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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Study on electricity characteristics of electro-magnetic vibration-induced micro-generators

Chen, Ssu-ting 28 August 2007 (has links)
With the flourishing development of MEMS, it is possible to combine micro-sensors with micro-actuator and apply to the organ transplant in medical fields or as an embedded sensor on buildings or bridges. Generally batteries is are used as the kinetic energy source, but it involves the issue of recycling. Therefore, development of a self-generator utilizing vibrational source from environment is another better choice. This study succeeds in building up the transform mode of electricity in an electro-magnetic vibration-induced micro-generator. The electricity characteristics of micro-generator are obtained by Mathematical software analysis. MEMs technology can be used to fabricate and assemble the microstructure , planar coils and magnetic films. The analytic results of maximum power and minimum volume by using a mathematics model are achieved. The validity of this model is verified by comparing the theoretical and experiment data from the literature.
2

Design and fabrication of in-plane micro-generator using low temperature co-fire ceramics

Chen, Yong-Jheng 05 September 2012 (has links)
This study focuses on the design, fabrication, test and application of in-plane rotary electromagnetic micro-generator to obtain a high power output. The micro-generator comprises multilayer planar low temperature co-fired ceramics (LTCC) Ag micro-coil and multipole hard magnet of Nd/Fe/B. Finite element simulations have been carried out to observe electromagnetic information. The study also establishes analytical solutions for the micro-generator to predict the induced voltage. Three different configurations of planar micro-coils investigated, which are sector-shaped, circle-shaped, and square-shaped micro-coils. A prototype of the micro-generator is as small as 9¡Ñ9¡Ñ1 mm3 in volume size. The experimental results show that the micro-generator with sector-shaped micro-coil has the highest power output of 1.89 mW, and the effective value of the induced voltage of 205.7 mV at 13,325 rpm is achieved. In application, this study designed and fabricated a planar rotary electromagnetic energy harvester with a low rotary speed for use in bicycle dynamos. Finite element analysis and the Taguchi method were used to design this dynamo system. LTCC technology was applied to fabricate Ag planar multilayer coils with 20 layers. A 28-pole magnet Nd/Fe/B with an outer diameter of 50 mm and a thickness of 2 mm was also sintered and magnetized. This harvester system was approximately 50¡Ñ50¡Ñ3 mm3 in volume. The experimentally induced voltages for 20-layer coils were 1.539 V at the rotary speeds of 300 rpm. The power output was 0.788 mW with an external resistance load of 740 £[, and the efficiency was 26.62%. This harvester is capable of powering a minimum of 200 light emitted diodes (LEDs) (forward voltage (VF) <2.2 V and 20 mA) using a rotary speed of 250 rpm, and can be used for bicycle dynamo lighting.
3

Design and Fabrication on Vibration-Induced Electromagnetic Micro-Generators Using LTCC Technology

Lu, Weng-Long 30 July 2010 (has links)
This work presents design and fabrication technologies on vibration-induced electromagnetic micro-generators using LTCC (Low temperature co-fire ceramic) processes. LTCC fabrication with some special advantages has simplistically processes and multilayer stack procedure, resulting in a micro-inducer can consist of the multilayer silver (Ag) induction micro-coils and a helical ceramic micro-spring. Highly electrical conductible Ag and its multilayer micro-coil structures can enhance the power output of generators. This work is composed of three parts. The first part describes the design of two kinds of micro-generator; a magnetic core generator (MCG) and sided-magnet generator (SMG). According to their respective structures, an analytical mode is also developed to investigate its resonant frequency and the spring constant of the micro-spring, as well as the bending stress and fatigue life of the supporting beam. The voltage output, current output and power output on the helical induction micro-coils, as well as the relationship of vibration amplitude versus vibration frequency in the vibrating system are calculated. The second part introduces how to integrate the Ag multilayer induction micro-coils and the helical ceramic micro-spring using LTCC technique, and organize the design and fabrication of LTCC micro-inducers. From the fabrication procedures, it is known that a stacking error places a limit on the total numbers of micro-coils layer. The experimental results verify that the application of LTCC to the fabrication of micro-inducers is feasible, and that the phenomenon of plane warpage, volumetric shrinkage, layer delamination and surface crack of sintered ceramic structures has been fully controlled. In the third part, measurement setup, vibrating tests and experiments on generating electricity are completed. The performances with different-structure devices are evaluated. Voltage output, current output and power output, as well as changing trends of power density with respect to the layer number of induction micro-coils and magnets are discussed. Relationship of the electrical parasitical damping coefficient versus the vibration amplitude and vibration velocity, relationship between the induced inductor and the current output, the power output depending on the electrical load resistance and differences between fabrication lots are investigated. At last, comparisons between analytical and experimental power output are conduced. For MCG micro-generator, the analytical value is 0.88 mW, about 13.6% smaller than the experimental value of 1 mW. For SMG micro-generator, the analytical value is 1.73 mW, about 10.7% larger than the measured value of 1.56 mW. The analytical models are verified. In the MCG device, the experimental results show that a maximum voltage output of 25.19 mV, a current output of 82.9 mA and a power density of 2.36 mW/cm3 under 120 Hz frequency and 0.03-mm amplitude are obtained. In addition, when operated at 69 Hz vibration frequency and vibration amplitude of 0.03 mm, the experimental maximum voltage output, current output and power density of the SMG device are 44.5 mV, 83.1 mA and 2.17 mW/cm3, respectively. Except the power density, other electricity performances of SMG device are better than MCG. Apparently, the power density of MCG and SMG device presented by this study competes favorably with the results from other devices in the literature.
4

Optimalizace vibračního mikrogenerátoru. / Optimalization of vibration microgenerator

Kurfűrst, Jiří January 2009 (has links)
The article describes how to produce energy necessary for sensor supply. These generators are used as a local source operating on vibratory principle. Mechanical vibrations that occur in moving machines, in nature etc. are used in order to gain required energy. So are kinesis principles and analysis employed in some of the avaible generators. It also contains patent and literary background research. Work is oriented to solving mechatronic perimeter, in the concrete micro - generator. Mechatronic perimeter piles from seat power control parts and mechanical parts, where common solving equation system leads to correct solving. Mentioned analyses be of consequence for usage optimization methods artificial intelligence. Optimization method are used on optimum solving proposal micro - generator. To inquest dynamism system was used program Simulink (part of MATLAB), generator is buckthorn for f = 17 [Hz] acceleration yam = 0,5g [ms-2]. As a algorithm is used SOMA – All to one.

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