BRADLEY UNIVERSITY

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BRADLEY UNIVERSITY Department of Electrical and
Computer Engineering Sr. Capstone
Project Advisor Dr. Anakwa Student Paul Friend
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• Overview
• Background Information
• Halbach Array
• Inductrack
• Sensors
• Propulsion Methods

• Controls
• Physical Design
• Theories
• Parts and Equipment
• Schedule
• Resources

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• Background Information
• Inductrack
• Created by Richard F. Post in the late 1990s at
  Lawrence Livermore National Laboratory
• 20 meter test track
• Burst Propulsion

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• Background Information
• Inductrack
• Contracted by NASA for Satellite Launcher
• Low-Speed Urban Maglev Program

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• Halbach Array
• Created by Klaus Halbach
• Creates a strong, nearly one-sided magnet with a
  sinusoidal field by directing the magnetic
  fields.

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• Halbach Array
• Standard Formation
• Expanded Wavlength
• Doubled Method

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Halbach Array B0 Br (1 e-2pd/?)(sin(p/M))/
( p/M) Tesla B0 0.82843 (1/2 Gr. 38 NdFeB
Cube Magnets) Bx B0 sin((2p/?)x) e-(2p/?) (y1
y) Tesla By B0 cos((2p/?)x) e-(2p/?) (y1
y) Tesla
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• Inductrack
• Basic Methods
• Array of Inductors
• Laminated Copper
• Laminated Aluminum

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• Inductrack
• Array of Inductors
• Used in 1st Inductrack
• Insulated Litz-wire
• Ferrite Loading

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• Inductrack
• Laminated Copper
• Square Litz-wire bulks
• Used for Low-Speed Urban Maglev Program

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• Inductrack
• Laminated Copper Aluminum
• Thin Sheets
• Slots cut to guide eddy currents
• Slots terminated at ends for shorts

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• Inductrack
• Physics
• Lenzs Law
• Discovered in 1834
• Eddy currents created due to moving magnetic
  field
• (Not guided)

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Inductrack Physics Circuit Equation V L dI/dT
RI ?f0 cos(?t) V Lift/Drag
Ratio Lift/Drag ltFygt/ltFxgt ?L/R (2pv/?)
(L/R) Power Efficiency K ltFygt/ltFxgt (2p/?)
(L/R) Newtons/Watt
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Inductrack Physics ? optimum 4p y1 m Magnet
thickness of ?/5 Only valid for max. load for
min magnet weight and for original
Inductrack 501 levitated weight/magnet weight
ratio
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Inductrack Inductrack II
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• Sensors
• Types
• Velocity Sensor
• Optical Sensor
• Magnetic Sensor

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• Propulsion
• Types
• Linear Synchronous Motor (LSM)
• Linear Induction Motor (LIM)

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• Propulsion
• Linear Synchronous Motor (LSM)
• Used for Low-Speed Urban Maglev Program
• Allows for large air gap 25 mm
• Varied 3-phase frequency and current for contols
• Solid copper cables and laminated iron rails
• Works with Halbach array

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• Propulsion
• Linear Induction Motor (LIM)
• Typically electromagnets in train
• Aluminum ladder as track
• Levitation and propulsion aquired

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• Propulsion
• Modified Linear Induction Motor (LIM)
• Synchronized electromagnets
• Precision sensing required
• Controled via the current
• PWM
• Current Level

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• Controls
• Properties to Control
• (80515 Microcontroller Based)
• Levitation Hieght
• Direction
• Velocity

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• Controls
• Levitation Height Control
• Theory of current Low-Speed Urban Maglev Program
• Height by causing a phase shift
• Compromises the structure

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• Controls
• Direction and Velocity Control
• Modified Induction Motor (LIM)
• Sensing and Electromagnets

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• Controls
• Direction and Velocity Control
• Inputs
• Mode of Operation
• Velocity or Current
• Outputs
• Train Levitation
• Train Propulsion
• LCD Display

