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AC/DC Module Multiturn 1/4 , 1/2 symmetric geometery

Posted 1 lug 2013, 07:20 GMT-4 Low-Frequency Electromagnetics, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.3b 5 Replies

Khalid Hameed
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I build a 3D model of my inductor in AC/DC module using multiturn coil domain but it took too much computational time that even 16GB of RAM was not sufficient. So Edgar suggested to use 1/2 or 1/4 symmetery geomertry to reduce the computational time, but now I can't add Frequency domain study while using Numeric multiturn or 1/2 symmetery geometry. Am I going something wrong on the way or else
Btw I am calculating inductance of the coil at 100 kHz
Regards
Khalid Hameed
5 Replies Last Post 3 lug 2013, 08:13 GMT-4
Sergei Yushanov Certified Consultant
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Posted: 1 decade ago 1 lug 2013, 11:40 GMT-4
Khalid,

Attached is model of multi-turn coil with two symmetry planes.

Regards,
Sergei
Khalid, Attached is model of multi-turn coil with two symmetry planes. Regards, Sergei
Khalid Hameed
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Posted: 1 decade ago 1 lug 2013, 17:56 GMT-4
Hello Sergei

Thanks for your model file. I have gone through the model you provided but I dont understand the meaning of perfect magnetic conductor here in this context. In addition I tried to add perfect magnetic conductor in my model but it gives me an error "failed to find a solution, system matrix in zero".
I have also added output, as I have read doc that states that adding magnetic conductor will not violate current conservation which in my case is output? am i right or I am not specifying right boundary condition?

I have attached my model, its a copper coil excited with 30 A with surrounded air

Hello Sergei Thanks for your model file. I have gone through the model you provided but I dont understand the meaning of perfect magnetic conductor here in this context. In addition I tried to add perfect magnetic conductor in my model but it gives me an error "failed to find a solution, system matrix in zero". I have also added output, as I have read doc that states that adding magnetic conductor will not violate current conservation which in my case is output? am i right or I am not specifying right boundary condition? I have attached my model, its a copper coil excited with 30 A with surrounded air
Sergei Yushanov Certified Consultant
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Posted: 1 decade ago 2 lug 2013, 07:57 GMT-4
Khalid,

Perfect Magnetic Conductor (PMC) boundary condition

nxH=0

states that tangential component of magnetic field is zero at the boundary, meaning that magnetic field is normal to that boundary. In your case, this would be appropriate choice to account for symmetry plane at z=0.

I made couple changes in your setup and put my comments. Attached is your working model.

Regards,
Sergei
Khalid, Perfect Magnetic Conductor (PMC) boundary condition nxH=0 states that tangential component of magnetic field is zero at the boundary, meaning that magnetic field is normal to that boundary. In your case, this would be appropriate choice to account for symmetry plane at z=0. I made couple changes in your setup and put my comments. Attached is your working model. Regards, Sergei
Khalid Hameed
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Posted: 1 decade ago 2 lug 2013, 11:48 GMT-4
Thanks Sergei for your model, actually I have built my 2D axis symmetric, 2D and complete 3D models. But in this simple model as you suggested that the symmetry plane would be at z=0 but I wud also be adding a metal beneath this coil and after adding that in the model I get wierd results, there is no magnetization of the metal and it seems like solver is not taking the metal into consideration. I wonder why this symmetery calculations becomes so complex.
Any thoughts would be really helpful

Regards
Khalid
Thanks Sergei for your model, actually I have built my 2D axis symmetric, 2D and complete 3D models. But in this simple model as you suggested that the symmetry plane would be at z=0 but I wud also be adding a metal beneath this coil and after adding that in the model I get wierd results, there is no magnetization of the metal and it seems like solver is not taking the metal into consideration. I wonder why this symmetery calculations becomes so complex. Any thoughts would be really helpful Regards Khalid
Sergei Yushanov Certified Consultant
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Posted: 1 decade ago 3 lug 2013, 08:13 GMT-4
Khalid,

Seems that you mesh of the metal beneath the coil is not adequate. Generally, meshing strategy of the metal depends on the excitation frequency. Calculate skin depth and compare it to the dimensions of you metal object. You may need to resolve skin depth using Boundary Layer Mesh (BLM) or exclude metal part from computational domain and model only the fields and induced current on the surface of the metal using Impedance Boundary Condition.
Hard to give specific answer based on such general description of your issue.

Regards,

Sergei
Khalid, Seems that you mesh of the metal beneath the coil is not adequate. Generally, meshing strategy of the metal depends on the excitation frequency. Calculate skin depth and compare it to the dimensions of you metal object. You may need to resolve skin depth using Boundary Layer Mesh (BLM) or exclude metal part from computational domain and model only the fields and induced current on the surface of the metal using Impedance Boundary Condition. Hard to give specific answer based on such general description of your issue. Regards, Sergei

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