PhD student, Southern Cross University
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.
Abstract: Authors: Almuatasim Alomari ; Ashok Batra ; Arjun Tan ; Marius Schamschula Article URL: http://www.tandfonline.com/doi/full/10.1080/10584587.2016.1252663?ai=z4&mi=3fqos0&af=R Citation: Integrated Ferroelectrics Publication Date: 2016-12-14T08:40:43Z Journal: Integrated Ferroelectrics: An International Journal
Pub.: 14 Dec '16, Pinned: 16 Jul '17
Abstract: Authors: Tushar Nayyar ; Kunal Pubby ; Sukhleen Bindra Narang ; Ritendra Mishra Article URL: http://www.tandfonline.com/doi/full/10.1080/10584587.2016.1252660?ai=z4&mi=3fqos0&af=R Citation: Integrated Ferroelectrics Publication Date: 2016-12-14T08:40:46Z Journal: Integrated Ferroelectrics: An International Journal
Pub.: 14 Dec '16, Pinned: 16 Jul '17
Abstract: Recently, liquid flow over monolayer graphene has been experimentally demonstrated to generate an induced voltage in the flow direction, and various physical mechanisms have been proposed to explain the electricity-generating process between liquid and graphene. However, there are significant discrepancies in the reported results with non-ionic liquid: the observed voltage responses with deionized (DI) water vary from lab to lab under presumably similar flowing conditions. Here, a graphene-piezoelectric material heterostructure is proposed for harvesting energy from water flow; it is shown that the introduction of a piezoelectric template beneath graphene results in an obvious voltage output up to 0.1 V even with DI water. This potential arises from a continuous charging–discharging process in graphene, which is suggested to be a result of a relatively retarded screening effect of the water for the generated piezoelectric charges than that of the graphene layer, as revealed by first-principles calculations. This work considers a dynamic charge interaction among water, graphene, and the substrate, highlighting the crucial role of the underlying substrate in the electricity-generating process, which will greatly enhance understanding of the flow-induced voltage and push the graphene-water nanogenerator close to practical applications.
Pub.: 28 Dec '16, Pinned: 16 Jul '17
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
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
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
Abstract: This paper presents an elastic ribbon-like piezoelectric energy harvester which is targeted for skin-wearable devices by harnessing the movements of stretchable surfaces. The device aims to power up smart thin stick-on devices for healthcare monitoring. By embedding a ribbon-like PVDF film in a flexible elastomer, Ecoflex, the device is potentially able to stretch 34%, while maintaining internal strain of the film below its plastic deformation limit. Alternate electrode layout and bimorph configuration help to reduce charge cancellation, while increasing overall effectiveness. The harvester prototype with 225 mm(3) active volume is able to output 15.6 V at open-circuit upon stretching 26% and is capable of generating at least 121 nJ per cycle.
Pub.: 24 Feb '17, Pinned: 16 Jul '17
Abstract: This work summarizes the energy generation limits from walking employing a pendulum-based generation system. Self-winding wristwatches have exploited successfully this energy input technique for decades. Pendulum-based planar devices use the rotation to produce energy for inertial generators. Then the oscillations of body motion during locomotion present an opportunity to extract kinetic energy from planar generators. The sinusoidal motion of the center of gravity of the body, on the sagittal and frontal planes, and the limbs swinging are compliant with oscillating devices. Portable biomedical devices can extract energy from everyday walking to extend battery life or decrease battery size. Computer simulations suggest energy availability of 0.05-1.2 mJ on the chest, 0.5-2.5 mJ on the hip and 0.5-41 mJ on the elbow from walking.
Pub.: 24 Feb '17, Pinned: 16 Jul '17
Abstract: In this work, we prepared lead-free 0.5Ba(Zr0.2Ti0.8)O3−0.5(Ba0.7Ca0.3)TiO3 nanorods (BCTZ NRs) by using electrospinning method. XRD, FESEM and Raman were used to characterize BCTZ NRs. XRD pattern showed BCTZ NRs to have tetragonal phase structure. BCTZ NRs were used to fabricate a bio-compatible piezoelectric nanogenerator (pNG). In order to enhance the output property of pNG, dielectrophoresis was employed to align the BCTZ NRs in the PDMS matrix. By tapping the pNG, the open-circuit voltage (Voc) and short-circuit current (Isc) of ~0.8 V and ~7 nA were obtained, respectively. Furthermore, the pNG can be used as a water-drops counter. The good electric output performance of BCTZ made it suitable for some control systems of electronic devices.
Pub.: 09 Feb '17, Pinned: 16 Jul '17
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
Abstract: It has been shown that scavenging energy from raindrop impacts has the potential as a power source for electronic devices and act as an alternative method of generating electrical power. In this paper an energy harvesting module is developed consisting of multiple piezoelectric devices which use impacts of raindrops to generate electrical power. The effect on efficiency of the module with non-rectified or rectified outputs of each device connected in parallel is investigated. Additionally, the voltage, power and energy were found for different surface angles, surface conditions and impact regions for single devices with a view to maximise module efficiency.
Pub.: 20 Feb '17, Pinned: 16 Jul '17
Abstract: The difficulty of modeling energy consumption in communication systems leads to challenges in energy harvesting (EH) systems, in which nodes scavenge energy from their environment. An EH receiver must harvest enough energy for demodulating and decoding. The energy required depends upon factors, like code rate and signal-to-noise ratio, which can be adjusted dynamically. We consider a receiver which harvests energy from ambient sources and the transmitter, meaning the received signal is used for both EH and information decoding. Assuming a generalized function for energy consumption, we maximize the total number of information bits decoded, under both average and peak power constraints at the transmitter, by carefully optimizing the power used for EH, power used for information transmission, fraction of time for EH, and code rate. For transmission over a single block, we find there exist problem parameters for which either maximizing power for information transmission or maximizing power for EH is optimal. In the general case, the optimal solution is a tradeoff of the two. For transmission over multiple blocks, we give an upper bound on performance and give sufficient and necessary conditions to achieve this bound. Finally, we give some numerical results to illustrate our results and analysis.
