Another Switching Idea

[Breakable]

All those switching threads got me thinking and I have (I think) an original idea:
what about developing/using multiple lower power-lower voltage switches with very good control ratio and connecting them in parallel and/or serial. While one switch would not be able to hold sufficient voltage and/or amperage maybe it is possible to control them sufficiently well that multiple ones would.
Maybe serial connection would be better than parallel (could be more forgiving to mis-control). Also the use of vacuum tubes seems to be applicable in this scenario.

[mchargue]

As I understand the current switch, it comprises 12 spark-gaps to decrease the current density through any single conductor, (switch) and already represents a problem with timing between the various switches. Increasing the number would further decrease current density through any one switch, but would likely increase the timing problem.

Unless & until a better mechanism is put in place to resolve timing issues between switches, I’m not sure that you’d want to increase the count of them.

As for lower voltage, I think the plan is to increase the voltage in order to increase the amperage, so lowed voltages probably could not be a goal.

My $.02

Pat

[Will]

I think the link posted in the “Diamond Switches” thread (http://www.divtecs.com/research/high-current-high-voltage-igbt-switch/) is functionally just that. It’s “one” semiconductor switch made up of many switches on one piece of silicon.

[Breakable]

mchargue wrote:
Unless & until a better mechanism is put in place to resolve timing issues between switches, I’m not sure that you’d want to increase the count of them.
As for lower voltage, I think the plan is to increase the voltage in order to increase the amperage, so lowed voltages probably could not be a goal.
My $.02
Pat

I believe you misunderstood my “lover voltage” quote. I mean if you put a lot of switches in serial connection then they should be able to switch higher voltages together than each one separately.
On the other hand if you connect a lot of switches in parallel then they can switch higher current together than separately.
And if you take a lot of switches and connect them in serial and then connect those switching blocks in parallel, then you should be able to deal both with high voltage and current.
To illustrate:
http://imgur.com/xG1E6
B) is for voltage, C) is for current D)and E) is basically the same (E might have more tolerance).

I think better mechanism for switching is easier to find in lower voltage/lower amperage area. Transistors for example, still I am all about vacuum tubes, because they are cooler ;). Of course I am don’t have much understanding in EE, so probably the switching speed could be insufficient. Still I would be really excited about this idea if it could prove viable, as it seems to me it would allow folk outside of LPP to contribute some serious R&D in an open-source manner without having a fusion lab.

[Breakable]

Companion idea that could help make this more viable:
Use of solid state fuses, that burn out if a switch pre-fires so that switches that badly work are automatically disabled.
PS:Somebody with EE background please shut me down in case I am talking nonsense.

[Breakable]

Will wrote: I think the link posted in the “Diamond Switches” thread (http://www.divtecs.com/research/high-current-high-voltage-igbt-switch/) is functionally just that. It’s “one” semiconductor switch made up of many switches on one piece of silicon.

Yes, probably much better to sync using laser light, still maybe its possible with silicon semiconductors as well?

[Aeronaut]

mchargue wrote: As I understand the current switch, it comprises 12 spark-gaps to decrease the current density through any single conductor, (switch) and already represents a problem with timing between the various switches. Increasing the number would further decrease current density through any one switch, but would likely increase the timing problem.

Unless & until a better mechanism is put in place to resolve timing issues between switches, I’m not sure that you’d want to increase the count of them.

As for lower voltage, I think the plan is to increase the voltage in order to increase the amperage, so lowed voltages probably could not be a goal.

My $.02

Pat

This reminds me of the old Darlington Transistor configuration, where a fast, sensitive transistor drives the brute force switching transistor. Dusted off and applied to thyristors, why not? After all, 5 inch wafer processing assembly lines should be a dime a dozen in this 8 inch silicon wafer world.

Darren Snider posted this on the FB page recently- http://www.divtecs.com/research/high-current-high-voltage-igbt-switch/ which looks to me like it might be properly scalable.

[Breakable]

Well the usual stuff:think of a revolutionary idea, open the internet and find it researched, implemented and sold… 😀
It is good to hear that this idea is implemented, because that mens it is solid.
Are there any products available?
I am guessing it is all DOD stuff and no way to touch it and probably their parameters are not exactly what we would want.
So anyone would like to help investigate this idea further, as far as I can see what needs to be done:
1)Get the switching requirements for FOFU1
2)Find the appropriate semiconductors (or solid state devices)
3)Use the soldering iron

Also I the DTI mentions
http://en.wikipedia.org/wiki/Insulated-gate_bipolar_transistor
I wonder how they compare.

[MTd2]

Aeronaut wrote: Darren Snider posted this on the FB page recently- http://www.divtecs.com/research/high-current-high-voltage-igbt-switch/ which looks to me like it might be properly scalable.

But it says that the total power is 500MW. LPPX should require 300GW. 600 hundred of those things must not be that practical.

[Breakable]

I think it is quite practical if it results in a well controlled pulse. Comparably z machine switches were quite big as well.
There were days when computers used to take buildings and it was not considered impractical.

[MTd2]

The budget is quite tight, you know.

[Breakable]

Laser controlled plasma switches might be more expensive, it would be nice to compare all alternatives and see what is most cost effective.

[mchargue]

Breakable wrote: Laser controlled plasma switches might be more expensive, it would be nice to compare all alternatives and see what is most cost effective.

I would say that the most cost-effective switch is one that works reliably, and repeatably. It seems to me that, as the switch can be engineered separate from the FF reactor, tit should be. This would insulate (so to speak) the FF reactor experiments from the implementation of the switch, and allow research to proceed without the switch impeding progress.

But, the budget is tight, so I’d cast around in the industry, and see if I could find a design partner for that. A company with the requisite experience & expertise, and that’s willing to work toward a design in for the ultimate product. Just as there are (you internet) folks that work toward this for what it would mean for the future, there should be companies that feel the same way.

Can’t hurt to ask!

My $.02

Pat

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