Anyone have experience using PSUD2?

John S. · 24th January 2002, 11:23 PM

I've been using PSUD2 to design a power supply for a project amp and have run into a problem.This is a full wave type with a tube rectifier, pi filter, and 3 current taps. Peak current draw should be about 175ma and is reasonable for the design. It SHOULD work,but I keep getting an error message saying that "A current sink has pulled the voltage below zero for more than 5 mains cycles". I've tried dropping the current and still get the same message. Is there a bug in this program or what?

Petter · 26th January 2002, 09:22 PM

Hi,

You are probably getting this warning because you are using constant current source draw. The analogy goes like this:

1. The current source is perfect and starts immediately at full current.
2. The power supply takes some time to charge up, particularly when using inductors.
3. The current source makes the voltage across it negative which would not happen in real life.

I suggest you change into a resistive load, or set up stepping, say value 1: 0, value 2 to what current you want, time: 2 seconds (or any other value). Unless you have something really radical to confuse PSUD2 (I have done it), you should still end up with correct levels. I also suggest you turn on the soft start option as well to reduce the risk of confusing the simulator.

I did a lot of beta testing on PSUD2, and find it most useful. Quick, accurate enough etc. If nothing else, it is great value (being free

)

Petter

John S. · 26th January 2002, 09:41 PM

That sounds like what's going on. I figured that using constant current would probably model better in places where class A stages were tied to the supply. I wish there was some documentation to go with this program. I find help menus annoying with complex programs, especially CAD stuff. I want a manual, so I can read as I go along. The help menus put you on pause. I'm probably not the only one that feels this way. I DO admire the fact that Mr. Munro has put it out here for free. Can't imagine how much work went into it. Thanks for the reply and I'll give it a try.

John S. · 26th January 2002, 11:31 PM

I seem to have better results with the constant current loads and setting them up as stepped,rather than use the resistive loads. I tried modelling a couple of known power supplies and have a little better grasp of what's going on here. Now if I can just figure out the ESR on caps and the source impedance, I'll be in decent shape.

24th January 2002, 11:23 PM	#1
John S. diyAudio Member Join Date: Nov 2001 Location: Massachusetts	Anyone have experience using PSUD2? I've been using PSUD2 to design a power supply for a project amp and have run into a problem.This is a full wave type with a tube rectifier, pi filter, and 3 current taps. Peak current draw should be about 175ma and is reasonable for the design. It SHOULD work,but I keep getting an error message saying that "A current sink has pulled the voltage below zero for more than 5 mains cycles". I've tried dropping the current and still get the same message. Is there a bug in this program or what?

26th January 2002, 09:22 PM	#2
Petter diyAudio Member Join Date: Jan 2001 Location: Scandinavia	Inital conditions Hi, You are probably getting this warning because you are using constant current source draw. The analogy goes like this: 1. The current source is perfect and starts immediately at full current. 2. The power supply takes some time to charge up, particularly when using inductors. 3. The current source makes the voltage across it negative which would not happen in real life. I suggest you change into a resistive load, or set up stepping, say value 1: 0, value 2 to what current you want, time: 2 seconds (or any other value). Unless you have something really radical to confuse PSUD2 (I have done it), you should still end up with correct levels. I also suggest you turn on the soft start option as well to reduce the risk of confusing the simulator. I did a lot of beta testing on PSUD2, and find it most useful. Quick, accurate enough etc. If nothing else, it is great value (being free ) Petter

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
PSUD2 help needed	soundbadger	Tubes / Valves	5	2nd November 2007 04:27 PM
Psud2 Help	soundbadger	Tubes / Valves	5	31st October 2007 10:19 PM
PSUD2 Q on regulator	JoshK	Tubes / Valves	20	31st August 2007 09:27 PM
when using PSUD2, do you...	jarthel	Tubes / Valves	13	15th August 2006 02:08 AM
PSUD2 question	resident	Tubes / Valves	8	6th October 2004 12:02 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

26th January 2002, 09:41 PM	#3
John S. diyAudio Member Join Date: Nov 2001 Location: Massachusetts	That sounds like what's going on. I figured that using constant current would probably model better in places where class A stages were tied to the supply. I wish there was some documentation to go with this program. I find help menus annoying with complex programs, especially CAD stuff. I want a manual, so I can read as I go along. The help menus put you on pause. I'm probably not the only one that feels this way. I DO admire the fact that Mr. Munro has put it out here for free. Can't imagine how much work went into it. Thanks for the reply and I'll give it a try.

26th January 2002, 11:31 PM	#4
John S. diyAudio Member Join Date: Nov 2001 Location: Massachusetts	I seem to have better results with the constant current loads and setting them up as stepped,rather than use the resistive loads. I tried modelling a couple of known power supplies and have a little better grasp of what's going on here. Now if I can just figure out the ESR on caps and the source impedance, I'll be in decent shape.