Pub.: 15 Apr '17, Pinned: 16 Jul '17
Abstract: In this study, we propose an optimization scheme for the control of a piezoelectric wind energy harvester. The harvester is constructed by a blade in front and a magnet in the rear in order to sustain a magnetic repulsion by another magnet located on the stable harvester body in a contactless manner. For such a new harvester, the control scheme is missing in the literature in the sense that the harvester is new and an overall optimization study is required for such a device. In that context, the optimization has been realized by using a new current control law based on the harvester piezoelectric terminal voltage and the layer bending. The proposed control law can impose a second order linear dynamics although the magnetic effects can yield to nonlinear magnetic force relation. In order to improve the new control strategy, a Particle Swarm Optimization algorithm (PSO) has been applied, since there is a nonlinear dependency among the control parameters, the collected energy and the bending force mean values. According to results, the captured electrical power has a high increasing trend with respect to the only-voltage-based (OVB) control as the current study proves. On the contrary, the artifact of the method is that the obtained power is too low to increase the mean bending forces and it requires much complicated control system.
Pub.: 28 Feb '17, Pinned: 16 Jul '17
Abstract: Herein, we present the design technique of a resonant rectifier for piezoelectric (PE) energy harvesting. We propose two diode equivalents to reduce the voltage drop in the rectifier operation, a minuscule-drop-diode equivalent (MDDE) and a low-drop-diode equivalent (LDDE). The diode equivalents are embedded in resonant rectifier integrated circuits (ICs), which use symmetric bias-flip to reduce the power used for charging and discharging the internal capacitance of a PE transducer. The self-startup function is supported by synchronously generating control pulses for the bias-flip from the PE transducer. Two resonant rectifier ICs, using both MDDE and LDDE, are fabricated in a 0.18 μm CMOS process and their performances are characterized under external and self-power conditions. Under the external-power condition, the rectifier using LDDE delivers an output power POUT of 564 μW and a rectifier output voltage VRECT of 3.36 V with a power transfer efficiency of 68.1%. Under self-power conditions, the rectifier using MDDE delivers a POUT of 288 μW and a VRECT of 2.4 V with a corresponding efficiency of 78.4%. Using the proposed bias-flip technique, the power extraction capability of the proposed rectifier is 5.9 and 3.0 times higher than that of a conventional full-bridge rectifier.
Pub.: 20 Apr '17, Pinned: 16 Jul '17
Abstract: The use of energy harvesting technologies for supplying power generating energy to wireless devices and sensors, particularly in scenarios where it is difficult to exchange or recharge batteries, has recently attracted considerable research attention. In this context, we report the design of a piezoelectric energy harvesting system that can be used to harvest energy from the ocean. The harvester is composed of a piezoelectric cantilever structure and a magnet as the tip-mass of the piezoelectric module, atop which a rail (tube) with a metal ball is positioned. The system is tested with a setup that simulates ocean waves. Our findings indicate that our approach can be utilized in the design of multipurpose piezoelectric energy harvesting systems for low frequency vibration and in “sea-based” applications involving buoys and boats.
Pub.: 20 Apr '17, Pinned: 16 Jul '17
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
Abstract: Living subjects (i.e., humans and animals) have abundant sources of energy in chemical, thermal, and mechanical forms. The use of these energies presents a viable way to overcome the battery capacity limitation that constrains the long-term operation of wearable/implantable devices. The intersection of novel materials and fabrication techniques offers boundless possibilities for the benefit of human health and well-being via various types of energy harvesters. This review summarizes the existing approaches that have been demonstrated to harvest energy from the bodies of living subjects for self-powered electronics. We present material choices, device layouts, and operation principles of these energy harvesters with a focus on in vivo applications. We discuss a broad range of energy harvesters placed in or on various body parts of human and animal models. We conclude with an outlook of future research in which the integration of various energy harvesters with advanced electronics can provide a new platform for the development of novel technologies for disease diagnostics, treatment, and prevention.
Pub.: 22 Jun '17, Pinned: 16 Jul '17
Abstract: This paper proposes an optimization method for the rectifier circuit of a vibration energy harvesting system that uses macro-fiber composite (MFC) piezoelectric elements. MFC elements have previously been investigated intensively for piezoelectric energy harvesting. A bridge rectifier circuit composed of diodes and capacitors is often used as the rectifier circuit, which functions as an AC–DC converter. In contrast, a double-voltage rectifier circuit can generate twice the voltage of the bridge rectifier. In this study, both types of rectifier circuits are optimized by varying the values of the diode forward voltages and thecapacitance of the capacitors. In addition, the current–voltage characteristic and electric power efficiency of these rectifier circuits are evaluated and compared. The experimental results show that the electric power efficiency of the bridge rectifier circuit is higher than that of the double-voltage rectifier circuit at maximum electric power; however, the double-voltage rectifier circuit is suitable foruse in high voltage situations. In addition, the use of diodes with lower forward voltages leads to higher electric power efficiency, but the capacitance of the capacitors has no effect on electric power efficiency.
Pub.: 10 Jun '16, Pinned: 16 Jul '17