Katholieke Universiteit LeuvenEtienne Sabbelaan 53, B-8500 Kortrijk, Belgium - URL: www.kuleuven-kortrijk.be

Supporting Undergraduate Courseson 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.

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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)

Problem Statement

? how to teach the electromagnetic-field concept ?

simulation tasks• visualisation possibilities• cooking-book booby trap• perception remains „virtual“, „artificial“

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• simple and relevant example→ single-phase transformer

Integrated Laboratory Session

• 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• topic : electrical engineering is no part of the course• simulation : 3D, nonlinear iron, eddy currents, forces,

noise• experiments : lab precautions

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• 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)

Preparation

http://www.kuleuven-kortrijk.be/~u0005424/labtrf_english.pdf

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Approach

δ

no-load

short-circuit

+

+ +

+

+

grad

ually

bui

lt up

coil without core

coil with core

coil with core and air gap

transformer, no-load test

transformer, short-circuit test

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Approach

experimental numericalanalytical

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

3 tasks in parallel (student team)→ all result tables have 3 columns

analytical measured numerical

k

R1 Ω

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Approach

experimental numericalanalytical

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

compare and discuss results→ get insight in modelling assumptions← requires attention of teaching staff

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Approach

experimental numericalanalytical

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

detect (and cure) calculation and measurement errors yourself !

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Tasks

experimental numerical

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

analytical

2

Fe0

B

wr

Cu wrR

S

2magn

magn

N SL

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analytical

Tasks

numerical

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

experimental

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experimentalanalytical

Tasks

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

numerical

define geometry & mesh

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experimentalanalytical

Tasks

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

numericalsimulate magnetic field

CST EM STUDIO (www.cst.com)

are flux lines as expected ?link field plots to operation modes !

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experimentalanalytical

Tasks

δ

no-load

short-circuit

+

+ +

+

+

stud

ent A

stud

ent C

stud

ent B

numericalbeyond analytical formulaee.g. eddy currents → iron loss resistance

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Results

results achieved at April 23th, 2009by Ward Snoeck, Pieter Snauwaert and Hanne Deprez.

analytical measured numericalk 4.00 3.58 3.72

R1 Ω 11.2 11.6

R2’ Ω 5.0 4.8

RFe Ω 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

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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

Conclusions

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

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http://www.kuleuven-kortrijk.be/~u0005424/labtrf_english.pdf