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Hysteresis and Eddy current calculation using COMSOL 5.0

Posted 30 sept. 2015, 06:11 UTC−4 Low-Frequency Electromagnetics Version 5.2 1 Reply

Dhrubajyoti Sarmah
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Hi,

I am simulating an electrical motor in 2D using COMSOL 5.0. I need to find out the iron losses. For finding hysteresis loss I am using We=Kh*f*Bmax^2. But I am unable to find the value and unit of Kh(Hysteresis co-efficient) for Soft Iron(with losses).
In some papers I have found the unit of Kh is [W*s*T^-
3*m^-3], but when I put this unit then the unit of loss is becoming [m. A/s].
I have the following queries
1. How to find the hysteresis coefficient for any material?
2. How to find eddy current loss in 2D ?
Any help will be highly appreciated.

With Regards
Dhruba
1 Reply Last Post 1 avr. 2017, 16:10 UTC−4
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Hello Dhrubajyoti Sarmah

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Lasse Kløvstad
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Posted: 8 years ago 1 avr. 2017, 16:10 UTC−4
Hi, I have been researching the same thing for ages... I have read that the Steinmetz equations assuming sinusoidal flux is not a good approximation. So the equation I have ended up using in my comsol model is for hysteresis and eddy current losses respectively:

P_hyst [W]=(abs(rmm.Hx*d(rmm.Bx,TIME))+abs(rmm.Hy*d(rmm.By,TIME))+abs(rmm.Hz*d(rmm.Bz,TIME)))*L

P_eddy [W]=5e7 [S/m]*(0.35e-3 [m])^2 /12*(d(rmm.Bx,TIME)^2+d(rmm.By,TIME)^2) *L

and of course after a standard time simulation you just integrate over the areas you want to find the losses in the core :D

Where 5e7 [S/m] is the conductivity of the steel lamination and (0.35e-3 [m]) is the thickness.I think this will give me good information in comparing different machine designs. But I am unsure if it will give me a good estimation of the actual losses in a real machine...

The hysteresis formula was found in this video: www.comsol.com/video/modeling-rotating-electrical-machines-in-comsol-multiphysics

The Eddy current formula was found in this article and many more: Iron losses in electrical machines: Influence of different material models
O Bottauscio, A Canova, M Chiampi, M Repetto - IEEE transactions on magnetics, 2002

Hope this will contribute a little :D
Hi, I have been researching the same thing for ages... I have read that the Steinmetz equations assuming sinusoidal flux is not a good approximation. So the equation I have ended up using in my comsol model is for hysteresis and eddy current losses respectively: P_hyst [W]=(abs(rmm.Hx*d(rmm.Bx,TIME))+abs(rmm.Hy*d(rmm.By,TIME))+abs(rmm.Hz*d(rmm.Bz,TIME)))*L P_eddy [W]=5e7 [S/m]*(0.35e-3 [m])^2 /12*(d(rmm.Bx,TIME)^2+d(rmm.By,TIME)^2) *L and of course after a standard time simulation you just integrate over the areas you want to find the losses in the core :D Where 5e7 [S/m] is the conductivity of the steel lamination and (0.35e-3 [m]) is the thickness.I think this will give me good information in comparing different machine designs. But I am unsure if it will give me a good estimation of the actual losses in a real machine... The hysteresis formula was found in this video: https://www.comsol.com/video/modeling-rotating-electrical-machines-in-comsol-multiphysics The Eddy current formula was found in this article and many more: Iron losses in electrical machines: Influence of different material models O Bottauscio, A Canova, M Chiampi, M Repetto - IEEE transactions on magnetics, 2002 Hope this will contribute a little :D

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