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LAUNCHXL-F28379D: Conveting DCL PI C1 parameters to DCL PI C5 parameters

gG
Intellectual 915 points

Part Number: LAUNCHXL-F28379D

Hi,

My designed PI C1 controller is in series form doesn't work as I expected, because of no anti-windup. Therefore, I want to upgrade it to PI C5 form which has parallel form and anti-windup. Therefore, I need to convert PI C1 parameters to PI C5 parameters.

First of all, could you please provide me formula to convert kpd and kid parameters designed for PI C1 to PI C5?

Secondly, there are integrator upper and lower limit for PI C5. How can I decide them?

I'm using simulink models of this controllers to simulate my system. Firstly, I will try it at simulation first and after that reflect them to my c code.

Thank you in advance.

  • 0
    TI__Expert 7835 points

    For PI gain, since C1 is serial and C5 is parallel, here is the conversion formula:

    Kp_C5 = Kp_C1

    Ki_C5 = Kp_C1 * Ki_C1

    For the integrator limitation, you will need to decide based on your system characteristics and tuning / simulation. But for start up, you can set it to the same as output limit.

  • 0 in reply to Han Zhang6
    Intellectual 915 points

    Dear Han Zhang6,

    I just want to confirm it again. PI C1 and PI C5 are digital controllers. I thought that your above explained formula may only be applicable for analog controllers not for digital controllers.

    Could you please confirm it again?

    Depending on simulation of my system for PI C5, my controller performance is very dependent on integrator upper limit. Is there any ti application note available to tune PI C5 parameters?

    Thank you for your help...

  • 0 in reply to gG
    TI__Expert 7835 points

    For the gain formula, I can confirm. You can also easily derive them out for the block diagram in the user's guide of DCL.

    Regarding PI tuning, there is nothing special on our DCL library implementation. Please refer to control theory book or paper for more information.

  • 0 in reply to Han Zhang6
    Intellectual 915 points

    Hi,

    Thank you for your help. I got it.