Sonsivri
 
*
Welcome, Guest. Please login or register.
Did you miss your activation email?
December 09, 2016, 08:40:13 08:40


Login with username, password and session length


Pages: [1]
Print
Author Topic: Modulated HV power supply (ideas needed)  (Read 1442 times)
0 Members and 1 Guest are viewing this topic.
LithiumOverdosE
V.I.P
Senior Member
*****
Offline Offline

Posts: 289

Thank You
-Given: 246
-Receive: 396


« on: August 04, 2014, 01:43:16 01:43 »

I'm asking for a bit of brainstorming of the honourable members of Sonsivri.  Wink

I have two insulated HV plate electrodes which are place into ionic solution (FeCl3).
The goal is to observe the action of the ions due to electrostatic action and it works fine.

That HV DC signal (30 kV) have to be modulated with the signal whose amplitude should be 1000 V pk-pk (alternatively 750 V) and with frequency range of 1 Hz to 40 kHz.
For the experiments I use a simple Villard voltage mulitplier and it performs just fine with very little ripple (<5V).  
The capacity of the electrodes is <50 pF.


Originally I thought of using a custom made HV audio transformer and modulate output directly.
However, very high voltages would require tremendously big and complex transformer due to insulation limitations.

The second idea was to introduce one large DC cap and directly drive the output with the appropriate audio transformer in place.
The concept immediately fell apart because the low end of required spectrum would require very big cap with appropriate HV rating.

At this point I'm out of idea and any help would be appreciated.  Cool
Logged
DreamCat
Active Member
***
Offline Offline

Posts: 235

Thank You
-Given: 130
-Receive: 77



« Reply #1 on: August 04, 2014, 04:20:18 04:20 »

I think the flyback transformer from old big CRT TV is good choice, or you can custom one.
Here is the structure I recommand to you.
Logged

May be I expressed the wrong meaning, sorry for my bad english. Please correct it for me if you can.
LithiumOverdosE
V.I.P
Senior Member
*****
Offline Offline

Posts: 289

Thank You
-Given: 246
-Receive: 396


« Reply #2 on: August 04, 2014, 11:06:06 23:06 »

I considered the same approach but the capacity necessary for low frequency range would be quite large (too large for HV rating capacitors).
Logged
optikon
V.I.P
Hero Member
*****
Offline Offline

Posts: 604

Thank You
-Given: 460
-Receive: 1604


« Reply #3 on: August 05, 2014, 01:46:10 01:46 »

Transformers are such a natural choice for this task. Did you actually explore the size required? Seems to me, since the power is low, they might not be prohibitively large. I think there are ways transformers can be wound for high voltage so that wire insulation size is minimized thus resulting in a smallish design...
Logged

I can explain this to you. I can't comprehend it for you.
DreamCat
Active Member
***
Offline Offline

Posts: 235

Thank You
-Given: 130
-Receive: 77



« Reply #4 on: August 05, 2014, 04:37:58 04:37 »

I considered the same approach but the capacity necessary for low frequency range would be quite large (too large for HV rating capacitors).

according the structor in my image, the main voltage no need very large capacity. it has fixed frequency, you can set it to 20k~30kHz, but this frequency is nothing to do with modulate voltage.  the capacity determine by its load.
you may note that the main voltage is DC voltage, the modulate voltage superimposed on a DC voltage, so the 1kv transformer no need very high insulation class(grade).
« Last Edit: August 05, 2014, 04:51:39 04:51 by DreamCat » Logged

May be I expressed the wrong meaning, sorry for my bad english. Please correct it for me if you can.
LithiumOverdosE
V.I.P
Senior Member
*****
Offline Offline

Posts: 289

Thank You
-Given: 246
-Receive: 396


« Reply #5 on: August 05, 2014, 04:12:31 16:12 »

@optikon

Core size due to power is not the problem.
However, winding audio frequency transformer includes multiple, sandwiched layers which makes it larger and especially if the HV insulation is requirement (not to 30 kV though) so the required core is usually much bigger compared to narrow bandwidth transformer. Lips sealed

@DreamCat

You're correct. I missed the location of grounding.

This seems fine as a concept. Wink
I have to do a bit of experimenting to see what happens in real-life.
Logged
user77
Newbie
*
 Muted
Offline Offline

Posts: 11

Thank You
-Given: 0
-Receive: 4


« Reply #6 on: August 11, 2014, 09:58:54 09:58 »

I'm thinking, and if you try to use a coil sparkle? you can modulate the frequency, and I think also the voltage maybe with a pwm, but the output hv normally is 12-15kv, with a hv  doubler  maybe it's ok to you ... it's just an idea ...
Logged
LithiumOverdosE
V.I.P
Senior Member
*****
Offline Offline

Posts: 289

Thank You
-Given: 246
-Receive: 396


« Reply #7 on: August 13, 2014, 12:45:51 12:45 »

Did you mean ignition coil?

It would require non-commonly available HV parts and besides the ignition coil is limited in maximal frequency and introduce high inductance leakage.

