Supporting Undergraduate Courses
on Electromagnetism
by Field Simulation Exercises
IGTE, Graz, September 20th, 2010
Herbert De Gersem, Bart Vandewoestyne, Toon Roggen,
Eef Temmerman, Bart Van Damme, Koen Vandenbussche, Hans Pottel
The projects ''Physics experiments as starting point for interactive learning: from demonstration to exploration'' and
''Multidisciplinary learning environments for mechanics in biomedical, engineering and science education using
biomechanical examples'' are financially supported by the OI- and OOF-funds for educational innovation of the K.U. Leuven
and its association. The authors thank the CST AG for the classroom license of the CST Studio Suite.
Katholieke Universiteit Leuven
Etienne Sabbelaan 53, B-8500 Kortrijk, Belgium - URL: www.kuleuven-kortrijk.be
Problem Statement
course on electromagnetism: vectorial field
• lectures
: show field plots (but passive)
• exercises
: basically integrals, fields hidden
• (analytical field solutions → specialised courses)
• lab sessions : only global parameters (voltage, resistance)
? how to teach the electromagnetic-field concept ?
simulation tasks
• visualisation possibilities
• cooking-book booby trap
• perception remains „virtual“, „artificial“
2
Integrated Laboratory Session
• simple and relevant example
→ single-phase transformer
• integrated exercise
→ analytical calculation, field simulation, measurements
(exercises)
(simulations)
(lab experiments)
• requirements
•
•
•
•
1st year bachelor course
heterogeneous student groups (eng,phys,math,chem)
limited time (5 hours)
minimise teaching load (increasing student population)
• challenges
3
•
•
•
topic
: electrical engineering is no part of the course
simulation : 3D, nonlinear iron, eddy currents, forces, noise
experiments : lab precautions
Preparation
• introductory text
(to be read on beforehand)
• working principle
(reminder)
• technical aspects
(no part of the course!)
• analytical model
(no part of the course!)
• AC circuit solving
(preceeding exercises)
4
http://www.kuleuven-kortrijk.be/~u0005424/labtrf_english.pdf
Approach
+
+
+
δ
+ no-load
5
+ shortcircuit
gradually built up
coil without core
coil with core
coil with core and air gap
transformer, no-load test
transformer, short-circuit test
Approach
analytical
experimental
numerical
+
δ
+ no-load
analytical
k
6
+ shortcircuit
R1
Ω
measured
student C
+
student A
+
student B
3 tasks in parallel (student team)
→ all result tables have 3 columns
numerical
Approach
analytical
experimental
numerical
+
+ no-load
7
+ shortcircuit
student C
+
δ
student B
+
student A
compare and discuss results
→ get insight in modelling assumptions
← requires attention of teaching staff
+
+
δ
experimental
numerical
student C
+
student A
analytical
student B
Approach
+ no-load
8
+ shortcircuit
detect (and cure) calculation and
measurement errors yourself !
Tasks
analytical
L
experimental
numerical
 N 2 Smagn
magn
 Cu Swr
+
δ
+ no-load
9
+ shortcircuit
 Fe 
0
student C
wr
student B
+
R
student A
+
B2
+
+
δ
+ no-load
10
+ shortcircuit
experimental
numerical
student C
+
student A
analytical
student B
Tasks
Tasks
analytical
experimental
numerical
+
+ no-load
11
+ shortcircuit
student C
+
δ
student B
+
student A
define geometry & mesh
Tasks
+
+ no-load
12
+ shortcircuit
student C
+
δ
numerical
student B
+
student A
analytical
simulate
magnetic experimental
field
are flux lines as expected ?
link field plots to operation modes !
CST EM STUDIO (www.cst.com)
Tasks
experimental
beyondanalytical
analytical formulae
numerical
+
+ no-load
13
+ shortcircuit
student C
+
δ
student B
+
student A
e.g. eddy currents → iron loss resistance
Results
analytical measured numerical
k
14
4.00
3.58
R1
Ω
11.2
11.6
R2’
Ω
5.0
4.8
RFe
Ω
3.72
750
910
Lh
mH
35.7
32.2
33.3
Lσ1
mH
1.3
2.4
1.7
Lσ2’ mH
1.3
2.1
1.7
results achieved at April 23th, 2009
by Ward Snoeck, Pieter Snauwaert and Hanne Deprez.
Conclusions
for students
• process of simplification (reality → model)
• visualisation and interpretation of field plots
• (!) simulation and experiment next to each other
• comparison and discussion of results (differences!)
• analytical task boring, but necessary for checking
for teaching staff
• teaching load: increased in 2008 & 2009,
decreased since 2010
• introductory text should be of high quality
• persuade the students to compare and discuss the results
15
http://www.kuleuven-kortrijk.be/~u0005424/labtrf_english.pdf
16