DIY high voltage power supply - Page 1
Forum section: electronics / projects

author: kxenos
author_rank: Frequent Contributor
timestamp: April 08, 2013, 10:42:53 pm
content: Hello. As I have packed everything because I'm moving, I had nothing to do so I came up with a design for a high(ish) voltage DC power supply. It's just a theoretical exercise so I haven't yet verify if it actually works. Plus, I haven't seen any design like this and probably there is a good reason.Anyway, the concept is to use a dimmer to adjust the voltage of the primary side of a 1:1 transistor. The dimmer is adjusted by a variable resistor that is controlled by a control circuit.Please comment/suggest any thoughts. ThanksWhile moving I have realized that women are like air: They tend to take up all the space that is given. At least I got a bedroom to convert to workshop!

author: skipjackrc4
author_rank: Regular Contributor
timestamp: April 08, 2013, 11:51:57 pm
content: I'll leave the specific critiques to the experts, but using an SCR in front of a transformer to make "high" power linear DC supply has been done for decades. HP did it, and all the old Raytheon-Sorensen supplies did as well. It doesn't quite give you the regulation or control of other methods, but it handles high power pretty efficiently.If you wanted really good regulation while keeping the efficiency, you could do a hybrid SCR/regulator. Something where the SCR gets it close and then a linear regulator smooths everything else and is used for fine tuning. Stability could get a bit trickier, though.

author: skipjackrc4
author_rank: Regular Contributor
timestamp: April 08, 2013, 11:55:14 pm
content: Using this method and step up/down transformers, you can also get different voltage ranges. Sorensen went up to 600V on some of their supplies I believe, and down to 12V or lower.

author: krivx
author_rank: Frequent Contributor
timestamp: April 08, 2013, 11:59:45 pm
content: Am I reading this correctly or is there no feedback based on a measurement of the output voltage? It doesn't seem like it will actually regulate the HV output.

author: kxenos
author_rank: Frequent Contributor
timestamp: April 09, 2013, 12:14:28 am
content: Quote from: skipjackrc4 on April 08, 2013, 11:51:57 pmThis is what I thought. I wanted to use this circuit as a pre-regulator that willl provide the linear regulator with 5- 10V overhead. The feedback would come fron the linear reg. circuit. Obviously, this has been done before, so I have to find the correct service manual to study.

author: BravoV
author_rank: Super Contributor
timestamp: April 09, 2013, 12:20:05 am
content: Alternative, much better design imho ->Regulate a 0 to 500V, 10-mA power supply in a different way

author: skipjackrc4
author_rank: Regular Contributor
timestamp: April 09, 2013, 01:02:31 am
content: Quote from: BravoV on April 09, 2013, 12:20:05 amUnless I'm missing something here, this will only work well at low currents. The SCR-transformer method, with proper feedback, can operate at 100A fairly efficiently. I've got one of them sitting on a shelf at work. I never use it because I never need more than 30A, but still... That said, I like that design for low current.Quote from: kxenos on April 09, 2013, 12:14:28 amI'm not sure what country you're in and if the seller will ship there, but on the American eBay, there is a service manual for the Sorensen line that we have tons of at work. Let me know if you have issues getting one where you are, and I might be able to scrounge one up somewhere. I was doing maintenance on these things a few months ago. Not the highest tech pieces of equipment out there, but they sure are fun to poke around.http://www.ebay.com/itm/Sorensen-DCR-B-Series-DC-Supplies-Operating-Service-Manual-w-schematics-/200887748825?pt=BI_Books_Manuals&hash=item2ec5d7c8d9

author: ve7xen
author_rank: Super Contributor
timestamp: April 09, 2013, 01:09:37 am
content: This HP/Agilent reference covers most of the techniques used at a high-level. Service manuals for old-ish HP/Agilent supplies using these techniques should be easy to find - most of them are published on Agilent's website.http://cp.literature.agilent.com/litweb/pdf/5952-4020.pdf

author: skipjackrc4
author_rank: Regular Contributor
timestamp: April 09, 2013, 01:13:37 am
content: Quote from: ve7xen on April 09, 2013, 01:09:37 amThat looks pretty good. I love it when companies put their old service manuals online.

author: BravoV
author_rank: Super Contributor
timestamp: April 09, 2013, 01:37:43 am
content: Quote from: skipjackrc4 on April 09, 2013, 01:02:31 amOk, I was assuming the op is planning to do hv after reading the thread title "high voltage".

author: skipjackrc4
author_rank: Regular Contributor
timestamp: April 09, 2013, 01:44:15 am
content: Quote from: BravoV on April 09, 2013, 01:37:43 amFair point. I guess I was thinking he wanted up to rectified mains voltage, since he was using a 1:1 transformer. At that voltage range, an amp or more can be quite handy. Anyway, the OP has several options to choose from.

author: Marco
author_rank: Super Contributor
timestamp: April 09, 2013, 02:11:37 pm
content: Just trying to understand the circuit, the RC filter consisting of RV1/U3/C7 is there to create a sine which lags the mains voltage and peaks in it's second and fourth quadrant I assume, so you can trigger the triac in those regions?