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Very High Voltage Piezoelectric Power Supply - Digitaly Variable - Lightweight SMT

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Uriah

Mon Jul 16 2007, 03:41AM

Registered Member #898 Joined: Sun Jul 15 2007, 07:50AM
Location:
Posts: 20

I like Steve Conner's idea...
So this might work:

Using the circuit as I already have I could drive a pulse transformer with a winding ratio of 1:20 stepping the voltage from 2.46kV to 49.2kV which would be acceptable for my application. This output would be rectified back to DC with some protective output circuitry.

I am going to enclose the unit and cover the circuitry with Super Corona Dope. There will be two thermoelectric cooling panels. One to cool the pulse transformer that we are discussing as well as the PT, and the other panel to cool the IGBT and other surface mount components during constant operation.

Can someone suggest a website, book, or any such description on how to build custom pulse type transformers?

Any suggestions on how to shield the pulse transformer so that it does not interfere with anything around it?
I have a GyroChip, a microprocessor and various other flight instruments work in close proximity to the HV power supply, so this is a problem.

AND WHAT DOES THIS MEAN?
"It should also be driven by a bridge, and not in flyback mode as you drew. PWM regulation would get you rid of the linear regulator I see no purpose in."

I'll try and upload more details so check be within 3 days, as I work 7 days a week (which is starting to feel like one big day)...

I am only just beginning in electronic circuit design, with about 2 years experience with the electronic system and power supply I already have and am using for propulsion advancement.

For the help I receive from everyone here I will make sure to show everything that comes from this part of the project, including some flight test video. I am building the prototype I attached earlier in order to gain funding and money for college. It uses two types of propulsion. The first type is called One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) which causes Parastaltic flow. This effect is governed by the laws of Electrohydrodynamics (EHD).
The second type is called Electrogravitics and deals with solid dielectric materials instead of EHD which uses the air like a capacitor. Both produce thrust, but EHD provides a shock-tunnel in which there is almost no air resistance to slow the craft down.
Electrogravitics is my own personal work, I am just adopting the methods used by MIT, NASA, Atmosphere Glow, etc, to bring my craft to a new level of flight.

Regards,
Uriah

thedatastream

Mon Jul 16 2007, 09:06AM

Registered Member #505 Joined: Sun Nov 19 2006, 06:42PM
Location: Yorkshire!
Posts: 329

Please can you elaborate on the following specs

Input voltage range from the power supply
Maximum mechanical dimensions
Proximity and type of other equipment
Output load current and type (pulsed, constant, duty cycle)

Otherwise we can only make vague suggestions. The first thing to do when designing a circuit is to come up with as full a spec as possible based on the application. Otherwise, how do you know what you are designing?

Dr. Shark

Mon Jul 16 2007, 09:55AM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

Uriah wrote ...

AND WHAT DOES THIS MEAN?
"It should also be driven by a bridge, and not in flyback mode as you drew. PWM regulation would get you rid of the linear regulator I see no purpose in."

This one is easy to answer, Firkragg probably confused you because he put two different things into one sentence.

1) Right now you are adjusting the power of the circuit with the linear regulator - this burns a lot of power and I suppose you are constrained on batterys in you aircraft. Therefore you better keep the voltage constant and vary the pulse-width instead, this gives you the same power modulation with significantly lower losses.

2) You are using a single IGBT in what is called a flyback topology. This has some disadvantages in EMI, reliability and efficiency. If you use two or four IGBTs in a (half)-bringe arrangement, you would probably get a better performing system.

PS: Please explain what you mean by "Electrogravitics". This sounds a lot like pseudoscience to me, which could get you in conflict with the board rules.

Steve Conner

Mon Jul 16 2007, 12:07PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

You have looked at other hobbyist lifter designs, right? Much as I hate to recommend him, JL Naudin actually has built some good lifters and power supplies. However, they are very far from being able to lift their own weight plus the weight of the power supply.

I don't think you are very clear on what sort of power supply you actually need. Does the plasma discharge work best with DC? AC? some kind of pulsed power? If so, what kind? JL Naudin, or one of his collaborators, did some research on pulsed power with lifters.

My gut feeling is that you'll want high voltage DC to generate as much ion wind and thrust as possible, and TV flybacks work great for this. I've heard of people overdriving them up to 600 watts, which would easily be enough to get a conventional model aircraft driven by an electric motor and propeller off the ground. (If your thruster design can't produce as much thrust as a motor and propeller for the same electrical input, that is another problem altogether.)

