Energy Scavenging Devices Research Articles

PZT material: The great potential of future electricity cohort through vibration energy

Composite material and Vibration are the main research areas in which today’s industries are growing. This paper describes about the electrical energy generation for small power devices such as mobile phones, low powered lights and energy storage devices by using Lead Zirconate Titanate (PZT) with the help of ambient vibrations. A lot of vibration energy is being wasted which is in and around us. And also great research has been conducted to develop energy scavenging devices by using PZT materials. Therefore, this paper gives the knowledge about the piezoceramic material can become a potential source of electricity.

Redox-induced electricity for energy scavenging and self-powered sensors

Redox-based energy scavenging devices are based on utilizing oxidation and reduction reactions to generate electricity. The driving forces for these reactions come from many sustainable energy sources such as human fluids, waste heat, photon energy.

Probabilistic analysis and ghost-stochastic resonance of a hybrid energy harvester under Gaussian White noise

In this present work, a hybrid energy scavenger using two mechanisms of transduction namely piezoelectric and electromagnetic and subjected to the Gaussian white noise is investigated. The stochastic averaging method is used here in other to construct the Fokker–Plank–Kolmogorov equation of the system whose the statistic response in the stationary state is the probability density. The mean square voltage and current are obtained for different value of white noise intensities as the output power generated by piezoelectric circuit and electromagnetic circuit. In addition, combining the Gaussian white noise and coherence excitation, the Ghost-Stochastic resonance is observed through the mean residence time and improve the amount of energy harvested by the scavenger. The agreement between the analytical method and those obtained numerically validates the effectiveness of analytical investigations. The results obtained in this manuscript reveal that, while the natural frequency is absent in the external coherent force, the amount of energy harvested by the energy scavenging device can be improved for certain value of noise intensity.

Expected lifetime of fibrous nanogenerator exposed to cyclic compressive pressure

In this paper, in order to identify the lifetime of energy scavenging devices, the effect of a cyclic compressive load on the performance of polyvinylidene fluoride micro-nano fibrous nanogenerators was investigated, and the electrical output of layers was measured at different cycles and frequencies. Results showed that as the number of cycles increased at the constant frequency, the electrical output initially largely increased and then reached to a maximum level with a very gentle slope. Moreover, the crystalline structure and β-phase of the PVDF nanofibrous mats improved by applying a periodic compressive force. This study showed that, although the PVDF electrospun micro-nano fibers have suitable piezoelectric properties, it is necessary to make some post-treatment to fabricate an energy harvester with constant performance. Results also showed that when the number of cycles at a constant frequency increased, mechanical properties also improved. These results enable us to have an idea about the expected lifetime of a fibrous nanogenerator exposed to cyclic compressive pressure.

Thermoelectric Generator using Ice-Water Mixture as Heat Sink and Ambient Air as Heat Source

Thermoelectric generator can utilize various combinations of heat sink and heat source. In this paper, the performance of thermoelectric generator that uses surrounding air as heat source and coldness from ice-water mixture is presented. The objective was to evaluate the open circuit voltage produced by thermoelectric generator, at a range of differences in temperature between the cold and hot surfaces of module. In this work, the thermoelectric module was placed between aluminum heat sink and cold beverage container that contained ice-water mixture. The heat sink operates using the difference in buoyancy of surrounding air (i.e. natural convection). The hot and cold surfaces temperature of thermoelectric modules was measured using Type-K thermocouples. A digital multimeter was connected to the thermoelectric module for measurement of open circuit voltage. The open circuit voltage produced by the thermoelectric generator was linearly proportional to the magnitude of difference in temperature of two surfaces of a thermoelectric module. The electrical power produced by the generator was up to 14 miliWatt. A simple test showed that with a suitable voltage amplification device, this thermoelectric generator can supply enough power for LED bulbs. The finding presented is suitable for the development of energy scavenging devices, which is relevant to stand-alone power generation system.

High‐throughput Bit Flipping decoder for structured LDPC codes

Low-density parity-check (LDPC) codes are predominantly used in many energy scavenging devices, data centres, and communication devices. In this work, the authors propose a high-throughput parallel bit-flipping (BF) decoder using multithreshold BF algorithm. The decoder is endowed with features including low interconnect complexity, simpler computations, and high throughput. The decoder has been synthesised in 65 nm technology for (273, 191) and (1023, 781) finite-geometry LDPC (FG-LDPC) codes. These decoders require an area of 0 . 1 and 0 . 45 mm 2 , and they achieve an average throughput of 147 . 57 and 268 . 5 Gbps and energy efficiency of 0 . 92 and 0 . 91 pJ/bit for (273, 191) and (1023, 781) FG-LDPC codes, respectively. Compared to the state-of-the-art design, the proposed designs offer 4 . 5 times higher normalised throughput.

