Hey Jeremy,
Yes that looks like a great part and I can see how having the entire bridge
integrated would be great. That said, it is more expensive than two CM300
half bridge modules on ebay. For the same voltage-rated IGBTs, you
basically get twice the voltage across the primary with a full bridge vs
the half bridge, and with half the parts cost and half the drive power
required. So I like to use half bridges in my small coils. I would say you
can begin with this bridge at set your current limiter to a conservative
rating of say 300A and go up from there. If you're building a regular
DRSSTC driver, I'd keep the frequencies as low as possible, definitely sub
100khz. But as you use more advanced drive circuits for zero current
switching, you'll be able to push the currents up. I usually try to drive
my transistors no more than their peak current rating. Definitely does well
for reliability if you keep within the limits. :) IGBTs definitely explode
easily if you exceed their ratings AND switch at the wrong timing. That
said, I think Steve has pushed CM300s to 5000A before they exploded
(despite their 300A rating and 600A pulse rating). :-)
Guangyan
On Mon, Jul 7, 2014 at 7:01 AM, Jeremy Gassmann <jeremyee78@xxxxxxxxx>
wrote:
> Yeah, I definitely noticed the price tag. But comparing that to the
> CMM300 half bridge, it is on par with the price and it is all integrated
> into one package which I would think would help reduce parasicitcs. I guess
> this begs the question: what is the advantage of doing a half bridge versus
> a full bridge? I would assume that it would be higher power but I am still
> learning power electronics (I'm an RF engineer).
>
> I was also thinking that this part would kind of be one to grow
> into...basically I could start by running it way backed off (lower voltage
> and current) and reduce the chance of destroying it. That way I could learn
> with reduced risk of a costly mistake. Then once I am comfortable I can
> upgrade the power supply around it. Are these sound strategies to use or do
> IGBTs like to be driven more toward their limits? Thanks for the response
> and insight!
>
> Jeremy
>
> On Monday, July 7, 2014, Steve Ward <steve.ward@xxxxxxxxx> wrote:
>
> > Jeremy,
> >
> > The APTGLQ200H120G part looks outstanding, and the price tag matches
> that.
> >
> > Assuming you use a good driver that switches the IGBTs right near the
> zero
> > crossing in primary current, they should be capable of driving a fairly
> > large tesla coil. Id suggest operating within the 770A spec on the
> parts,
> > but at 600V thats quite powerful. Provided they have good cooling, one
> of
> > these parts could probably drive a 5-10kW coil.
> >
> > There really isnt an "Fmax" for a part, its a continuous curve of
> > "operating current vs frequency". Id suggest running at <100khz if you
> > really want to push the peak current level to the max, but they would
> still
> > work fine at less peak current and a higher frequency.
> >
> > Steve
> >
> >
> > On Sun, Jul 6, 2014 at 9:52 AM, Jeremy Gassmann <jeremyee78@xxxxxxxxx
> > <javascript:;>>
> > wrote:
> >
> > > Hello everyone. I am starting my journey on the DRSSTC road and have
> some
> > > questions regarding the heart of the system...the IGBT. There are a lot
> > of
> > > options out there including half bridge packages and even full bridge
> > > packages. Looking at the data sheets shows a lot of characteristics
> such
> > as
> > > input and output capacitance, rise and fall times, and switching
> energy.
> > My
> > > question is: what are the most important factors to look at when
> > selecting
> > > a device? Obviously current and voltage ratings are very important but
> > what
> > > about keeping capacitance as low as possible, etc? Are there any good
> > > documents out there the correlate these parameters to an fmax of the
> > > device?
> > >
> > > I did find a device that looks like it would be a good candidate: the
> > > Microsemi APTGLQ200H120G. It is a full bridge power module. Anyone work
> > > with this device or know if there any reasons not to use it? Thank you
> > all
> > > very much for the help!
> > >
> > > Jeremy
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