• State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 82 subscribers
  • Views 197 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TIDM-1000: F280039C

Smart Rotamac
Prodigy 60 points
Part Number: TIDM-1000
Other Parts Discussed in Thread: SFRA

Greetings of the day

Can I get the information related to the control loop COMPENSATION and how the values of Kp and Ki are calculated for TI-VIENNA kit of PFC and can I get that calculations from the Plant diagram?? 

#define PI ((float32_t)3.141592653589)

#define VIENNA_GI_GAINKP ((float32_t)2.0000000000)

#define VIENNA_GV_PI_KP ((float32_t) 0.3999748673)
#define VIENNA_GV_PI_KI ((float32_t) 0.0001256716)

#define VIENNA_GS_GAINKP ((float32_t)1.0000000000)

  • 0
    TI__Expert 5270 points

    Hello,

    This is obtained by runniing SFRA and compensation designer tools. 

    Please refer(6.4.2.1 and 6.4.2.2) in the design guide, that describes how the Kp, Ki values are obtained by using SFRA and then followed by compensation designer. 

    Best Regards,

    Uttam

  • 0 in reply to Uttam Reddy Pailla
    Prodigy 60 points

    Hello,

    Here i want to know that these Kp and Ki values are taken by Trial and Erroe method or by taking the SFRA data from the Hardward running followed by compensation designer tool then the tuned values are again run on the Hardware.

    If they are calculated then i want to get know about the calculations how they are.

    Best Regards

  • 0 in reply to Smart Rotamac
    TI__Expert 5270 points

    Hello,

    As mentioned above those are from using SFRA and compensator designer on the hardware. For example:  

    #define VIENNA_GI_GAINKP ((float32_t)2.0000000000)

    Best Regards,

    Uttam

  • 0 in reply to Uttam Reddy Pailla
    Prodigy 60 points

    Hello,

    The image what you have  sent is not opened and I want to get know that they are from the Trial and Error method. If you have any Simulation model for the PI Loop for the PFC and  can also get the transfer function for the PFC if available.

    Best Regrads

  • 0 in reply to Smart Rotamac
    TI__Expert 5270 points

    The image i share was from design guide, as pointed above its 6.4.2.2 from the design guide.

    Those are NOT trial and error NOR from simulation model.

    Those Kp, Ki are obtained by running it on actual hardware. Please understand how SFRA and design compensator works that might be the confusion here. 

    Once you run the system in open loop, by running SFRA tool you can obtain the plant model of the system i.e, bode plots which saves as excel file.

    Now, this data is passed to Design compensator tool, where data is loaded and select type of control (2p2z/3p3z...etc..) Now, adjusting the Kp, Ki, poles/zero values intuitively will give a closed loop response plots. 

    Let me know if you have any further questions.

    Regards,

    Uttam Reddy

  • 0 in reply to Uttam Reddy Pailla
    Prodigy 60 points

    Yes, I understood but here adjusting the Kp and ki means we have to test for the soo many values. May I know if there is any theoritical method for calculating the Kp and Ki for the system.

  • 0 in reply to Smart Rotamac
    TI__Expert 5270 points

    I am not aware of using other methods. 

    FYI, these digital compensator and SFRA tools use the equations itself. more showing in terms of GUI which is much simpler to understand your response--> as you have bode plots responses with open loop and adding the parameters how the closed loop response look like. 

    Unfortunately, this is done intutively. 

    Ideally, you need to be aware of what cutt-off freq, Gain margin is targeted for your system and then adjust the Kp value accordingly. Followed by adjusting your poles and zero to reach the expected cutt-off freq/gain margin. 

    Regards,

    Uttam