Optimization of the Compression-Based Piezoelectric Traffic Model (CPTM) for Road Energy Harvesting Application

This paper employs the Two-Degree-of-Freedom (2DOF) electromechanical model to show the probability of the piezoelectric approach as an option for energy scavenging devices in roadway applications. The passing vehicles are the main energy source for harvesting device. A 2DOF electromechanical model as the piezoelectric harvesting unit is applied to explain the harvester performance in a single lane road. APC piezoelectric ceramic (APC 855) is selected as the optimum piezoelectric material due to its high piezoelectric constant values and high piezoelectric charge constant. Also, in the traffic model, we employ a Cellular Automata (CA) model. The vehicle dynamics model is used to transfer information from the traffic model to the piezoelectric model. Combining both the traffic model, i.e. the piezoelectric and the vehicle dynamics model, results in the compression-based piezoelectric traffic model (CPTM). In a single-lane traffic model with different arrival rate I», a single circle-shaped Piezoelectric Cymbal Transducer (PCT) with thickness of 0.3 mm and diameter of 32 mm is applied, in which the produced power is 14.126 W and 29.746 W and 6.47 W. Based on these outcomes, if we lay multiple PCT arrays along the highway road, a large amount of power can be produced. Hence, a great potential is shown by the proposed electromechanical-traffic model for applications related to the macro-scale roadway electric power generation systems.

Reconfigurable System for Wireless Power Transfer (WPT) and Near Field Communications (NFC)

In this paper, it is investigated the possibility of using near field communication (NFC), normally applied for communicating two proximity devices, to power-up external circuitry, such as low power wireless sensors, or energy scavenging devices. For this purpose, the possibility of combining both features in a single system, able to communicate with neighboring devices via NFC and to transfer power from one device to another [wireless power transfer (WPT)], has been studied. After taking considerations on antenna design, both for NFC and WPT, a reconfigurable circuitry optimized for data and energy transfer is proposed. The circuit provides optimal close proximity wireless magnetic communications, and is able to use the same device for optimal energy transfer. This feature has been implemented and demonstrated using PCB antennas, NFC reader with a mobile phone or NFC-tag and a circuitry for charging an external Io-Li battery. The results show an improvement of the energy transfer when such circuit capability is turned on.

Performance of energy scavenging device by considering fatigue of PZT

Purpose Purpose is to design the energy harvesters and to know the limit of the application of load on the PZT material. Fatigue failures of the designed products is merely bothering the modern engineers and scientists for the research communities of all fields. Especially in the field of Micro Electromechanical Systems (MEMS), durability of low power systems is very important under the climates of both at high temperature and low temperature zones. And also continuous electrical power requirement is important for the MEMS and wireless sensor networks. Electricity is the greatest crisis in the world on one side and on the other side, durability of smart devices such as mobile phones, laptops, compact devices, computer spare parts are unrecyclicable batteries for reducing the rate of pollution in the environment. Design/methodology/approach By considering these problems, authors have taken up a research in finding the first fatigue characteristics, which are fatigue failure and durability of ferroelectric material as lead zirconate titanate, and then designed the scavenging device by using harmonically excited vibrations for getting optimum power output which is about 15.6 mW. Findings Under the resonance operated condition at the frequency of about 50 Hz, a prototype of scavenging device is about 90 V AC peak-to-peak voltage and the durability of scavenging device is 9.715 years. Originality/value Durability of PZT at different environmental conditions plays a very important role for the continuous function of low power devices. The output of PZT may change when the working time increases in addition with the mechanical properties.

Structural approaches for enhancing output power of piezoelectric polyvinylidene fluoride generator

Flexible piezoelectric generators have attracted considerable attention in recent years on account of their potential applications in mechanical energy scavenging devices using portable, wearable, and implantable electronics. Key issues for realizing a flexible piezoelectric generator include insufficient output power generation and poor efficiency at low frequency. We therefore propose structural approaches to enhancing the output power of the flexible piezoelectric generator using polyvinylidene fluoride. Specifically, we propose the use of a substrate and curved structure, and optimization of the aspect ratio of the generator for maximizing output power density. Through these approaches, induced stress and output voltage of the generator are analyzed by finite element modeling and validated through experiments. Considering these results for generator optimization, we fabricate a multilayered flexible curved generator, which produces ~200V of the peak output voltage and ~2.7mA of the peak output current. The output power density of the generator reaches ~17mW/cm2, which is sufficient to drive various commercial electronics as a power source. Furthermore, it is demonstrated that this power source can illuminate 952 LED bulbs. This conceptual technology can provide the groundwork to enhancing the output power of conventional piezoelectric generators, thereby enabling novel approaches to realizing self-powered systems.

