Two different frequency inputs in Steady State AC Magnetic 2D

Mohammad Hamza Azam
Mohammad Hamza Azam Altair Community Member
edited September 2021 in Community Q&A

Please help! as I have tried my best to somehow introduce two distinct frequencies of AC supply for two different coils with different values of current. The first coil with 2A current and 200Hz while the second one should be introduced with 2mA current and 20KHz frequency. For now, I can only put 200Hz frequency which is asked at the start of the application.

I would be glad if you help.

Best Regards

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Best Answer

  • SimonGuicheteau
    SimonGuicheteau
    Altair Employee
    edited September 2021 Answer ✓

    Hello,

     

    the steady state application only works at a single frequency unfortunately. In some cases you can simulate both frequencies individually and add some of the results but most of the time the correct way of modelling is to set a transient model with both sine wave applied.

    The time step needs to be small enough for your 20 kHz frequency (20 steps per period ideally) which gives a time step of 0.0000025s over 0.005s for one larger period of the 200 Hz sine wave. This will make 2000 steps which is a lot in this case due to the difference of frequency, you can try to increase the time step but you need to have enough points to see the 20 kHz effect.

     

    Cheers

Answers

  • SimonGuicheteau
    SimonGuicheteau
    Altair Employee
    edited September 2021 Answer ✓

    Hello,

     

    the steady state application only works at a single frequency unfortunately. In some cases you can simulate both frequencies individually and add some of the results but most of the time the correct way of modelling is to set a transient model with both sine wave applied.

    The time step needs to be small enough for your 20 kHz frequency (20 steps per period ideally) which gives a time step of 0.0000025s over 0.005s for one larger period of the 200 Hz sine wave. This will make 2000 steps which is a lot in this case due to the difference of frequency, you can try to increase the time step but you need to have enough points to see the 20 kHz effect.

     

    Cheers

  • Mohammad Hamza Azam
    Mohammad Hamza Azam Altair Community Member
    edited September 2021

    Hello,

     

    the steady state application only works at a single frequency unfortunately. In some cases you can simulate both frequencies individually and add some of the results but most of the time the correct way of modelling is to set a transient model with both sine wave applied.

    The time step needs to be small enough for your 20 kHz frequency (20 steps per period ideally) which gives a time step of 0.0000025s over 0.005s for one larger period of the 200 Hz sine wave. This will make 2000 steps which is a lot in this case due to the difference of frequency, you can try to increase the time step but you need to have enough points to see the 20 kHz effect.

     

    Cheers

    Thank you soo much for your time and kind reply. Really appreciate it. I have tried to do it using sine functions in transient model with time step of 0.00000166s but solution is showing horizontal line for both currents. Regards
  • SimonGuicheteau
    SimonGuicheteau
    Altair Employee
    edited September 2021

    Thank you soo much for your time and kind reply. Really appreciate it. I have tried to do it using sine functions in transient model with time step of 0.00000166s but solution is showing horizontal line for both currents. Regards

    If needed, you can test with an empty project only containing the circuit to ensure the signals created and the time steps are enough.

  • Mohammad Hamza Azam
    Mohammad Hamza Azam Altair Community Member
    edited September 2021

    If needed, you can test with an empty project only containing the circuit to ensure the signals created and the time steps are enough.

    Thank you! Mr. Simon you made my day.