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TMS320F28069M: How to Increase Driving Power

Louis Zhu
Expert 1675 points
Part Number: TMS320F28069M

My application is fluid pump controller that has been developed based on Lab10d. The pump works well at 6000 rpm with 20 psi back pressure. When the speed is increased to 7000 rpm or the back pressure is increased to 30 psi, the pump stalls. When either the speed command or the back pressure reduces, the pump was able to resume operation. Attached is the real time watch window data, you can see that the Iq is 5.2A that is below its max setting 15A, and Vq is 0.29 PU. Increasing Kp_Idq does not improve the performance. Please note that we have only two current sensors on phase A and B respectively. Please advise what shall be changed in order to achieve higher driving power.

  • 0
    TI__Guru** 109810 points

    The information is not enough to get a clear answer. You can check below information and record them before the motor stop.
    1. gMotorVars.Vs, gMotorVars.OverModulation
    2. All variable in ctrlHandle[0]->pid_spd, ctrlHandle[0]->pid_Id, ctrlHandle[0]->pid_Iq.
    3. ctrlHandle[0]->maxVsMag_pu
    4. Snapshot two phase current waveform during the motor from running to stopping.

    5. Disable OVM since the current sensor num is 2.

    You can increase dc bus voltage to have a test first (increase 10~25%), to see whether the speed can run up to 7000rpm.

  • 0 in reply to Yanming Luo
    Expert 1675 points
    Hi Yanming,
    Thanks for your reply. Before I get into the further testing, I want to let you know that the pump was able to speed up to 8500 rpm without back pressure. The issue was, when the fluid back pressure increases, the motor stalls. I'll get you more test info.
    Louis
  • 0 in reply to Louis Zhu
    Expert 1675 points

    Yanming,

    Here are Expression window captures, other waveforms will be provided when available. Hope that you have some idea from the captures.

  • 0 in reply to Louis Zhu
    TI__Guru** 109810 points
    From these variables snapped, the motor should run up to more high speed. Maybe you have to record the transient value for these variables from run to stop.

    You can refer to lab09 to disbale OVM without using SVGENCURRENT related functions.

    Can you try to increase the dc bus voltage from 12V to 15V for a test to see what will happen?
  • 0 in reply to Yanming Luo
    Expert 1675 points
    Yanming,
    It turned out that there were no issues in the software solution, it was due to the current limit on the power supply. The 12V voltage dropped when its current limit was reached. Increasing the current limit allows the pump to run at 8000 rpm at 30 psi, the requirements are met.
    Thank you very much for your prompt support!
    Louis
  • 0 in reply to Louis Zhu
    TI__Guru** 109810 points
    Hi Louis,

    Great. I will close this thread, please let's know if have any further assistant.