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TMDSHVMTRPFCKIT, D-axis current PI MACRO out problem!

byunghun moon
Intellectual 360 points


Hi 

I'm using  TMDSHVMTRPFCKIT v2.1.

when SpeedRef is constant_IQ(0.333), every time I turn the motor, D-axis current PI macro out value change to approx. -0.02 to -0.05.

why does this happen? I can't understand. Q-axis output is almost constant.

For this reason, I can't calculate exact Vd value from current PI out. 

Please explain why this is happening!

  • 0
    TI__Guru** 116400 points
    What's the Umin and Umax for Id PI regulator? This is a current close loop that the PI out of Id maybe always near Zero if you set the reference Id to Zero if the motor is a SPM. You can monitor the Id PI to see the reference and feedback which should be very close.
  • 0
    TI__Mastermind 27200 points

    The output of the D-axis PI regulator is the commanded Vd voltage, not the measured Vd.  The integrating action of the PI controller forces the output (Ds) to be whatever it needs to be to ensure measured D-axis current converges on Idref.  At steady speed, the PI controller inputs should be the same, but the controller output need not be zero. It depends on the motor.  I am told that motor saliency often results in a small negative value on the commanded Vd.

    Regards,

    Richard

  • 0 in reply to Richard Poley
    Intellectual 360 points
    Thanks Richard.
    I know your explain.

    But turning the motor over multiple times, I found strange phenomena.
    I'm using EMj04 (SPMSM ) & TMDSHVMTRPFCKIT v2.1 & HVPM_Sensored_Servo code.

    I always give 1000RPM command, motor is running well at 1000RPM.
    BUT!! PI controller out( = Vd,Vq command voltage) changes without constant.
    Sometimes even D-axis PI controller out(Vd) is positive value!!!!!!!
    Theoretically, Vd = -wr*Lq*Iq to make Id = 0 in steady state!

    why does this happen?

    I think if SpeedRef is constant, whenever I run motor, pi controller out(vd,vq) should be always consistent.

    Because I use Vd,Vq command to my algorithm, I have to solve this problem.

    please answer detailed explanation!!
  • 0 in reply to byunghun moon
    TI__Guru** 116400 points
    Not keeping a constant value which is a ideal state, just near a constant value if there is no nay changes on run status, for example, input voltage, load, reference, motor shaft friction. This is for both Vd and Vq output though you set the reference speed to a constant value, Vq depends on motor load also.