scholarly journals Design, analysis and dynamic phenomena of MEMS capacitive power harvester

2015 ◽  
Author(s):  
◽  
Jianxiong Zhu
Keyword(s):  
High Efficiency ◽  
Experimental Testing ◽  
Electrostatic Force ◽  
Electrical Power ◽  
Micro Electro Mechanical System ◽  
Power Harvesting ◽  
Power Harvester ◽  
Self Powered ◽  
Dynamic Phenomena ◽  
Rocking Instability

Unwanted vibrations are all around us in our daily life. These vibrations can effectively be converted into electrical power through capacitive device. Even though the amount of power generated is small ([mu]W), it is still sufficient to drive certain devices, such as devices in the field of Micro Electro Mechanical System (MEMS). We call these functional devices "self-powered devices". This dissertation describes design, modeling, analysis, dynamic simulation and experimental testing of MEMS variable capacitors which are used for power harvesting based on external vibration. More specifically, it includes the electrostatic force and the forces provided by the stopper designed to prevent direct impact between capacitive plates. To more accurately reflect the status of power harvesting, rocking instability is discussed as well. However, the onset of rocking instability leads to more complicated dynamic phenomena. This dissertation not only introduces equation theory derivation and dynamic behaviors of the MEMS capacitive harvester, but also presents a comparison of power harvesting at broad frequencies and different amplitudes. These conclusions are helpful for the design of high efficiency "self-powered" MEMS capacitive power harvester.

Dynamic Study of MEMS Variable Capacitive Device for Power Harvesting

2012 ◽  
Author(s):  
Jianxiong Zhu ◽  
Z. C. Feng ◽  
Jie Lin ◽  
Nuh Sadi Yuksek ◽  
Mahmoud Almasri
Keyword(s):  
Symmetry Breaking ◽  
Parallel Plate ◽  
Period Doubling ◽  
Dynamic Responses ◽  
Parallel Plate Capacitor ◽  
Moving Plate ◽  
Power Harvesting ◽  
External Forces ◽  
Dynamic Phenomena ◽  
Rocking Instability

This work shows the complicated dynamic responses of the MEMS parallel plate capacitor for power harvesting resulting from the onset of rocking instability. Rocking instability or symmetry breaking is a relatively new area of study as it pertains to plate instability. It is important because the instability decreases the total amount of power that can be harvested especially when the tips of the moving plate make contact with the fixed plate. Two different designs characterized by the number of variable capacitors are studied. Power harvesting is achieved by the motion of a moving plate under external forces of vibration. The dynamics of the moving plate under sinusoidal excitations are obtained using numerical integration. We show that capacitive plates can become non-parallel due to the onset of rocking instability. Complicated dynamic phenomena including period doubling and chaos can occur. Consequently, the harvested power is greatly reduced when rocking instability occurs.

High Efficiency Electromagnetic Energy Harvester for Railroad Application

2013 ◽  
Author(s):  
John Wang ◽  
Teng Lin ◽  
Lei Zuo
Keyword(s):  
Energy Harvester ◽  
High Efficiency ◽  
Vibration Energy Harvester ◽  
Power Harvesting ◽  
Speed Regulation ◽  
Dc Power ◽  
Higher Power ◽  
Power Harvester ◽  
Health Monitoring Systems ◽  
Conversion Technologies

A mechanical motion rectifier (MMR) based energy harvester is designed to harness the vibrational power from railroad track deflections due to passing trains. Whereas typical existing vibration energy harvester technologies are built for low power applications of milliwatts range, the proposed harvester will be designed for higher power applications such as major track-side equipment. This includes warning signals, switches, and health monitoring systems, which typically require a power supply of 10–100 Watts. To achieve this goal we implement the MMR, a newly patented motion conversion mechanism which efficiently transforms irregular pulse-like bidirectional linear vibration into regulated unidirectional rotational motion. The single-shaft MMR design improves previously developed motion conversion technologies, increasing energy harvester efficiency and power harvesting potential. Features of the MMR include bidirectional to unidirectional motion conversion and flywheel speed regulation. Its advantages include improved reliability, efficiency, and steadier output power. Harvester prototype testing results illustrate features and benefits of the MMR based harvester, showing reduction of continual system loading, regulation of generator speed, and capability for continuous DC power generation.

scholarly journals Near-field thermophotovoltaics for efficient heat to electricity conversion at high power density

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rohith Mittapally ◽  
Byungjun Lee ◽  
Linxiao Zhu ◽  
Amin Reihani ◽  
Ju Won Lim ◽  
...  
Keyword(s):  
Power Density ◽  
High Power ◽  
High Efficiency ◽  
Near Field ◽  
Electrical Power ◽  
Photovoltaic Cells ◽  
High Power Density ◽  
Pv Cell ◽  
Electrical Power Output ◽  
Power Densities

