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INSTASPIN-BLDC: over current protection to avoid demagnetizing with launchxl-f28069m + boostxl-drv8301

Mariano
Intellectual 370 points
Part Number: INSTASPIN-BLDC


hello, the engine manufacturer tells us that to avoid motor demagnetization we must limit the current peaks to 10 [A]. 

What type of protection do you recommend?

I understand that the phenomenon of demagnitization also occurs due to inadequate work frequencies, this motor is of low inductance and we are using at 70kHz. 

There is some formula to calculate this frequency?.


thanks.
  • 0
    TI__Guru** 115510 points

    1. You'd better use a hardware over current protection circuit to do this, like a on-chip comparator of F280269, or a external comparator to limit the peak current and switch off the pwm output if there is a over current.

    2. What's mean 70kHz? Is it pwm frequency? And what frequency do you want to calculate? There is a motor speed feedback, you can calculate the electrical frequency according to the feedback speed.

  • 0 in reply to Yanming Luo
    Intellectual 370 points
    hi Yanming,

    is on chip comparator of F280269 fast enough to limit the current peak?
    if you switch off the pwm output, how the FOC control handle this situation ? How does it recover the control?

    The PWM frequency (USER_PWM_FREQ_kHz 50.0) , how you calculate this?

    thanks