Response Analysis of Asymmetric Monostable Harvesters Driven by Color Noise and Band-Limited Noise

In this paper, we investigate the response of asymmetric potential monostable energy harvesters (MEHs) excited by color noise and band-limited noise. The motivation for this study is that environmental vibrations always have the characteristic of randomness, and it is difficult to modulate a perfectly symmetric MEH. For the excitation of exponentially correlated color noise, the moment differential equation was applied to evaluate the output performance of the asymmetric potential MEHs. Numerical and theoretical analyses were carried out to investigate the influence of noise intensity and internal system parameters on the output power of the system. Our results demonstrate that the output performance of the asymmetric MEH decreases with the increase in the correlation time, which determines the character of the color noise. On the contrary, the increase in the asymmetric degree enhances the output power of the asymmetric MEH subjected to color noise. For the band-limited noise excitation, numerical simulation is undertaken to consider the response of the asymmetric MEHs, and outcomes indicate that the frequency bandwidth and center frequency have a significant influence on the output performance. Regarding the asymmetric potential, its appearance leads the MEHs to generate higher output power at lower frequencies and this phenomenon is more obvious with the increase in the degree of asymmetry. Finally, we observed that the characteristics of the response bandwidth of asymmetric MEHs subjected to band-limited noise excitation are similar to the response under harmonic excitation.

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Theoretical Analysis and General Characteristics for Nonlinear Vibration Energy Harvesters

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac453d ◽

2021 ◽

Author(s):

Hanxiao Wu ◽

Zhi Tao ◽

Haiwang Li ◽

Tiantong Xu ◽

Wenbin Wang ◽

...

Keyword(s):

Output Power ◽

Numerical Study ◽

Power Line ◽

Energy Harvesters ◽

Output Performance ◽

Equivalent Time ◽

Time Average ◽

Mechanical Damping ◽

Limit Power ◽

Nonlinear Energy

Abstract In this paper, we present a systematic theoretical and numerical study of the output performance of nonlinear energy harvesters. The general analytical expression of output power for systems with different combinations of nonlinear stiffness and nonlinear damping, as well as symmetrical and asymmetrical systems, have been derived based on harmonic balance method, observing compliance with numerical results. We theoretically prove that there is a limit power for all nonlinear systems which is determined exclusively by the vibrator mass, excitation acceleration, and mechanical damping. The results also indicate that for symmetrical stiffness systems, the asymmetrical damping components have no effect on the output performance. Additionally, we derived semi-analytical solutions of the matching loads and numerically investigated the influence of nonlinear coefficients on the output power with matched load. When the load matches device parameters and is much larger than the internal resistance, the equivalent time-average damping is equal to the mechanical damping. Although the matching load and output power vary with the nonlinear coefficients, the normalized power and matching resistance ratio follow a power function, named matching power line, which is independent of the structural parameters. With the improvement of the equivalent time-average short-circuit damping in the vibration range, the normalized power moves to the right end of the matching power line, and the output power approach to the limit power. These conclusions provide general characteristics of nonlinear energy harvesters, which can be used to guide the design and optimization of energy harvesters.

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On the Effects of Structural Coupling on Piezoelectric Energy Harvesting Systems Subject to Random Base Excitation

Aerospace ◽

10.3390/aerospace7070093 ◽

2020 ◽

Vol 7 (7) ◽

pp. 93

Author(s):

Hamidreza Masoumi ◽

Hamid Moeenfard ◽

Hamed Haddad Khodaparast ◽

Michael I. Friswell

Keyword(s):

Energy Harvesting ◽

Mechanical Response ◽

Harmonic Excitation ◽

Point Of View ◽

Analytical Models ◽

Energy Harvesters ◽

Piezoelectric Energy ◽

Novel Approach ◽

Band Limited ◽

Multi Body

The current research investigates the novel approach of coupling separate energy harvesters in order to scavenge more power from a stochastic point of view. To this end, a multi-body system composed of two cantilever harvesters with two identical piezoelectric patches is considered. The beams are interconnected through a linear spring. Assuming a stochastic band limited white noise excitation of the base, the statistical properties of the mechanical response and those of the generated voltages are derived in closed form. Moreover, analytical models are derived for the expected value of the total harvested energy. In order to maximize the expected generated power, an optimization is performed to determine the optimum physical and geometrical characteristics of the system. It is observed that by properly tuning the harvester parameters, the energy harvesting performance of the structure is remarkably improved. Furthermore, using an optimized energy harvester model, this study shows that the coupling of the beams negatively affects the scavenged power, contrary to the effect previously demonstrated for harvesters under harmonic excitation. The qualitative and quantitative knowledge resulting from this analysis can be effectively employed for the realistic design and modelling of coupled multi-body structures under stochastic excitations.

