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Original question:

CCS/TMS320F28054F: Lab21, the equation of excitation frequency

CCS/TMS320F28035: HFI frequency

Nick ZHU
Prodigy 110 points
Part Number: TMS320F28035

Tool/software: Code Composer Studio

Hi,I'm evaluating HFI on TMS320F2803x . I found HFI calculation equation  on TMS320F28054F (https://e2e.ti.com/support/microcontrollers/f/171/t/653462?tisearch=e2e-sitesearch&keymatch=ipd)

  • 0
    TI__Guru** 114200 points
    Yes, you might refer to the formula to calculate the injection signal frequency. The f is close to 10*fc=10*(R/(2*PI()*L), and select a right frequency based on the PWM frequency.
  • 0 in reply to Yanming Luo
    Prodigy 110 points
    Thanks , I missed my question in the post . luckly you got what i meant .
    my test motor feature is Rs= 0.61 Ω Lq= 5.22mH Ld=2.73mH
    L= (Lq+ Ld )/2= (5.22+2.73)/2 =3.975mH
    10*fc = 10* ( 0.61/(2* 3.14159 * 0.003975)) = 244.23Hz
    as you mentioned , exicitation frequency must be less than 244.23Hz. am i right ?
  • 0 in reply to Nick ZHU
    TI__Guru** 114200 points
    It doesn't must equal the calculated value, you might use a frequency near the calculated number, higher than the motor rated frequency. The final frequency should be a number that the pwm frequency is its integral multiple to generate the high injection signal easily. You may use 300Hz or 450Hz if the PWM frequency is 9kHz in your case.