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LAUNCHXL-F28069M: HIGH CURRENT RIPPLE Question //// INSTASPIN-FOC

Georgi Gospodinov
Prodigy 115 points
Part Number: LAUNCHXL-F28069M

Hello Guys,

We currently use LAB-5A  with ebike BLDC hub motor 24V; 20 Poles ; 250 - Rated power. We are facing high current ripples shown on the attached pictures. 

Additionally I attached the user.h file. Is It normal behavior beside the fact of surface mount magnets ? May I tune something more to reduce the ripples ? 

    3755.user_j1.h

Waiting for you to reply,

Sincerely,

Georgi Gospodinov

  • 0
    TI__Guru** 109780 points

    What speed is the motor running at? Is the speed higher than the rated speed?

    What load is adding on the load? Is it a constant load? Or a variant load?

    Can you check the feedback and output values of the Iq PI regulator?

    And you may try to increase the dc bus voltage to see what happens when do the test at the same speed and load.

  • 0 in reply to Yanming Luo
    Prodigy 115 points

    Hi Yanming  and thank you for your reply ! 

    What speed is the motor running at?

    The speed is 1500 rpm.

      Is the speed higher than the rated speed?

    I don't know because it's missing from the datasheet. Probably 1500 it's maximum that controller can achieve because of the back EMF. 

    What load is adding on the load?

    It's currently running at no load. Only inertia added by the spokes and the wheel. 

    Can you check the feedback and output values of the Iq PI regulator?

    Do you mean the current feedback ? Regarding the values of Iq PI regulator they are as follows : Ki = 0.030 (Q-24) ; Kp = 0.49 (Q-24);

    And you may try to increase the dc bus voltage to see what happens when do the test at the same speed and load.

    Increasing the DC bus voltage results in higher speed of rotation, applying load results in higher and even more deformation of the current.

    PS : The pictures above are averages values. 

    Sincerely,

    Georgi

  • 0 in reply to Georgi Gospodinov
    TI__Guru** 109780 points

    Do you run lab02b to identify the motor parameters for lab05a?

    Can you try to run the motor with lab05b using speed-closed loop and set the target speed as you want in lab05a?

  • +1 in reply to Yanming Luo
    Prodigy 115 points

    Do you run lab02b to identify the motor parameters for lab05a?

    Absolutely

    Can you try to run the motor with lab05b using speed-closed loop and set the target speed as you want in lab05a?

    I tried , but the current  results the same form

    I managed to change the form by setting  USER_MAX_VS_MAG_PU        (0.5774). It's still sounds noise to me.