Investigation of useful ambient vibration sources for the application of energy harvesting

Abstract— Ambient vibration is one of the popular sources for energy harvesting due to its ubiquitous present in almost everywhere. For the past few years it has attracted many interests in the design and development of vibration based micro generators for low power electronic applications. The aim of this paper is to investigate on useful ambient vibration sources which would have great potential for the application of energy harvesting. Commonly the acceleration level of ambient vibration is low, in the range < 1 g-level. In this study, the vibration sources from industries (machinery), home appliances and moving vehicle are compiled and compared with suitable energy harvesters designed by other researchers. It may serve as a good guideline for the researchers in designing resonant devices such as the vibration based micro-power generators

Design Considerations of MEMS Based Piezoelectric Cantilever for Harvesting Energy

One of the challenges of miniature electronic system such as those work as a part of a wider wireless sensor system is to provide sustainable electrical power source to all the electronic components in a small enclosure of sensor node. However, as the size of the micro-power generator reduces, the physical limitations as well as the reduction of output power become the major concerns of the usefulness of a miniature energy harvester. In this paper, the design is taking into considerations of the mechanical as well as the electrical properties of an unimorph piezoelectric cantilever. These encompassed the natural frequency and the neutral axis of the structure. Resistive load was also being investigated for optimizing the electrical output power of the micro-generator. It was found that the issue of the maximum deflection of the cantilever is more prominent than the stress on the cantilever for a miniature device. The adjustment on the neutral axis as well as on matching with resistive load are also important in generating optimum electrical output power

Comparison Study between Four Poles and Two Poles Magnets Structure in the Hybrid Vibration Energy Harvester

Vibration energy harvester is receiving considerably amount of interest for the past decade. Many improvements such as making it tunable, broadband based and hybrid harvester have been demonstrated in the literature, generally to exploit more electrical energy from the ambient. In this paper, we study the arrangements of the magnets that referred to as cantilever beam proof mass, as means for generating greater electrical power output. The harvesters consist of piezoelectric cantilever beam with two different arrangements of magnets; two poles magnets and four poles magnets attached to its free end tip. A coil is placed underneath the magnets arrangement, so that when the harvester is being excited by external vibration, both piezoelectric and electromagnetic transducer will generate electrical energy. In this paper, a comparison study in terms of generated output voltage, induced current and generated electrical power output are presented. Experimental results show that, four pole magnets type harvester is capable of generating greater electrical power as compared the two pole magnets type harvester when exposed to its resonant frequency at 1g acceleration ( 1g = 9.8 ms-2 ) . This implies that by incorporating a proper magnets arrangement, the harvester is capable of producing greater power output

Hybrid Vibration Energy Harvester Based On Piezoelectric and Electromagnetic Transduction Mechanism

Vibration energy harvester converts kinetic energy from ambient vibration into electrical energy. Many energy harvesters in the literature use single element transducer, either piezoelectric, electromagnetic or electrostatic for above purpose. In this paper, a hybrid based energy harvester that integrates with both, piezoelectric and electromagnetic transducers is developed and examined. The energy harvester uses four pole magnets arranged onto a piezoelectric cantilever beam free end, to produce stronger magnetic field over a stationary coil. When the harvester is excited by an external vibration, both piezoelectric and electromagnetic generates electrical energy or power. Experimental results shows that piezoelectric capable to generate optimum power of 2.3mW in a 60k resistive load, while electromagnetic generates 3.5mW power in a 40 resistive load, when vibrated at its resonant frequency 15Hz, and at 1g (1g=9.8ms-2) acceleration. By efficiently integrating both piezoelectric and electromagnetic transducers, more power could be generated as compared to a single transducer over its size

Electrophoretic deposition and heat treatment of steel-supported pvdf-graphite composite film

Polymeric poly(vinyliden fluoride) (PVDF) is nontoxic. It possesses a better mechanical flexibility and requires a lower synthesis temperature, as compared to the piezoceramic counterparts. In order to achieve a competitive advantage against the current piezoelectric sensor, graphite could replace a more expensive silver-palladium as the electrodes for the piezoelectric PVDF. This paper reports the preliminary results on the synthesis of steel-supported graphite- PVDF/PVDF/graphite-PVDF composite films using the two-step process, consisted of the electrophoretic deposition (EPD) and heat treatment. The composite films were characterized by means of the optical microscopy, scanning electron microscopy, X-ray diffraction and differential scanning calorimetry. The heat treated graphite-PVDF electrode deposited by EPD provides adequate mechanical strength for the subsequent depositions of pure PVDF layer and the second layer of graphite-PVDF composite electrode. However, the final heat treatment stage did not eliminate the fine and large cracks of the composite film, which might be attributed to high residue stresses and weak bonding between graphite and PVDF particles in the post-heat treated composite films. Nevertheless, the increase in final heat treatment temperature of the composite film at Stage 3 improved the graphite and PVDF grain alignment, as well as its crystallinity

