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TMS320F280049C: Frequency of the interrupt issue

Cherry Zhou
Mastermind 22235 points

Part Number: TMS320F280049C

Hi team,

The customer would like to use 280049c as a totem pole pfc with an input frequency of 400 hz, and the current loop calculation duty cycle is placed in an interrupt.

For this 400-hz input, how much should the interrupt frequency be set? Is 50 kHz OK?

Could you help resolve this issue? Thanks.

Best Regards,

Cherry

  • 0
    TI__Mastermind 22235 points

    Hi,

    May I know is there any updates?

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Expert 4200 points

    Hi Cherry.

    It depends on your control loop desgin but as a rule of thumb, the control loop bandwidth has to be at least 10 time higher than input frequency which means you need to set it as low as 4 kHz. Also, PWM switching impacts the phase margin and you need to set pwm switching 10 times higher than the control loop bandwidth.

    Assuming that your interrupt frequency is the same as PWM frequency, 50 kHz is marginal. To get the enough phase margin, 100 kHz would be a better choice.

    This is just a basic guideline and the customer has to run simulation and check the frequency response first before the implementation.

    Best,

    John