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Long-Term Stability of Ferroelectret Energy Harvesters

Materials ◽

10.3390/ma13010042 ◽

2019 ◽

Vol 13 (1) ◽

pp. 42 ◽

Cited By ~ 1

Author(s):

Muhammed Kayaharman ◽

Taylan Das ◽

Gregory Seviora ◽

Resul Saritas ◽

Eihab Abdel-Rahman ◽

...

Keyword(s):

Output Power ◽

Operating Conditions ◽

Constant Stress ◽

Center Frequency ◽

Term Stability ◽

Energy Harvesters ◽

Long Term Stability ◽

Stress Cycling ◽

Piezoelectric Charge

Cellular polypropylene (PP) has been recently used in energy harvesting applications. In this work, we investigate its viability and long-term stability under various operating conditions. Specifically, the effect of constant stress and stress cycling on output power and long-term stability of ferroelectret energy harvesters is analyzed. Our findings show that after 112 days constant stress significantly increases the piezoelectric charge constant d 33 and output power from 0.51 μW for a stress-free harvester to 2.71 μW. It also increases the harvester center frequency from 450 to 700 Hz and decreases its optimal resistance from 7 to 5.5 M Ω .

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Influence of Bias Angle on Output Performance of Nonlinear Asymmetric Energy Harvesters: Experimental Investigation

Volume 8: 30th Conference on Mechanical Vibration and Noise ◽

10.1115/detc2018-85479 ◽

2018 ◽

Author(s):

Wei Wang ◽

Junyi Cao ◽

Ying Zhang ◽

Chris R. Bowen

Keyword(s):

Energy Harvesting ◽

Power Output ◽

Performance Enhancement ◽

Vibrational Energy ◽

Experimental System ◽

Harmonic Excitation ◽

Nonlinear Phenomena ◽

Energy Harvesters ◽

Output Performance ◽

Piezoelectric Energy

In recent decades, the technique of piezoelectric energy harvesting has drawn a great deal of attention since it is a promising method to convert vibrational energy to electrical energy to supply lower-electrical power consumption devices. The most commonly used configuration for energy harvesting is the piezoelectric cantilever beam. Due to the inability of linear energy harvesting to capture broadband vibrations, most researchers have been focusing on broadband performance enhancement by introducing nonlinear phenomena into the harvesting systems. Previous studies have often focused on the symmetric potential harvesters excited in a fixed direction and the influence of the gravity of the oscillators was neglected. However, it is difficult to attain a completely symmetric energy harvester in practice. Furthermore, the gravity of the oscillator due to the change of installation angle will also exert a dramatic influence on the power output. Therefore, this paper experimentally investigates the influence of gravity due to bias angle on the output performance of asymmetric potential energy harvesters under harmonic excitation. An experimental system is developed to measure the output voltages of the harvesters at different bias angles. Experimental results show that the bias angle has little influence on the performance of linear and monostable energy harvesters. However, for an asymmetric potential bistable harvester with sensitive nonlinear restoring forces, the bias angle influences the power output greatly due to the effect of gravity. There exists an optimum bias angle range for the asymmetric potential bistable harvester to generate large output power in a broader frequency range. The reason for this phenomenon is that the influence of gravity due to bias angle will balance the nonlinear asymmetric potential function in a certain range, which could be applied to improve the power output of asymmetric bistable harvesters.

