Hi
I am in need of a way to make a HV but I’m low on funds, space, skill etc etc. One thing though, IT HAS TO BE DC.

Starting voltage 12v. I'm looking for 10KV or there abouts...

The application is going to be a circuit which delivers a HV pulse to 1 high resistance load then to the 2nd, 3rd...and 10th. So I need some kind of switching as well.

Another requirement is that I will need to adjust the actual speed which it outputs from 1 to 2 to 3 to 4 etc, I’m thinking anywhere from 0-50khz.

LOL ok if you could give me any help it would be much appreciated thnx Rufe0

 

I suspect that the electrical switching of the high voltage (0-50khz, really!) is going to be much more difficult then developing it Lets see what people have to offer, it should be instructional.

Lefty

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Measurement changes behavior

 

I am thinking of having 10 different voltage multiplyers however they would only be pulsed for a short period and would not have time to charge the caps. Plus it will require a high parts count...

 

Sound much like the ignition system for a multicylinder gasoline engine - coil for high voltage - distributor to select one of several spark plugs. More of a mechanical solution but maybe sufficient for your needs.

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stevez

 

Use ignition coils and switch the 12V charging line to the primaries with P-channel devices.

 

I'd use a modern TV flyback, most output DC has they have the voltage multiplier unit and filter capacitor built-in.

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I will definitely prototype a distributor type design. I had thought of this but there are a few problems. Mainly the actual building of it in an accurate and repeatable way. I think I will need 2 spinning discs with 20 contacts each. A high speed brushless motor will give me good and easy control over the switching speed. It would work and work probably well enough but I would much rather have an all electronic circuit design.

If the device works well and the complete product actually works well then I will probably need to manufacture about 100 of them for the foreseeable future, by which that time I will start having them professionally made.

I have seen some articles on distrobutorless ignition systems. Apparently they use FETs actually on the HV side of the coil but this cannot be true, the highest voltage ones I can find are 1700v and far too expensive. Unless they are using a much lower voltage coil than normal.

If I was to have 10 coils and switch them on the 12v side am I going to get the same power delivery? The coil must need a certain amount of time to actually 'power up' before it emits, which would mean far less power/voltage is getting through to the HV side at HF which is unacceptable.

 

The single ignition coil version that I intended to describe was replaced by the more modern multiple coil version - most likely as a result of need for improved reliability as well as the possible improved control over spark timing. The multi-coil version might make it less of a mechanical systems challenge.

A 1995 Chevrolet that I owned had a 4 cylinder engine with two coils and no distributor. It fired two cylinders at a time - one cylinder when it needed to fire - the other could fire 360 crankshaft degrees out of synch with no affect at all. It reduced the number of coils. I mention this in case your project could tolerate the voltage pulse at other times as a way of simplifying things.

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stevez

 

I'm afraid not no. It may also be necesary to completely insulate those outputs that are not active. Ie a disconnection of both poitive and negative connections to inactive outputs... Although this is something I would like to play with, possibly if 1 is poitive then 7,6 and 5 could be negative. Or 8,7,6,5 and 4...
experimentation required