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Moving Magnet and Changing Field Lines due to Hall Effect Sensor

Posted 22 janv. 2022, 02:03 UTC−5 Low-Frequency Electromagnetics, Mesh, Results & Visualization Version 5.6 3 Replies

Valeriya K
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Hi! I am new to COMSOL, and my task is to simulate changing magnetic field lines with respect to the distance between the magnet and Hall Effect sensor. Hall Effect sensor, in my case, is a semiconductor plate with an electric potential inside. I have finally found a way to move the magnet closer to the sensor (using the moving mesh). However, the magnetic lines seem to ignore the changed position of the magnet and stay on their initial place. Also, how can I make gradual change of magnet's position (and its field lines) with respect to time? So that that process can be shown in animation. For example, at second 1, the magnet is X mm away from the sensor and the field lines look like this; then at second 2, the magnet is closer to the sensor and the lines are like that; etc.

Sorry for the messy explanation, I hope that the screenshots make it clearer. Thank you!

3 Replies Last Post 23 janv. 2022, 10:57 UTC−5
Edgar J. Kaiser Certified Consultant
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Posted: 3 years ago 22 janv. 2022, 11:01 UTC−5
Updated: 3 years ago 22 janv. 2022, 11:03 UTC−5

Hi Valeriya,

this may be a frames issue. Check if you display the material frame or the spatial frame. For anything moving in the model you need to display in the spatial frame.

For a time dependent movement you add a time dependent mesh movement.

Out of curiosity, what impact of the hall sensor on the magnetic field are you expecting? Does the material have magnetic permeability different from 1? Or are you interested in induced current by the movement? In the latter case, if you have induced current in the model, you need to use a vector potential approach and you must properly set up the mixed formulation boundary.

In case time dependent effects (induction) are not important, you may also try a parameterized geometry and you don't need the moving mesh then.

Cheers Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hi Valeriya, this may be a frames issue. Check if you display the material frame or the spatial frame. For anything moving in the model you need to display in the spatial frame. For a time dependent movement you add a time dependent mesh movement. Out of curiosity, what impact of the hall sensor on the magnetic field are you expecting? Does the material have magnetic permeability different from 1? Or are you interested in induced current by the movement? In the latter case, if you have induced current in the model, you need to use a vector potential approach and you must properly set up the mixed formulation boundary. In case time dependent effects (induction) are not important, you may also try a parameterized geometry and you don't need the moving mesh then. Cheers Edgar
Valeriya K
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Posted: 3 years ago 23 janv. 2022, 09:35 UTC−5

Thank you! My goal is to know the distance between the magnet and the sensor by looking at the electric potential in this sensor. So, I basically need to simulate the moving magnetic field and see how the potential differs inside the Hall sensor. From there, I can find some relationship between the distance from magnet to sensor and potential within it.

I am actually not sure if I need to use time dependence. But I am still confused how to show that relationship on animation (a magnet moving towards the sensor and the changing/increasing potential)... :(

Thank you! My goal is to know the distance between the magnet and the sensor by looking at the electric potential in this sensor. So, I basically need to simulate the moving magnetic field and see how the potential differs inside the Hall sensor. From there, I can find some relationship between the distance from magnet to sensor and potential within it. I am actually not sure if I need to use time dependence. But I am still confused how to show that relationship on animation (a magnet moving towards the sensor and the changing/increasing potential)... :(
Edgar J. Kaiser Certified Consultant
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Posted: 3 years ago 23 janv. 2022, 10:57 UTC−5

You can generate animations from a time dependent study and also from a parametric study, such as a geometry parameterization. Animations are nice for qualitative visualization. You can also generate diagrams as a function of time or a geometry parameter. Those are more quantitative.

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
You can generate animations from a time dependent study and also from a parametric study, such as a geometry parameterization. Animations are nice for qualitative visualization. You can also generate diagrams as a function of time or a geometry parameter. Those are more quantitative.

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