Hello,

I am trying to recreate the characteristic current draw of V1 for a six pulse bridge rectifier (see here: https://abm-website-assets.s3.amazonaws.com/impomag.com/s3fs-public/embedded_image/2016/11/Figure B (page 19).jpg ).

Despite being a simple circuit (?), I run into problems when varying the parameters of the circuit. For R=40 the simulation runs fine, for R=50 the simulation time seems to wait forever. When varying parameters I either ran into a "time step too small" error or a "singular matrix" error.

I have tried:

• ... selecting a diode model - https://forum.allaboutcircuits.com/threads/3-phase-rectifier-ltspice-simulation.19137/
• ... adding a 1MEG resistor between the voltage sources and the ground
  
• ... setting an initial load for the capacitance via e.g IC=0.001
• ... adding 1m resistors in the line

However, nothing really helped. Do you have any ideas?

 

hi,
If I follow you correctly.?
Using a 40R or 50R the sim is almost instantaneous for me.?

E

 

Sorry, you are right. This version of the circuit simulates until R=100, but not for R=150.

P.s.: The version I was referring to is attached in this post. It simulates for R=40, but not for R=50 OR R=30

 

Sim in post #3 runs ok for me for any value from 30 to 50. What version of LTS are you using? Which OS?

 

 

@Alec_t : Thank you for trying it out. Your result surprises me. I am using LTS XVII, just did a fresh reinstall from their website. My machine runs Win7. Why would it run on your machine and not on mine?

@Bordodynov : I believe you simulated the circuit from my first post. In that post, I attached another circuit, not the relevant one, which can be found in my second post (post #3). Sorry for my error.

 

P.s.: More accurately, R=30 simulates, but takes minutes instead of less than one second for R=40. R=50 has not finished within about 10 minutes.

P.s.s.: It seems to work if I choose Control Panel > SPICE > Engien > Solver > "Alternate" instead of "normal". Still, I believe a cleaner solution would be to make the circuit more realistic by introducin additional resistors or properties. I am grateful for any more hints.

 

See

 

Why would it run on your machine and not on mine?

One of life's mysteries . I'm running the latest LTS XVII update on Win 10.

 

Hi

I just added some resistance to each voltage source.
Simulation completed in 210 milliseconds.



eT

 

Adding the series resistance seems to do the trick. Even if I add an inductance of 0.4mH to the 1Ohm resistance, it simulates within seconds with the normal solver. Thanks a lot @eetech00 !