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torque and identity pair

Posted 23.06.2013, 10:00 GMT-4 Low-Frequency Electromagnetics Version 5.2a 5 Replies

Giovanna Abbiati
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Hi! I'm working on a 3-phase synchronous motor with interior permanent magnets. I have to perform both stationary and time dependent simulations. I split the air gap into two parts connected by an identity pair wih an applied copntinuity in magnetic vector potential. When I try to calculate forces and torques, with the "force calculation" law, on the boundaries connected by the identity pair I always obtain zero (N or Nm) for any position of the rotor!
I've noticed that this happens too with the "2D generator" in the model library.
Do someone know why this happens? And what can I do to overcome the problem??
Thanks
J.
5 Replies Last Post 08.07.2017, 12:29 GMT-4
Madhu Maheshwari
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Posted: 1 decade ago 23.06.2013, 21:48 GMT-4
Hi,

I am also working on three phase synchronous motor, could you share your model here so that I can see and tell you because mine is working fine.

Thanks
Madhu
Hi, I am also working on three phase synchronous motor, could you share your model here so that I can see and tell you because mine is working fine. Thanks Madhu
Jens Krause
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Posted: 1 decade ago 24.06.2013, 07:05 GMT-4
Hallo Giovanna,

how do you define the domains for the force calculation? You cannot extend the force calculation
to the boundary of the indentity pair. There must be a ring of air in between.

Regards

Jens
Hallo Giovanna, how do you define the domains for the force calculation? You cannot extend the force calculation to the boundary of the indentity pair. There must be a ring of air in between. Regards Jens
Giovanna Abbiati
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Posted: 1 decade ago 25.06.2013, 01:42 GMT-4
Hi! Thank you for your answer. If I need to compute the torque (for example cogging torque) in the middle of the air gap, do you mean I have to move the identity pair?Should I place it a bit nearer to the stator or shoul I compute the torque on another boundary nearer to the rotor??
Thanks
J.
Hi! Thank you for your answer. If I need to compute the torque (for example cogging torque) in the middle of the air gap, do you mean I have to move the identity pair?Should I place it a bit nearer to the stator or shoul I compute the torque on another boundary nearer to the rotor?? Thanks J.
Zhi Xu
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Posted: 8 years ago 06.02.2017, 04:59 GMT-5
Hi Giovanna

I'm running the same problem as you did. My model is also an interior mounted PMSM and no matter what initial position for the rotor is given, the average torque is always zero with an amplitude of maximum torque of the machine. I also built a simplified model: one pole model and suprisely this issue won't happen. So I am wondering have you solved this problem? Looking forward to your response.

Best regards
Zhi
Hi Giovanna I'm running the same problem as you did. My model is also an interior mounted PMSM and no matter what initial position for the rotor is given, the average torque is always zero with an amplitude of maximum torque of the machine. I also built a simplified model: one pole model and suprisely this issue won't happen. So I am wondering have you solved this problem? Looking forward to your response. Best regards Zhi
Maria-Sofia Pechlivanidoy
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Posted: 7 years ago 08.07.2017, 12:29 GMT-4
I have the same problem with the torque? Are you compute the cogging torque? Has anybody compute Arkkio torque for a PMSM? Can anyone attach his model program file?
2D or 3D or both.
Best regrards.
I have the same problem with the torque? Are you compute the cogging torque? Has anybody compute Arkkio torque for a PMSM? Can anyone attach his model program file? 2D or 3D or both. Best regrards.

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