Fred Bloggs wrote in message
news:b49418cb-4c68-4b8e-9334-d90e35f8da2e@googlegroups.com...
> The worst parameter is going to be the high loss factor. Let us know how
> it works out for you. A design note on KoolMu CMC design with leads to
> other references: http://tinyurl.com/jcybza4
On Friday, September 16, 2016 at 10:04:06 PM UTC-4, P E Schoen wrote:
> Fred Bloggs wrote in message
> news:e9c0c935-87c0-476a-9556-3ae8ec40d0b0@googlegroups.com...
>
> > I think you'll find the choke cores don't have much of a volt-time product
> > because in the typical application the differential voltage induces zero
> > core flux and the common mode operation is at relatively small voltages.
> > Another problem is they should be using core material formulated to be
> > lossy at high frequency- similar to suppression beads.
>
> I posted a comment on the DIYelectricCar forum and got a reply saying that
> these chokes worked for him and he found they handled a hipot test up to 6
> kV. However, he seems to be using a larger version, something like this:
>
> http://www.digikey.com/product-detail/en/wurth-electronics-inc/744866392/732-7134-ND/5352953
>
> Here is an image of the populated board showing these inductors:
>
> http://www.paulandsabrinasevstuff.com/onlinestore.html#!/3-Phase-POPULATED-AND-TESTED-AC-Control-Driver-Board/p/59121602/category=16287307
>
> Paul
The worst parameter is going to be the high loss factor. Let us know how it works out for you. A design note on KoolMu CMC design with leads to other references: http://tinyurl.com/jcybza4
Reply by P E Schoen●September 16, 20162016-09-16
Fred Bloggs wrote in message
news:e9c0c935-87c0-476a-9556-3ae8ec40d0b0@googlegroups.com...
> I think you'll find the choke cores don't have much of a volt-time product
> because in the typical application the differential voltage induces zero
> core flux and the common mode operation is at relatively small voltages.
> Another problem is they should be using core material formulated to be
> lossy at high frequency- similar to suppression beads.
On Wednesday, September 14, 2016 at 3:16:31 AM UTC-4, P E Schoen wrote:
> I have seen a design for a high-power (200kW) AC motor controller that uses
> dual-inductor AC line chokes for a DC-DC converter for IGBT gate drive power
> supplies.
> http://enginuitysystems.com/pix/electronics/200kW_AC_Controller_p3.png
>
> I have found some chokes rated 500 uH and 1 amp, with 250 VAC rated
> isolation, for less than a dollar each:
> http://www.mouser.com/ds/2/212/KEM_LF0016_SU9V-9H-372621.pdf
> http://www.mouser.com/ProductDetail/KEMET-NEC-Tokin/SU9H-10005/?qs=sGAEpiMZZMsVJzu5wKIZCRKkZmKdbMQOj5JKMlEVxjU%3d
>
> I'm going to order a few of these to see if they will work for the SCR
> trigger board I am designing. I might not trust them for 480 VAC mains, but
> there are some applications that will be used on 120 or 240 VAC mains which
> should be safe. The graph for this part shows an impedance of about 300 ohms
> at 60 kHz, so I would figure this works out to a magnetizing current of
> about 40 mA for a 12V square wave. The split bobbin probably makes for a
> fair amount of leakage inductance, but my prototype of similar construction
> has about 5% (25 uH) and they work just fine.
>
> Has anyone tried this? Are there any issues with such a design?
I think you'll find the choke cores don't have much of a volt-time product because in the typical application the differential voltage induces zero core flux and the common mode operation is at relatively small voltages. Another problem is they should be using core material formulated to be lossy at high frequency- similar to suppression beads.
>
> Thanks,
>
> paul
Reply by Winfield Hill●September 14, 20162016-09-14
P E Schoen wrote...
>
> "John Larkin" wrote ...
>> Winfield Hill wrote:
>
>>> I like the +20,-4V 100mA modules from MornSun (QA01C) and MPD (IG120-20).
>>> 3.5kVac. Same pinout. Only 3.5pF of I/O capacitance! Nice. About $6
>>> qty 10.
