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CURATOR
A pinboard by
Iman Izadgoshasb

PhD student, Southern Cross University

PINBOARD SUMMARY

Design an energy harvester using piezoelectric materials to harvest electricity from human motions

piezoelectric materials can convert pressure and vibration to electricity. I have made a prototype in the lab using a complicated mechanical system can generate continuous electricity from every day human motions. This electricity can be used to power mobile phones, sensors or medical devices. So in future, human motions can power smarthphones.

18 ITEMS PINNED

Numerical modeling of shape and topology optimisation of a piezoelectric cantilever beam in an energy-harvesting sensor

Abstract: Abstract Piezoelectric materials are excellent transducers for converting mechanical energy from the environment for use as electrical energy. The conversion of mechanical energy to electrical energy is a key component in the development of self-powered devices, especially enabling technology for wireless sensor networks. This paper proposes an alternative method for predicting the power output of a bimorph cantilever beam using a finite-element method for both static and dynamic frequency analyses. A novel approach is presented for optimising the cantilever beam, by which the power density is maximised and the structural volume is minimised simultaneously. A two-stage optimisation is performed, i.e., a shape optimisation and then a “topology” hole opening optimisation.AbstractPiezoelectric materials are excellent transducers for converting mechanical energy from the environment for use as electrical energy. The conversion of mechanical energy to electrical energy is a key component in the development of self-powered devices, especially enabling technology for wireless sensor networks. This paper proposes an alternative method for predicting the power output of a bimorph cantilever beam using a finite-element method for both static and dynamic frequency analyses. A novel approach is presented for optimising the cantilever beam, by which the power density is maximised and the structural volume is minimised simultaneously. A two-stage optimisation is performed, i.e., a shape optimisation and then a “topology” hole opening optimisation.

Pub.: 01 Jan '17, Pinned: 16 Jul '17

A Miniature Magnetic-Force-Based Three-Axis AC Magnetic Sensor with Piezoelectric/Vibrational Energy-Harvesting Functions.

Abstract: In this paper, we demonstrate a miniature magnetic-force-based, three-axis, AC magnetic sensor with piezoelectric/vibrational energy-harvesting functions. For magnetic sensing, the sensor employs a magnetic-mechanical-piezoelectric configuration (which uses magnetic force and torque, a compact, single, mechanical mechanism, and the piezoelectric effect) to convert x-axis and y-axis in-plane and z-axis magnetic fields into piezoelectric voltage outputs. Under the x-axis magnetic field (sine-wave, 100 Hz, 0.2-3.2 gauss) and the z-axis magnetic field (sine-wave, 142 Hz, 0.2-3.2 gauss), the voltage output with the sensitivity of the sensor are 1.13-26.15 mV with 8.79 mV/gauss and 1.31-8.92 mV with 2.63 mV/gauss, respectively. In addition, through this configuration, the sensor can harness ambient vibrational energy, i.e., possessing piezoelectric/vibrational energy-harvesting functions. Under x-axis vibration (sine-wave, 100 Hz, 3.5 g) and z-axis vibration (sine-wave, 142 Hz, 3.8 g), the root-mean-square voltage output with power output of the sensor is 439 mV with 0.333 μW and 138 mV with 0.051 μW, respectively. These results show that the sensor, using this configuration, successfully achieves three-axis magnetic field sensing and three-axis vibration energy-harvesting. Due to these features, the three-axis AC magnetic sensor could be an important design reference in order to develop future three-axis AC magnetic sensors, which possess energy-harvesting functions, for practical industrial applications, such as intelligent vehicle/traffic monitoring, processes monitoring, security systems, and so on.