Comparison Study between Four Poles and Two Poles Magnets Structure in the Hybrid Vibration Energy Harvester

Vibration energy harvester is receiving considerably amount of interest for the past decade. Many improvements such as making it tunable, broadband based and hybrid harvester have been demonstrated in the literature, generally to exploit more electrical energy from the ambient. In this paper, we study the arrangements of the magnets that referred to as cantilever beam proof mass, as means for generating greater electrical power output. The harvesters consist of piezoelectric cantilever beam with two different arrangements of magnets; two poles magnets and four poles magnets attached to its free end tip. A coil is placed underneath the magnets arrangement, so that when the harvester is being excited by external vibration, both piezoelectric and electromagnetic transducer would generate electrical energy. In this paper, a comparison study in terms of generated voltage output, induced current and generated electrical power output are presented. Experimental results show that, the new approach; four pole magnets type harvester is capable of generating greater electrical power as compared to the conventional approach; two pole magnets type harvester, when exposed to its resonant frequency at 1g acceleration ( 1g = 9.8 ms-2 ) . This implies that by incorporating a proper magnets arrangement, the harvester is capable of producing greater power output

Bandwidth Widening Strategies for Piezoelectric Based Energy Harvesting from Ambient Vibration Sources

Due to the fact that the ambient vibration sources are random and unpredictable, therefore a vibration based energy harvesting device is desirable to be able to operate at wider bandwidth in an envelop of frequency range to generate maximum electrical output. In this paper, various ambient vibration from household appliances, machineries, vehicle and moving vehicle were measured and investigated. The second part of the paper will discuss the strategies to harvest these ambient vibration sources. An array of piezoelectric multi-cantilever is proposed to address the issue of single piezoelectric cantilever with high Q-factor. Two configurations of multi-cantilever were fabricated in a form that elevated from the substrate as freestanding structures. One with six cantilevers of constant width but different lengths and another with five cantilevers of constant length but different widths. The measurement and experimental results show a frequency band of 200 Hz to 300 Hz as a common bandwith between the vibration sources and the capability of miniature piezoelectric energy harvester in harvesting maximum electrical energy

A Perspective Review on Numerical Simulations of Hemodynamics in Aortic Dissection

Aortic dissection, characterized by separation of the layers of the aortic wall, poses a significant challenge for clinicians. While type A aortic dissection patients are normally managed using surgical treatment, optimal treatment strategy for type B aortic dissection remains controversial and requires further evaluation. Although aortic diameter measured by CT angiography has been clinically used as a guideline to predict dilation in aortic dissection, hemodynamic parameters (e.g., pressure and wall shear stress), geometrical factors, and composition of the aorta wall are known to substantially affect disease progression. Due to the limitations of cardiac imaging modalities, numerical simulations have been widely used for the prediction of disease progression and therapeutic outcomes, by providing detailed insights into the hemodynamics. This paper presents a comprehensive review of the existing numerical models developed to investigate reasons behind tear initiation and progression, as well as the effectiveness of various treatment strategies, particularly the stent graft treatment

Analysis on the voltage stability on transmission network with PV interconnection

Voltage stability means the ability of the power system network to maintain steady-state voltage value at all buses in the system under normal condition and after being subjected to a disturbance. This research highlights the effect of solar photovoltaic (PV) as the subject of disturbance to the network system as this kind of energy source has emerged towards higher level of integration into the national grid. High penetration of solar PV into the grid may cause several issues of stability and security to the system particularly effecting the normal voltage and line overloading. This research is focused on the simulation of power flow to study the transmission network behavior with and without the solar PV interconnection. To accomplish the research objectives, the network system will be modelled in a software known as Power System Simulator for Engineering (PSSE). The simulation result will be discussed and analyzed using Voltage Stability Indices (VSI) to prove and strengthen the theory behind the literature review