buck boost converter

Discussion in 'The Projects Forum' started by lapputappu, Nov 26, 2009.

  1. lapputappu

    Thread Starter New Member

    Nov 25, 2009
    16
    0
    Hiiiiii frnds i hav simulated a buck-boost converter in matlab simulink for 24v iinput to 160 v output . basically it is only using the topology of boost converter . i m attaching the design of boost concerter. and also the output after getting boosted .
    The problem is the output contains too much ripples and harmonics and variation in output dc voltage .
    so can anyone help me in this topic how to control this .....
     
  2. kokkie_d

    Active Member

    Jan 12, 2009
    72
    0
    Hi,

    You forgot to attach your design.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You may have tried to attach a file that was too large, or not in an acceptable format.

    The best way is to make a screen print using Ctrl+PrintScreen or Alt+PrintScreen, and paste the image into MS Paint. Save it as a .png file. .png format files are compact and are not "lossy" like .jpg files are.

    Then use the "Go Advanced" button below the text box, and on the next screen click the "Manage Attachments" to select your image files to upload.
     
  4. lapputappu

    Thread Starter New Member

    Nov 25, 2009
    16
    0
    sorry frnd i hav reloaded the picture if u can den plz thanx in advance
    here u can see that the output is across the parellel resisitance and capacitor which is about 340v . this can be minimised by reducing the inductor value
     
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  5. SgtWookie

    Expert

    Jul 17, 2007
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    Your values for R1 and C1 are not very realistic.
    R1 is 50 Ohms. Increase it.
    C1 is 2.5uF. Increase it.
    It is not surprising that you have a huge amount of noise at your output.

    You could add an inductor just after the diode to remove some of the noise.
     
  6. lapputappu

    Thread Starter New Member

    Nov 25, 2009
    16
    0
    as per u i increased the value of res nd cap
    as r1 =8e3
    c1=50e-5
    and the obtained output is i m attaching .

    After applying inductor nxt to the diode it reduces the output value and also produces interruption in output like slow increment in output
     
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  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    Reduced the output voltage? All you had before was noise spikes! Now you have something that you can work with.

    It looks like you did not allow as much time for the simulation to run as you did in the previous simulation that was all noise.

    You did not post an image of your modified circuit.

    The added inductor needs to be between the diode and the load.

    It will help to reduce the noise more if there is another capacitor, perhaps 33uF, from the junction of the diode and new inductor, and ground.
     
  8. lapputappu

    Thread Starter New Member

    Nov 25, 2009
    16
    0
    thanx yaar but plz dis tym my system is out of order
    so i will post the new circuit after sum days
     
  9. lapputappu

    Thread Starter New Member

    Nov 25, 2009
    16
    0
    now my simulation work is over .
    this time i hav to implement this topology to make a hardware of dis system so can anybody plz help me to make hardware of this project
    like the components used
    circuit diagram implemented
     
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