Re: The goo inside of IGBT modules.

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

At 08:08 AM 9/16/2004 -0600, you wrote:
>Original poster: "Harold Weiss" <hweiss-at-new.rr-dot-com>
>Hi Steve,
>
>You could use those Peltier junctions to drop the temprature on the sinks
>below ambient temp.  The only problem I see is that you would need even
>bigger heat sinks.  You can get some pretty good drops in temprature with
>them, I had one that could drop 120 degrees, and was supposedly used to cool
>the seeker head for the Sidewinder missile.  That thing could make almost
>instant ice cubes.
>
>David E Weiss

If you go to Melcor's web site http://www.melcor-dot-com (they're the big maker 
of Peltier devices) they've got a bunch of charts and stuff to show how to 
get various temperature drops.

As a practical matter, the Peltier is not a very efficient cooler, and is 
practical only for very small things (CCD sensors being a notable 
example).  You can get about 40-50 degrees C from each stage, but at each 
stage, you add a lot of extra heat that has to be rejected (on the order of 
5x?), so you wind up with a pyramid.

1W from device: Peltier cooler #1: 6W: Peltier cooler #2: 120W to free air...

Here's an example, though: CP1.0-7-06 from Melcor (about 8x8mm)
Hot side temp 50C
Qmax = 1.6W
Delta T max = 77C
Imax 3.1 A
Vmax 0.90V
Module resistance .27 ohms

so, you're putting in about 2.8 W to move 1.6W, and now you've got to 
dissipate 4.4W..

If you're looking to move hundreds of watts, liquid cooling and mechanical 
refrigeration is the way to go.

HOWEVER... your real problem is not getting the cold, but getting the heat 
out of the package and into the cold plate.



> > Original poster: "Steve Ward" <steve.ward-at-gmail-dot-com>
> >  >
> >  > You're not by any chance contemplating to remove the gel and adding a
>pump
> >  > and internal forced oil cooling to your IGBT modules, are you?  ;-)
> >
> > Hehe... it had been considered.  The manner which im using the IGBTs
> > can cause a lot of transient heating, and i was really curious if
> > there was some other way of getting the dies even cooler (increase my
> > thermal headroom).  Im not sure if im willing to go so far as oil
> > cooled though.  Maybe just get the baseplates further below ambient
> > temp.
> >
> > Steve
> >