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October 20, 2025
Question

STPOWER Studio simulation stuck at iteration zero

  • October 20, 2025
  • 6 replies
  • 366 views

I am attempting to use STPOWER Studio to run a thermal simulation but every time I start a simulation it just sits at 0% complete, showing Simulation in progress: iteration counter [ 0 / 63]. Has anyone run into this problem?  Any suggestions on what might be the issue?

This is my configuration:

I/O Summary: STGIPNS3H60T-H

 

Simulation Parameter STEP_0

PWM Modulation

-

Steady State

-

Simulation Time

15 s

DC Link Voltage

300 V

RMS Phase Current

1 A

Output Power

216.37 W

Output Voltage

156.15 V

Output Frequency

60 Hz

Switching Frequency

21 kHz

Power Factor

800 m

Modulation Index

850 m

Ambient Temperature

25 °C

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    6 replies

    ST Employee
    October 22, 2025

    Dear Customer,

    We apologize for the inconvenience.

    Based on the information provided, we were unable to reproduce the issue.

    Could you please try running the simulation again to verify whether the problem persists?

    The code is hosted on the AWS platform, which has experienced technical issues in recent days affecting several services.

    If the problem persists, don't hesitate to contact us again.

    To reproduce the issue, please attach the exported project to your request (by clicking the "Export" button in the toolbar).

     

     

     

    CarmeloVICCICA_0-1761134757235.png

     

     

    PRitt.1Author
    Explorer
    October 22, 2025

    Thanks Carmelo,

    I tried again today but the simulation still failed to run.   Attached is the exported file

    Thanks for your help,
    Phil

    PRitt.1Author
    Explorer
    October 22, 2025

    It looks like I can get the simulation to run if I use one of the heatsink options but "without heatsink" fails to run.  Unfortunately "without heatsink" is the one I am most interested in.   Can I work around it by using a Fixed heatsink Rth with a specific C/W?

    ST Employee
    October 22, 2025

    Hi Phil,

    You are right.

    The correct behavior is to open a dialog window to inform the user about the failed condition.

    CarmeloVICCICA_0-1761142012735.png

    Our team is investigating the code to find the root cause and resolve the issue immediately.

    Regarding your question:
    Sure, you can use the option "Fixed Heatsink Rth" to analyze the behavior.

    We apologize for the inconvenience.

    I will keep you informed when the bug is fixed.

    Regards.

    Carmelo.

     

    PRitt.1Author
    Explorer
    October 22, 2025

    Thanks Carmelo

    > Sure, you can use the option "Fixed Heatsink Rth" to analyze the behavior

    Can you tell me what the C/W value should be in order to simulate the no heatsink case?

    Best regards,
    Phil

    ST Employee
    October 23, 2025

    Hi Phil,

    The engineers have solved the issue.

    Now, in production, there is a new backend version, BE 6.1.1.

    For your project, the engine sends an error message regarding the Tcase temperature.

    It is necessary to decrease the current to 0.35A to obtain a result.

    In the attachment, you can find the updated project.

    Regards,
    Carmelo

    PRitt.1Author
    Explorer
    October 23, 2025

    Hi Carmelo,

    Thanks for the quick fix!

    Just out of curiosity, why is the error regarding the Tcase temp rather than the junction temperature?  I would have thought the later was the limiting factor.  (BTW it would be great if the simulation could show Tcase (or even the NTC value)  vs time in addition to Tj so that I could compare my real world measurements with the simulation)

    One other minor question:  Why is minimum DC link voltage 300V?  Our application uses 30V

    Best regards,
    Phil

    ST Employee
    October 24, 2025

    Hi Phil,

    Regarding your first question:

    The tool’s engine assumes that the system is already at thermal steady state. Ideally, the system is turned off and on again, starting from the calculated case temperature to determine the evolution of the junction temperature.

    Our models include only the thermal resistance values (junction-to-ambient and junction-to-case), and do not provide thermal impedance values. Consequently, the tool cannot determine the evolution of the case temperature over time.

    For further information, please refer to the user manual available with the tool:
    https://eds.st.com/power-studio/docs/

    Regarding your second question:

    Why is minimum DC link voltage 300V?
    The STPOWER Studio tool is intended exclusively for high-voltage applications.

    The STGIPNS3H60T-H (https://www.st.com/resource/en/datasheet/STGIPNS3H60T-H.pdf) device is suitable for the following applications:

    • 3-phase inverters for motor drives
    • Roller shutters, dishwashers, refrigerator compressors, air conditioning fans, draining and recirculation pumps

    For low-voltage applications, it is recommended to consider other types of products.

    Regards.

    Carmelo