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TMS320F28335: SVGEN "Transfer Function"

Eric Riff
Prodigy 50 points
Part Number: TMS320F28335

Hello, i'm using the Sensorless FOC for ACI and i'm having trouble to understand how the SVGEN_dq module works.
My issue is related to predict the phase voltage that the inverter will generate when i set the values of Vq and Vd (trough a Ipark module). Can anybody help me to calculate a "transfer function" like Vphase=f(Vq,Vd,Vdc)? Thanks!

  • 0
    Expert 2550 points
    Dear Eric Riff,

    In this case, you can consider the transfer function between input and output of SVGEN as a G(s) = ZOH, because this function only simplely implement a conversion or calculation to transfer digital signals to PWM signals.

    Hope to help!
  • 0 in reply to Tran Binh Duong
    Prodigy 50 points
    Hi Tran! Thanks for the help but i think i mislead you by saying transfer function. What i need is a function like Vphase=f(Ud,Uq,Vdc). I need to find a way to calculate the rms phase voltage that i will apply with my inverter when i set Ud and Uq to my SVGEN_DQ module for a given Vdc voltage.
    Thanks in advance!
    Eric.
  • 0 in reply to Eric Riff
    TI__Guru** 115440 points

    To get a exact phase RMS voltage, you can use the adc results of phase and dc-bus voltage or pwm output duty cycle to calculate the RMS value.
    Va_rms=SQRT((Va(0)^2+...+Va(n)^2)/n), n is the sample point number of motor electric frequency
    n=f_motor/f_pwm, f_motor->motor electric frequency, f_pwm->voltage sample frequency.