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LTspice sim of inverter just grinds to a halt?

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cupoftea

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Hi,
Do you know why the attached LTspice sim just stops working at about 56ms?
 

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  • 50hzINVERTER.zip
    5.7 KB · Views: 97

First guess is a numerical problem in one or more of
the element models, that has gotten the simulator
"out over its skis" to where it can't back down the
timestep enough to get convergence (because the last,
was insane and the insanity does not repeat neatly).

zero-capacitance nodes (as often are found in
behaviorals) are one way to get there. LT loved behaviorals
for a couple of reasons (one being, you don't get to
look inside their encrypted ones - so good luck with
the debug).

Try optional transient algorithms like Euler and higher
order TrapGear (if those are accessible - never spent
that much time with LTSpice options). Try setting a cmin
value to load down the matrix some, which could hold
things that blow up to NaN now, to a valid floating point
range.

Barf messages might point to a node that fails to converge
(if you let it sit long enough). If you set the sweep time to
barely before the error-time, you might be able to eyeball
some "well, that's not right..." that leads to the culprit.
 
LTspice isn't really well performing in power electronics and similar non-linear circuit simulations. A general hint to improve convergence is to add SPICE directive ".options cshunt=1e-15".

You may also want to review respective discussions at https://groups.io/g/LTspice/topics
 
Thanks, ill take a look, the LTspice sim now works, but is extremely slow...any tips on speeding this particular sim up appreciated?
 

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  • 50hzINVERTER_jan3_SINE CHEAT.zip
    7 KB · Views: 99

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