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Transformer Simulation Issues – Clarification Required
Posted 24 févr. 2026, 01:33 UTC−5 5 Replies
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I am simulating a transformer with primary and secondary coils wound around the core limb. During the simulation, I encountered the following issues:
1. Issue with B-H Curve and Flux Density • I have assigned the B-H curve as the material property for the core. • After running a stationary study, the maximum flux density (Bmax) is showing approximately 400 T. • This value is physically unrealistic, since ferrite materials typically saturate around 0.3–0.5 T.
Question: Why is the simulation showing 400 T? Where could I be making a mistake in the setup?
2. Open Circuit and Short Circuit Giving Same Results
• When I excite one coil (either with voltage or current), • And apply open-circuit or short-circuit conditions to the other coil, • The simulation results remain the same in both cases. This behavior is unexpected because: • In open-circuit condition, only magnetizing current should flow. • In short-circuit condition, high current limited by leakage inductance should flow.
*Question: Why are both cases producing identical results? What mistake in the modeling or boundary conditions could be causing this issue? *
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First of all you must add another Ampere's law with the BH constitutive relation for the core domain. There may be more issues.
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
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Thanks @Edgar J. Kaiser for your valueable suggestion. Now can you address the second doubt.
- Open Circuit and Short Circuit Giving Same Results
- When I excite one coil (either with voltage or current), and apply open-circuit or short-circuit conditions to the other coil, The simulation results remain the same in both cases. This behavior is unexpected because:
- In open-circuit condition, only magnetizing current should flow.
- In short-circuit condition, high current limited by leakage inductance should flow.
*Question: Why are both cases producing identical results? *
**Below is the attached modified COMSOL file with the two pictures as with V=0 and I=0 in coil 2 **
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A transformer isn't working in stationary conditions. So it doesn't matter if the secondary coil is open or shorted, because nothing is happening there. You must apply a time dependent current e.g. a sine function to the primary coil and use a respective time dependent study to see any induction into the secondary coil. I think there are transformer examples in the application library and also contributions in the COMSOL blog. I recommend to check those. You should also make yourself familiar with the theory of transformers and inductive devices.
Cheers Edgar
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
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Hello,
In continuation of my transformer study, after going through the examples and the tutorial videos, I implemented a time-dependent study with a sinusoidal current excitation applied to the primary coil and the secondary coil short-circuited.
However, I am still encountering convergence issues, and I am unable to determine the exact cause of the problem.
Your guidance in identifying and resolving this issue would be highly beneficial to me.
Thank you for your time and support.
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Anushka,
Your transformer is very similar to the ecore transformer example in the application library. Try to follow this example in all detail and it should work.
Best regards Edgar
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
