Multisim simulation freezes

[rnbd81]

Hi all

I've played around with multisim for a couple years now, but just now began to really utilize the simulation features of the program.  I noticed that transient analysis of very basic circuits seem to operate just fine, but anything more than that (especially those utilizing pwm controls) bog down after some ridiculously short period of time.  Also, before it freezes, things like the oscilloscope output operate quite slowly.  I've attached my circuit for reference, and help from all you wonderful folks out there.  What am I doing wrong?

The error fix wizard doesn't really take care of the problem.

FYI, this is a high power inverter circuit for which I would like to investigate the out performance characteristics by varying the frequency of the triangle wave and/or adjusting the amplitude of the sine wave from 0 to 1. The goal is to produce sinusoidal current output to the primary of the transformer.  The leakage inductance and conductor resistances have been modeled, as well as an inductive load on the transformer secondary.

Thanks!

[rnbd81]

PS

I noticed that if I delete the inverter circuit and just measure the dual pwm output voltages from the comparator things simulate just fine.  Perhaps my IGBT's are wrong? 

[Miguel_V]

Hello,

If this is about your simulation stopping due to your timestep being too small, I managed to get your circuit working properly be changing the relative tolerance. So after you select which simulation you want to run, go to Analysis options » Use custom settings » Customize and change the RELTOL (relative error tolerance) value to 0.01.

Hope this helps,

[rnbd81 · Accepted solution]

Yea I tried that a few days ago along with all the other typical timestep fixes and it still didn't work. The solution was to replace the igbt's with idealized voltage controlled switches and antiparallel schottky barrier diodes....and ground the transformer floating seconday. It works now