DC transformer, x-Chapters 9x.16

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Winfield Hill

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Oct 20, 2019, 11:25:30 AM10/20/19
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x-Chapters 9x.16, about DC transformers, AKA bus
converters. It's a synchronous dc-dc converter,
with in/out voltage ratio set by a fixed switching
duty cycle. Like ac transformers, they transfer
power in either direction, as a function of who's
above the ratio. The current-ratio also obeys
the voltage-ratio rule, like an ac transformer.
As bus-converters, they're used to convert a 48V
distributed bus, to lower voltages for local use.

https://www.dropbox.com/s/nrp5paq1j1u5756/9x.16_DC-xfmr.pdf?dl=1


--
Thanks,
- Win

DecadentLinux...@decadence.org

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Oct 20, 2019, 11:42:42 AM10/20/19
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Winfield Hill <winfie...@yahoo.com> wrote in news:qohu9001kk1
@drn.newsguy.com:
Anything in your book on how a big 10kVA line conditioning
transformer works?

You know, the ones with cap banks in them that put out at 60Hz even
when the line or freq sags.

We had a back up generator that caused our UPS systems to fail to
notice the power being back up, and it was due to the generator
somehow making not quite sinosidal waveform or maybe it was full of
spikes... not sure, but these transformers in line with the
generator output fixed the issue.

"Sola" is the most common brand I see, and is what we installed in
the house in Virginia. It was 750 Lbs overall for the 20kVA capacity
we needed.

Arie de Muynck

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Oct 20, 2019, 11:50:03 AM10/20/19
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Nice chapter!

Fig 9.2.73, upper right terminals should be Vout(HV) not Vout(LV).

Arie


Winfield Hill

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Oct 20, 2019, 12:19:59 PM10/20/19
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Winfield Hill wrote...
The circuit schematic and PCB board in the photo
is PWR-671, in my RIS-671 project file. It uses
an IR2085 for PWM and MOSFET driving, and has a
zener+7812, so Vmax could be up to 450V, if R13,
D3, elec caps, and MOSFETs are chosen properly.

https://www.dropbox.com/s/wy58c0yxuc6lda8/PWR-671-1_pcb.pdf?dl=1

I first created it for a magnet-control project.
Three different voltages were needed, with 150W
capability, this way we needed only one module.
As the field coils were switched on and off, the
energy went back into the big source-supply cap.


--
Thanks,
- Win

Winfield Hill

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Oct 20, 2019, 12:24:29 PM10/20/19
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Arie de Muynck wrote...
Thanks, Arie, I've made a note for our next printing.


--
Thanks,
- Win

Winfield Hill

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Oct 20, 2019, 5:46:30 PM10/20/19
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Winfield Hill wrote...
>
>Winfield Hill wrote...
>>
>> x-Chapters 9x.16, about DC transformers, AKA bus
>> converters. It's a synchronous dc-dc converter,
>> with in/out voltage ratio set by a fixed switching
>> duty cycle. Like ac transformers, they transfer
>> power in either direction, as a function of who's
>> above the ratio. The current-ratio also obeys
>> the voltage-ratio rule, like an ac transformer.
>> As bus-converters, they're used to convert a 48V
>> distributed bus, to lower voltages for local use.
>>
>>https://www.dropbox.com/s/nrp5paq1j1u5756/9x.16_DC-xfmr.pdf?dl=1
>
> The circuit schematic and PCB board in the photo
> is PWR-671, in my RIS-671 project file. It uses
> an IR2085 for PWM and MOSFET driving, and has a
> zener+7812, so Vmax could be up to 450V, if R13,
> D3, elec caps, and MOSFETs are chosen properly.
>
>https://www.dropbox.com/s/wy58c0yxuc6lda8/PWR-671-1_pcb.pdf?dl=1

Correction: Although most of IR's HV MOSFET driver
ICs work to 600V, the IR2085 is only good to 130V.
But it's faster, with deadtimes as low as 50ns.

Lasse Langwadt Christensen

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Oct 21, 2019, 12:40:17 PM10/21/19
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what on earth was that schematic drawn in?


klaus.k...@gmail.com

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Oct 21, 2019, 1:08:03 PM10/21/19
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Win, you really need to cover Royer and Royer Jensen converters. That was the original DC Transformers

Williams paper on optimising Roger efficiency is excellent

Cheers

Klaus

Winfield Hill

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Oct 21, 2019, 1:31:03 PM10/21/19
to
>
> Win, you really need to cover Royer and Royer Jensen
> converters. That was the original DC Transformers
>
> Williams paper on optimising Roger efficiency is excellent

Thanks, Klaus, I'm sure you're right. But I have
very little experience with them at this point.
Maybe you'd like to conribute a guest section?


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Thanks,
- Win

klaus.k...@gmail.com

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Oct 22, 2019, 3:59:10 AM10/22/19
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Certainly, all though I am no expert, still more to learn

I will send you a message on LinkedIn

Cheers

Klaus

Winfield Hill

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Oct 22, 2019, 4:12:43 AM10/22/19
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>
> I will send you a message on LinkedIn

Sorry, I'm not linked in. :-) Just
use my yahoo email, which is up-to-date.


