Daniel,
I have seen this issue before. I believe that the problem is that the solver is increasing the step size until it steps over all of your activity and misses it. Your model has no dynamics so the accuracy condition is not being triggered in the solver, the solver responds by taking larger and larger steps. Eventually it steps over all of your activity. (Your triangle waveform is perfect -- I can pick any point in time at random and have the full accuracy of that waveform) You can see this if you check off "All Solver points" in the settings and run the simulation, then do plot properties and under datasets check "show data points". You will now see all your solver points and you can see it jump across regions -- in fact it is likely timed perfectly to hit all the zero points of your triangle waveform. So as far as the solver is concerned, there is no problem (although you miss all the activity!)
To fix the problem do one (or more) of the following:
- set your simulation time to better match the dynamics -- i.e. look at a few milliseconds of simulation.
- set a maximum step size that is less than the period of the triangle so it must get the triangle waveform.
- change to the CVODES solver -- I have found this tends not to jump over predetermined waveforms as much as DASSL does.
- don't worry about it until you hook up the inverter model to something dynamic -- at which point the solver must meet accuracy constraints and will adjust the stepsize as needed. (you still might need to set a maximum step size but I think most situations will fix themselves automatically). As an exercise drop a voltage source and a resistor in there and see what happens.
Regards