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How to define the current flow direction in Magnetic field current only interface for extraction of Inductance?

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Can any one explain how to define current flow direction for extraction of Inductance using MFCO interface in comsol.


3 Replies Last Post Aug 26, 2022, 9:32 a.m. EDT
Philipp Buchsteiner COMSOL Employee

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Posted: 2 years ago Aug 26, 2022, 4:45 a.m. EDT
Updated: 2 years ago Aug 26, 2022, 5:22 a.m. EDT

Hi Phanindra,

the direction of current flow is normal to the selected Terminal boundary. You can reverse the direction of current flow by clicking the respective button, see screenshot.

The depicted model is the "CircuitExtractor_blog_case3_RLC_FrequencyPCBCoils_reset.mph" from the following blog post: https://www.comsol.de/blogs/extracting-electrical-circuits-from-electromagnetics-simulations/

Kind regards, Philipp

Hi Phanindra, the direction of current flow is normal to the selected Terminal boundary. You can reverse the direction of current flow by clicking the respective button, see screenshot. The depicted model is the "CircuitExtractor_blog_case3_RLC_FrequencyPCBCoils_reset.mph" from the following blog post: Kind regards, Philipp


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Posted: 2 years ago Aug 26, 2022, 8:32 a.m. EDT

Dear Philipp,

Thank you for your kind answer.

1) What is the significance of Ground sub-node in the Conductor node ? Where should I give Ground sub-node. In the tutorial link https://www.comsol.de/model/inductance-matrix-calculation-of-pcb-coils-89921 for 8 conductors both Ground and Terminal sub-nodes are defined and for 4 conductors only Terminal sub-node is defined .

2) How should we decide where should be Terminal and Ground node to be defined ?

Please share your thoughts.

Kind regards, Phanindra.

Dear Philipp, Thank you for your kind answer. 1) What is the significance of **Ground sub-node** in the **Conductor node** ? Where should I give Ground sub-node. In the tutorial link https://www.comsol.de/model/inductance-matrix-calculation-of-pcb-coils-89921 for **8 conductors** both **Ground and Terminal** sub-nodes are defined and for **4 conductors** only **Terminal sub-node** is defined . 2) How should we decide where should be Terminal and Ground node to be defined ? Please share your thoughts. Kind regards, Phanindra.

Please login with a confirmed email address before reporting spam

Posted: 2 years ago Aug 26, 2022, 9:32 a.m. EDT

Dear Philipp,

Thank you for your kind answer.

1) What is the significance of Ground sub-node in the Conductor node ? Where should I give Ground sub-node. In the tutorial link https://www.comsol.de/model/inductance-matrix-calculation-of-pcb-coils-89921 for 8 conductors both Ground and Terminal sub-nodes are defined and for 4 conductors only Terminal sub-node is defined .

2) How should we decide where should be Terminal and Ground node to be defined ?

Please share your thoughts.

Kind regards, Phanindra.

I am asking this because in my case I had 3 loops which I need to define the current flow in each power loop. I need to extract the INDUCTANCE due to these 3 loops in the module. I defined 3 conductor nodes and a Terminal sub-node for each conductor node. The solution I got does not has any meaning as per my knowledge. Even the Magnetic flux density Norm distribution is not correct. The Flux density distribution is only shown on one conductor side. Current flows in each conductor from Terminal face of each conductor in the direction shown by arrows.

Can anyone explain the solution for this case?

>Dear Philipp, > >Thank you for your kind answer. > >1) What is the significance of **Ground sub-node** in the **Conductor node** ? Where should I give Ground sub-node. In the tutorial link https://www.comsol.de/model/inductance-matrix-calculation-of-pcb-coils-89921 for **8 conductors** both **Ground and Terminal** sub-nodes are defined and for **4 conductors** only **Terminal sub-node** is defined . > >2) How should we decide where should be Terminal and Ground node to be defined ? > >Please share your thoughts. > >Kind regards, >Phanindra. > I am asking this because in my case I had 3 loops which I need to define the current flow in each power loop. I need to extract the INDUCTANCE due to these 3 loops in the module. I defined 3 conductor nodes and a Terminal sub-node for each conductor node. The solution I got does not has any meaning as per my knowledge. Even the Magnetic flux density Norm distribution is not correct. The Flux density distribution is only shown on one conductor side. Current flows in each conductor from Terminal face of each conductor in the direction shown by arrows. Can anyone explain the solution for this case?

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