Good Evening All.

I am trying to combine two separate circuits. The 1st. is a self-resonating TANK/LC circuit derived from the days of radio about 80 years ago. The second is a Current limiting PWM circuit which I have been using now for about 2 years in my vehicles (brute force hydrolysis). I have All three of the circuits set up and running in LTspice. Both the first and second circuit run fine and as expected in LTspice.
When I combine (or try to combine them, I am probably missing some obvious solution to this), I get the wanted waveform and function ONLY when I connect a simulated load of 29 amp.s or greater between the two circuits.
I'm not sure what effect this simulated load has on making the two circuits function as wanted. Apparently something is not balanced in the circuit.
The idea to combine the two circuits is to end up w/ a circuit which automatically finds resonance, takes that waveform and gates it via the current limiting PWM. This would allow some level automatic regulation of the in-resonance waveform.
This is indeed what happens w/ the LTspice simulation.
Here is the link for the files: http://tech.groups.yahoo.com/group/LTspice/files/ Temp/
I have already uploaded to the LTspice group at Yahoo.
The file is : PMW modified_self_resonating.zip
Just go down the page and double click on the file.
I would appreciate any and all comments regarding this circuit. I am by far only a novice, and could benefit from the experience of a forum such as this one.
Thanks in advance
Lost_bro

 

Hello,

The link does not work.
You can upload the attachments here in the AAC.

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Bertus

 

You have to be a member of the Yahoo! LTSpice group in order to have access to the files area.

To save some time/trouble, the .zip file is attached to this post.

LM339.sub goes in \Program Files\LTC\SwitcherCad\lib\sub
potentiometer_gm.lib goes in \Program Files\LTC\SwitcherCad\lib\sub
potentiometer_standard.asy goes in \Program Files\LTC\SwitcherCad\lib\sym
There was no .sym file supplied for the LM339.
The .ASC files go in \Program Files\LTC\SwitcherCad

There is a .jpg image in the .zip that does not get extracted to the SwitcherCad directory.

 

I don't suppose you noticed, but you have your load on the source terminal of the MOSFET, and as a result, there is no way for you to maintain Vgs=10v once the MOSFET turns on. If you hold down the ALT key while clicking on M1 during the simulation, you'll see that the MOSFET is dissipating about 150 Watts of power.

 

Good afternoon SgtWookie

Yes, your absolutely right. I went ahead and modified the diagram, placing the the connection to the TANK cir. directly to the emitter on M1.
Please note that the Simulated load is necessary to get the PWM to simulate in LTspice.
Both circuits as drawn do what I want them to do. Check the waveform of the votage of TANK circuit, and the waveform at the emitter of M1. Looks Good.
Then: disconnect the Simulated Load from the emitter at M1 and connect it to Point X , don't forget to erase the ground at Point X also.
Now, the timing Cap in the PWM (C1) is no longer regulating the frequency of the LM339. The entire PWM side of the circuit is operating at the resonant frequency of the tank circuit.
How to uncouple them so the PWM will actively gate (I know it is NOT technically gating because I am manipulating the Collector and not the Gate) the tank circuit but not be affectd by the resonant frequency of the tank circuit?
Is it possible to make the circuit do what I want it to?
The JPEG in the file is what the gated waveform looks like (the wavefrom I am trying to produce). I produced it manipulating the last version of the Pwm, but of course the circuit was not functional in real life.

Thanks for the suggestions
Lost_bro

 

Good afternoon SgtWookie

Yes, your absolutely right. I went ahead and modified the diagram, placing the the connection to the TANK cir. directly to the emitter on M1.
Please note that the Simulated load is necessary to get the PWM to simulate in LTspice.

You have used the current source as a constant current.
Right-click the current source, click the Advanced button, and check the "This is an active load" box on the right, under "Parasitic properties".

Otherwise, it will continue to output current even while the MOSFET is off.
Did you know that the 4148 diodes are only rated for 100mA? They would get rather crispy rather quickly with 30A flowing through them.

Both circuits as drawn do what I want them to do. Check the waveform of the voltage of TANK circuit, and the waveform at the emitter of M1. Looks Good.

M1 does not have an emitter. M1 is a MOSFET. It has a gate terminal, a source terminal, and a drain terminal.

Then: disconnect the Simulated Load from the emitter at M1 and connect it to Point X , don't forget to erase the ground at Point X also.
Now, the timing Cap in the PWM (C1) is no longer regulating the frequency of the LM339. The entire PWM side of the circuit is operating at the resonant frequency of the tank circuit.

How to uncouple them so the PWM will actively gate (I know it is NOT technically gating because I am manipulating the Collector and not the Gate) the tank circuit but not be affectd by the resonant frequency of the tank circuit?
Is it possible to make the circuit do what I want it to?

