Daniel Egede Rasmussen TE-MPE-PE 1
PSpice modelling of the RQTF circuits
Thanks toArjan Verweij & Emmanuele Ravaioli
19/07/2012
TE-MPE Technical Meeting 19-07-2012
Daniel Egede Rasmussen TE-MPE-PE 2
The RQTF circuit
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πΌπ·πΆπΆπ β πΌππππππ‘ πππππππ‘β πΏπ πΌπ·πΆπΆπππ‘
LHC600A-10VMQT
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Electrical model in PSpice
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Power converter Thyristor
Magnet
R//
Switch
REE
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Thermal analogy in PSpice
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By E. Ravaioli
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Verification
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I ADCCT
I A simulatedDCCT
Event of 15th of April 2008 β 20h01
Curr
ent [
A]
Time [sec]
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Magnet current
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Curr
ent [
A]
Time [sec]
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Energy dissipation
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Circuit component
Event 080415-200144 400A 1 MQT QuenchingEnergy[kJ] Energy[%] Energy[%] Energy[%]
Total 35.5 100 100 100R// 2.8 8 8.6 32.1
Magnets 25.7 72.3 69.4 12.4REE 6.3 17.6 19.8 50.5
Rcrowbar 0.6 1.6 1.8 3.9
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Temperature
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48.1K
Time [sec]
Tem
pera
ture
[K]
400A 1 MQT quenchin
g
38.6K 52.3K
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Failure modes
1. 1 of the 8 parallel resistances turns into an open circuit.2. The switch parallel to the energy extraction resistor fails to
open.3. A combination of the two above
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R// open circuit
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Curr
ent [
A]
Time [sec]
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R// open circuit
Circuit component Energy [kJ] Temperature [K]
Magnet with open R// 1.2 34.1
Max of other magnets in circuit 3.6 49.5
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Tem
pera
ture
[K]
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R// open circuit
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ππππ=πΏ
1π β β
1π πππ
πππππ=πΏπ πππ
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R// open circuit
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Energy extraction failure
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Daniel Egede Rasmussen TE-MPE-PE 15
Energy extraction failure
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Circuit part
Normal operation
Switch failure8 magnets
Switch failure1 magnet
Energy[%]
Temp[K]
Energy[%]
Temp[K]
Energy[%]
Temp[K]
R// 8 - 1.7 - 52.3 -Magnets 72.3 48.1 96.6 51.9 26.4 68.8
REE 17.6 - 0 - 0 -Rcrowbar 1.6 - 2.7 - 17.9 -
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Combination failure
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Quench
57.6% of the energy 95K @ 535A
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Conclusions
β’ PSpice is a powerful tool for analysing circuit behaviour and failure cases.
β’ Preliminary studies of possible improvements.β’ Care must be taken when fitting.β’ Models should be verified with data from several
events at different currents.β’ A library of models is needed for post mortem
analysis.
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Daniel Egede Rasmussen TE-MPE-PE 1819/07/2012
Thank you for your attention