I prefer working with ferrite cores and commonly available components.
This means I'll probably make custom made transformer and use resonant voltage multiplier.
Logged
Ichan
Hero Member
*****
Offline Offline

Posts: 840

Thank You
-Given: 312
-Receive: 387



WWW
« Reply #8 on: August 13, 2014, 05:30:27 17:30 »

Brainstorming here, seems the requirement have some similarities with DC excited CO2 laser power supply.



Usually the output is around 20 - 30 KV DC, and has analog and pwm input to control the output - i do not know much about the detail.

-ichan.
Logged

There is Gray, not only Black or White.
LabVIEWguru
Senior Member
****
Offline Offline

Posts: 267

Thank You
-Given: 223
-Receive: 553



« Reply #9 on: August 13, 2014, 11:41:50 23:41 »

Lithium overdose:

http://www.repairfaq.org/sam/lasersam.htm

This is Sam's Laser Faq. I don't know if you've ever see it before, but it is a very, very large FAQ concerning lasers.
Logged
kreutz
Junior Member
**
Offline Offline

Posts: 68

Thank You
-Given: 179
-Receive: 25


« Reply #10 on: September 22, 2014, 03:37:07 03:37 »

I don't see any reference to the ionic current you use, but depending on that current (if it is a low current) you could use a high impedance 30 Kv dc generator (flyback with voltage multiplier +  series resistor is ok) and a variable parallel load (current modulated using a HV vacuum tube with grid).
Logged
sadman
Active Member
***
Offline Offline

Posts: 231

Thank You
-Given: 718
-Receive: 688



« Reply #11 on: September 28, 2014, 10:48:43 10:48 »

hi friend LithiumOverdose

Please have a look to this may be help full

https://hackaday.io/project/1787-High-Voltage-Regulated-Power-Supply

http://www.hardhack.org.au/hv_reg_power

sadman
Logged
hef4015
Newbie
*
Offline Offline

Posts: 7

Thank You
-Given: 11
-Receive: 1


« Reply #12 on: October 02, 2014, 09:22:46 09:22 »

I didn't follow all the links, but here comes a quick suggestion:
* make or buy a 30 kV DC power supply  Grin
* use a transformer to transfer some energy to 30 kV potential  Cheesy
* build a HV generator with 1 kV amplitude using MOSFETs, can be controlled by an arbitrary waveform generator, module connected to the 30 kV potential  Cool

I've seen similar systems before. Just make sure you do not touch the high voltages...  Lips sealed
Logged
LithiumOverdosE
V.I.P
Senior Member
*****
Offline Offline

Posts: 289

Thank You
-Given: 246
-Receive: 396


« Reply #13 on: October 04, 2014, 02:56:27 02:56 »


Thx sadman, but the voltage is quite a bit lower than required.


and a variable parallel load (current modulated using a HV vacuum tube with grid).

Parallel load at 30 kV?
Did you had any particular tube in mind?


* build a HV generator with 1 kV amplitude using MOSFETs, can be controlled by an arbitrary waveform generator, module connected to the 30 kV potential  Cool

I've seen similar systems before. Just make sure you do not touch the high voltages...  Lips sealed

Could you please elaborate on this idea?
I didn't quite get it.
Logged
borberk
V.I.P
Senior Member
*****
Offline Offline

Posts: 298

Thank You
-Given: 309
-Receive: 598


« Reply #14 on: October 05, 2014, 11:20:22 11:20 »

How much current draws your electrostatic electrodes at 30kV to be in doubt about value of capacitor in HV source? What is DC equivalent resistance of electrodes emerged in water solution of FeCl3?
Logged
kreutz
Junior Member
**
Offline Offline

Posts: 68

Thank You
-Given: 179
-Receive: 25


« Reply #15 on: October 12, 2014, 05:22:08 17:22 »

 
Quote
Parallel load at 30 kV?
 
Did you had any particular tube in mind?

for example: http://www.jogis-roehrenbude.de/Russian/GP5/GP5.pdf

Just search on the internet. H.V. Shunt regulators were frequently employed a few years ago, many were originally used for Color TV HV regulation, they are still used on some pulsed Xray generators (up to 150 kv).

kreutz

Logged
kreutz
Junior Member
**
Offline Offline

Posts: 68

Thank You
-Given: 179
-Receive: 25


« Reply #16 on: November 09, 2014, 09:44:57 21:44 »

I found this info, it might help depending on your requirements. It is an audio modulated flyback HV p.s. I suggest increasing the flyback switching frequency to at least 80 kHz ( 2x audio frequency bandwidth (=40khz as per your messages) as per Nyquist), it will be necessary to redesign the flyback transformer for this purpose.

http://boginjr.com/electronics/hv/flyback-driver-2/
Logged
Pages: [1]
Print
Jump to:  


DISCLAIMER
WE DONT HOST ANY ILLEGAL FILES ON THE SERVER
USE CONTACT US TO REPORT ILLEGAL FILES
ADMINISTRATORS CANNOT BE HELD RESPONSIBLE FOR USERS POSTS AND LINKS

... Copyright 2003-2999 Sonsivri.to ...
Powered by SMF 1.1.18 | SMF © 2006-2009, Simple Machines LLC | HarzeM Dilber MC