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Modelling and control of segmented long-stator permanent-magnet linear synchronous motorsLines, Christopher Roger 11 March 2014 (has links)
A novel control strategy for segmented long-stator permanent magnet linear synchronous
motors is presented that is particularly suited to ropeless hoisting. The
stator (primary) is segmented into modular sections that are shorter than the moving
reaction plate (secondary) and a single voltage source inverter per conveyance is
used to power the energised sections. Efficient partial excitation of the stator is
achieved with an intermediate switching layer placed between the stator sections and
the inverter. The common voltage supplied to the sections is controlled with any
standard motor vector control technique. Computer simulation and a purpose-built
laboratory prototype show the strategy to be effective. There is scope for future
research into full sensorless control of the proposed arrangement and a method of
further modulating the supply voltage for those stator sections that are only partially
covered by the reaction plate, particularly when operating at higher speeds.
Stemming from initial efforts to mathematically model the linear motor, a novel
electromagnetic modelling approach was formulated. This hybrid magnetic-equivalentcircuit
(MEC) and finite element method (FEM) approach is suited to efficient
dynamic simulation and is explicated with a worked example. The method yields
accurate results when compared with pure FEM. An MEC formulation is used for
highly-permeable polygonal regions, whereas the magnetic field outside these regions
is solved, by superposition, as the combined effect of boundary conditions that
interface with those MEC regions and any magnetic sources. The required parameter
sets for solving the field outside the regions represented as MECs are purely dependent
on the geometry of the problem space and are thus precomputed. The force acting
on a chosen group of moving components is calculated using an approximation of the
Maxwell Stress Tensor method. Future research could address the present limitation
that the highly-permeable regions are meshed using exclusively-rectangular flux tube
elements.
A dynamic simulation model that caters for the discontinuities of a segmented
stator was ultimately derived using an extended space-vector approach and its
implementation as a generic Simulink R
blockset is detailed. The motor parameters are
determined from static FEM solutions over the range of reaction plate displacement,
assuming no magnetic saturation.
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Field analysis and design of a moving iron linear alternator for use with linear engineRerkpreedapong, Dulpichet. January 1999 (has links)
Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains v, 92 p. : ill. Includes abstract. Includes bibliographical references (p. 82-83).
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Investigation, analysis and design of the linear brushless doubly-fed machineSeifkhani, Farroh 08 February 1991 (has links)
This thesis covers the efforts of the design, analysis,
characteristics, and construction of a Linear Brush less Doubly-Fed
Machine (LBDFM), as well as the results of the investigations and
comparison with its actual prototype.
In recent years, attempts to develop new means of high-speed,
efficient transportation have led to considerable world-wide interest
in high-speed trains. This concern has generated interests in the
linear induction motor which has been considered as one of the more
appropriate propulsion systems for Super-High-Speed Trains (SHST).
Research and experiments on linear induction motors are being
actively pursued in a number of countries. Linear induction motors are
generally applicable for the production of motion in a straight line,
eliminating the need for gears and other mechanisms for conversion
of rotational motion to linear motion.
The idea of investigation and construction of the linear brushless
doubly-fed motor was first propounded at Oregon State University,
because of potential applications as Variable-Speed Transportation
(VST) system. The perceived advantages of a LBDFM over other LIM's
are significant reduction of cost and maintenance requirements.
The cost of this machine itself is expected to be similar to that
of a conventional LIM. However, it is believed that the rating of the
power converter required for control of the traveling magnetic wave
in the air gap is a fraction of the machine rating. The constructional
design of the machine is such that the primary contains two 3-phase
windings. One of these 3-phase systems is connected directly to the
utility grid; the second 3-phase system, with a different number of
poles, is connected to a power electronic converter which has the
capability of providing adjustable frequency and amplitude of voltage
or current. The speed of the traveling magnetic field can be varied
simply by controlling the output frequency of the power electronic
converter. The design of the actual machine is such that the two
3-phase systems laid in the primary of the machine are magnetically
decoupled from each other because of the difference in pole number
of the two systems, (e.g. 6-pole and 2-pole for the test prototype
machine in our research lab). The other degree of freedom that this
machine provides, is the operation of the machine under two distinct
speeds by implementing the pole change technique. This mode of
operation can give only discrete changes in speed, however, it
provides efficient running at those speeds with a minimum of control
mechanism. On the other hand, it is anticipated that the LBDFM with
two actively fed windings will produce a continuously adjustable speed
over a wide range. Hence, LBDFM will be superior if it can be designed
to function effectively. / Graduation date: 1991
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Modeling and control of linear motor feed drives for grinding machinesXie, Qiulin. January 2008 (has links)
Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Steven Y Liang; Committee Member: Chen Zhou; Committee Member: David G Taylor; Committee Member: Min Zhou; Committee Member: Shreyes N Melkote.
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Advanced propulsion systems for linear motion with high performance requirements /Zhou, Xiaolin. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 71-79). Also available on the World Wide Web.
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An investigation of high speed, thin steel rotor, annular, double sided, linear induction motorsPeabody, Frank Gerald January 1988 (has links)
The objective of this dissertation is to analyse the performance of a linear induction motor suitable to drive a circular saw blade. A selection of analytical methods available from the field of electrical machine theory was used to investigate the particular type of motor. The theoretical analysis is supported by an extensive experimental investigation.
Although LIMs have been designed, analyzed and applied in other applications, significant differences exist between those LIMs and the one used for the new application. These include: the annular shaped motor, the smaller air gap, and the rotor which is thin and made of steel. Because of these differences, the methods used by previous investigators were not sufficient to design the LIM required.
The theoretical analysis used a selection of methods described in the literature to quantify the effect of the rotor material, the end effect and the edge effect. New methods are described to analyse the effect of the annular shape, the normal forces on the rotor and the coil connection. In addition, a new consideration in the optimisation of these type of motors is described. An extensive experimental program was undertaken. Six different linear motors were constructed with output powers ranging from one to fifty kWatts. In addition, inverters, dynamometers, flux measurement apparatus, speed measurement, thrust measurement and friction measurement apparatus were designed and constructed. The effects on performance of slot harmonics, winding connections, the end effect and the edge effect were measured.
Several contributions to the field of electrical machine theory are presented. The first is a new annular disc motor resistivity correction factor. Second, is the analysis of the effects of poles in parallel versus in series in linear induction motors. Third, is the experimental comparison between odd and even pole designs. The fourth is a second optimum goodness consideration for LIMs, which had not previously been considered. The fifth is the analysis of the rotor/stator attractive force for magnetic rotor double sided motors and a description of the flux (crenelated flux) which causes the force. Finally, a criterion for when the re-entry effect may occur is presented. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate
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Helical rail guns : the application of linear electric motors to aircraft launchingFitch, Osa Edward. January 1982 (has links)
Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1982 / Vita. / Includes bibliographical references (leaf 185). / by Osa Edward Fitch. / B.S. / B.S. Massachusetts Institute of Technology, Department of Physics
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Modulating dynamic stiffness of a direct-drive brushless linear DC motorMiller, Joel Christopher 08 1900 (has links)
No description available.
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Two-stroke linear engineNandkumar, Subhash. January 1998 (has links)
Thesis (M.S.)--West Virginia University, 1998. / Title from document title page. Document formatted into pages; contains x, 82 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 69-70).
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Design, construction, and testing of a combined magnetic levitation and propulsion system.Atlas, Michael January 1977 (has links)
Thesis. 1977. B.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / B.S.
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