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TMS320F28027F: Lab20 to Lab11a Migration

Noah Erickson
Prodigy 170 points
Part Number: TMS320F28027F


Hi E2E,

I am attempting to rebase a project from Motorware16 Lab20 to Motorware18 Lab11a and am having a slight issue. I have the migration complete but cannot reach any target RPM in Lab11a. The speed always falls about 85%-93% short of the speed reference target RPM. Another interesting data point is that my gMotorVars.Flux_VpHz variable in the updateGlobalVariables functions is also follows this trend of being slightly lower than I would expect.

Some info about my project:

  • Custom hardware implementation
  • Target Processor is TMS320F28027F.
  • PWM Frequency is 10kHz.
  • Target RPM is 19,000 RPM on a 4 pole PMSM. Ls is about 117uH, Rs is about 53mOhm, flux is 0.0437 V/Hz
  • I am not intending on using RsRecalc, PowerWarp, RsOnline, Overmodulation or Field Weakening.

Does E2E have any insight into this issue?

Please let me know if I am missing any information that could help solve this and thanks in advance for any help!

  • 0
    TI__Guru** 116400 points
    It seems like the PWM frequency is too low in your project since the motor is a low inductance and high-speed motor. Please refer to lab02c that is for low inductance.

    And what rate speed, rated power and the input voltage is the motor? Please make sure that the input voltage and the maximum current are enough for the high speed.
  • 0 in reply to Yanming Luo
    Prodigy 170 points

    Hi Yanming,

    Thanks for the reply.

    We are targeting 19,000 RPM at 108V and about 1kW of output power. I believe the input voltage and maximum current are sufficient for the high speed because Lab20 can meet this target but I am unable to in Lab11.

  • 0 in reply to Noah Erickson
    TI__Guru** 116400 points
    Please try lab11a directly that don't need to migrate anything in lab20 to it. And please check if the maximum current and USER_MAX_VS_MAG_PU are set correctly.
    Please post some current waveforms if you still have any issues, that should help us to solve the question.
    Please check the PI controllers of Id, Iq, and Speed in expression window, and post a picture about these variables if possible.
  • 0 in reply to Yanming Luo
    Prodigy 170 points

    Hi Yanming,

    Thanks again for the response. Yesterday afternoon I discovered I did something silly where I was clearing the speed PID Ui variable every so often. Removing this fixed the issue and this post can be closed.

    Thanks!

    Noah