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Anisotropic and B-H Curve

Posted 14 juin 2011, 08:30 UTC−4 Low-Frequency Electromagnetics 1 Reply

Przemek Kluska
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Hi,

I simulate simple choke in 2D Time domain. I faced a problem where I need to apply nonlinear magnetic material with different B-H Curves in different directions.
I don't see such option. Is it even possible?
I see there is possibility to apply anisotropic MUR Curves. But even if I compute my model for isotropic MUR Curve calculated from B-H Curve I don't obtain the same results. Moreover I can't see any linearity then (like harmonics in the current waveforms). I've tried different methods of MUR Curve's extrapolation and interpolation but result is always similar.
In Ampere's Law branch as 'Constitutive relation' I select 'Relative permeability' -> 'From material'. In the 'Material Contents' I see that relative permeability is described by 'MUR(normB[1/T])'.

I would be grateful for any hint,
Przemek
1 Reply Last Post 1 avr. 2015, 03:20 UTC−4
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Hello Przemek Kluska

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Jens Krause
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Posted: 9 years ago 1 avr. 2015, 03:20 UTC−4
Hi Przemek,

my solution is unorthodox (meaning not in the Comsol-way), maybe there is a better solution.

First you must be careful when setting up the HB-function. I have (Hx,Hx,Hz) as a function of (Bx,By,Bz) (vector maps to vector). This mapping must be the gradient of an energy-functional, otherwise energy conservation is not valid.

Then I tweak Comsol by entering the H's into the "equation view". This is not visible by default and you have to careful not to break things. On the top level of the "Ampere's law" feature I set it to use HB-function but what is entered there will be overwritten by what is done in the "equation view"

Regards
Jens
Hi Przemek, my solution is unorthodox (meaning not in the Comsol-way), maybe there is a better solution. First you must be careful when setting up the HB-function. I have (Hx,Hx,Hz) as a function of (Bx,By,Bz) (vector maps to vector). This mapping must be the gradient of an energy-functional, otherwise energy conservation is not valid. Then I tweak Comsol by entering the H's into the "equation view". This is not visible by default and you have to careful not to break things. On the top level of the "Ampere's law" feature I set it to use HB-function but what is entered there will be overwritten by what is done in the "equation view" Regards Jens

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