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Re: [TCML] IGBT paralleling
DC, I would be interested to see a datasheet for these 2400V 2400A modules.
As far as i know Powerex doesn't even make igbt's that are rated for 2400v
The Highest rated 2400A module they make is for 1700v
http://www.pwrx.com/pwrx/docs/cm2400hc_34n.pdf Their next step in voltage
is the 2500V and the highest rating they come in is 1200A
http://www.pwrx.com/pwrx/docs/cm1200hc-50h.pdf
Even these modules that they actually make are pretty darn unsuitable for
DRSSTC use or even SISG due to their extremely slow switching times. For
the CM2400HC-34N the td(OFF) is 1.2uS. The CM1200HC-50H is even worse with
a td(OFF) of 2.5uS! Point being is big igbt's are going to be very slow and
pretty useless for tesla coils unless you have a very very low resonant
frequency. I would suspect this "igbt" that DC has to have very similar
switching speeds.
On Sun, Jul 11, 2010 at 1:04 PM, DC Cox <resonance@xxxxxxxxxxxx> wrote:
> You really can't go wrong with the PowerEx series of IGBTs. For a pig
> powered unit I would consider the CM600s or CM1200s. Yes, a bit expensive
> but they work great and are extremely rugged due to their "trench gate"
> design.
>
> They make CM300 which work good for a coil with 4-5 ft spark, CM600,
> CM1200,
> and for the really big monsters CM2400 (that's 2400 Volt, 2400 Amp!!).
>
> I completed a design for a coil with a pair of CM2400s on each corner of
> the
> H bridge. It uses a pole xmfr to get the drive voltage up to 1,800 Volts
> and runs at 60 kVA using a 50 kVA xmfr. Coil is 49" dia. x 35 feet long.
>
> Haven't built it yet, but hope to before I get much older.
>
>
>
> Dr. Resonance
>
> On Sun, Jul 11, 2010 at 11:16 AM, Scott Bogard <sdbogard@xxxxxxxxx> wrote:
>
> > Hi John,
> > By chance is there a compiled list somewhere of "good IGBTs" that
> > are used and those that aren't. Anyway back to the original question, is
> it
> > possible to parallel them? Lets say for kicks I'm building a dual pig
> > powered 30kVa magnifier with a LTR cap (I'm clearly not, we are talking
> > theoretical here.) Clearly the peak currents will be beyond any
> reasonably
> > priced IGBT, is it possible to parallel lesser current units to handle
> the
> > load, and what would that entail? Thanks.
> >
> > Scott Bogard.
> >
> > On 7/10/2010 5:09 PM, John Forcina wrote:
> >
> >> Those IGBT's seem far from ideal. The TO220 package is a very poor
> choice
> >> as far as thermal conductivity and the datasheet says it all 0.75C/W.
> You
> >> will not be able to remove enough heat from the surface of the IGBT die
> >> quick enough between current pulses and the device will fail. They do
> not
> >> have a internal anti-parallel diode so adding that externally will add
> to
> >> the final cost also. Not to mention doing that will add additional loop
> >> area and stray inductance between units. One more thing is the
> switching
> >> times are surprisingly slow for that small of a unit. td(OFF) 96ns.
> It's
> >> not that slow however it does seem slow for that small of a device. I
> >> have
> >> seen much better overall performance from larger IGBT's. My suggestion
> is
> >> to just spend more money and use IGBT's that have been used and proven
> to
> >> work in Tesla Coils time and time again. There must be some reason that
> >> we
> >> all use them ;)
> >>
> >> On Sat, Jul 10, 2010 at 4:38 PM, Scott Bogard<sdbogard@xxxxxxxxx>
> wrote:
> >>
> >> Interesting,
> >>> I am in the wee beginning stages of building my first SISG, and
> as
> >>> such am in the market for IGBTs. I found these, which look very
> >>> inexpensive
> >>> and have decent ratings.
> >>>
> >>>
> >>>
> http://www.newark.com/fairchild-semiconductor/hgtp12n60a4/single-igbt-600v-54a/dp/90B5642
> >>> My thinking is if heat is a problem or peak current, can I just
> parallel
> >>> them? at $1.50 a pop it seems infinitely better than 1 $18 IGBT of
> >>> nearly
> >>> the same ratings... I didn't look at temperature or package
> information
> >>> yet, so maybe there is a problem there.
> >>>
> >>> Scott Bogard.
> >>>
> >>>
> >>> On 7/10/2010 8:26 AM, McCauley, Daniel H wrote:
> >>>
> >>> Scott,
> >>>>
> >>>> The electric ratings may be the same or similar, but you also have to
> >>>> compare the mechanical ratings - in particular the thermal ratings.
> >>>> This
> >>>> would be junction-to-case thermal impedances etc... The expensive
> IGBTs
> >>>> that are commonly used in DRSSTCs are usually ISOBLOC type packages
> >>>> which
> >>>> excellent thermal impedances. Compare this vs. a TO-247 package of
> the
> >>>> same
> >>>> die.
> >>>>
> >>>> And when comparing a TO-247 package to an ISOBLOC, keep in mind that
> you
> >>>> STILL NEED to add a thermal insulator between the TO-247 and heatsink,
> >>>> which
> >>>> just makes the thermal impedance even worse. The ISOBLOC (or SOT-227)
> >>>> doesn't require a thermal interface other a small smidgeon of thermal
> >>>> grease
> >>>> or a graphite pad.
> >>>>
> >>>> Dan
> >>>> http://www.easternvoltageresearch.com
> >>>> DRSSTC, SSTC, Flyback, Plasma Speaker Kits
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> -----Original Message-----
> >>>> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> >>>> Behalf Of Scott Bogard
> >>>> Sent: Friday, July 09, 2010 9:52 PM
> >>>> To: Tesla Coil Mailing List
> >>>> Subject: EXTERNAL: [TCML] IGBT paralleling
> >>>>
> >>>> Greetings all,
> >>>> So, after a bit of researching I've noticed there are IGBTs on
> >>>> Newark with exactly the same ratings as some of the SSTC approved
> IGBTs,
> >>>> but
> >>>> at 1/10th the price. What makes these others so special that they are
> >>>> better, and if it is just a matter of peak current ratings, since
> IGBTs
> >>>> are
> >>>> gate driven, can we just parallel a few to get the required pulse
> >>>> current
> >>>> rating? I ask because I've not heard of anybody doing this, then
> again
> >>>> I've
> >>>> only begun to research SSTC a little bit ago. Just musing.
> >>>>
> >>>> Scott Bogard.
> >>>> _______________________________________________
> >>>> Tesla mailing list
> >>>> Tesla@xxxxxxxxxx
> >>>> http://www.pupman.com/mailman/listinfo/tesla
> >>>> _______________________________________________
> >>>> Tesla mailing list
> >>>> Tesla@xxxxxxxxxx
> >>>> http://www.pupman.com/mailman/listinfo/tesla
> >>>>
> >>>> _______________________________________________
> >>>>
> >>> Tesla mailing list
> >>> Tesla@xxxxxxxxxx
> >>> http://www.pupman.com/mailman/listinfo/tesla
> >>>
> >>> _______________________________________________
> >> Tesla mailing list
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> >>
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