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SRedd.5
SRedd.5
Senior III
April 16, 2023
Solved

SVPWM implementation different from documentation

There is mistake in either the documentation or the source code, which one is correct please advise.

__weak uint16_t PWMC_SetPhaseVoltage(PWMC_Handle_t *pHandle, alphabeta_t Valfa_beta)

{

wUAlpha = Valfa_beta.alpha * (int32_t)pHandle->hT_Sqrt3;

 wUBeta = -(Valfa_beta.beta * ((int32_t)pHandle->PWMperiod)) * 2;

}

 

But if you compare with the documentation

0693W00000biAOdQAM_image.png

In the alpha code the PWM period (T) is missing.

In the beta code additional 2 is found.

Why there is a difference? Please help.

    This topic has been closed for replies.
    JKong.3
    JKong.3Best answer
    Associate III
    August 14, 2023

    for someone with the same question, in mc_config.c -> PWMC_R3_2_Handle_t PWM_Handle_M1, 
    there is .hT_Sqrt3 = (PWM_PERIOD_CYCLES*SQRT3FACTOR)/16384u

    PWM_PERIOD_CYCLES is in tick (clock freq / pwm freq), and SQRT3FACTOR is 16384 * sqrt(3) * 2

    so there's 2 also in Ualpha, so Ualpha and Ubeta is doubled in code

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    2 replies

    SRedd.5
    SRedd.5Author
    Senior III
    April 18, 2023

    Any help on this?

      JKong.3
      JKong.3Best answer
      Associate III
      August 14, 2023

      for someone with the same question, in mc_config.c -> PWMC_R3_2_Handle_t PWM_Handle_M1, 
      there is .hT_Sqrt3 = (PWM_PERIOD_CYCLES*SQRT3FACTOR)/16384u

      PWM_PERIOD_CYCLES is in tick (clock freq / pwm freq), and SQRT3FACTOR is 16384 * sqrt(3) * 2

      so there's 2 also in Ualpha, so Ualpha and Ubeta is doubled in code

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