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PID Loop for Single Phase Inverter

Bhuvaneshwar kanade54447
Intellectual 680 points


Dear All,

               I have implimented PI loop for inverter to generate 230Vac in output. (ommited D term)

While configuring Voltage PI with Current PI and apply short circuit test Voltage PI value increases a lot and vice-versa.

Please Suggest what to do in this case. If system in Current PI (Current Limit) what should be done for Voltage PI calculation.

And if System in Voltage PI loop what to do of Current PI loop.

             I am new in PI loops and code written by me working fine in stand alone.

Thank You 

  • 0
    Guru 192875 points

    Hi Bhuvan,

    Please go through the basic fundamentals first 

    Refer: http://perso.uclouvain.be/anthony.papavasiliou/public_html/LCL.pdf

    Secondly, check for the correct algorithms for when these loops should be used. I'm using both these loops for the inverter application and follow a particular algorithm.

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Intellectual 680 points

    Hi Gautam,

            Thanks for your suggestion.

    Tha PI loop implemented by me is as follows and as per standard (i think, might not be perfect)

    error = ref - feedback

    prop_term = error * Kp

    sum of error = sum of error + error

    Integral term = sum of error * Ki

    integral term > max value

    integral term = max value

    PID out = prop_term + integral term

    this PID out i am using as multiplication factor (modulation index) for sine table.

    I am running this loop after receiving ADC sample in same rate of PWM for sine wave generation.

    I have omitted Derivative term.

    Is this correct ? or need any modification ?

    I have omitted Derivative term because it will make system slow (i think) that's why omitted it.

    Should i include Derivative term in Single Phase sine wave inverter is it recommended or usefull ?

    How to set Kp and Ki because in my case i have set Kp first then changed Ki to get good response ?

    When i am applying certain havy load 50% on system it gives spikes at output and stables later.

    How can i improve it ?

    Sorry for so many questions because i am struggling with it from past 1 month.

    Thank You in advance.

    Bhuvaneshwar

  • 0 in reply to Bhuvaneshwar kanade54447
    Guru 192875 points

    Hi Bhuvan,

    Please go through this post for more info:

    http://e2e.ti.com/support/microcontrollers/c2000/f/171/t/273451.aspx

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Intellectual 680 points

    Hi Gautam,

    This link shows need of IQMATH, but i want to know if my loop which i have mailed previously is it right one or need changes.

    My Questions are as follows.

    "

    The PI loop implemented by me is as follows and as per standard (i think, might not be perfect)

    error = ref - feedback

    prop_term = error * Kp

    sum of error = sum of error + error

    Integral term = sum of error * Ki

    integral term > max value

    integral term = max value

    PID out = prop_term + integral term

    this PID out i am using as multiplication factor (modulation index) for sine table.

    I am running this loop after receiving ADC sample in same rate of PWM for sine wave generation.

    I have omitted Derivative term.

    Is this correct ? or need any modification ?

    I have omitted Derivative term because it will make system slow (i think) that's why omitted it.

    Should i include Derivative term in Single Phase sine wave inverter will it be recommended or useful ?

    How to set Kp and Ki because in my case i have set Kp first then changed Ki to get good response ?

    When i am applying certain heavy load 50% on system it gives spikes at output and stables later.

    How can i improve it ?

    Sorry for so many questions because i am struggling with it from past 1 month.

    "

    Thank You in advance.