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Find the range of K for stability

  1. Mar 14, 2017 #1
    1. The problem statement, all variables and given/known data
    Find the range of K for the closed loop system to be stable.
    ##G_{OL}(s) = \frac{10}{s-5}##

    2. Relevant equations


    3. The attempt at a solution
    ##G_{CL}(s) = \frac{KGol}{1+Gol}##
    ##G_{CL}(s) = \frac{10K}{s-5+10K}##
    ##-5+10K>0##
    ##K>\frac{1}{2}##
    is this correct?
     
  2. jcsd
  3. Mar 14, 2017 #2

    LvW

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    No - the quation for Gcl is not correct (assuming Gol is the open-loop gain and K is the negative feedback factor).
    We have Gcl=Gol/(1-LG)
    with Loop Gain LG= - Gol*K.
     
  4. Mar 14, 2017 #3

    donpacino

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    Gold Member

    In this context I am guessing that K is the amplifier block before the open loop gain that can be adjusted, also known as the DC gain of the controller. I am guessing Gol is really the open loop gain of the plant.
     
  5. Mar 14, 2017 #4

    donpacino

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    Gold Member

    Jdoe10, can you provide us with a block diagram or more information?
     
  6. Mar 15, 2017 #5

    LvW

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    jdoe10 - please, please, be so kind and give us the chance (necessary information) to answer your question.
     
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