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UCD3138A: Non Linear PID for Hard-Switching Full-Bridge DC-DC Converter

user4357894
Intellectual 260 points
Part Number: UCD3138A

Dear lan,


I have a question about Non Linear PID  for Hard-Switching Full-Bridge DC-DC Converter,   the frequent  is 174kHz.

Programmable Non-Linear Limits for automated modification of filter coefficients, The max cross-over frequency is 5.6kHz.

When do output dynamic test, within a period  the Duty  reduced from 40% to 10%.

I wonder whether the dynamic trigger the fastest  PID coefficients，the fastest PID can adjust the duty ratio quickly  within a cycle? I don't understand the loop can be adjusted so fast., just one period. can you give me some opinion?

I also want to know in detail how to switch PID coefficients according Non-Linear Limit in UCD3138A? For example, change KP ,KI , KD in turn  or  modify the KP ,KI , KD as a whole?

Whether the way of change PID will affect dynamic response?


Best Wishes

LEI

  • 0
    TI__Intellectual 1390 points
    Lei,
    Do you use PCM control or voltage mode control. If it is PCM, you can use a separate DPWM to generate sample signal and set its frequency to be much higher than the switching frequency. In this way, the duty cycle can be quickly changed even within a switching cycle.
    However, if you use voltage mode control in which the DPWM edges are decided by the event register decided by CLA output, it cannot be changed out of the event_update_window to avoid the pules extension issue.

    Best Regards
    Frank