AbstractThermophotovoltaic approaches that take advantage of near-field evanescent modes are being actively explored due to their potential for high-power density and high-efficiency energy conversion. However, progress towards functional near-field thermophotovoltaic devices has been limited by challenges in creating thermally robust planar emitters and photovoltaic cells designed for near-field thermal radiation. Here, we demonstrate record power densities of ~5 kW/m2 at an efficiency of 6.8%, where the efficiency of the system is defined as the ratio of the electrical power output of the PV cell to the radiative heat transfer from the emitter to the PV cell. This was accomplished by developing novel emitter devices that can sustain temperatures as high as 1270 K and positioning them into the near-field (<100 nm) of custom-fabricated InGaAs-based thin film photovoltaic cells. In addition to demonstrating efficient heat-to-electricity conversion at high power density, we report the performance of thermophotovoltaic devices across a range of emitter temperatures (~800 K–1270 K) and gap sizes (70 nm–7 µm). The methods and insights achieved in this work represent a critical step towards understanding the fundamental principles of harvesting thermal energy in the near-field.

scholarly journals Triboelectric Effect Enabled Self-Powered, Point-of-Care Diagnostics: Opportunities for Developing ASSURED and REASSURED Devices

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 337
Author(s):  
Navneet Soin ◽  
Sam J. Fishlock ◽  
Colin Kelsey ◽  
Suzanne Smith
Keyword(s):  
High Efficiency ◽  
Resource Constraints ◽  
Point Of Care ◽  
Wearable Sensors ◽  
Middle Income ◽  
Physiological Signal ◽  
Point Of Care Diagnostics ◽  
Self Powered ◽  
Triboelectric Nanogenerators ◽  
Triboelectric Effect

The use of rapid point-of-care (PoC) diagnostics in conjunction with physiological signal monitoring has seen tremendous progress in their availability and uptake, particularly in low- and middle-income countries (LMICs). However, to truly overcome infrastructural and resource constraints, there is an urgent need for self-powered devices which can enable on-demand and/or continuous monitoring of patients. The past decade has seen the rapid rise of triboelectric nanogenerators (TENGs) as the choice for high-efficiency energy harvesting for developing self-powered systems as well as for use as sensors. This review provides an overview of the current state of the art of such wearable sensors and end-to-end solutions for physiological and biomarker monitoring. We further discuss the current constraints and bottlenecks of these devices and systems and provide an outlook on the development of TENG-enabled PoC/monitoring devices that could eventually meet criteria formulated specifically for use in LMICs.

Self-Powered Multifunctional Instrumented Knee Implant

2018 ◽  
Author(s):  
Mohsen Safaei ◽  
Steven R. Anton
Keyword(s):  
Finite Element ◽  
Energy Harvesting ◽  
Knee Replacement ◽  
Center Of Pressure ◽  
Experimental Testing ◽  
Sensory System ◽  
Implant Design ◽  
Total Force ◽  
Self Powered

Computational modeling, instrumented linkages, optical technologies, MRI, and radiographic techniques have been widely used to study knee motion after total knee replacement (TKR) surgery. Information provided by these methods has helped designers to develop implants with better clinical performance and surgeons to obtain an improved understanding of the stability and mobility of the joint. Correspondingly, overall patient satisfaction with respect to the reduction in pain and recovery of normal functioning of the joint has been improving. However, about 20% of patients are still not fully satisfied with their surgical outcomes. The main obstacle in the current state-of-the-art is that a comprehensive post-operative understanding of knee balance is still unavailable, mostly due to a lack of in vivo data collected from the joint after surgery. This work presents an attempt to develop a self-powered instrumented knee implant for in vivo data acquisition. The knee sensory system in this study utilizes several embedded piezoelectric transducers in the tibial bearing of the knee replacement in order to provide sensing and energy harvesting capabilities. Through a series of analytical modeling, finite element simulation, and experimental testing, the performance of the suggested system is evaluated and a dimensionally optimized design of an instrumented TKR is achieved. More specifically, a comprehensive platform is established in order to combine the knowledge of embedded piezoelectric sensors and energy harvesters, musculoskeletal modeling of the knee joint, multiphysics finite element modeling, additive manufacturing techniques, image processing, and experimental knee loading simulation in order to achieve the experimentally validated and optimized instrumented knee implant design. The cumulative work presented in this article encompasses three main studies performed on the sensing performance of the proposed design: first, preliminary parametric studies of the effect of local dimensional and material parameters on the electromechanical behavior of the embedded sensory system; second, investigation of the ability to sense total force and center of pressure location; and third, evaluation of an enhanced system with the ability to sense compartmental forces and contact locations. Additionally, the energy harvesting capacity of the system is investigated to ensure the achievement of a fully self-powered sensory system. Results obtained from the experimental analysis of the system demonstrate the successful sensing and energy harvesting performance of the designs achieved in this study.

scholarly journals Self-Power Dynamic Sensor Based on Triboelectrification for Tilt of Direction and Angle

