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TIDM-1000: Inductor voltage drop feedforward

Part Number: TIDM-1000
Other Parts Discussed in Thread: TIDM-02013


I don't quite understand this part of the inductor voltage drop feedforward,the screenshot of the program is as follows

I looked at other thread but didn't get an answer that solved my doubts.

Can you help explain how adding this feedforward item(L*di/dt) will help with control?

What aspects of performance can be improved by this function?

Are there any relevant documents that can be provided for study?

Looking forward Your explanation.


  • Feed forward terms are used to predict what will happen and react before the thing occurs. In this case it appears to be predicting a voltage drop at the inductor due to the step size of the inductor current reference. Using this information it is and trying to compensate proactively rather than reactively.

    The above wiki describes it simply with a house. The idea is that when a door opens you know the room's temperature will drop. In this case you can use feedforward control by turning on a heater when a door opens rather than waiting for the thermostat to provide feedback that the room's temperature has dropped.

    In this analogy, similar to the voltage-drop compensation above, can lead to greater stability of the controlled parameter by reacting before the feedback path's delay.


  • Have you verified this function? Could you show me the waveforms?

    Are there any side effects or should I pay attention to adding this function?

    Because I also found this function in the totem pole pfc of TIDM-02013, but the voltage drop feedforward term was not added to the calculation of duty.

  • I did not personally verify this function, I'll see what I can find, but I don't expect to have any waveforms.

    Side effects that I would look for would be over/under compensation due to the FF term. In this case it looks like the FF term is just trying to preemptivlely move the PFC's duty down to the reference. I believe this is just to help track the reference more closely, with less phase delay.

    Correct TIDM-02013 did not utilize the FF term. The power factor was acceptable, so this was not evaluated.