Technological challenges of developing wireless health and usage monitoring systems

Ling, Chung Seng; Hewitt, Dan; Burrow, Steve G; Clare, Lindsay; Barton, David A. W.; Wells, Dan M.; Lieven, Nicholas A J

doi:10.1117/12.2008757

Cited by 11 publications

(7 citation statements)

References 25 publications

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“…However, it hampers the development of wireless sensor networks because chemical batteries have maintenance, environmental and size issues. In recent years, it is concerned and studied how to harvest environment energy and convert it into electric power [1][2][3]. The vibration harvester has been paid more attention because vibration happens in anywhere and anytime.…”

Section: Introductionmentioning

confidence: 99%

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Modeling and Analysis of an Up-conversion Electret Electrostatic Energy Harvester

Niu¹,

Gao²,

Gao³

2018

Proceedings of the 2018 International Conference on Energy Development and Environmental Protection (EDEP 2018)

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In order to reduce the environmental sensitive frequency of electret-based vibration electrostatic energy harvester (E-VEH), an up-conversion structure is designed. This harvester is a double cantilever structure includes a low frequency beam and high frequency beam. Electret is bounded to the high frequency beam, the low frequency beam vibrates excited by environment, and impacts the high frequency beam. The model of this structure is established and analyzed firstly. Then a prototype is made and tested. According to the measurement result, this kind of structure can convert part of the vibration energy within the vibration frequency between 1Hz and 70Hz into electrical energy under the action of the excitation load with the amplitude is 8m/s 2. This indicates that the up-conversion structure can validly reduce the sense frequency of E-VEH, and can expand the harvester work bands.

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Section: Introductionmentioning

confidence: 99%

“…While the free end has a deformation of M z under force, the deformation of cantilever at τ is Deformation of the HFB Where L the length of HFB is, τ is the distance from the fix end of HFB. According to the equation(1) and equation…”

mentioning

confidence: 99%

Modeling and Analysis of an Up-conversion Electret Electrostatic Energy Harvester

Niu¹,

Gao²,

Gao³

2018

Proceedings of the 2018 International Conference on Energy Development and Environmental Protection (EDEP 2018)

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show abstract

“…With the development of micro-nano-technology, the volume of the sensor becomes smaller and smaller, and the signal processing circuit becomes smaller and smaller. The overall system has become smaller, but the power supply has not become smaller [5,6].…”

Section: Introductionmentioning

confidence: 99%

Integrated Power Supply for MEMS Sensor

Liu¹,

Jin²,

Gao³

et al. 2018

MEMS Sensors - Design and Application

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The recent expansion of wireless sensor networks and the rapid development of low-power consumption devices and MEMS devices have been driving research on harvester converting ambient energy into electricity to replace batteries that require costly maintenance. Harvesting energy from ambient environment vibration becomes an ideal power supply mode. The power supply module can be integrated with the MEMS sensor. There are many ways to convert ambient energy into electrical energy, such as photocells, thermocouples, vibration, and wind and so on. Among these energy-converting ways, the ambient vibration energy harvesting is more attractive because the vibration is everywhere in our daily environment. Based on the analysis of the basic theory of the electret electrostatic harvester, the basic equations and equivalent analysis model of electret electrostatic harvester are established. The experimental tests for the output performance of electret electrostatic harvester are completed. For the electret material, the material itself can also provide a constant voltage to avoid the use of additional power, which provides an effective way for electrostatic harvesting. Therefore, the electret electrostatic harvesting structure is a kind of ideal energy harvesting method using ambient vibration and can be easily integrated with the MEMS system.

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“…Wireless sensor networks and low power devices have experienced remarkable growth in recent years, which raises the possibility of harvesting energy from the environment to replace the chemical batteries that currently raise maintenance, environmental and size issues [1][2][3]. Therefore, research has recently been focused on harvesting mechanical energy, especially on converting vibration energy into electric energy, and three mechanisms have been proposed: piezoelectric, electromagnetic and electrostatic [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Electret Length Optimization of Output Power for Double-End Fixed Beam Out-of-Plane Electret-Based Vibration Energy Harvesters

Gao

Liu

et al. 2017

Energies

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Thanks to miniaturization, it is now possible to imagine self-powered systems that can harvest energy from the environment to produce electrical energy. Out-of-plane electret-based vibration energy harvesters (E-EVHs) are an effective and inexpensive energy harvester type that has attracted much attention. Increasing the capacitance of variable capacitors is an effective way to improve the output power of E-EVHs. In this paper, firstly an accurate capacitance theoretical model of a double-ended fixed beam out-of-plane E-EVHs which has 97% reliability compared with FEM (COMSOL Multiphysics) results is presented. A comparison of capacitance between the double-ended fixed beam structure and a cantilever structure of the same size indicates that the double-ended fixed beam structure has greater capacitance and capacitance variation. We apply this theoretical capacitance model to the mechanical-electrical coupling model of double-ended fixed beam out-of-plane E-EVHs and study harvesters' output performances for different electret lengths by numerical and experimental method, respectively. There exists an optimal electret length to harvest maximum power in our simulation results. Enhanced electrostatic forces with increasing the electret length emphasizes the soft spring effect, which widens the half power bandwidth and lowers the resonance frequency. Increasing the length of the electret can reduce the resistance of the optimum load. The experimental results show trend consistent with the numerical predictions. The maximum output power can reach 404 µW (134.66 µW/cm 2 /g) at the electret length of 40 mm when the external acceleration and the frequency were 5 m/s 2 and 74 Hz, respectively. The maximum bandwidth reaches 2.5 Hz at the electret length of 60 mm. Therefore, the electret length should be placed between 40 mm and 60 mm, while ensuring a higher output power and also get a larger bandwidth in practical applications.

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Technological challenges of developing wireless health and usage monitoring systems

Cited by 11 publications

References 25 publications

Modeling and Analysis of an Up-conversion Electret Electrostatic Energy Harvester

Modeling and Analysis of an Up-conversion Electret Electrostatic Energy Harvester

Integrated Power Supply for MEMS Sensor

Electret Length Optimization of Output Power for Double-End Fixed Beam Out-of-Plane Electret-Based Vibration Energy Harvesters

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