--
Thanks,
- Win

Winfield Hill

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Oct 22, 2019, 4:40:26 AM10/22/19
to
Lasse Langwadt Christensen wrote...
>
> Winfield Hill wrote...
>> Winfield Hill wrote...
>>>
>>> x-Chapters 9x.16, about DC transformers ...
>>>
>>>https://www.dropbox.com/s/nrp5paq1j1u5756/9x.16_DC-xfmr.pdf
>>
>> The circuit schematic and PCB board in the photo
>> is PWR-671, in my RIS-671 project file. It uses
>> an IR2085 for PWM and MOSFET driving, and has a
>> zener+7812, so Vmax could be up to 130V, if R13,
>> D3, elec caps, and MOSFETs are chosen properly.
>>
>> https://www.dropbox.com/s/wy58c0yxuc6lda8/PWR-671-1_pcb.pdf
>
> what on earth was that schematic drawn in?

Yes, it doesn't look as good as most of my schematics.
But it was drawn 10 years ago in PCAD, and then imported
into Altium. More relevant, it was done quickly, using
the standard schematic component images, which are big
and clunky. With those images, one needs to allow more
space between things or it looks a mess. With a little
extra care, PCAD can make very nice schematics. So can
Protel and Altium, although not quite as nice as PCAD.
None of them are decent drawing programs, they don't let
you decently control line widths, angles, curves, etc.
Altium does let us pick font types, fine-tune sizes, and
set snap grids.

We use Illustrator for our book's figures, but that's a
lot more time consuming. We make a careful hand drawing
that's as close as possible to our final expected figure.
Our publisher, C.U.P., hires our drawings out to a firm
in India, where a few of their staff have become quite
proficient, after doing many hundreds of our schematics.

Paul has become a true Illustrator expert, and fixes and
cleans up their work, then we sit together and hand edit
each one for a final pass. But even with this high level
of scrutiny, it's amazing what stupid careless mistakes
leak through. When you're adjusting line spacing, etc.,
it's easy to overlook that the wire is going to the wrong
place, etc. I try to examine the drawing in stages, first
scanning for one type of issue, like part values, then
for another, wiring connections, then the component shape,
etc. But in the process we have still ended up with some
silly errors, like +,- symbols backwards on op-amps, etc.


--
Thanks,
- Win

jla...@highlandsniptechnology.com

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Oct 22, 2019, 11:51:06 AM10/22/19
to
On 22 Oct 2019 01:40:10 -0700, Winfield Hill <winfie...@yahoo.com>
wrote:
Our once chronic bug was flipping an opamp symbol to make the + and -
inputs fit the circuit nicely, which also flipped the power pins,
which we then connected V+ on top, V- on bottom, which was wrong. That
is now on our PCB checklist, and we assign someone to check it yet
again just for luck.

I think PADS makes nice looking schematics, but it's inclined towards
jaggies.

How many copies of AoE have been sold?



--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Winfield Hill

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Oct 22, 2019, 12:11:45 PM10/22/19
to
>
> Our once chronic bug was flipping an opamp symbol to make
> the + and - inputs fit the circuit nicely, which also
> flipped the power pins, which we then connected V+ on
> top, V- on bottom, which was wrong. That is now on our
> PCB checklist, and we assign someone to check it yet
> again just for luck.

I've made that mistake, but some time ago created a
second op-amp symbol to use to solve that issue.

> How many copies of AoE have been sold?

I dunno. In its 15th printing now, but that doesn't
mean 150k copies. Probably between 75k and 125k.


--
Thanks,
- Win

John Larkin

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Oct 22, 2019, 2:35:08 PM10/22/19
to
On 22 Oct 2019 09:11:29 -0700, Winfield Hill <winfie...@yahoo.com>
wrote:

>jla...@highlandsniptechnology.com wrote...
>>
>> Our once chronic bug was flipping an opamp symbol to make
>> the + and - inputs fit the circuit nicely, which also
>> flipped the power pins, which we then connected V+ on
>> top, V- on bottom, which was wrong. That is now on our
>> PCB checklist, and we assign someone to check it yet
>> again just for luck.
>
> I've made that mistake, but some time ago created a
> second op-amp symbol to use to solve that issue.

You can still pull up the wrong symbol!

>
>> How many copies of AoE have been sold?
>
> I dunno. In its 15th printing now, but that doesn't
> mean 150k copies. Probably between 75k and 125k.

I've bought a dozen or two. I give them to new hires if they don't
have one already. Plus my copies at work, at home, and in the cabin.

Thanks!



--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

Winfield Hill

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Oct 22, 2019, 5:01:57 PM10/22/19
to
John Larkin wrote...
>
> Winfield Hill wrote:
>> jla...@highlandsniptechnology.com wrote...
>>>
>>> How many copies of AoE have been sold?
>>
>> I dunno. In its 15th printing now, but that doesn't
>> mean 150k copies. Probably between 75k and 125k.
>
> I've bought a dozen or two. I give them to new hires
> if they don't have one already. Plus my copies at work,
> at home, and in the cabin.
>
> Thanks!

You've bought about 0.02% of all the copies!


--
Thanks,
- Win

John Larkin

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Oct 22, 2019, 6:59:40 PM10/22/19
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On 22 Oct 2019 14:01:36 -0700, Winfield Hill <winfie...@yahoo.com>
wrote:
And enough of Phil's books to put his kids through college for about
nine minutes.
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