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Simulation of leakage flux from transformer

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Hello.

I've tried to simulate a quantity of leakage flux from transformer by using COMSOL 4.3a. To do this, I made a simple transformer model with LiveLink for AutoCAD.(I want to attach mph file, but its size is too big to attach)
And I chose "mef" module for simulation. But an error message comes out. Here is the message.

The following feature has encountered a problem:

Failed to find a solution.
Divergence of the linear iterations.
Returned solution is not converged.
- Feature: Stationary Solver 1 (sol1/s1)
- Error: Failed to find a solution.

I'm a beginner of COMSOL, so I can't find any solutions to fix this error. Is there any way to fix this error?

Regards,

Mizuki

5 Replies Last Post 18 mars 2013, 15:52 UTC−4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 13 mars 2013, 07:05 UTC−4
Hi

the error messages are difficult also for trained users ;) if that is of any help ...

First of all MEF is a heavy solver looking after both A (magnetic) and V the voltage, do you really need the V in your case ? Else MF is lighter, often its worth to start simple i.e. in MF solving only for A then when it works OK add replace by MEF to add V effects hence you know if the issue is from A or V, now you cannot.

A common ewrror in MEF is to forget to give a conductivity for all domains (even the air) , or define a node for domain(s) using only MF as a sub node to MEF (then you do not need any conductivity


--
Good luck
Ivar
Hi the error messages are difficult also for trained users ;) if that is of any help ... First of all MEF is a heavy solver looking after both A (magnetic) and V the voltage, do you really need the V in your case ? Else MF is lighter, often its worth to start simple i.e. in MF solving only for A then when it works OK add replace by MEF to add V effects hence you know if the issue is from A or V, now you cannot. A common ewrror in MEF is to forget to give a conductivity for all domains (even the air) , or define a node for domain(s) using only MF as a sub node to MEF (then you do not need any conductivity -- Good luck Ivar

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Posted: 1 decade ago 13 mars 2013, 23:47 UTC−4
hello,

Thank you for advices. And I attach a zip file which is mphbin file. By the way, I'm trying to simulate with MF module, but I can't define current in winding. When I want to simulate flux leakage, isn't current definition needed?

Regards,

Mizuki
hello, Thank you for advices. And I attach a zip file which is mphbin file. By the way, I'm trying to simulate with MF module, but I can't define current in winding. When I want to simulate flux leakage, isn't current definition needed? Regards, Mizuki


Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 14 mars 2013, 02:34 UTC−4
Hi

first of all you do not really need to zip a mph file its already zip type. ;)
It's better to EDIT clear all solution - clear all mesh - File reset history - File Save as new_name, then upload

You have added only the geometry there, in MF add a "single turn coil domain" (as you have modelled the turns there), then to single turn coil add a boundary sub node (for example onto 5 and a gnd sub node to 32

use a "fine" mesh in automatic mode, or select a finer one only for the coil domain

You need to add Ampere Law node specifically for the soft iron if you have a BH curve to use

Check the model library Single_coil_boundary_feed.mph or ask support for it if its not in the model gallery

The main issue you will have is the mesh density, you need a few elements between the coil windings to resolve the air part correctly, one way to improve the mesh locally is to surround the coil by a tube a few mm outside of the coil and mesh fine this region

--
Good luck
Ivar
Hi first of all you do not really need to zip a mph file its already zip type. ;) It's better to EDIT clear all solution - clear all mesh - File reset history - File Save as new_name, then upload You have added only the geometry there, in MF add a "single turn coil domain" (as you have modelled the turns there), then to single turn coil add a boundary sub node (for example onto 5 and a gnd sub node to 32 use a "fine" mesh in automatic mode, or select a finer one only for the coil domain You need to add Ampere Law node specifically for the soft iron if you have a BH curve to use Check the model library Single_coil_boundary_feed.mph or ask support for it if its not in the model gallery The main issue you will have is the mesh density, you need a few elements between the coil windings to resolve the air part correctly, one way to improve the mesh locally is to surround the coil by a tube a few mm outside of the coil and mesh fine this region -- Good luck Ivar

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Posted: 1 decade ago 14 mars 2013, 05:29 UTC−4
hello,

thank you for advices. To make simulation easy, I made three turns coil model covered with a tube(Please check attached file).
I chose MF module and used single turn coil domain. In single turn coil domain, I chose Boundary Feed for 26, and Ground for 19. But the same error message came out. Is a cause of this error mesh too?

Element size(Free tetrahedral):
windings:fine
tube:fine
air:fine

Regards,

Mizuki
hello, thank you for advices. To make simulation easy, I made three turns coil model covered with a tube(Please check attached file). I chose MF module and used single turn coil domain. In single turn coil domain, I chose Boundary Feed for 26, and Ground for 19. But the same error message came out. Is a cause of this error mesh too? Element size(Free tetrahedral): windings:fine tube:fine air:fine Regards, Mizuki


Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 18 mars 2013, 15:52 UTC−4
Hi

Sorry I should have expressed myself better (but I tried myself without getting to a good result) its the cylindrical part I was thinking of embedding inside a tube shape, or even two cylinders. because you have a small gap between the windings, and you need a few elements in between, your domain to mesh is complex for the meshing algorithm (looping topology is tricky and you have large differences in section/gaps. Your issue is to get a good mesh all around the coil. then get it coarser towards the external air domain, else you would run out of RAM before finishing ;)

You could also consider a cylinder section and the "multi-turn coil domain" rather than the detailed coiled wire

--
Good luck
Ivar
Hi Sorry I should have expressed myself better (but I tried myself without getting to a good result) its the cylindrical part I was thinking of embedding inside a tube shape, or even two cylinders. because you have a small gap between the windings, and you need a few elements in between, your domain to mesh is complex for the meshing algorithm (looping topology is tricky and you have large differences in section/gaps. Your issue is to get a good mesh all around the coil. then get it coarser towards the external air domain, else you would run out of RAM before finishing ;) You could also consider a cylinder section and the "multi-turn coil domain" rather than the detailed coiled wire -- Good luck Ivar

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