>
>> That's nice, two high-isolation supplies in one brick. Just right for
>> powering opamps, too. Sometimes just a little negative voltage is all you
>> need.
>
>> I use the single and dual CUI bricks even when I don't need isolation.
>> This one is slick: www.cui.com/product/resource/pds1-m.pdf
>
> Murata also makes some nice 2W DC-DC converters for IGBTs,
> MOSFETs, and SiC devices (about $8):
> http://www.mouser.com/ds/2/281/kdc_mgj2-318966.pdf
Lots of choices. Quote: "Ultra low coupling capacitance",
but they don't give a value. 3.5pF is sweet spec value.
--
Thanks,
- Win
Reply by P E Schoen●September 14, 20162016-09-14
"John Larkin" wrote in message
news:4lritbhm1beapqdvvgg29vr0vakpumoa45@4ax.com...
> On 14 Sep 2016 07:46:15 -0700, Winfield Hill <hill@rowland.harvard.edu>
> wrote:
>> I like the +20,-4V 100mA modules from MornSun (QA01C) and MPD (IG120-20).
>> 3.5kVac. Same pinout. Only 3.5pF of I/O capacitance! Nice. About $6
>> qty 10.
> That's nice, two high-isolation supplies in one brick. Just right for
> powering opamps, too. Sometimes just a little negative voltage is all you
> need.
> I use the single and dual CUI bricks even when I don't need isolation.
> This one is slick:
"Tim Williams" wrote in message news:nrb5f4$l0f$1@dont-email.me...
> CMCs are only good for about 1-2W. If that's all you need, then go for
> it.
Actual gate current about 200-300 mA with 12 VDC open circuit. So maybe
2.4-3.6 watts, but if the impedance causes the output voltage to drop
(without much power due to inductance) then it might be fine.
> Hardly any need for current limiting either, thanks to the huge leakage.
> Just make the driver a little oversized. It's "impedance protected" like
> all those tiny AC motors! ;-)
> Wowww, that schematic is laughable. ATtiny instead of a 555. Driving an
> IXDD604. Guessing they don't know their asses from their stack of
> cookbooks. Wait, the fine print says "from Instructables"? The closer
> you look at it, the harder you laugh...LOL!
That is actually an earlier version of the AC controller sold by
PaulAndSabrina, for DIY EVs, and apparently they work quite well:
http://www.paulandsabrinasevstuff.com/onlinestore.html#!/EV-Boards/c/16287307/offset=0&sort=normal
The ATtiny (or an equivalent Microchip PIC) is really a much better choice
than a 555 because you can program the dead time between alternate square
wave pulses. The cost is comparable, and rather insignificant. The IXDN604,
with 4A output and only about $1.80, is also a pretty good alternative to a
four-MOSFET bridge.
Paul
Reply by John Larkin●September 14, 20162016-09-14
On 14 Sep 2016 07:46:15 -0700, Winfield Hill
<hill@rowland.harvard.edu> wrote:
>John Larkin wrote...
>>
>> You could buy a complete potted dc/dc converter for a few dollars.
>> There are also reasonably priced converters rated for kilovolts of
>> isolation.
>
> I like the +20,-4V 100mA modules from MornSun (QA01C)
> and MPD (IG120-20). 3.5kVac. Same pinout. Only
> 3.5pF of I/O capacitance! Nice. About $6 qty 10.
That's nice, two high-isolation supplies in one brick. Just right for
powering opamps, too. Sometimes just a little negative voltage is all
you need.
I use the single and dual CUI bricks even when I don't need isolation.
This one is slick:
www.cui.com/product/resource/pds1-m.pdf
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Reply by Winfield Hill●September 14, 20162016-09-14
John Larkin wrote...
>
> You could buy a complete potted dc/dc converter for a few dollars.
> There are also reasonably priced converters rated for kilovolts of
> isolation.
I like the +20,-4V 100mA modules from MornSun (QA01C)
and MPD (IG120-20). 3.5kVac. Same pinout. Only
3.5pF of I/O capacitance! Nice. About $6 qty 10.
--
Thanks,
- Win