But if you wanted pulses of very high peak power, you'd need a custom pulse transformer instead of a flyback, and a different driver circuit.

Also, please don't mention electrogravitics here. There are plenty of other tin-foil hat forums you can go to for that: we prefer to keep discussion inside the established laws of physics, and leave the tin foil hats in the orgone accumulator where they belong.

Uriah

Mon Jul 16 2007, 12:14PM

Registered Member #898 Joined: Sun Jul 15 2007, 07:50AM
Location:
Posts: 20

No problem about the pseudoscience.

I'll spend some time and upload a CAD model and the rest of the specifications tonight.

-Uriah

Uriah

Tue Jul 17 2007, 05:47AM

Registered Member #898 Joined: Sun Jul 15 2007, 07:50AM
Location:
Posts: 20

The output of the PT will be 2.46kV 2.8mA at 65.5kHz, so the output of the discharge capacitor will be between 3.668A to 1.834A (50Hz to 100Hz).

Did I get my math correct?

65,500Hz
---------- = 655 x 2.8mA = 1,834mA (1.834A)
100Hz

65,500Hz
---------- = 1310 x 2.8mA = 3,668mA (3.668A)
50Hz

At 2.46kV that would mean an output between 9170 and 4511.64Watts would be achieved!!!...

NOW HOW DO I PICK A CAPACITOR FOR THE DISCHARGE CAPACITOR?

I have never worked on ANYTHING like this, so I am greatly confuzed at this point.

The more watts out of this power supply I can get, the better. So should I still use a pulse transformer as suggested or does the peak power constrain that at this point?

Note: For reference the PT is 2.6x2.6x0.5inches in the diagram below...

Regards, Uriah

Steve Ward

Tue Jul 17 2007, 04:08PM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

Did I get my math correct?

65,500Hz
---------- = 655 x 2.8mA = 1,834mA (1.834A)
100Hz

65,500Hz
---------- = 1310 x 2.8mA = 3,668mA (3.668A)
50Hz

At 2.46kV that would mean an output between 9170 and 4511.64Watts would be achieved!!!...

Im sorry but you seem to have some odd concepts about how "electricity" works. Even your math (which i would consider extremely rough and highly oversimplified) while correct in itself, does not properly describe your system (making it "wrong"). A frequency conversion does not change the current. And if you are thinking about the pulsing effect, then its still not
nearly that simple. You would have to discuss peak current (which is dependent on the output capacitor, and the load, and can be solved via differential equation). From here you could find the RMS current if you wanted which can be approximated simply from knowing the average energy dissipated over time and the resistance of the load. Keep in mind conservation of energy this whole time!

Your output power can not exceed the input power (on average). Your peak power can in fact be very high, but as i said, your current calculation is completely meaningless.

I feel bad coming down so hard on you, but these are concepts you really ought to know.

Conundrum

Fri Jul 27 2007, 11:50PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

hmm.. was looking at something like this a while back for a self-contained lifter, the basic idea was to use one or more (possibly several) cockroft-walton multipliers driven from PZT laptop inverters with the outputs connected in parallel via HV diodes.

In fact, you can now buy multiple inverter modules ready made, used for large flat screens.

It may be possible to tap off the drive from a single unit, and use this to feed many more piezos with their own drive transistors and resonant circuit, though you would lose some output this way.

-A
-A

Tesladownunder

Fri Aug 03 2007, 04:35PM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

I think the whole concept of lifters/propulsion units is so hard to get going and critical in supply that they seem unlikely to get past concept. Great if you have 80kV and no supply.

Dr Resonance claims to have made a self levitating one but steerability was poor. No pictures due to commercial sensitivity or DAARPA if I recall.

I have my own ideas how this efficiency and the whole aerodynamics might be able to be improved. One day when I get a few weeks to spare on pie in the sky stuff.....

Tesladownunder

Marko

Fri Aug 03 2007, 04:45PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

This thing looks much more like ion-powered glider than a conventional lifter, requiring much less push so it may in the end be feasible.

Still, small motor and propeller would be orders of magnitude more efficient.

Regarding conventional lifters, I know everyone would think that ion-powered Airship would be super cool. But most of lifters we make are like order of magnitude too inefficient.

Even If we could make small and lightweight power supply, there is no such a battery with enough energy and power density to make this feasible.

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