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LTspice simulation

Discussion in 'General Electronics Discussion' started by meysaminter, May 23, 2012.

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  1. meysaminter

    meysaminter

    4
    0
    May 14, 2012
    Hi,
    I want to simulate a power supply circuit in LTspice . but when I begin the simulation , it takes very long time and after two days it is steel simulating!!!!
    during the simulating the " Damped Pseudo-Transient Analysis ...." fraze apear in software .I don't know my circuit has problem or my simulation progress ? simulating file and related library files for parts is attached . plz help me with this problem .
     

    Attached Files:

  2. Harald Kapp

    Harald Kapp Moderator Moderator

    9,544
    1,970
    Nov 17, 2011
    WIthout loading the complete simulation:
    Your circuit (Draft1.asc) has two completely separated sub-circuits (to the ledt of transformer and photocoupler and to the right of transformer and photocoupler). While physically this is correct, this is a problem for the SPICE algorithm because the two sub-circuits are independent (mathematically).
    Try adding GND to the left sub-circuit (for simulation only)
    OR
    connect the emitter and cathode of the photocoupler's transistor and LED by a large resistor (e.g. 10 Meg).
    This will couple both sub-circuits and enable SPICE to calculate the matrices.

    A desperate alternative is to add additional capacitances (.OPTIONS cshuntintern) or resistors (.OPTIONS gshunt) from every node to GND. Use these Options with a lot of caution!


    Harald
     
  3. meysaminter

    meysaminter

    4
    0
    May 14, 2012
    ok I corrected the circuit and now LTspice can simulate it but I want to have 1000 volt output and now it has 0 volt !!!! can anybody help me to correct the circuit?
     

    Attached Files:

  4. Harald Kapp

    Harald Kapp Moderator Moderator

    9,544
    1,970
    Nov 17, 2011
    Sorry, no idea. The simulation gives awkward results like the power supply not being 20 V (but the model is set to 20 V).

    I suggest you break down the circuit and start by getting subcircuits going first.
    As a first step you could remove the transformer and the TL494 and TL431. Just control the IR2110 by a pulse waveform source and get the MOSFEt control working.
    Next add the transformer and get it going.
    Next add the TL494 (but not the TL431) and get the PWM controller working (use a fixed voltage source instead of the TL431/optocoupler feedback circuit)
    Finally add the TL431 feedback circuit and get that going.

    By now everything should work.

    Harald
     
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