Using a dual-inductor line filter as a DC-DC transformer?

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 

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

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

I provided test results in my other thread, but just for continuity and 
relevance, here they are again:

Here are the results for the KEMET common mode chokes:
http://www.mouser.com/ProductDetail/Kemet/SU9H-R10008/?qs=%2fha2pyFaduh%252bSC%2f65OsEwc0sJu9M0D2ipyQscEx%2f7yD8UXfpiRfuJQ%3d%3d

L(10 kHz) = 1.28 mH
L(leak) = 15.8 uH
R(10 kHz) = 2.41 ohms
R(100 Hz) = 0.225 ohms

At 90 kHz:
12V    0.22A    2.64W    9.31V    0.282A    2.62W    99%

http://enginuitysystems.com/pix/electronics/SU9H-R10008_12V_33R_90kHz_3121.jpg

At 71 kHz:
12V    0.24A    2.88W    9.66V    0.293A    2.83W    98%

http://enginuitysystems.com/pix/electronics/SU9H-R10008_12V_33R_70kHz_3122.jpg

I added 0.01A to the input current to avoid going over unity ;)

Seems like this common mode choke is actually quite capable of being used as 
a 2W DC-DC converter for a current souce like the

SCR gate drive, or the low average draw application of MOSFET or IGBT drive. 
And it is also a cheap $0.89 part.

Thanks,

Paul