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Switched reluctance motor - rotor and stator deformation - How?
Posted Oct 28, 2012, 5:43 p.m. EDT 5 Replies
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Hi.
I am building a 2D model in which I would like to showcase how the stator and especially the rotor of a switched reluctance motor deforms because of the radial and tangential magnetic force on the rotor, caused by the present magnetic field - dependant of the rotor position.
I have already made the geometry and chosen the materials but don't know exactly where to go next - what to choose from the model library and how to implement it.
Electromechanics? Rotating Machinery? The first step would probably be to calculate the magnetic flux ( Magnetic fields model) which I'm working on, but don't have an exact idea how to do further calculations.
Thank you so much for any hints and insight in your workflow, ideas, tutorials .... in advance.
regards, Jan
I am building a 2D model in which I would like to showcase how the stator and especially the rotor of a switched reluctance motor deforms because of the radial and tangential magnetic force on the rotor, caused by the present magnetic field - dependant of the rotor position.
I have already made the geometry and chosen the materials but don't know exactly where to go next - what to choose from the model library and how to implement it.
Electromechanics? Rotating Machinery? The first step would probably be to calculate the magnetic flux ( Magnetic fields model) which I'm working on, but don't have an exact idea how to do further calculations.
Thank you so much for any hints and insight in your workflow, ideas, tutorials .... in advance.
regards, Jan
5 Replies Last Post Nov 23, 2012, 2:34 a.m. EST
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Posted:
1 decade ago
Hi
I would say start simple ;)
get your 2D CAD model (external or with COMSOL),
make the geometry after the laws of "rotary machinery" i.e. having 2 unions of stator and rotor parts separate in geometry assembly mode with a circle centred on the rotor cutting the air-gap in the middle. But start with the simpler MF physics. Then get your field and forces calculations running for the static position(s).
And then finally rebuild your model in Rotary machinery, to get the rotations running
It's worth to exercise the model library examples to a few times ;)
--
Good luck
Ivar
I would say start simple ;)
get your 2D CAD model (external or with COMSOL),
make the geometry after the laws of "rotary machinery" i.e. having 2 unions of stator and rotor parts separate in geometry assembly mode with a circle centred on the rotor cutting the air-gap in the middle. But start with the simpler MF physics. Then get your field and forces calculations running for the static position(s).
And then finally rebuild your model in Rotary machinery, to get the rotations running
It's worth to exercise the model library examples to a few times ;)
--
Good luck
Ivar
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Posted:
1 decade ago
I have done some of that - I have the 2D geometry done in Comsol, rotor, which I can "rotate" by changing the rotation and also the magnetostatic physics with which I calculated the magnetic field.
But here I get stuck - how to do this part
"Then get your field and forces calculations running for the static position(s). "
?
Any hint/suggestion is more than welcome.
regards, Jan
But here I get stuck - how to do this part
"Then get your field and forces calculations running for the static position(s). "
?
Any hint/suggestion is more than welcome.
regards, Jan
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Posted:
1 decade ago
Hi
to define the forces, you need to add a force domain node on hte domains which are moved or feel the forces you desire. Then you must ensure they are fully surrounded by air (else the caculation will fail due to the mu_r, and that the mesh is fine around these boundaries, as you need to get correct flux values
Chekc the model library examples
--
Good luck
Ivar
to define the forces, you need to add a force domain node on hte domains which are moved or feel the forces you desire. Then you must ensure they are fully surrounded by air (else the caculation will fail due to the mu_r, and that the mesh is fine around these boundaries, as you need to get correct flux values
Chekc the model library examples
--
Good luck
Ivar
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Posted:
1 decade ago
Hi!
I have calculated the correct torque now. And with the Maxwell stress tensor I could determine the combined stress on the stator.
Still having trouble though, how to calculate/plot the radial component of the force on the rotor.
With the force calculation node apparently working as it should (or else the torque wouldn't be correct) - and taking the deformation aside for now - getting the radial force is just another derived value from the already made computation, right?
If that's true - does anyone have any experience with calculating it? Any suggestions?
Thank you for you answers in advance.
Jan
I have calculated the correct torque now. And with the Maxwell stress tensor I could determine the combined stress on the stator.
Still having trouble though, how to calculate/plot the radial component of the force on the rotor.
With the force calculation node apparently working as it should (or else the torque wouldn't be correct) - and taking the deformation aside for now - getting the radial force is just another derived value from the already made computation, right?
If that's true - does anyone have any experience with calculating it? Any suggestions?
Thank you for you answers in advance.
Jan
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Posted:
1 decade ago
Hi
depending on the version you have you have the option to calculate forces on domains (but these should ideally be all surrounded by air, or the same material to get the correct force values, and you should take care with the mesh and particularly sharp edges, that makes field concentration, which show up as rather large errors in the force calculation values.
Then if you motor is rotating rapidly, you should not forget the other radial "centrifugal forces", these can be added easily with a structural body force expressed accordingly in a cylindrical coordinate (I believe there is some models in the model library, if not check the model gallery)
--
Good luck
Ivar
depending on the version you have you have the option to calculate forces on domains (but these should ideally be all surrounded by air, or the same material to get the correct force values, and you should take care with the mesh and particularly sharp edges, that makes field concentration, which show up as rather large errors in the force calculation values.
Then if you motor is rotating rapidly, you should not forget the other radial "centrifugal forces", these can be added easily with a structural body force expressed accordingly in a cylindrical coordinate (I believe there is some models in the model library, if not check the model gallery)
--
Good luck
Ivar