LTspice sim of Two transistor forward wont run.."singular matirx" error

[Flyback]

Hi,

Do you know why this LTspice sim of a two transistor forward wont run? The error message says “singular matrix node N029”.

 

[alec_t]

It ran for me (albeit so slowly I gave up after ~2mS), with "skip initial operating point solution" checked. At what sim stage did you get the error message?

 

[Flyback]

Thanks, Ive got a bit further now..as attached..but still not working

 

[alec_t]

This is what I'm seeing at what I assume is the output :-

Is that what you expect? What do you mean by 'not working'?

 

[Flyback]

..thanks, it should be working like this..(attached)..ie giving 100w at 24v at output

 

[alec_t]

I suggest you divide the circuit into manageable chunks, sim each chunk separately and hope to identify the chunk that's causing the problem.

 

[unclejed613]

usually if LTSpice has trouble establishing a stable operating point (errors are usually "time step too small, singularity matrix node(node-name)", or veeeeeery slooooow operation, it's because there's something causing the circuit to be unstable, such as positive feedback connected somewhere that expects negative feedback.