Hybridized electromagnetic-triboelectric nanogenerator

Due to the energy crisis, more and more research works have been focused on the renewable energies in the environment for solving the issues of the power sources. Harvesting mechanical energy in our daily life has been attracting more and more attentions due to its potential capability for providing power source to drive some sensors without the external Li-ion batteries. As one of the most commonly available energies, mechanical energy can be effectively converted into electricity by using some energy scavenging devices, such as electromagnetic generators, piezoelectric nanognerators, and triboelectric nanogenerators. Many researches have been achieved to high-efficient conversion from mechanical energy into electricity. By choosing the different materials or changing the structure of the energy harvesting device, the output performance of the device can be enhanced. New approaches need to be exploited for largely increasing the conversion efficiency of the energy harvesting devices. A hybridized electromagnetic-triboelectric nanogenerator is to utilize electromagnetic and triboelectric nanogenerators to simultaneously scavenge mechanical energy from one mechanical motion. As compared with the individual energy harvesting units, the hybridized nanogenerator has much larger output power, higher conversion efficiency so that it can be used to solve the power source issue of some electronic devices with larger power consumption. The hybridized nanogenerators have the potential applications in self-powered sensors, wearable devices, and networks. The recent development of hybridized nanogenerator will be described in this review.

Feasibility of Energy-Autonomous Wireless Microsensors for Biomedical Applications: Powering and Communication.

In this review, biomedical-related wireless miniature devices such as implantable medical devices, neural prostheses, embedded neural systems, and body area network systems are investigated and categorized. The two main subsystems of such designs, the RF subsystem and the energy source subsystem, are studied in detail. Different application classes are considered separately, focusing on their specific data rate and size characteristics. Also, the energy consumption of state-of-the-art communication practices is compared to the energy that can be generated by current energy scavenging devices, highlighting gaps and opportunities. The RF subsystem is classified, and the suitable architecture for each category of applications is highlighted. Finally, a new figure of merit suitable for wireless biomedical applications is introduced to measure the performance of these devices and assist the designer in selecting the proper system for the required application. This figure of merit can effectively fill the gap of a much required method for comparing different techniques in simulation stage before a final design is chosen for implementation.

Field operational testing for safety improvement of freight trains using wireless monitoring by sensor network

Today, the majority of wagon failures on railroad systems are because of the poor maintenance of ball bearings, which causes emergent stops and delays. The existing stationary detectors, lack in predicting failures which cause troubles in scheduling maintenance. During the fall of 2011, a trial was performed by applying a wireless sensor network (WSN) aboard a train wagon with the objective to demonstrate a proof of concept for monitoring the temperature of ball bearings aboard the train wagon. This trial investigates several key aspects when applying sensor networks such as radio wave propagation, energy scavenging and performance of the WSN aboard the wagon. Two wireless links were used in the WSN. The aboard network communicates at 2.45 GHz, and the external communication is an 868 MHz radio frequency identification radio link. Since the energy in the WSN node is limited, appropriate energy scavenging devices are also presented and evaluated in a lab environment. Effort has been made to overcome these problems. The energy consumption in the network is still a problem; the most promising energy scavenging technique is piezoelectric harvesting by vibrations, which in the experiments scavenged 2.32 mW.

A Similarity on Energy Exchange Between Resonance and Synchronization

This research focuses on a possibility to scavenge energy from fluid flow including turbulence. Based on turbulent mechanics, energy scavenging devices are expected to have nonlinear characteristics to accept wide-band-spectrum power distributed in turbulence. A magnetoelastic beam is adopted as one of candidates of energy scavenging devices. The magnetoelastic beam is excited in a nonlinear magnetic field formed by two magnets. In this paper, we estimate the possibility of energy exchange at synchronization as the scavenging mechanism, with considering the similarity to resonance.

