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Lecture 10: Magnetic
Levitation
IEE Culminating Lab
&
Timely Curricular Information
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
1
Magnetic Levitation Experiment
• Magnets or magnetic materials can be
suspended either using magnetic attraction or
repulsion and permanent or electromagnets.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
2
Magnetic Levitation
• Trains can magnetically fly over a roadbed
with position sustained by some kind of
control system
• Force can either be attractive or repulsive
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
3
Some Commercial Products
http://www.gadgets4sure.com
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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The Physics of Levitron
• The spinning top keeps itself stabilized
vertically while the magnetic base keeps the
top suspended.
• http://www.levitron.com/
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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The Physics of Levitron
• The top actually precesses around the
vertical axis (like the earth on its axis).
• There is a range of stable revolutions per
second (20-30). The weight must also be set
to exactly balance gravity.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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2 Minute Quiz
• Specify any design issue for repulsive
levitation
• Specify any design issue for attractive
levitation
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Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment:
How the Globes Are Suspended
IR Emitter
Electromagnet
Control Circuit
IR Detector
IR Light Beam
Ball to be suspended
• From Barry’s Coilgun Design Site
• Barry’s design is slightly more advanced
• http://www.oz.net/~coilgun/levitation/home.htm
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
• Close up photos showing levitation of washer
and ball bearing with magnet attached. Some
preferred orientation is necessary for stability.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
Unblocked Beam
Blocked Beam
• The position of the suspended object
(here a ball) is sensed by how much of
an IR beam is blocked by the object.
• This requires an IR emitter and an IR
detector.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
Blocked Beam
• The emitter puts out a constant light intensity.
• The detector signal is amplified and
compared with a reference voltage.
• The output of the comparison drives the
electromagnet.
• If the ball is too high (detected IR signal too
small), the coil current is reduced.
• If the ball is too low (detected IR signal too
large), the coil current is increased.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
From Radio Shack
Mini-Notebooks
• The IR emitter and detector are powered just
like the LEDs we used previously. The
resistor in series gives us the best operation
and also protects the diode.
 Lab 2 on Diodes has the resistor.
 Labs 5, 6, and 7 drive the LEDs directly.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
• The photo emitter and detector circuits
to be used in the experiment
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
Inverting Op-amp
Buffer
• The circuit is constructed of the op-amp
configurations we saw in Lab 4.
• The actual circuit must also contain some
mathematical operation for stable control.
• This control in this case is analog. There are
many other options.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
Inverting Op-amp
Buffer
• For the inverting op-amp
VOUT  VIN
• For the buffer
23 May 2017
Rf
R1
VOUT  V IN
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
From Detector
Buffer
Buffer
• First, two buffer circuits are used to isolate
the control function (which we will return to).
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
Bias Buffered Input to Summing
Inverting Op-amp
23 May 2017
Inverting Op-amp
Introduction to Engineering Electronics
K. A. Connor
17
Maglev Experiment
• Voltage from op-amps drives transistor which
provides the current for the electromagnet.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment
Control
• How does the control work?
• We need to look at different types of control.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev: Types of Control
Oven Temp
Set Point Temp
Power
• On-Off Control (also called Bang-Bang)
• Commonly used for thermostats. When the
temperature is to low (bang) it is on. When the
temperature is too high (bang) it is off.
• Note the large excursions in temperature and that
hysteresis is used to delay turn on and turn off.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
20
Maglev: Types of Control
Set Point Temp
Oven Temp
For 3 gains
• Proportional Control
W  AP (TS  TO )
• The power W is proportional to the difference in
temperature between the set point and the actual
temperature. Note as gain increases, the temperature
becomes more unstable but can get closer to the set point.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev: Types of Control
Oven Temp
Set Point Temp
Power
• Proportional-Integral-Differential Control (PID)
d TS  TO 


W  AP TS  TO   AD
 AI  TS  TO dt 
dt


• Works the best but is more mathematically
demanding since it is 3rd order.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev: Types of Control
• Proportional-Integral Control (PI): In a simple
system where noise may be a problem, the
derivative term is not used. This is the
approach used in the Embedded Control
Class.
• More on control can be found at Feedback
and Temperature Control from the University
of Exeter and the Hacker’s Diet (really!) by
John Walker.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Maglev Experiment: Controller
In
Out
• For a resistor:
• For a capacitor:
23 May 2017
V  IR
1
V   Idt
C
Introduction to Engineering Electronics
K. A. Connor
24
Controllers
• PID Controllers can be implemented
many, many different ways.
• Analog input can be converted to digital
and then processed in the digital
domain before being converted back to
analog to drive the coil.
 Digital circuitry can be used.
 A microcontroller (like in Embedded
Control) can be programmed
 Other options may be discussed in the next
lecture.
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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Some Registration Week Information on
Majors Related to IEE
•
•
•
•
•
•
•
Electrical Engineering
Computer and Systems Engineering
Electric Power Engineering
EE/CSE Dual Degree
EE/EPE Dual Degree
CSE/CS Dual Degree
EE/Applied Physics Dual Degree
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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ECSE Undergraduate Advisor
• David Nichols – Available for advice any
time Monday, Wednesday and
mornings on Thursday. (JEC 6002)
• Email: [email protected]
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Introduction to Engineering Electronics
K. A. Connor
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Electrical Engineering
Science, Math,
H&SS Core
Engineering Core
Restricted Electives
23 May 2017
EE Core
Concentration
Introduction to Engineering Electronics
K. A. Connor
ECSE Core
Free Electives
28
Electrical Engineering
Science, Math,
H&SS Core
•
•
•
•
•
•
•
Chem Mat I
Calculus I&II
Differential Eqns
Physics I&II
CS I
H&SS (5) + PD II
Applied Math Elective
23 May 2017
Engineering Core
•
•
•
•
•
•
•
IEA
IEE
EG&CAD
IED
Embedded Control
PD I&III
Multidisciplinary
Elective
Introduction to Engineering Electronics
K. A. Connor
29
Electrical Engineering
ECSE Core
EE Core
• Electric Circuits
• Computer Components
and Operations
• Signals & Systems
• Probability for Engr.