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Study on the Output Performance of a Nonlinear Hybrid Piezoelectric-Electromagnetic Harvester under Harmonic Excitation

Acoustics ◽

10.3390/acoustics1020021 ◽

2019 ◽

Vol 1 (2) ◽

pp. 382-392 ◽

Cited By ~ 3

Author(s):

Haipeng Liu ◽

Shiqiao Gao ◽

Junru Wu ◽

Ping Li

Keyword(s):

Resonant Frequency ◽

Output Power ◽

Average Output Power ◽

Energy Harvester ◽

Harmonic Excitation ◽

Average Output ◽

Hybrid Energy ◽

Output Performance ◽

Hybrid Energy Harvester ◽

Nonlinear Hybrid

The nonlinear energy harvester has become a hot topic due to its broad bandwidth and lower resonant frequency. Based on the preliminary test and analyses in our previous work, further analyses and tests on the influence of parameters, including the nonlinear magnetic force of the hybrid energy harvesting structure on its output performance under harmonic excitation, are performed in this paper, which will provide powerful support for structural optimization. For designing a nonlinear piezoelectric-electromagnetic hybrid energy harvester, the state equation of electromechanical coupling, the harmonic response and average output power, voltage, and current of a nonlinear hybrid energy harvester under harmonic excitation are derived by the harmonic balance method. The effects of the excitation acceleration and the external load on the output performance of the nonlinear hybrid energy harvester are verified through experimental tests. The results showed that the output power of the nonlinear hybrid energy harvester increases with the increase in the acceleration of harmonic excitation, and the increase is affected by external load. When the piezoelectric-electromagnetic hybrid harvester operates at the optimal load and the resonant frequency, the average output power reaches its maximum value and the increase of the load of the piezoelectric unit makes the resonant frequency of the energy harvesting system increase. Compared with linear harvesting structures, the nonlinear hybrid harvester has better flexibility of environmental adaptability and is more suitable for harvesting energy in low-frequency environments.

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Power Density Improvement of Piezoelectric Energy Harvesters via a Novel Hybridization Scheme with Electromagnetic Transduction

Micromachines ◽

10.3390/mi12070803 ◽

2021 ◽

Vol 12 (7) ◽

pp. 803

Author(s):

Zhongjie Li ◽

Chuanfu Xin ◽

Yan Peng ◽

Min Wang ◽

Jun Luo ◽

...

Keyword(s):

Power Density ◽

Output Power ◽

Energy Harvester ◽

Hybrid Energy ◽

Energy Harvesters ◽

Piezoelectric Patch ◽

Piezoelectric Energy ◽

Electromagnetic Transduction ◽

Self Powered ◽

Power Densities

A novel hybridization scheme is proposed with electromagnetic transduction to improve the power density of piezoelectric energy harvester (PEH) in this paper. Based on the basic cantilever piezoelectric energy harvester (BC-PEH) composed of a mass block, a piezoelectric patch, and a cantilever beam, we replaced the mass block by a magnet array and added a coil array to form the hybrid energy harvester. To enhance the output power of the electromagnetic energy harvester (EMEH), we utilized an alternating magnet array. Then, to compare the power density of the hybrid harvester and BC-PEH, the experiments of output power were conducted. According to the experimental results, the power densities of the hybrid harvester and BC-PEH are, respectively, 3.53 mW/cm3 and 5.14 μW/cm3 under the conditions of 18.6 Hz and 0.3 g. Therefore, the power density of the hybrid harvester is 686 times as high as that of the BC-PEH, which verified the power density improvement of PEH via a hybridization scheme with EMEH. Additionally, the hybrid harvester exhibits better performance for charging capacitors, such as charging a 2.2 mF capacitor to 8 V within 17 s. It is of great significance to further develop self-powered devices.

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Performance analysis of a lever piezoelectric energy harvester for roadway applications

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x211001445 ◽

2021 ◽

pp. 1045389X2110014

Author(s):

Guangya Ding ◽

Hongjun Luo ◽

Jun Wang ◽

Guohui Yuan

Keyword(s):

