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LAUNCHXL-F28027F: LAUNCHXL-F28027F

Rajan Joshi
Expert 1020 points
Part Number: LAUNCHXL-F28027F
Other Parts Discussed in Thread: MOTORWARE

I was trying to generate maximum torque at lowest speed possible.

When I do add the load however, the motor starts to vibrate and does not move. I am using Lab 05b from the motorware library. 

I was wondering if there is a smooth way to increasing the torque so that it can overcome a specific amount of load. 

Thank you, 

Rajan Joshi

  • 0
    TI__Guru** 115500 points
    What low speed are you testing on? It's difficult to run very stably with heavy load at very low speed. You can try to change the Kp and Ki of speed and current PI regulator first which can improve the low speed performance, and the accurate stator resistance in user.h and good current/voltage feedback signal can improve the low speed performance also.
  • 0 in reply to Yanming Luo
    Expert 1020 points
    I am running at 200 rpms or 0.2krpms.

    I do have a load attached and i have tried to play with the gain values. I have come up with some values that are suitable but it still does not work 100% of the times.

    Also another question i had was when switching direction with load on, is there any way of stopping the motor right away other than the run identify flag. I feel like when i turn it on and off it doesn't really stop for any time it just starts up almost instantaneously.
  • 0 in reply to Rajan Joshi
    TI__Guru** 115500 points
    What's the rated speed of motor? What percent is 200rpm to rated speed? You have to tune the PI and use a accurate motor parameters to run such low speed with high load.

    In instaSPIN, the pwm will be disable without any voltage output from inverter to motor when setting the run flag to zero, motor will go into free fall for some time if inertia is very high and friction is low.
  • 0
    Expert 2130 points
    Not knowing the inductance - it's difficult. Your motor may not be able to rotate slowly at the specified voltage.
  • 0 in reply to Yanming Luo
    Expert 1020 points
    The motor is rated for 8220 rpm and I am trying to run it at 200 rpm, almost about 2.5 % of the rated speed.

    Now I am running into another issue..... when I try to run the motor I can see that the EstState and the CtrlState are both on online but hte motor is not spinning. I can feel the wires heating up like crazy.

    Would you happen to know what the problem might be?
  • 0 in reply to Rajan Joshi
    TI__Guru** 115500 points
    The 200rpm is too low to run stably with over full load, you need to use different speed and current PI parameters for low and high speed.
    The motor stalled, it means that the estimated angel and speed is not right. Did the fault appear in starting or running? You have to add a fault check to protect and exit this fault. And you need to do Rs recalibration to get a accurate value to improve the startup performance.
  • 0 in reply to Yanming Luo
    Expert 1020 points
    I do perform Rs re calibration every time i try to run the motor. The fault appears after the re calibration is complete and the controller state goes into online mode.

    How do i correct the estimated angle and the speed ?

    thank you,

    Rajan
  • 0 in reply to Yanming Luo
    Expert 1020 points
    When I do use the motor identification, I can get the parameters correctly but when I try to run it after the parameters are achieved in lab 2b, the motor stalls and heats up.

    I am not understanding why, i was able to run the motor with the same code before.