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Concept for a modular assembly direct drive permanent magnet generator : Development of model and winding schemeSkoog, Henric January 2010 (has links)
In this thesis, a concept for a modular assembly direct drive permanent magnetgenerator is presented. The maximum forces that act on the different parts of thegenerator during normal operation have been calculated and used in solid mechanicsimulations in SolidWorks. The result is a rough first draft of a generator designwhere the stator has been divided into five modules and the rotor into six modules.This division is done in order to avoid symmetries in the generator that could lead toproblems with self-oscillation.The modulization of the stator brings about certain difficulties, both for the magneticcircuit and for the winding scheme. Different solutions for optimization of themagnetic circuit are analyzed from both a physical and a construction technicalperspective. A winding scheme is produced and the winding process tested in awinding dummy produced according to the conceptual generator design.
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Kardiale Magnet-Resonanz-Tomographie bei Patienten vor und nach chirurgischer Ventrikelrekonstruktion – Analyse potentieller Prädiktoren der postoperativen Herzfunktion –Hüther, Jan 02 May 2012 (has links) (PDF)
Die DOR-Plastik (Surgical Ventricular Reconstruction, SVR) ist ein chirurgisches Verfahren zur Rekonstruktion ventrikulärer kardialer Strukturen bei Herzinsuffizienz-Patienten mit apikaler A- und Dyskinesie. Jedoch gibt es spätestens seit dem negativen Ergebnis einer großen multizentrischen Studie (STICH-trial, Jones et al. 2009 [1]) eine Kontroverse über den tatsächlichen prognostischen Nutzen der Operation. Ziel dieser Arbeit war es in diesem Zusammenhang mittels kardialer Magnet-Resonanz-Tomographie (Cardiac Magnetic Resonance, CMR) generierte potentielle Prädiktoren der funktionellen Erholung nach der DOR-Plastik zu analysieren. Dafür wurden in dieser Arbeit bei 24 Patienten die kardialen Volumina, die kardiale Funktion, das lokale und totale myokardiale Narbengewebe und verschiedene geometrische Indizes bestimmt und ausgewertet.
Es konnte gezeigt werden, dass die quantitative Ermittlung des basalen myokardialen Narbengewebes und des apikalen Volumenindex (AVI) dabei helfen könnten, eine Subgruppe von Patienten zu definieren, die von der DOR-Plastik profitiert.
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Noise reduction control strategy of a permanent magnet synchronous machine for vehicle applicationsDoolittle, Randy Gene 15 May 2009 (has links)
The purpose of this work was to investigate a permanent magnet synchronous machine
which will be produced by an industry partner of the Institut für Stromrichtertechnik und
Elektrische Antriebe (ISEA) an institute of the Rheinisch Westfälisch Technische
Hochschule - Aachen, Germany (RWTH).
The machine manufacturer noted certain abnormalities with the frequency spectrum
produced by an electric machine that they were developing; this problem was brought to
ISEA in order to be investigated. My work continues the work of my supervisor, Dipl.-
Ing Matthias Bösing, and seeks to further examine the machine for a much wider range
of operating points, determine the relationship between current amplitude, harmonics,
control angle and rotor position on radial force components of the machine and therefore
stresses on the stator; which are the primary causes of electrical machine noise. Rather
than investigate acoustic issues in particular, the study was limited to the study of
electromagnetically generated radial force ripple, which is the cause of stator deflection
modes and therefore the emission of sound waves.
The primary results of this thesis researched the operation of a permanent magnet
synchronous machine and described its behavior with regards to force, torque, and force
and torque ripple and their spectrums versus numerous parameters, including control
angle, secant current and rotor position. Next, the work used provided data, literature
and the simulation results for this thesis in order to deconstruct the operation regions of the particular machine and therefore link the causes of particular noise spectral
components to the operation of the machine. From this it was possible to identify
potential ways to eliminate these areas of noise. Following this, the thesis examined a
particular abnormality in the torque and force waveforms produced by the machine and
devised actions which could correct this abnormality. After identifying this asymmetry,
the work explored how to choose an optimal control strategy for eliminating particular
harmonics based on the simulated operating points and a desired command torque.
