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LAUNCHXL-F28027F: Piccolo28027f + DRV8305

Vaishali Sabnis
Prodigy 180 points
Part Number: LAUNCHXL-F28027F
Other Parts Discussed in Thread: DRV8305

Hello

I am using motor which could run upto 80000rpm. I am using Piccolo28027f and DRV8305 for controlling motor.

Motor specifications are:

Inertia 3.15 kg-m2, Continuous stall current=3.31A, Peak torque=122.9Mnm, Continuous stall torque=7.98mNm, Inductance=0.030mH,Resistance=0.46 ohm

I started with lab 1 and finished upto lab05b. By using Lab02 i found out valyues of Rs, Ls_d and Ls_q, Flux.

Rs=0.46ohm

Ls_d & Ls_q=0.000030H

Flux=0.0042794

Also  I am getting,

spd_kp=10.8

spd-ki=0.0542

idq-kp=0.150

idq-ki=0.767

But for these values motor doesn't run smoothly. It takes more current. But  if I change

spd_kp=10.8

spd-ki=0.0542

idq-kp=0.00150

idq-ki=0.0767 Motor runs perfectly fine and current it takes is also very less.

 why it is happening & how to change these parameters.

  • 0
    TI__Guru** 109730 points

    That's normal. You might try to use lab02c to identify the motor parameters. The calculation gain values of the controller are just a reference value for most motors, you still need to tune the gains of the speed and current PI controller according to the motor and its system. 

  • 0 in reply to Yanming Luo
    Prodigy 180 points

    Thank you for yoyr reply.

    1. Can you guide me in finding out gain values. 

    2. How to update these gain values in program? Beacause I will burn program in microcontroller and will set speed at which it should run. I will not use GUI. So how i can update these parameters in program?

  • +1 in reply to Vaishali Sabnis
    TI__Guru** 109730 points

    Yes, you need to set the gains on project.

    You can find the function below in proj_labxx.c

            // update Kp and Ki gains

            updateKpKiGains(ctrlHandle);

    And then you might add the following codes in font of updateKpKiGains(ctrlHandle)

    gMotorVars.Kp_Idq = Kp_Idq_set_value;

    gMotorVars.Ki_Idq = Ki_Idq_set_value;

    gMotorVars.Kp_spd = Kp_spd_set_value;

    gMotorVars.Ki_spd = Ki_spd_set_value;