Pub.: 18 Feb '17, Pinned: 16 Jul '17

Theoretical modeling of piezoelectric energy harvesting in the system using technical textile as a support

Abstract: An approach to harvesting electrical energy from a mechanically excited piezoelectric element has been described. The topic of this paper studies the most important properties of piezoelectric polymer polyvinylidene fluoride (PVDF) in energy harvesting. We have chosen to develop a recovery application within the clothes. By the use of a piezoelectric energy harvester capable to convert the mechanical energy produced by the knee during walking to an electrical energy. This will be achieved by replacing the traditional textile of the kneepad with the one that is made of the technical textile based on acrylic knitted and PVDF as a patch stuck on the textile. Furthermore, PVDF has many unique features, such as excellent mechanical behavior, large strain without structure fatigue, which enables it to act strongly as the load bearing member, and corrosion resistance. The technical textile, functioning as multifunctional wearable human interfaces, is considered today as a useful tool in several energy fields. In this paper, a smart structure based on piezoelectric polymer (PVDF) has been presented, which a power analytical model, based on the frequency, the geometrical parameters and other factors were investigated. Furthermore, the set of numerical results illustrating the harvested power for a given size of the device has been performed and discussed and how this harvested power may be used as a source for a wearable device. Finally, the theory presented in this study can be used for the realization of other optimal designs, for a wearable sensor with low consumption and so on. Copyright © 2017 John Wiley & Sons, Ltd.

Pub.: 21 Feb '17, Pinned: 16 Jul '17

Flexible piezoelectric nano-composite films for kinetic energy harvesting from textiles

Abstract: This paper details the enhancements in the dielectric and piezoelectric properties of a low-temperature screen-printable piezoelectric nano-composite film on flexible plastic and textile substrates. These enhancements involved adding silver nano particles to the nano-composite material and using an additional cold isostatic pressing (CIP) post-processing procedure. These developments have resulted in a 18% increase in the free-standing piezoelectric charge coefficient d33 to a value of 98 pC/N. The increase in the dielectric constant of the piezoelectric film has, however, resulted in a decrease in the peak output voltage of the composite film. The potential for this material to be used to harvest mechanical energy from a variety of textiles under compressive and bending forces has been evaluated theoretically and experimentally. The maximum energy density of the enhanced piezoelectric material under 800 N compressive force was found to be 34 J/m3 on a Kermel textile. The maximum energy density of the enhanced piezoelectric material under bending was found to be 14.3 J/m3 on a cotton textile. These results agree very favourably with the theoretical predictions. For a 10x10 cm piezoelectric element 100 µm thick this equates to 38 μJ and 14.3 μJ of energy generated per mechanical action respectively which is a potentially useful amount of energy.

Pub.: 17 Jan '17, Pinned: 16 Jul '17

A piezoelectric impact-induced vibration cantilever energy harvester from speed bump with a low-power power management circuit

Abstract: An energy harvesting system for road speed bumps was proposed, which consists of a piezoelectric impact-induced vibration cantilever energy harvester and a low-power power management circuit. The piezoelectric impact-induced vibration cantilever was used to harvest the energy from speed bump as it is suitable for converting the low-frequency mechanical impact to high-frequency vibrations. Furthermore, considering the characteristics of piezoelectric energy harvester for speed bumps, a high-efficiency and low-power power management circuit was designed to collect the electric energy from the harvester. A buck-boost DC–DC switching converter is used to match the impedance of PZT and so as to obtain the maximum energy from the harvester, and a wake-up circuit is designed to reduce the power dissipation of the power management circuit itself. A prototype of the piezoelectric impact-induced vibration cantilever energy harvesting system was constructed and the experiment results showed that, the controller in the power management circuit consumed only 3% of the ideal energy generated by one tire in the awake mode and less than 1% of it in the sleep mode. The efficiency of the circuit was around 74% at various vehicle speeds. In addition, the total ideal energy generated by one piezoelectric cantilever from one car passing the speed bump was 1.26 mJ. This energy was exhausted by the power management circuit without sleep mode within 25 s, whereas with sleep mode, the energy of 0.82 μJ was delivered to the battery. Therefore, the sleep mode function in the circuit is essential to reduce the energy loss and improve the efficiency of the speed bump energy harvester.

Pub.: 21 Dec '16, Pinned: 16 Jul '17