I don't know why you're trying to do this. The "electrolyzer cell" will have some resonant frequency due to the capacitance of the plates and the inductance of the wiring, but in order to break down the water to it's elements, you need to pass current through it. About the best you can possibly hope for is 70% efficiency on a very good day with a tailwind while going downhill.

The JPEG in the file is what the gated waveform looks like (the wavefrom I am trying to produce). I produced it manipulating the last version of the Pwm, but of course the circuit was not functional in real life.

Of course not.

It's based on wild-eyed claims by people who somehow think they can overcome the laws of conservation of energy. What they're actually doing is reaching their hand into your wallet while you're not looking.

 

Good evening SgtWookie

Thanks for the fast response.

You have used the current source as a constant current.
Right-click the current source, click the Advanced button, and check the "This is an active load" box on the right, under "Parasitic properties"./QUOTE]

Yes, I was in a hurry. Have included the corrected file.

Otherwise, it will continue to output current even while the MOSFET is off.
Did you know that the 4148 diodes are only rated for 100mA? They would get rather crispy rather quickly with 30A flowing through them/QUOTE]

Yes, if the 4248 diodes were part of the actual finished circuit they would cook rather nicely.

As I said...

Please note that the Simulated load is necessary to get the PWM to simulate in LTspice./QUOTE]

Please note that the diodes are enclosed within the Simulated Load Circle.

M1 does not have an emitter. M1 is a MOSFET. It has a gate terminal, a source terminal, and a drain terminal./QUOTE]

Yes, I was thinking about Q1 when I wrote that.

I don't know why you're trying to do this. The "electrolyzer cell" will have some resonant frequency due to the capacitance of the plates and the inductance of the wiring, but in order to break down the water to it's elements, you need to pass current through it. About the best you can possibly hope for is 70% efficiency on a very good day with a tailwind while going downhill./QUOTE]

Well my friend, Science makes progress utilizing the foundations of another just as much as it does when new foundations are built.
I do not critique the other. In this game I listen to all suggestions and then draw My own conclusions.
I am well aware of Tesla, Edison, Stanley Meyers, etc.
I also believe everyone is entitled to there own opinions.
I come to this forum to Learn from the more experienced.
I hope I have not offended anyone with my point of view.

Still my question remains unanswed:

Please review my latest ( and hopefully correct) upload. This time the two circuits are interconnected (at the DRAIN of the MOSFET) and the Load is set correctly.
Please note the 'Gated' waveform I want the utilize.
Please note that w/o the LOAD, it will not Gate the tank circuit.
Do you know any tricks for making the circuit perform as needed, ie: to make the circuit run, gated tank circuit, w/o the Load in place?
I would greatly appreciate the Electronics advice.

I thank you for your time.

Lost_bro

 

I eliminated your 20A current source model because I don't feel that it's realistic to assume that your cell will have a constant current across it.

What I do feel is realistic, is a relatively constant voltage drop across it, depending upon the current flow through it. This is better modeled using a semiconductor diode, or a series of diodes.

I've replaced your current source with four diodes rated for 25A; they're in the default LTSpice library.

Changing to a more realistic load model made it necessary to decrease the values of R1 and C1. Since there is no inductance in the load, the current is an "all or nothing" affair. Attempting to control current through a diode load w/o inductance using simple PWM will be rather fruitless, as you will see. Adding an inductor in series with the load will smooth things out.

I did some cleaning up on your schematic. All of the spice parameters were combined into a single list. I cleaned up the potentiometer symbol file, since it was off-center. If you start using this new .asy file, you will see that the alignment is different from your original. It has the potentiometer_standard.sub as a model included in the .asy file so you no longer need to have that .include in spice directives.

You seem to like to sprinkle lots of diodes around, for what reason I don't know.

 

Good evening SgtWookie

Thanks for the fast reply.

I will review your suggestions and get back to post ASAP.

Have a great evening

Lost_bro

 

How lovely of you to patronize us -

Well my friend, Science makes progress utilizing the foundations of another just as much as it does when new foundations are built.
I do not critique the other. In this game I listen to all suggestions and then draw My own conclusions.
I am well aware of Tesla, Edison, Stanley Meyers, etc.
I also believe everyone is entitled to there own opinions.
I come to this forum to Learn from the more experienced.
I hope I have not offended anyone with my point of view.

We've had run-ins with similar free spirits in the past. There was never a good outcome. Something about pointing out that science doesn't respond well to wishing.

You are free to peruse the threads linked to in the sticky - http://forum.allaboutcircuits.com/showthread.php?t=28067

But I'm afraid the topic has come to a close.