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flying start Startup problem

Evaluation board:  drv8301-hc-evm revd

Lab 10e Flying Start

Using the same motor parameters and PI parameters as Lab10a, almost all parameters are set the same, why Lab10a can start smoothly and run normally at 200~2000rpm, but Lab 10e cannot start smoothly and only run normally after shaking for a few seconds, why? Which parameters should be modified to solve the smooth startup problem of Lab 10e?

  • The engineer supporting this is on vacation and will reply when he is back, thanks for the patience.
  • Is the vacation over? TI engineers are urged to provide solutions

  • Did you have any current waveform to show your question? What load is added on the motor to enable the flying start? and the motor is standstill when enable flying start?
    A precise Rs is very important to start the motor, especially under load, tune FS_SPEED_MIN and FS_MAX_CHECK_TIME in flyingStart.h according to your system, don't set a too small value for both parameters.
  • What do these two parameters mean? How does the value of each parameter affect the startup of the motor?

    Nominal voltage V 24
    No load speed rpm 60800
    No load current mA 282 
    Nominal speed rpm 57500
    Nominal torque (max. continuous torque) mNm 23.6
    Nominal current (max. continuous current) A 6.45
    Stall torque mNm 561
    Stall current A 149
    Max. efciency % 91.6
    Terminal resistance W 0.161
    Terminal inductance mH 0.0171
    Torque constant mNm/A 3.76
    Speed constant rpm/V 2540
    Speed/torque gradient rpm/mNm 109
    Mechanical time constant ms 2.04
    Rotor inertia gcm 1.79

  • FS_SPEED_MIN is the minimum switching speed, the feedback will be set to ZERO if it is less than the FS_SPEED_MIN value.
    FS_MAX_CHECK_TIME is the time of duration to calculate the average feedback speed.
    1. Please make sure the motor parameters are identified correctly in lab02b, the stator resistance plays a significant role in the accuracy of the estimated parameters for a startup or low speed running.
    2. Disable the force angle and tune the speed controller.