the residual phase, the nonlinear vibration electromechanical coupling system is equivalent to a single degree of freedom system, which contains the energy-dependent frequency functions. Then the corresponding drift and diffusion coefficients of the averaged Ito^ stochastic differential equation for the equivalent nonlinear system are derived, which are dependent on the correlation time of Gaussian colored noise. The probability density function (PDF) of stationary responses is derived through solving the associated Fokker–Plank–Kolmogorov (FPK) equation. Finally, the mean-square electric voltage and mean output power are analytically obtained through the relation between the electric voltage and the vibration displacement, and the output power has a linear square relationship with the electric voltage, respectively. The main results on probabilistic response of VEH system are obtained to illustrate the proposed stochastic averaging method, and Monte Carlo (MC) simulation method is also conducted to show that the proposed method is quite effective.