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Half-symmetry air coil frequency domain simulation

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I created a simple coil model for frequency domain simulation. It uses half-symmetry for the domains and homogenized multi-turn circular for the coil.

The stationary simulation completed without any problem. However, error saying "Matrix has zero on diagonal" occured for frequency domain simulation.

Please let me know where is the problem. Thank you!



3 Replies Last Post 5 nov. 2020, 23:12 UTC−5
Robert Koslover Certified Consultant

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Posted: 4 years ago 4 nov. 2020, 21:52 UTC−5

Hmm. It executed without generating any error message, on my computer. Perhaps a Comsol Multiphysics employee can help you. Or maybe, just restart Comsol Multiphsics, open the file you uploaded to the forum, and try again. Maybe it will work this time. :)

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Hmm. It executed *without* generating any error message, on my computer. Perhaps a Comsol Multiphysics employee can help you. Or maybe, just restart Comsol Multiphsics, open the file you uploaded to the forum, and try again. Maybe it will work this time. :)

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Posted: 4 years ago 4 nov. 2020, 22:35 UTC−5
Updated: 4 years ago 5 nov. 2020, 06:22 UTC−5

Thank you Robert. I followed your suggestion to run the uploaded file. It worked without such error.

However, the operator linper() is not used in the model. The simulation result (field) is zero.

I added the operator to the coil current as linper(1[A]). Simulation did not converge. I then remebered the model may need "Gauge Fixing for A-field". I did that and had it converged to a solution looking sensible.

Based on the knowledge gained with this model, I created a 1/4-3D motor (coil, magnet and soft iron). The geometry is basically a revolved version of the loudspeaker transducer application example. Spring foundation is used in solid to contraint the coil. It will not fly away in the presence of Lorentz force.

The stationary study again completed without problem. I have tried many different options but still can't get the frequency domain simulation going without errors. The errors seem to happen at the third step (freq domain perturbation) of the study. Any idea?

Thank you Robert. I followed your suggestion to run the uploaded file. It worked without such error. However, the operator linper() is not used in the model. The simulation result (field) is zero. I added the operator to the coil current as linper(1[A]). Simulation did not converge. I then remebered the model may need "Gauge Fixing for A-field". I did that and had it converged to a solution looking sensible. Based on the knowledge gained with this model, I created a 1/4-3D motor (coil, magnet and soft iron). The geometry is basically a revolved version of the loudspeaker transducer application example. Spring foundation is used in solid to contraint the coil. It will not fly away in the presence of Lorentz force. The stationary study again completed without problem. I have tried many different options but still can't get the frequency domain simulation going without errors. The errors seem to happen at the third step (freq domain perturbation) of the study. Any idea?


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Posted: 4 years ago 5 nov. 2020, 23:12 UTC−5
Updated: 4 years ago 6 nov. 2020, 05:23 UTC−5

Just discovered the problem was related to using soft iron with losses and freq. set too low at 10 Hz.

Just discovered the problem was related to using soft iron with losses and freq. set too low at 10 Hz.

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