Erik Aylen

San José State UniversityDepartment of Mechanical EngineeringME 295A Mechanical Engineering Project I

Design and Control of Linear Induction Motorsfor an Automated Transit Network

December 10, 2013

(Vectus PRT, 2013)

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Where We Can Be:Automated Transit Networks

How It Can Be Done:Simulation and Control

Where We Are Now:Linear Motors in Modern Transit Systems

This presentation focuses on the use of linear induction motors for transit vehicle propulsion.

Linear Induction Motors:Benefits, Design, and Construction

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Primary windings

(Lee, Park, et al., 2008)

(University of Michigan, 2011)

Secondary plate

Linear induction motors (LIMs) can deliver contactless linear force instead of rotational torque.

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Linear motors offer capabilities that rotary motors cannot.

(Daily Courier, 2013)

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Linear motors offer capabilities that rotary motors cannot.

(China Photos/Getty Images, 2008)

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Linear motors can serve as effective propulsion for controlled-access transit vehicles.

(Wikimedia Commons, 2008)

Secondary plate runs the length of the track.

Short primary system:

Primary coils are on the underside of the vehicle.

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The long primary system mounts the primary coils along the length of the guideway.

(International Maglevboard, 2006)

Primary coils are stationary.

Secondary is mounted on the vehicle.

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Linear motors are currently being used in many transit systems worldwide.

(Hellinger and Mnich, 2010)

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Each implementation is site-specific. There is no one-size-fits-all solution.

The technology to build a successful Automated Transit Network already exists and is being put to use worldwide.

Ultra Global PRT at London Heathrow Airport

VectusSuncheon Bay,

South Korea

2getthereMasdar City,United Arab Emirates

(Ultra Global PRT, 2010)

(Vectus PRT, 2013)

(2getthere, 2013)

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An interdisciplinary group here at SJSU is designing SuperWay – an ATN for Silicon Valley.

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The speed and safety performance numbers required for an ATN are achievable using LIMs.

Vehicle Mass: 1100 kgCruise Speed: 22 m/sHeadway for Brick Wall Stop: 3.7 sHeadway for 0.5 g Stop: 1.4 s

Nominal Fore/Aft Acceleration: 1.125 m/sForce Required: 2000 NEnergy Required: 450 kJPower Required: 23 kW

Emergency Stop: 3.0 m/sForce Required: 4500 NPower Required: 50 kW

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LIMs have become more viable with improvements in processing power.

MATLAB /Simulink

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However, LIMs have inherent drawbacks, notably much lower electrical efficiency than rotary motors.

End effects cause as much as a 40% increase in steady-state current vs. rotary devices. (Motlagh, 2012)

Typical values of air gap for wheeled vehicles (non-maglev) are ≥ 12mm.(Hellinger, Mnich, 2010)

Larger air gap spacing and vibrational variance can reduce efficiency by 70%. The air gap of a LIM is an important indicator of vehicle transmission efficiency. (Wu et al., 2010)

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Development work on this project will continue through Spring 2014.

Upcoming tasks for next semester:1.Solidify my understanding of LIM thrust vs. rotary motor torque equations2.Build or acquire: LIM, power electronics, small cart/bogie

OR: use full-scale SuperWay cabin3.Model applicable hardware using Simulink4.Develop a motor control algorithm

Month: Jan Feb Mar Apr MayTask: Week of: 27 3 101724 3 10172431 7 142128 5 1219Mathematical work Build/acquire hardware Simulink modeling Algorithm development Write Report Edit Report Presentation Report Due

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Hardware acquisition and testing

Mathematical model and control software development

In summary, this project will provide guidance for the implementation of LIM propulsion in the SuperWay ATN.

Questions?