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2384 ◽  
Author(s):  
Hyeonhee Roh ◽  
Inkyum Kim ◽  
Jinsoo Yu ◽  
Daewon Kim
Keyword(s):  
Electrical Power ◽  
Stable Operation ◽  
Huge Number ◽  
Channel System ◽  
Active Sensor ◽  
Electrostatic Induction ◽  
Wide Range ◽  
Self Powered ◽  
The Internet Of Things ◽  
Great Development

With the great development of the Internet of Things (IoT), the use of sensors have increased rapidly because of the importance in the connection between machines and people. A huge number of IoT sensors consume vast amounts of electrical power for stable operation and they are also used for a wide range of applications. Therefore, sensors need to operate independently, sustainably, and wirelessly to improve their capabilities. In this paper, we propose an orientation and the tilt triboelectric sensor (OT-TES) as a self-powered active sensor, which can simultaneously sense the tilting direction and angle by using the two classical principles of triboelectrification and electrostatic induction. The OT-TES device consists of a rectangular acrylic box containing polytetrafluoroethylene (PTFE) balls moved by gravity. The output voltage and current were 2 V and 20 nA, respectively, with a PTFE ball and Al electrode. The multi-channel system was adopted for measuring the degree and direction of tilt by integrating the results of measured electrical signals from the eight electrodes. This OT-TES can be attached on the equipment for drones or divers to measure their stability. As a result, this proposed device is expected to expand the field of TES, as a sensor for sky and the underwater.

scholarly journals Engineering and experimental testing of two-wavelength laser-assisted device for photocoagulation of eye tissue

2013 ◽  
Vol 6 (2) ◽  
pp. 10-15
Author(s):  
Yury Sergeevich Astakhov ◽  
Yevgeny Leonidovich Akopov ◽  
Aleksandr Anatolevich Ivanov ◽  
Mariya Alexeevna Smirnova ◽  
Leonid Nikolaevich Panteleev ◽  
...  
Keyword(s):  
High Efficiency ◽  
Experimental Testing ◽  
Wide Spectrum ◽  
Retinal Disease ◽  
Primary Objective ◽  
3D Analysis ◽  
Potential Candidate ◽  
Living Tissue ◽  
Wide Range ◽  
Retinal Photocoagulation

Retinal photocoagulation is believed to be one of most efficient methods to treat many retinal abnormalities. By now, a number of lasers operating at different wavelengths, irradiation intensities, and exposure times have been tested in search of optimal parameters for each type of retinal photocoagulation. Taking into consideration a wide range of such parameters, the primary objective of the present study was to develop a device that would combine the potentials of different lasers into a single universal laser-assisted coagulator (ULAC) equally suitable for a wide diversity of retinal disease. Important issue would be the creation of an experimental model allowing an operative evaluation of the coagulating effect induced by the ULAC. The sources of coherent irradiation to be combined were DPSS and diode lasers (532 and 810 nm, respectively). Through two individual fibers, irradiation generated by each of the lasers entered the optical blender to be further directed to the target, now via a single fiber. The target termed the “surrogate of living tissue” was a mixture of donor human blood and chicken egg white, which corresponded, respectively, to the chromophore and thermocoagulating agent, both sensitive to laser beams at 532 and 810 nm. As a result, irradiation of surrogate of living tissue by a laser under the trial caused the formation of a coagulate and its firm adhesion to the coverslip, after that the coagulate was separated from the unaffected surrogate of living tissue followed by its 3D-analysis. In conclusion, the whole procedure, while being relatively non-expensive and easy to perform, has proved to be simple enough for testing of a wide spectrum of coagulation-inducing parameters, whatever laser was used. Moreover, even the initial experiments have shown the high efficiency of the ULAC as a potential candidate for the application in ophthalmological practice.

scholarly journals Caracterización en línea de la dinámica temporal de señales para el monitoreo del sistema eléctrico de potencia

2020 ◽  
pp. 26-34
Author(s):  
Francisco Román Lezama-Zárraga ◽  
Jorge de Jesús Chan-González ◽  
Meng Yen Shih ◽  
Roberto Carlos Canto-Canul
Keyword(s):  
Nonlinear Oscillations ◽  
Electrical Power ◽  
Orthogonal Basis ◽  
Basis Functions ◽  
Electrical Power System ◽  
Transient Phenomena ◽  
On Line ◽  
Measurement Units ◽  
Dynamic Phenomena

The characterization of dynamic phenomena is essential for monitoring the Electrical Power System subject to disturbances. This article proposes an On-line time systematic approach to analyze and characterize the temporal evolution of transient and nonlinear oscillations in these systems. Two methods are used; the first method is based on a local decomposition of the signal under study into orthogonal basis functions to obtain the dynamics of transient oscillations. Next, a second method is applied to those orthogonal basis functions to obtain analytical signals and characterize the instantaneous amplitude, phase and frequency attributes of the oscillations and determine a physical interpretation of the system’s behavior. The proposed methodology is a time-frequencyenergy analysis which can be applied to the timesynchronized Phasor Measurement Units measurements. The results demonstrate that the proposed methodology provide an accurate characterization of transient phenomena with non-stationary effects.

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