pspice problem

Discussion in 'Homework Help' started by crazyengineer, Jun 4, 2012.

  1. crazyengineer

    Thread Starter Member

    Dec 29, 2010
    156
    2
    Hello! For my power electronics research, I have to run a simulation of a buck-boost converter using Orcad. However, when I run the file, I keep running into this error

    "Convergence problem in transient analysis at Time = 33.82E-06
    Time step = 363.8E-21, minimum allowable step size = 2.000E-18"


    I included the file as a reference
     
  2. WBahn

    Moderator

    Mar 31, 2012
    17,768
    4,804
    A lot of things can cause convergence problems. One of the most common is any node that is isolated (known as a charge storage node) or is multistable (such as a registor or other memory element).

    If you can identify any of those nodes, then put Initial Conditions on them that seem reasonable. This will almost always let it converge if this is the problem.

    Don't have stimulus inputs that make instantaneous changes; be sure they all have reasonable rise/fall times. Also, make sure that you have some dead time at the beginning of your simulation in which nothing is happening.

    Another thing to look at is the integration method. There are generally several to choose from. Each has strengths and weaknesses so using a different method might be a better match for the kinds of transients you have in your circuit.

    There are lots of other things you can try, as well, but let's see if any of these solve the problem, first.
     
    absf likes this.
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