Finally, the research built on the previous work by supplementing the method of current
harmonic injection for eliminating radial force harmonics in this machine, with a method
of determining an optimal operating point before the injection currents are calculated.
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A Multi-axis Compact Positioner with a 6-coil Platen Moving Over a Superimposed Halbach Magnet MatrixNguyen, Vu Huy 2011 May 1900 (has links)
A multi-axis compact positioner is designed and implemented in this thesis. The single-moving-part positioner is designed to move in the magnetic field generated by a superimposed concentrated-field permanent magnet matrix. The compact positioner is primarily for the stepping and scanning applications that require 3-DOF planar motions. In which, the travel ranges in two orthogonal directions are on the order of 100 mm. The moving platen, which has the size of 185.4 mm x 157.9 mm and weighs 0.64 kg, mainly comprises of a plastic frame and six copper coils. It is actuated in the horizontal plane by flowing six independent electric currents into the coils. The platen is supported against gravity by three air bearings.
Force calculation is based on the Lorentz force law. With a current-carrying rectangular coil placed in the magnetic field of the supper-imposed Hallbach magnet matrix, the force acting on the coil is calculated by volume integration. The distances between the longer sides and between the shorter sides of the rectangular coil are designed to fit a half pitch and one pitch of the Hallbach magnet array, respectively. Therefore, the volume integration is simplified considerably. The force-current relation for the entire platen with six coils is derived.
Three Hall-effect sensors are attached to the moving platen to measure the magnetic flux densities at the center points of the sensors. The position of the moving platen is determined by the field solution of the magnet matrix and the magnetic flux densities sensed by the Hall-effect sensors. A new discrete PID-like controller is proposed and tested. For the step responses with the step sizes within 1000 micrometers, the overshoots and the steady state errors are negligible. The achieved velocity in x is 10.50 cm/s and in y is 16.25 cm/s, respectively. The achieved acceleration in x is 43.75 cm/s^2 and in y is 95.59 cm/s^2, respectively. The achieved travel ranges are 15.24 cm in x, 20.32 cm in y, and 0.21 rad in the rotational motions about the vertical axis. The positioning resolution in x and y is 8 micrometers with the rms positioning error of 6 micrometers. The positioning resolution in rotation about the vertical axis is 130 microrad.
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noneChen, Fu-Te 26 July 2006 (has links)
Abstract
not only influence on development of basic industries in a country but relate with business cycle. Hi-tech industries grow rapidly and play a key role with ¡§innovation¡¨ in stock market. The trends of hi technology make people forget that traditional industries not only keep existing but play a great role of economic activities. Historically speaking, Electric wire and cable industries still exist and even stably develop.¡C
I hope to apply the following theories including innovation management, dependence of resources and product life cycle to explain why traditional industries are not sunset industries. Besides, I also chose Feng-chin Corporation as a case with best skills at magnet wire manufacturing to explain how a company keeps his competitive advantages in the matured market. Through case study and theory applied, the followings are concluded.
1. With less possibilities the products are replaced, the greater possibilities of continuity of the industry. In aspects of attributes of product itself, no alternatives appear to substitute for the copper and therefore the magnet wire industry would not disappear as the raw materials with the copper. Even though we can find the new material to replace the copper, the magnet wire industry will still exist with other alternative to replace the copper. When PLC model are applied, the products with greater continuity represent highly matured products. Hence, the products with greater continuity have the following characteristics including less possibilities to be replaced, highly matured and unclear decline stage, and high dependence of the below companies.
2. In low value added industries, individual company should emphasize on process innovation and diversified customers. The Feng-chin Corporation struggles to innovate technologically and in process by the following ways.
(1) They make traditional products into hi-technology industries by raise added values.
(2) They concentrate on costing down and their own field
(3) They well utilize their resources to enforce the mutual-depend relationship with the below companies.
Likewise, in the industries which pursue economic scales to reduce the cost, it is more important to diversify the costumers when they have the following characteristics including high matured products, high pricing products and lower mobility of the equipments.
