Hello all,
I waited for nearly two month now and even the target of ten has not been reached.
I can't ask to all interested DIYErs to wait more and so i decide (for now) to cancel the group buy,
in it's actual form.
Now, i want to completely finish my own unit, but i will change my plan about the panels
and finally use FrontPanel Express to make the panels instead of Lexans.
So, i don't bury the project and i will back to you as soon i will completed my unit.
Anyway, and as i said before, I will try to offer a new group-buy but only for the bare PCB alone,
with the better price possible (i look for a new PCB manufacturer).
It's much less time consuming for me, and many have wondered the PCB alone.
Best regards.
Frex
I waited for nearly two month now and even the target of ten has not been reached.
I can't ask to all interested DIYErs to wait more and so i decide (for now) to cancel the group buy,
in it's actual form.
Now, i want to completely finish my own unit, but i will change my plan about the panels
and finally use FrontPanel Express to make the panels instead of Lexans.
So, i don't bury the project and i will back to you as soon i will completed my unit.
Anyway, and as i said before, I will try to offer a new group-buy but only for the bare PCB alone,
with the better price possible (i look for a new PCB manufacturer).
It's much less time consuming for me, and many have wondered the PCB alone.
Best regards.
Frex
Hi!
I was interested in possibly constructing this but it seems to have died a death!
Has Frex or any other Member got the Original Design Files and Programming Software so I can make one of these designs, even if there's no means of purchasing any more PCBs via the Group Buy I can still get them made individually!
(I would be happy to pay a reasonable sum for the Design Folder so all Member Frex's hard work isn't all in vain!)
What about winding the magnetics?
Chris Williams
I was interested in possibly constructing this but it seems to have died a death!
Has Frex or any other Member got the Original Design Files and Programming Software so I can make one of these designs, even if there's no means of purchasing any more PCBs via the Group Buy I can still get them made individually!
(I would be happy to pay a reasonable sum for the Design Folder so all Member Frex's hard work isn't all in vain!)
What about winding the magnetics?
Chris Williams
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Hello,
This project is not dead for as i even made lot of work on CPLD software on it this year.
Note that if you want to build the project it need lot of work (and money).
Anyway, i haven't yet seen any lab PSU with such output power and regulation/noise
performance is this size/weight range. So I'm very happy with.
The last concern where i work (when i find time with the others active projects)
is the accuracy on current regulation (CC mode).
In fact the LT3081 current regulation mode is temperature dependent.
So, the CC mode set value is not so accurate than we could expected.
Magnetic parts has been made by hands and there is no special difficulty to make them.
Only one set of PCB of the design has been made (mine !), because the minimum order
for the batch was not reached. So, for lower quantity the total building cost become too high.
So, for building one full unit, you must have this in mind.
So, i will post these next days some picture of the PSU with the final enclosure and panels.
Regards.
Frex
This project is not dead for as i even made lot of work on CPLD software on it this year.
Note that if you want to build the project it need lot of work (and money).
Anyway, i haven't yet seen any lab PSU with such output power and regulation/noise
performance is this size/weight range. So I'm very happy with.
The last concern where i work (when i find time with the others active projects)
is the accuracy on current regulation (CC mode).
In fact the LT3081 current regulation mode is temperature dependent.
So, the CC mode set value is not so accurate than we could expected.
Magnetic parts has been made by hands and there is no special difficulty to make them.
Only one set of PCB of the design has been made (mine !), because the minimum order
for the batch was not reached. So, for lower quantity the total building cost become too high.
So, for building one full unit, you must have this in mind.
So, i will post these next days some picture of the PSU with the final enclosure and panels.
Regards.
Frex
Looks great. All of your projects are really first class. I like your use of PCBs as front and rear panels.
Thank you for the compliment Chris, anyway here it's not PCB's for front and rear panels.
They are in machined anodized aluminum and engraved by FrontPanelExpress services.
Frex
Ah, I think the last project you did with red panels were PCBs? The color looked almost like blue soldermask
.This is/was an interesting project with some curious design decisions.