Applications
23 May 2017
• Analog Electronics or
Digital Electronics
• Fields and Waves I
• Microelectronics
Technology
• Lab Elective
Introduction to Engineering Electronics
K. A. Connor
30
Electrical Engineering
Concentration
•
•
•
•
•
•
•
Specified Electives
Automatic Controls
Comm & Info Proc
Computer Hardware
Electromagnetics
Electronic Circuits
Power Electronics
Manufacturing or
Entrepreneurship
• Microelectronics
• Individualized
23 May 2017
• Lab Elective
• Design Elective (no longer
included in concentration)
Introduction to Engineering Electronics
K. A. Connor
31
Electrical Engineering
Free Electives
Restricted Electives
• Any ECSE or EPOW
• Used to satisfy
concentration
• Can also include one
ENGR course
23 May 2017
• Any course at all
• Usually used up for dual
degrees
• Most students take
additional technical
courses
• See undergrad handbook
Introduction to Engineering Electronics
K. A. Connor
32
Computer and Systems Engineering
Science, Math,
H&SS Core
Engineering Core
Restricted Electives
23 May 2017
CSE Core
Concentration
Introduction to Engineering Electronics
K. A. Connor
ECSE Core
Free Electives
33
Computer and Systems Engineering
Science, Math,
H&SS Core
•
•
•
•
•
•
•
•
Chem Mat I
Calculus I&II
Differential Eqns.
Physics I&II
CS I&II
Data Structures & Alg.
H&SS (5) + PD II
Applied Math Elective
23 May 2017
Engineering Core
•
•
•
•
•
•
•
IEA
IEE
EG&CAD
IED
Embedded Control
PD I&III
Multidisciplinary
Elective
Introduction to Engineering Electronics
K. A. Connor
34
Computer and Systems Engineering
ECSE Core
CSE Core
• Electric Circuits
• Computer Components
and Operations
• Signals & Systems
• Probability for Engr.
Applications
23 May 2017
• Computer Architecture,
Networks and Operating
Systems
• Software Engineering
Elective
Introduction to Engineering Electronics
K. A. Connor
35
Computer and Systems Engineering
Concentration
•
•
•
•
•
Specified Electives
Automatic Controls
Comm & Info Proc
Computer Hardware
Computer Systems
Manufacturing or
Entrepreneurship
• Individualized
23 May 2017
• Software Engineering
Elective
• Design Elective (no longer
included in concentration)
Introduction to Engineering Electronics
K. A. Connor
36
Computer and Systems Engineering
Free Electives
Restricted Electives
• Any ECSE or CSCI
• Used to satisfy
concentration
• Can also include one
ENGR course
23 May 2017
• Any course at all
• Usually used up for dual
degrees
• Most students take
additional technical
courses
• See undergrad handbook
Introduction to Engineering Electronics
K. A. Connor
37
Electric Power Engineering
Science, Math,
H&SS Core
Engineering Core
Restricted Electives
23 May 2017
EPE Core
Concentration
Introduction to Engineering Electronics
K. A. Connor
ECSE Core
Free Electives
38
Electric Power Engineering
Science, Math,
H&SS Core
•
•
•
•
•
•
Chem Mat I&II
Calculus I&II
Differential Eqns
Physics I&II
C Prog. For Engineers
H&SS (5) + PD II
23 May 2017
Engineering Core
•
•
•
•
•
•
•
•
•
•
•
IEA
Engr. Proc. Or IEE
EG&CAD
IED
MAU
Modeling & Control of
Dynamic Systems
Embedded Control
Electronic Instrumentation
PD I&III
Thermal & Fluids Engr.
Multidisciplinary Elective
Introduction to Engineering Electronics
K. A. Connor
39
Electric Power Engineering
ECSE Core
EPE Core
• Electric Circuits
• Fields & Waves I
• Signals & Systems
23 May 2017
• Power Engineering
Fundamentals
• Electromechanics
• Semiconductor Power
Electronics
• EPE Lab
• EPE Design
Introduction to Engineering Electronics
K. A. Connor
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Electric Power Engineering
Concentration
Specified Electives
• Not required for EPE
degree
• Optional Concentration
in Power Electronics
Systems -- Includes
courses from EPOW,
ECSE, & MANE
23 May 2017
• Technical Elective – any
course in Engineering or
Science above the 2000
level
Introduction to Engineering Electronics
K. A. Connor
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Electric Power Engineering
Free Electives
• Any course at all
• Usually used up for dual
degrees
• Most students take
additional technical
courses
• See undergrad handbook
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
42
Dual Degrees
• EE/CSE – Includes
only the CSE
concentrations (130
credits)
• CSE/CSYS –
Includes all CSE
concentrations (131
credits)
23 May 2017
• EE/EPE – Includes
only the Power
Electronics
concentration (131
credits)
• EE/Applied Physics
– Includes only the
Microelectronics
concentration (132
credits)
Introduction to Engineering Electronics
K. A. Connor
43
Recent Changes
• Check ECSE webpage during registration
period
• New Undergraduate Handbook
• New design course options
 ECSE Design
 Control Systems Design
 Other courses will be changing
• Please check advising information on a
regular basis
23 May 2017
Introduction to Engineering Electronics
K. A. Connor
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