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Original question:

Help in defining my BLDC Hub Motor parameters in Universal Motor Control Lab Project

TMS320F280025C: UNIVERSAL MOTOR CONTROL PROJECT - BLDC MOTOR NOT STARTING WHEN ALREADY MOVING REVERSE DUE TO GRAVITATIONAL FORCE IN A RAMP

Anil Sudhakaran
Expert 1125 points

Tool/software:

Hi,

Using Sensorless (FAST) mode  for BLDC motor control.   2 Wheeler Application

Have one issue.....

In a ramp,  while vehcile  is moving reverse due to gravitational force, at that time when throttle is applied, motor is not starting.

When vehicle  is standstill in a ramp , apply throttle, it starts.

Please suggest what to look for.

Thanks,

Anil

  • 0
    TI__Expert 5935 points

    Hi Anil

    The expert for this topic is currently on Vacation. Please expect a response after June 25.

    Thanks

    Amir

  • 0 in reply to Amir Hussain
    TI__Genius 11076 points

    Anil,

    Is Flying Start enabled or disabled in your application?

    Regards,
    Jason Osborn

  • 0 in reply to Jason Osborn
    Expert 1125 points

    Hi Jason,

    Flying start  is enabled.

    Below section of the code was culprit..

    • if(obj->speed_int_Hz >= 0.0f)
      {
                   PI_setMinMax(obj->piHandle_spd, 0.0f, obj->startCurrent_A);
      }
      else
      {
                  PI_setMinMax(obj->piHandle_spd, -obj->startCurrent_A, 0.0f);
      }

    At the time throttle is given, actual speed is negative (since vehicle is moving in  reverse).   

    speed_int_Hz was building up from negative (actual speed). Till it crosses zero to wards positive, Iq was zero. This was causing motor not to move for some time

    Modified code as below...

    PI_setMinMax(obj->piHandle_spd, -obj->startCurrent_A, obj->startCurrent_A);

    Had to disable forced angle  >   flagEnableForceAngle = FLASE for smoth speed transition from negative to positive.

    Regards,

    Anil

  • 0 in reply to Anil Sudhakaran
    TI__Genius 11076 points

    Anil,

    Thank you for letting us know what solved the issue! Glad to hear things seem to be working now.

    Regards,
    Jason Osborn