Key words: innovation management product life cycle magnet wire industry continuity
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Extended EMF Observer for Wide Speed Range Sensorless Control of Salient-pole Synchronous Motor DrivesOkuma, Shigeru, Doki, Shinji, Ohnuma, Takumi January 2010 (has links)
No description available.
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Vakuumverfahren zur Abscheidung funktioneller Schichten für elektrische KontakteKupfer, Hartmut, Hecht, Günther, Ackermann, Eckehard 04 March 2010 (has links) (PDF)
Der Einsatz von Edelmetallen für die Oberflächenveredelung von Steckverbinderkontakten bietet in zunehmendem Maße ökonomische Schwierigkeiten. Die Ursache dafür ist die Entwicklung der Preise und die Verfügbarkeit für diese Materialien. Ein Ausweg ist, sofern das die speziellen Einsatzbedingungen erlauben, eine Beschichtung mit Unedelmetallen. Übereinstimmend mit Veröffentlichungen in der Literatur wurden dafür bisher zunächst Zinn und seine Legierungen verwendet.
Zinn und Zinnlegierungen wurden mittels Magnetronzerstäubung abgeschieden. Die chemische Zusammensetzung der Schichten wurde mit der Elektronenstrahlmikroanalyse (ESMA) bestimmt. Die Kontakteigenschaften der Schichten wurden anhand von Korrosionstests und der Messung des Kontaktwiderstandes beurteilt.
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Design, analysis, control and application of permanent magnet brushless dual-memory machinesLi, Fuhua, 李富华 January 2014 (has links)
Conventional PM machines have fixed PM excitation and can only perform flux-weakening by controlling the d-axis current. This current incurs the power dissipation and reduces the efficiency during flux-weakening operations.
Memory machines change this situation by introducing the memory function, namely magnetizing or reversely magnetizing Al-Ni-Co PMs to change the air-gap flux density. This provides another new way to realizing flux-weakening. And the elimination of the flux-weakening d-axis current improves the overall efficiency. But the single-memory machines have lower power density due to the low-energy Al-Ni-Co PMs.
By incorporating the memory concept and with the intention of improving the power density, the DC-excited PMBL dual-memory machines have been proposed and implemented, based on two kinds of PMs which are high-coercivity Nd-Fe-B PMs and low-coercivity Al-Ni-Co PMs. The Nd-Fe-B PMs provide a strong magnetic field to excite high air-gap flux density; while the Al-Ni-Co PMs can be forward magnetized to strengthen the magnetic field produced by Nd-Fe-B PMs or can be reversely magnetized to cancel that field. Consequently the air-gap flux density can be controlled within a wide range.
A series of design principles on such kind of dual-memory machine are devised for guidance. The key design principles involve how to determine the number of salient poles on the stator and rotor, how to choose the surface areas and thicknesses of the two kind of PM pieces and how to size the rotor dimension.
Generally, increase on the proportion of Nd-Fe-B PMs will raise the base field and the load capacity. On the other hand, increment on the proportion of Al-Ni-Co PMs will extend the controllable flux range. Analysis is also carried out on the equivalent magnetic circuit to formulate the magnetizing force exerted on Al-Ni-Co PMs.
The machine model is analyzed by using time-stepping FEM (TS-FEM) and co-simulation of FEM software and Matlab Simulink. The dynamic reverse magnetizing processes are simulated and presented in details under different magnetizing current. In addition the effect of adding iron bridges between the two kinds PMs is also evaluated by simulations.
Furthermore, the control methods are evaluate by simulations and experiments. The direct torque control (DTC) scheme is adapted to this doubly-salient dual-memory machine and a torque estimator is proposed to facilitate the DTC method. Both of the simulation results and the experimental results confirm the validity of the proposed design principles and the effectiveness of the control methods.
