TransformerPS1S2 Issue

[tomhajjar]

I'm having issues trying to get a 6-phase rectifier circuit to work. I sent the netlist over to the ngspice guys and they found a possible error with .SUBCKT Transformers_TransformerPS1S2. The netlist line "R3 nSPlus nSplus {RS1}" is wrong. There may be other errors in the .SUBCKT.

https://sourceforge.net/p/ngspice/discussion/133842/thread/c4ecc7c227/

6_Phase_Rectifier.zip

TODO list:

• Fix short circuit in transformer model
• Add TD parameter for sine source
• Deprecate red AC source

[ra3xdh]

I have fixed the short circuit in the library by the latest commit, but the convergence error remains. I cannot say why this simple circuit still give the convergence error in Ngspice. You can grab the fixed library here: https://raw.githubusercontent.com/ra3xdh/qucs_s/current/library/Transformers.lib

[tomhajjar]

Holger recommendation is shown below. I cannot find "chgtol" in the Qucs Transient properties settings.

You may add this line to the netlist.
.options abstol=10u chgtol=1e-10 method=gear
Because you have high voltages, chgtol and abstol reduce the precision requirements, especially the gear method here yields a transient solution. It looks strange though, and you should simulate up to 1 s to see the output signal decay.

[ra3xdh]

Yes, the options helps. You may use the .OPTIONS device.

[tomhajjar]

Output is wrong. Supposed to look like the following.

Dietmar made the following comment:

"The first gnd node in transformer is obsolete and can removed in subckt definition and call."

If I disable TRAN1, the output is unchanged...

[tomhajjar]

Holger said to use Delay instead of Phase for the AC source. This and the changes to Transient Parameters allows the analysis to be correct starting at T=0 instead of having to wait a long time for the system to settle. Holgers explanation points out why I was having so many issues.

#362

Can the new Spice "ac Voltage Source" have VO (offset), VA (amplitude), FREQ (frequency), TD (delay), THETA (damping) and PHASE (phase) added as the default entry parameters? Presently it has "Vac" which is meaningless. The "V source" usage is a bit confusing.

Dietmar pointed out that the "gnd" entry for .SUBCKT Transformers_TransformerPS1S2 as shown below is unused. Is this a mistake?

.SUBCKT Transformers_TransformerPS1S2 gnd nPplus nPneg nSplus nSneg nSPct L1=0.5 L2=0.125 L3=0.125 K12=0.99 K13=0.99 K23=0.99 Rp=2 Rs1=1 Rs2=1

Attached is the "good and bad" schematics.

6_Phase_Rectifier.zip

[ra3xdh]

Can the new Spice "ac Voltage Source" have VO (offset), VA (amplitude), FREQ (frequency), TD (delay), THETA (damping) and PHASE (phase) added as the default entry parameters?

Yes, you may use the generic SPICE source for this purpose:

Dietmar pointed out that the "gnd" entry is unused. Is this a mistake?

No, this is done intentionally for Qucs compatibility. This node never caused problems before.

[tomhajjar]

The "ac Voltage Source" at the bottom of the Sources menu is a Spice only component so Qucs compatibility isn't an issue. It has a single default entry of "Vac" which is wrong. ngspice thinks it is a DC source. Why was this device created when "V Source" is already available?

Can you alter "ac Voltage Source" by adding all the parameters to the Menu so the User can change them?

[ra3xdh]

Yes, I have just added the TD and VO parameters for AC source. This fix will be available since the new release.

[tomhajjar]

The "ac Voltage Source" at the bottom of the Sources menu will still be wrong if not changed or deleted. Why was it created?

[ra3xdh]

Why was it created?

This device was added by @MikeBrinson long time ago. I cannot say what was the purpose for this device. I am also finding two type of source confusing. I may delete it in the next release. The V source device would be sufficient if one need full SPICE definition.

[ra3xdh]

I have deprecated the red AC source. The remaining issues with the transformer library will be fixed in #367 Closing this as completed.