Thermal modelling in Flux - Questions from a beginner
Hello,
I am struggling to analyze the thermal behaviour of an electric motor. My goal is to design a motor first in FluxMotor and then calculate the electromagnetic and thermal behaviour for a specific working point in Flux.
I noticed that FluxMotor has the function to export a Flux 2D model. I would like to calculate the thermal behaviour over time of each component inside the EM for my specific operating point. There are two options inside FluxMotor to export an Flux 2D model : a static model and a transient model. I have multiple questions regarding this export options:
- Inside the static thermal model, I have to enter the the inputs "Speed, stator joule and iron losses, magnet losses and rotor iron losses". Except for the speed I do not know the exact values for each thermal loss. Where do I obtain these values? Do I have to calculate the losses inside a prior electromagnetic calculation inside Flux?
- Will the exported model be able to calculate the temperature over time? Or do I have to export an a transient model ?
- Regarding the transient model: FluxMotor asks me to put in the temperature of the winding, endwinding, magnet etc. before exporting the Flux2D model. Why are these temperatures needed to export the model? Does the exported model use these values as a constant temperature for calculating the (temperature dependent) losses? This would mean that this exported model is not suitable to calculate the thermal behaviour of the electric machine, right?
I am a beginner to the Flux Software. What would be a good starting point for learning the use of thermal calculations inside Flux?
Best Answer
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Hello Melih,
Below you will find answers to your questions.
1. Normally, these losses are computed within FluxMotor so you can take these values from the results you obtained from the working point computation.
2. with the "static thermal model you will have the Steady State application in the model, that means that you will find the steady state temperatures.
3. Yes, there is no automatic export for the transient thermal model.
You could export the "static model" and easily convert the application to transient directly in Flux: [Application --> Convert current application--> to Transient Thermal].
Please remember to add the "volumetric heat capacity" to the materials.
Best regards,
Letizia
1
Altair EmployeeAnswers
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Hello Melih,
Below you will find answers to your questions.
1. Normally, these losses are computed within FluxMotor so you can take these values from the results you obtained from the working point computation.
2. with the "static thermal model you will have the Steady State application in the model, that means that you will find the steady state temperatures.
3. Yes, there is no automatic export for the transient thermal model.
You could export the "static model" and easily convert the application to transient directly in Flux: [Application --> Convert current application--> to Transient Thermal].
Please remember to add the "volumetric heat capacity" to the materials.
Best regards,
Letizia
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Hello Melih,
About your last request, you will find the example "Brushless IPM motor - thermal analysis" here: https://help.altair.com/flux/Flux/Help/english/UserGuide/English/topics/Examples2D_en.htm
The same example is also available from the Flux Supervisor; it explains the difference between steady state and transient computation. Models and related documents are also available.
Please, update the FluxMotor version if you have the opportunity to do it, version 2023 is available on our website.
Best regards,
Letizia
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Letizia Ferrara_21767 said:
Hello Melih,
Below you will find answers to your questions.
1. Normally, these losses are computed within FluxMotor so you can take these values from the results you obtained from the working point computation.
2. with the "static thermal model you will have the Steady State application in the model, that means that you will find the steady state temperatures.
3. Yes, there is no automatic export for the transient thermal model.
You could export the "static model" and easily convert the application to transient directly in Flux: [Application --> Convert current application--> to Transient Thermal].
Please remember to add the "volumetric heat capacity" to the materials.
Best regards,
Letizia
Hi Letizia,
Thank you for your response. Regarding question 1: When I calculate the sine wave efficiency map inside FluxMotor, only the values for the "joule losses" and "iron losses" are given. Inside the export window for the Flux2D model, I have to name the
- stator joule losses,
- stator iron losses,
- magnet losses and
- rotor iron losses.
Unfortunately there is not distinction inside FluxMotor to where exactly the iron losses are occurring. Does the 2023 version of FluxMotor show me them in more detail? Or what is the best approach for my problem here?
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Letizia Ferrara_21767 said:
Hello Melih,
About your last request, you will find the example "Brushless IPM motor - thermal analysis" here: https://help.altair.com/flux/Flux/Help/english/UserGuide/English/topics/Examples2D_en.htm
The same example is also available from the Flux Supervisor; it explains the difference between steady state and transient computation. Models and related documents are also available.
Please, update the FluxMotor version if you have the opportunity to do it, version 2023 is available on our website.
Best regards,
Letizia
Thank you as well for this recommendation. I found this example as well but didn't try it yet. I guess I should work in this first before designing my own machine.
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Melih Ayyildiz_22506 said:
Hi Letizia,
Thank you for your response. Regarding question 1: When I calculate the sine wave efficiency map inside FluxMotor, only the values for the "joule losses" and "iron losses" are given. Inside the export window for the Flux2D model, I have to name the
- stator joule losses,
- stator iron losses,
- magnet losses and
- rotor iron losses.
Unfortunately there is not distinction inside FluxMotor to where exactly the iron losses are occurring. Does the 2023 version of FluxMotor show me them in more detail? Or what is the best approach for my problem here?
Hello Melih,
To obtain the detailed iron losses you can carry out the working point analysis; you will find the power balance section in the table of the results; the losses are computed for the working point.
However, the iron losses are normally develop in the stator for the most part, due to the change in the local magnetic field, so you can consider 97% of the iron losses in the stator and 3% in the rotor, just to have an idea.
Best regards,
Letizia
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