The final build price seems a bit out of touch with 20v output limit and 3 digit displays. I bet it would have gained more traction utilizing the LT3081 closer to its voltage limit, using like a single 4x20 display, and an Arduino or a PIC or something.
Not sure if I'm misunderstanding but is the transformer custom? Also couldn't the preregulator feedback circuit been have done with like 1/10th of the components (just a couple of resistors and a PNP)?
The final build price seems a bit out of touch with 20v output limit and 3 digit displays. I bet it would have gained more traction utilizing the LT3081 closer to its voltage limit, using like a single 4x20 display, and an Arduino or a PIC or something.
Not sure if I'm misunderstanding but is the transformer custom? Also couldn't the preregulator feedback circuit been have done with like 1/10th of the components (just a couple of resistors and a PNP)?
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Transformer winding question
Hi Frex,
Can you provide some info on transformer winding? Specifically,
1) What is the turns ratio?
2) What Litz wire gauge did you use?
3) Did you wind the 3 secondaries side-by-side or on top of each other?
4) How did you determine what your Lm(magnetizing) and Ll(leakage) inductances are? Did you just measure it by opening and shorting the secondary windings?
Thanks in advance!
Richard
Hi Frex,
Can you provide some info on transformer winding? Specifically,
1) What is the turns ratio?
2) What Litz wire gauge did you use?
3) Did you wind the 3 secondaries side-by-side or on top of each other?
4) How did you determine what your Lm(magnetizing) and Ll(leakage) inductances are? Did you just measure it by opening and shorting the secondary windings?
Thanks in advance!
Richard
Hello Richard,
You can download to the link below the full winding procedure I wrote few years ago
for the project. I think you would find all fabrication info.
EPSUX3v1 PFC inductor and LLC transformer specs.
For the 4), yes.
Magnetizing inductance is measured with secondaries open,
and leakage inductance with all secondary in short-circuit.
I hope that will help a little !
Regards.
Frex
You can download to the link below the full winding procedure I wrote few years ago
for the project. I think you would find all fabrication info.
EPSUX3v1 PFC inductor and LLC transformer specs.
For the 4), yes.
Magnetizing inductance is measured with secondaries open,
and leakage inductance with all secondary in short-circuit.
I hope that will help a little !
Regards.
Frex
Thanks for the link, Frex. Is there a reason you did not use the 0.4mm wire for the transformer? Seems like it would still take the 100KHz switching frequency even after considering skin effect.
Did you do all the magnetic design by hand, or did you use a manufacturer's calculator? Seems like it can be overwhelming. I was hoping to reuse transformers from bad ATX power supplies. Not sure if that's a good approach. Thoughts?
Did you do all the magnetic design by hand, or did you use a manufacturer's calculator? Seems like it can be overwhelming. I was hoping to reuse transformers from bad ATX power supplies. Not sure if that's a good approach. Thoughts?
Hello,
Is is much better to use litz wire instead of of 0.4mm diameter wire, even at 100kHz.
There is also the proximity effect that has to be take in account.
Anyway, for convenience you can use multiple 0.4mm (or less) diameter wires instead.
All the magnetic design has been made by me, with a prototype before to check and adjust parameters.
LLC transformer design is a little tricky, it must need to take in account leakage of transformer.
I will recommend you some reading like this one :
Designing an LLC Resonant Half-Bridge Power Converter
Of course with some search you will find many others interesting resources.
Some IC manufacturer have excel spreadsheets to help design parts calculation.
Best regards.
Frex
Is is much better to use litz wire instead of of 0.4mm diameter wire, even at 100kHz.
There is also the proximity effect that has to be take in account.
Anyway, for convenience you can use multiple 0.4mm (or less) diameter wires instead.
All the magnetic design has been made by me, with a prototype before to check and adjust parameters.
LLC transformer design is a little tricky, it must need to take in account leakage of transformer.
I will recommend you some reading like this one :
Designing an LLC Resonant Half-Bridge Power Converter
Of course with some search you will find many others interesting resources.
Some IC manufacturer have excel spreadsheets to help design parts calculation.
Best regards.
Frex