Direct-write PVDF nonwoven fiber fabric energy harvesters via the hollow cylindrical near-field electrospinning process

One-dimensional piezoelectric nanomaterials have attracted great attention in recent years for their possible applications in mechanical energy scavenging devices. However, it is difficult to control the structural diameter, length, and density of these fibers fabricated by micro/nano-technologies. This work presents a hollow cylindrical near-field electrospinning (HCNFES) process to address production and performance issues encountered previously in either far-field electrospinning (FFES) or near-field electrospinning (NFES) processes. Oriented polyvinylidene fluoride (PVDF) fibers in the form of nonwoven fabric have been directly written on a glass tube for aligned piezoelectricity. Under a high in situ electrical poling field and strong mechanical stretching (the tangential speed on the glass tube collector is about 1989.3 mm s−1), the HCNFES process is able to uniformly deposit large arrays of PVDF fibers with good concentrations of piezoelectric β-phase. The nonwoven fiber fabric (NFF) is transferred onto a polyethylene terephthalate (PET) substrate and fixed at both ends using copper foil electrodes as a flexible textile-fiber-based PVDF energy harvester. Repeated stretching and releasing of PVDF NFF with a strain of 0.05% at 7 Hz produces a maximum peak voltage and current at 76 mV and 39 nA, respectively.

Energy Scavenging Device Based on Electric Field in Substations

Wireless sensor network has many advantages while energy supplying is a main limit. However, energy scavenging technology affords an efficient solution, especially in high voltage substations, there is swarmed with strong electromagnetic field, and the scavenging device based on electric field has an irreplaceable advantage. An equivalent mathematical model of the converter was established to study the energy harvesting effect. Another model of conditioning circuitry was further built to analyze the factors affecting charging current. Finally, several main factors and corresponding methods are analyzed to improve the energy scavenging efficiency.

Analysis and Design of Conditioning Circuitry Used for Energy Scavenging Device

Energy scavenging device used for smart grid can achieve energy from electromagnetic field and convert it into electricity to power wireless sensors within substations. Due to the energy collected by the energy scavenging unit is unstable, a conditioning circuitry is essential. A conditioning circuitry is proposed, and modeling method is also established accordingly. Both large-signal model and dynamic disturbance model of the topology are presented as to analyze the static and dynamic characteristics. Remarkably, one duty cycle of the sensors is divided into the launch period and dormant period. At different period, their equivalent impedance is different, so the performance of conditioning circuit at different stages is analyzed. To realize it, a feedback control circuit should be considered in the design of the topology. Further, simulation based on PSIM is done to certify effectiveness of the proposed topology and optimized parameters.

Analysis and Optimization of Magnetic Energy Converters for Wireless Sensors in Substation

With the development of wireless sensor networks, energy supplying problem become critical. However, energy scavenging technology provides an efficient solution method, and it is the principal element for wireless sensors to facilitate on-site self-powering. A magnetic energy converter which can convert magnetic field energy to power is proposed when there is sufficient magnetic energy in substations. By modeling this converter, the inductive factor was defined to present energy harvesting capability and optimization was realized in terms of framework material, structural parameters and turns of coils. The research results present theoretical basis for optimal design of the energy scavenging devices.

Experimental Research of Energy Harvesting and Storage Based on Ferroelectric Materials

The concept of energy harvesting works towards developing self-powered devices that do not require replaceable power supplies. Energy scavenging devices are designed to capture the ambient energy surrounding the electronics and convert it into usable electrical energy. A number of sources of harvestable ambient energy exist, including waste heat, vibration, electromagnetic waves, wind, flowing water, and solar energy. While each of these sources of energy can be effectively used to power remote sensors, the structural and biological communities have placed an emphasis on scavenging vibrational energy with ferroelectric materials. Ferroelectric materials have a crystalline structure that provide a unique ability to convert an applied electrical potential into a mechanical strain or vice versa. Based on the properties of the material, this paper investigates the technique of power harvesting and storage.

Characterization of a high-power piezoelectric energy-scavenging device based on PMN-PT piezoelectric single crystals

In this paper, we present the calculations and the results for vibration-energy-scavenging performances based on a piezoelectric single-crystal beam. Using the measured mechanical damping ratio and electro-mechanical coupling coefficient of a novel cantilever structure device, we calculated the output performances and compared them with the measured results. A device based on a bimorph cantilever structure with a proof mass was designed to have a natural resonance frequency of about 60 Hz, and the energy-scavenging capability of piezoelectric single crystal was measured. The results showed that several tens of AC volts and a few milliwatts power were achieved under a 0.1 grms vibration condition. Also using this device and a commercial power management circuit, we performed Li-ion battery charging experiment.