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Controls Direction and Velocity Control Modes of
Operation 0.) Open Loop Backwards Current
Input1.) Closed Loop Backwards Velocity Input
with Control2.) Backwards Coast with No
Propulsion3.) Stop4.) Forwards Coast with No
Propulsion5.) Closed Loop Forwards Velocity
Input with Control6.) Open Loop Forwards Current
Input
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Controls Free Running Position Detector Inputs
Current Direction Addressed
Sensor Outputs Addresses Senosr
Addresses Electromagnets Velocity
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Controls Open Loop Modes 0 6 Inputs
Current Level Direction Outputs
Current
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Controls Closed Loop Modes 1 5 Inputs
Velocity Direction
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• Controls
• Coast Modes 2 4
• Direction is indicated for sensor prediction
• Utilizes free running position detector with no
  current
• Velocity still displayed
• Stop Mode 3
• Pulse electromagnets in front of train
• Position detector can not be used
• Details have not been worked out

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• Controls
• High Power DC Switching Current Control
• Power MOSFET
• Insulated -gate bipolar transistor (IGBT)
• Gate-turn-off thyristor (GTO)

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Controls Current Converted Converts current
levels 0 - 256 (0-FF hex) to increasing current
levels using PWM and resistor paths
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Controls Magnet Addresser Directs current to each
individual electromagnet using an array of
switches for each section, and corresponding
placement in each section.
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Physical Design Materials Wood and 1/16 Aluminum
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• Testing
• Inductrack Testing
• Use of a horizontal or lateral wheel
• Utilized by Post

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• Theories
• Disk Method
• Wheel Method
• Tractor Tread Method
• Paddle Wheel Method

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Standards Table of standards used by the
Low-Speed Urban Maglev Program Will be used
for concepts to keep in mind
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Patents Richard F. Post Magnetic Levitation
System for Moving Objects U.S. Patent
5,722,326 March 3, 1998 Richard F.
Post Inductrack Magnet Configuration U.S. Patent
6,633,217 B2 October 14, 2003 Richard F.
Post Inductrack Configuration U.S. Patent 629,503
B2 October 7, 2003 Richard F. Post Laminated
Track Design for Inductrack Maglev System U.S.
Patent Pending US 2003/0112105 A1 June 19,
2003 Coffey Howard T. Propulsion and
stabilization for magnetically levitated
vehicles U.S. Patent 5,222,436 June 29, 2003
Coffey Howard T. Magnetic Levitation
configuration incorperating levitation, guidance
and linear synchronous motor U.S. Patent
5,253,592 October 19, 1993 LeviEnrico
ZabarZivan Air cored, linear induction
motor for magnetically levitated systems U.S.
Patent 5,270,593 November 10, 1992 Lamb Karl
J. Merrill Toby Gossage Scott D. Sparks
Michael T. Barrett Michael S. U.S. Patent
6,510,799 January 28, 2003
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Schedule Tentative schedule Weeks 1
4 Development and testing of tracks Weeks 5
8 Development of a propulsion method Weeks 9
10 Integration of the propulsion and the
Inductrack Weeks 11 13 Propulsion
Controls Week 14 Finish Loose Ends Based on
progress, meetings with Dr. Anakwa will determine
the direction the project will take after each
step
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Parts and Equipment 40 - 1/2 NdFeB, Grade 38
Cubes 90.00 40 - 1/4 NdFeB, Grade 38
Cubes 14.40 Litz-wire Bulks, Copper Sheets,
Aluminum Sheets, Wheels, Conductive balls, and
Electromangets Cart/Train non inductive materials
and CNC router machine time provided by
Midwestern Wood Products Co.
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• Resources
• Many Documents by Richard F. Post (LLNL)
• General Conversation with Richard F. Post (LLNL)
• General Conversation with Phil Jeter (General
  Atomics)
• General Conversation with Hal Marker (Litz-wire)
• General Converastion with Dr. Irwin (Bradley
  University)