Output Power ◽

Energy Harvester ◽

Open Circuit ◽

Traffic Load ◽

Energy Harvesters ◽

Speed Sensor ◽

Piezoelectric Energy ◽

Optimal Load ◽

Self Powered ◽

Output Characteristics

A novel lever piezoelectric energy harvester (LPEH) was designed for installation in an actual roadway for energy harvesting. The model incorporates a lever module that amplifies the applied traffic load and transmits it to the piezoelectric ceramic. To observe the piezoelectric growth benefits of the optimized LPEH structure, the output characteristics and durability of two energy harvesters, the LPEH and a piezoelectric energy harvester (PEH) without a lever, were measured and compared by carrying out piezoelectric performance tests and traffic model experiments. Under the same loading condition, the open circuit voltages of the LPEH and PEH were 20.6 and 11.7 V, respectively, which represents a 76% voltage increase for the LPEH compared to the PEH. The output power of the LPEH was 21.51 mW at the optimal load, which was three times higher than that of the PEH (7.45 mW). The output power was linearly dependent on frequency and load, implying the potential application of the module as a self-powered speed sensor. When tested during 300,000 loading cycles, the LPEH still exhibited stable structural performance and durability.

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Model Reduction of Piezoelectric Energy Harvesters Subject to Band-Limited, Stochastic Base Excitation

Volume 2: Mechanics and Behavior of Active Materials; Integrated System Design and Implementation; Bio-Inspired Materials and Systems; Energy Harvesting ◽

10.1115/smasis2012-7995 ◽

2012 ◽

Author(s):

Adam M. Wickenheiser

Keyword(s):

White Noise ◽

Design Optimization ◽

Broadband Noise ◽

Degree Of Freedom ◽

Single Degree Of Freedom ◽

Energy Harvesters ◽

White Noise Excitation ◽

Single Degree ◽

Piezoelectric Energy ◽

Band Limited

In many scenarios where vibration energy harvesting can be utilized — particularly those involving bio-motions or environmental disturbances — energy sources are broadband and non-stationary. On the other hand, design procedures have been predominantly developed for harmonic or white noise excitation, specifically for single degree of freedom approximations of the transducer. In this paper, a general approach for design optimization of cantilevered, piezoelectric energy harvesters in the presence of band-limited, white-noise excitation is outlined. For this study, human and vehicular motions are considered; these complex waveforms are distilled into a small set of dominant features with regard to their impact on the power output of the device. Criteria based on modal participation factors, including pre-filtering of the disturbance, are used in guiding the reduction of the input and plant degrees of freedom in order to make the design optimization problem tractable. This process determines the error in assuming a low-order model for the transducer in the presence of broadband noise that may excite multiple modes of vibration. Furthermore, this study considers the quantitative impact of charge cancellation in higher modes and the benefits of inserting multiple electrodes along the length. To illustrate these methods, energy harvesters are designed for acceleration data collected from walking and car idling. It is shown that a simple method that is a generalization of naïve approaches that assume harmonic or white noise excitation and a single degree of freedom can determine which simplifications are appropriate and the inaccuracies that can be expected from them.

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A Two-Stage X-Band 20.7-dBm Power Amplifier in 40-nm CMOS Technology

Electronics ◽

10.3390/electronics9122198 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2198

Author(s):

Zhichao Li ◽

Shiheng Yang ◽

Samuel B. S. Lee ◽

Kiat Seng Yeo

Keyword(s):

Output Power ◽

Effective Conductivity ◽

Building Blocks ◽

Cmos Technology ◽

Center Frequency ◽

Cmos Process ◽

Two Stage ◽

Power Added Efficiency ◽

X Band ◽

Compact Size

For higher integration density, X-band power amplifiers (PAs) with CMOS technology have been widely discussed in recent publications. However, with reduced power supply voltage and device size, it is a great challenge to design a compact PA with high output power and power-added efficiency (PAE). In the proposed design, a 40-nm standard CMOS process is used for higher integration with other RF building blocks, compared with other CMOS PA designs with larger process node. Transistor cells are designed with neutralization capacitors to increase stability and gain performance of the PA. As a trade-off among gain, output power, and PAE, the transistor cells in driving stage and power stage are biased for class A and class AB operation, respectively. Both transistor cells consist of two transistors working in differential mode. Furthermore, transformer-based matching networks (TMNs) are used to realize a two-stage X-band CMOS PA with compact size. The PA achieves an effective conductivity (EC) of 117.5, which is among the highest in recently reported X-band PAs in CMOS technology. The PA also attains a saturated output power (Psat) of 20.7 dBm, a peak PAE of 22.4%, and a gain of 25.6 dB at the center frequency of 10 GHz under a 1 V supply in 40-nm CMOS.

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