Eventually, this dual-memory machine is proposed as a pole-changing wind power generator and a pole-changing EV machine. Simulation and experimental results have verified the validity of the pole-changing scheme and the pole-protection scheme. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
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A comparison of permanent magnet motor structures for traction drive applications in hybrid electric vehicles /Han, Lin, 1982- January 2008 (has links)
This thesis presents a detailed comparison of the torque-speed characteristics of three permanent magnet synchronous machine designs based on how the magnets are mounted. The machines investigated are an interior permanent magnet machine, an interior-rotor surface-mounted machine and an exterior-rotor surface-mounted machine. They are designed for traction drives in hybrid electric vehicles. Two sets of comparisons based on the same machine volume and starting torque are performed. Important issues, such as machine mass and cost, cogging torque, and flux-weakening capability are addressed. Computer simulations were performed to estimate their performances and the results are presented. Design guidelines and tradeoffs of their performances are extracted from the simulation results. Relative strengths and limitations of different PM machine types are highlighted.
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Investigation of CaIr1-xPtxO3 and CaIr0.5Rh0.5O3 : structural properties, physical properties and stabilising conditions for post-perovskite oxidesHirai, Shigeto January 2011 (has links)
Our understanding of the nature of Earth’s D” region was changed significantly by a recent finding by Murakami et al. (2004), who revealed a phase transition from perovskite to post-perovskite structure in MgSiO3 at about 125 GPa and 2500 K, corresponding to conditions of the lowermost mantle. A perovskite to post-perovskite phase transition accounts for many unusual features of the D” region, including its notable seismic anisotropy, and also accounts for the unusual topology of the D” discontinuity. However, the experimentally synthesised post-perovskite phase of MgSiO3 is not quenchable to ambient conditions, which means that many of its physical properties remain difficult to determine. On the other hand, there are several post-perovskite oxides, CaIrO3, CaPtO3, CaRhO3 and CaRuO3, which can be quenched to ambient conditions, maintaining their structure. High pressure synthesis of CaIr1-xPtxO3 solid solutions (x = 0, 0.3, 0.5, 0.7) and CaIr0.5Rh0.5O3 was conducted at the University of Edinburgh and Geodynamics Research Center, Ehime University, and structures and physical properties of these novel post-perovskite materials determined. Substantial [100] grain growth was observed in all solid solutions leading to pronounced texture even in powdered materials. Temperature-independent paramagnetism above 150 K and small magnetic entropy observed in heat capacity measurements suggest that CaIrO3 is an intrinsically weak itinerant ferromagnetic metal, while electrical resistivity measurements show that it is a narrow bandgap semiconductor, possibly due to grain boundary effects. CaIrO3 undergoes a magnetic transition at 108K and possesses a saturated magnetic moment of 0.04 μB. Doping with Pt or Rh induces Curie-Weiss paramagnetism and suppresses the magnetic transition. The anisotropic structure and morphology of CaIrO3 combined with the Ir4+ spin-orbit coupling results in a large magnetic anisotropy constant of 1.77 x 106 Jm-3, comparable to values for permanent magnet materials. A new high-pressure phase of CaIr0.5Pt0.5O3 was synthesised at 60GPa, 1900K using a laser-heated DAC (diamond anvil cell) at GRC, Ehime University. Its Raman spectra resemble those of perovskite phases of CaIrO3 and CaMnO3, implying that CaIr0.5Pt0.5O3 undergoes a post-perovskite to perovskite phase transition with increasing pressure. I estimate an increase in thermodynamic Grüneisen parameter γth across the post-perovskite to perovskite transition of 34 %, with similar magnitude to (Mg,Fe)SiO3 and MgGeO3, suggesting that CaIr0.5Pt0.5O3 is a promising analogue for experimentally simulating the competitive stability between perovskite and post-perovskite phase of magnesium silicates in Earth’s lowermost mantle. Such estimation is reliable since the estimated and directly calculated thermodynamic Grüneisen parameter γth from heat capacity show consistent values. The marked effect that Pt has on stabilising the post-perovskite structure in CaIr1-xPtxO3 solid solutions explains why the post-perovskite to perovskite phase transition has not been observed for CaPtO3 in contrast to other quenchable post-perovskite oxides: CaIrO3, CaRhO3 and CaRuO3.Work presented here demonstrates that CaIrO3 solid solutions can be used to provide new insight into factors stabilising post-perovskite structures in Earth’s lowermost mantle.
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