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To find mutual inductance and coupling coefficient

Posted Jan 3, 2014, 6:42 a.m. EST Low-Frequency Electromagnetics Version 4.3b 4 Replies

kishore naik
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Dear all
I modelled a 3D spiral coil with two turns, of two different coil separated by distance. I applied the current density for the coils. I want to evaluate self inductance and mutual inductance between the coils then coupling coefficient. I evaluated self inductance by L= 2*Wm/I^2, where Wm is energy stored and I is current. Now i have to find the mutual inductance between the coils (as i done this using multiturn coil domain in 2D, but i dont have any idea how to use by in case of current density applied to coil as in global evaluation there is no inductance parameter ). I am attaching link here, as i can not attach model due to size

drive.google.com/file/d/0B7S7tMagjLw1OHk5SlNoTVQ5Qzg/edit?usp=sharing
--
kishore Naik Mude
4 Replies Last Post Dec 3, 2015, 6:44 p.m. EST
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Hello kishore naik

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Mathieu Gendron
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Posted: 9 years ago Dec 3, 2015, 11:42 a.m. EST
Hello Kishore,

Have you find a solution to your problem? I'm trying to get similar results in COMSOL 4.4.

I want to compute the coupling coefficient between a single turn coil with a round cross section and a flat plate at frequencies between 50 kHz and 150 kHz. The plate and the coil have linear permeability. I built a 2D axisymmetric mf model where I used single turn coil domains for the coil and the plate. I imposed a 1A current in the coil and 0V in the plate.

I computed the mutual inducance using M = Vplate/(Icoil*omega*j) and the self inductances using the magnetic energy in the coil domain (L1) and in the plate domain (L2). I computed the induced voltage (Vplate) doing the volume integral of the vector potential (j*omega*int(mf.Aphi)/Area). I must do something wrong because the coupling coefficient I get is too small (k = 0.0001).

Any hints would be appreciate.

Mathieu Gendron
Hello Kishore, Have you find a solution to your problem? I'm trying to get similar results in COMSOL 4.4. I want to compute the coupling coefficient between a single turn coil with a round cross section and a flat plate at frequencies between 50 kHz and 150 kHz. The plate and the coil have linear permeability. I built a 2D axisymmetric mf model where I used single turn coil domains for the coil and the plate. I imposed a 1A current in the coil and 0V in the plate. I computed the mutual inducance using M = Vplate/(Icoil*omega*j) and the self inductances using the magnetic energy in the coil domain (L1) and in the plate domain (L2). I computed the induced voltage (Vplate) doing the volume integral of the vector potential (j*omega*int(mf.Aphi)/Area). I must do something wrong because the coupling coefficient I get is too small (k = 0.0001). Any hints would be appreciate. Mathieu Gendron
kishore naik
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Posted: 9 years ago Dec 3, 2015, 11:50 a.m. EST

HI Mathieu,
I found this, by just diving K= M/L (In My case LT and LR is same). What is distance between your coils. Just check current density, coil parameters you applied is correct or not.
--
kishore Naik Mude
HI Mathieu, I found this, by just diving K= M/L (In My case LT and LR is same). What is distance between your coils. Just check current density, coil parameters you applied is correct or not. -- kishore Naik Mude
Mathieu Gendron
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Posted: 9 years ago Dec 3, 2015, 12:17 p.m. EST
Hi Kishore,

Thank you for your quick answer. The distance between the coil and the plate vary between 1 and 10 mm, I expect k to be between 0.7 and 0.2. In my case, I don't think I can use k=M/L because the plate and the coil don't have the same self inductance.

Best regard,

Mathieu
Hi Kishore, Thank you for your quick answer. The distance between the coil and the plate vary between 1 and 10 mm, I expect k to be between 0.7 and 0.2. In my case, I don't think I can use k=M/L because the plate and the coil don't have the same self inductance. Best regard, Mathieu
Girish Kamath
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Posted: 9 years ago Dec 3, 2015, 6:44 p.m. EST
Hi Mathieu,
Perhaps the reason for the low inductance value is because the plate is in short circuit mode due to the application of V = 0V across it. The inductance value would then be the short circuit inductance as seen from the coil side. You can also cross check the value obtained with the energy method. Here,
0.5*L*I^2 = W (energy calculated over the entire volume)

Thanks,

Girish
.



Hello Kishore,

Have you find a solution to your problem? I'm trying to get similar results in COMSOL 4.4.

I want to compute the coupling coefficient between a single turn coil with a round cross section and a flat plate at frequencies between 50 kHz and 150 kHz. The plate and the coil have linear permeability. I built a 2D axisymmetric mf model where I used single turn coil domains for the coil and the plate. I imposed a 1A current in the coil and 0V in the plate.

I computed the mutual inducance using M = Vplate/(Icoil*omega*j) and the self inductances using the magnetic energy in the coil domain (L1) and in the plate domain (L2). I computed the induced voltage (Vplate) doing the volume integral of the vector potential (j*omega*int(mf.Aphi)/Area). I must do something wrong because the coupling coefficient I get is too small (k = 0.0001).

Any hints would be appreciate.

Mathieu Gendron


Hi Mathieu, Perhaps the reason for the low inductance value is because the plate is in short circuit mode due to the application of V = 0V across it. The inductance value would then be the short circuit inductance as seen from the coil side. You can also cross check the value obtained with the energy method. Here, 0.5*L*I^2 = W (energy calculated over the entire volume) Thanks, Girish . [QUOTE] Hello Kishore, Have you find a solution to your problem? I'm trying to get similar results in COMSOL 4.4. I want to compute the coupling coefficient between a single turn coil with a round cross section and a flat plate at frequencies between 50 kHz and 150 kHz. The plate and the coil have linear permeability. I built a 2D axisymmetric mf model where I used single turn coil domains for the coil and the plate. I imposed a 1A current in the coil and 0V in the plate. I computed the mutual inducance using M = Vplate/(Icoil*omega*j) and the self inductances using the magnetic energy in the coil domain (L1) and in the plate domain (L2). I computed the induced voltage (Vplate) doing the volume integral of the vector potential (j*omega*int(mf.Aphi)/Area). I must do something wrong because the coupling coefficient I get is too small (k = 0.0001). Any hints would be appreciate. Mathieu Gendron [/QUOTE]

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