Multi-parameter Model Validation of an Energy Harvester Frequency Up-conversion Mechanism Under Stochastic Excitation

Edwards, Bryn; Aw, Kean C.; Hu, Aiguo Patrick

doi:10.1016/j.proeng.2014.11.650

Cited by 4 publications

(6 citation statements)

References 4 publications

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“…However, as vibration in real-world applications will contain additional frequency components and be stochastic in nature, it is difficult to predict the performance of the system and verify the validity of the model from such experiments alone (Halvorsen, 2008). Therefore, for validation of the mechanism concept and model, validation experiments were performed in Edwards et al (2014), with a vibration source containing significant additional noise components and across multiple device parameters. The validation was considered in two ways.…”

Section: Mechanical Validation Experimentationmentioning

confidence: 99%

Mechanical frequency up-conversion for sub-resonance, low-frequency vibration harvesting

Edwards

2016

Journal of Intelligent Material Systems and Structures

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This article presents analysis and model validation of a single cantilever frequency up-conversion mechanism under stochastic excitation when configured as an electromagnetic energy harvester. The results show that the mechanism is able to achieve an increase in the root mean square velocity of the cantilever end when excited at frequencies below the natural frequency of the beam in the range of 3–7 Hz, as compared to a simple cantilever. The maximum observed gains in root mean square velocity from the experiment varied from 69% at a fundamental excitation frequency of 7 Hz to 153% at 3 Hz for cantilevers with natural frequencies in the range of 8.5–13.3 Hz as compared to a simple cantilever device with the same range of natural frequency. Comparison between the experimental and simulation results demonstrates that the mathematical model of the mechanical system is able to predict the response under such excitation conditions with 99% of the points in the parameter space being fitted at the 95% confidence level. Configured as an electromagnetic harvester based on low-frequency vibration, the device has been shown in the experiment to have a potential gain in average power delivery of 91.5% compared to a simple cantilever structure.

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Section: Mechanical Validation Experimentationmentioning

confidence: 99%

Mechanical frequency up-conversion for sub-resonance, low-frequency vibration harvesting

Edwards

2016

Journal of Intelligent Material Systems and Structures

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“…This displacement will subsequently cause a collision between the NdFeB mass and the PZT cantilever, resulting in a displacement of the PZT beam and a large impulse force applied to the NdFeB mass. From our previous work [8], such an interaction will result in a high frequency oscillation of the NdFeB mass and a period of multiple contacts between the mass and the PZT beam. This high frequency oscillation of the magnetic mass induces a current in a copper coil which is stationary relative to the supporting structure and provides the primary power output of the harvester.…”

Section: Device Conceptmentioning

confidence: 93%

“…With both the piezoelectric and low frequency cantilevers clamped in the support structure, the separation distance between the bottom of the magnetic end mass and the piezoelectric beam was measured using a Vernier calliper to be approximately 2 mm for all of the samples. Estimating the maximum positive displacement of the PDMS mass to be approximately 5 mm, from our previous work [8], the effective scale length [10] of the active volume of the structure is 23.8 mm.…”

Section: Prototype Fabrication and Parameter Estimationmentioning

confidence: 95%

“…Consequently, should the electromechanical coupling of the electromagnetic transducer be sufficiently high, then it would be expected that the addition of an auxiliary piezoelectric transducer would lead to a decrease in the power output of the electromagnetic harvester. Within the size constraints of the device previously presented [8], however, the achievable effective electrical damping from electromagnetic induction will be significantly lower than optimal due to scaling effects [10]. It is expected, therefore, that there will be significant room for additional power to be extracted through the introduction of a second transducer.…”

Section: Device Conceptmentioning

confidence: 97%

“…In our previous work [7], we have presented a single-cantilever frequency up-conversion structure, where the cantilever beam functions as both driving and generating oscillators. With such a structure, the velocity of the cantilever end-mass may be increased [8] and configured as an electromagnetic harvester [9], this structure has demonstrated potential to increase average power output under low frequency, stochastic excitation below the resonant frequency of the cantilever beam as compared to a simple cantilever structure; having average power outputs between 12.5 and 22.5 μW in the excitation frequency range of 3-7 Hz. However, due to the scaling of electromagnetic induction at small device sizes [10], the output voltage of this structure is very low, having a maximum root mean squared (rms) voltage of 10 mV in the frequency range tested.…”

Section: Introductionmentioning

confidence: 99%

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Validation of a hybrid electromagnetic–piezoelectric vibration energy harvester

Edwards

2016

Smart Mater. Struct.

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This paper presents a low frequency vibration energy harvester with contact based frequency up-conversion and hybrid electromagnetic–piezoelectric transduction. An electromagnetic generator is proposed as a power source for low power wearable electronic devices, while a second piezoelectric generator is investigated as a potential power source for a power conditioning circuit for the electromagnetic transducer output. Simulations and experiments are conducted in order to verify the behaviour of the device under harmonic as well as wide-band excitations across two key design parameters—the length of the piezoelectric beam and the excitation frequency. Experimental results demonstrated that the device achieved a power output between 25.5 and 34 μW at an root mean squared (rms) voltage level between 16 and 18.5 mV for the electromagnetic transducer in the excitation frequency range of 3–7 Hz, while the output power of the piezoelectric transducer ranged from 5 to 10.5 μW with a minimum peak-to-peak output voltage of 6 V. A multivariate model validation was performed between experimental and simulation results under wide-band excitation in terms of the rms voltage outputs of the electromagnetic and piezoelectric transducers, as well as the peak-to-peak voltage output of the piezoelectric transducer, and it is found that the experimental data fit the model predictions with a minimum probability of 63.4% across the parameter space.

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Development of different frequency up-conversion components in vibration energy harvesters

Zhuo,

Lu,

Cao

et al. 2025

Renewable and Sustainable Energy Reviews

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Multi-parameter Model Validation of an Energy Harvester Frequency Up-conversion Mechanism Under Stochastic Excitation

Cited by 4 publications

References 4 publications

Mechanical frequency up-conversion for sub-resonance, low-frequency vibration harvesting

Mechanical frequency up-conversion for sub-resonance, low-frequency vibration harvesting

Validation of a hybrid electromagnetic–piezoelectric vibration energy harvester

Development of different frequency up-conversion components in vibration energy harvesters

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