Singular Matrix error node on LTSpice

[Stephane38]

Hi,

I have designed some piezo harvested circuits designed in LTspice as attached.
The first one is a simple case, the piezo is modelised by the current source I1 and the C1 capacitor. Then there is an diode bridge and finally a storage capacitor C2.

In the second design, I added a sw which has to closed when the I1 current reach 0A (SSDC).
When i want to run my design with an 0.025A, it poped up with "Singular Matrix: check node entre- Iteration no4"
BUT when I change to a 0.024A, there is no pb and I have the results I want.

Then the last circuit arrives, it's the same with an inductor (SSDCI).
It poped up with "Singular Matrix: check node n001 Iteration no4"
So there is a pb with C1 node. When I add a node to n001, the problem is solved but that isn't the results I want to use the diode bridge rectifier (like the first circuit but with an switch).

If someone can help me please ?

 

[alec_t]

Use 'real' diodes instead of the default generic ones and the sims should run ok.
Welcome to ETO!

 

[eTech]

Hi,

I have designed some piezo harvested circuits designed in LTspice as attached.
The first one is a simple case, the piezo is modelised by the current source I1 and the C1 capacitor. Then there is an diode bridge and finally a storage capacitor C2.

In the second design, I added a sw which has to closed when the I1 current reach 0A (SSDC).
When i want to run my design with an 0.025A, it poped up with "Singular Matrix: check node entre- Iteration no4"
BUT when I change to a 0.024A, there is no pb and I have the results I want.

Then the last circuit arrives, it's the same with an inductor (SSDCI).
It poped up with "Singular Matrix: check node n001 Iteration no4"
So there is a pb with C1 node. When I add a node to n001, the problem is solved but that isn't the results I want to use the diode bridge rectifier (like the first circuit but with an switch).

If someone can help me please ?

Hi

Use the "startup" option with the tran statement, like this:

tran 2 startup

or check the checkbox "Start external DC supply voltages at 0v:".

If you don't do this then the simulator expects the user to set all initial operating conditions.

After I checked this box all ran with no issues.

eT

 

[Stephane38]

Use 'real' diodes instead of the default generic ones and the sims should run ok.
Welcome to ETO!

Thanks a lot it is working now!

Hi

Use the "startup" option with the tran statement, like this:

tran 2 startup

or check the checkbox "Start external DC supply voltages at 0v:".

If you don't do this then the simulator expects the user to set all initial operating conditions.

After I checked this box all ran with no issues.

eT

Hey, it didn't fixed my pb but it is good to know!

Thanks guys