Re: Power supply design help needed

From: Tweetldee (masondg4499_at_comcast99.net)
Date: 09/18/04 

Date: Sat, 18 Sep 2004 15:59:11 GMT

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:414B4A75.5D0B22FF@hotmail.com...
>
>
> Robert Wolcott wrote:
>
> > I am a mechanical engineering student at Oregon State University and
plan to
> > build a high power laser (20 Watt CuBr) as my senior project. I have
been
> > researching the design for a few years and have solutions for everything
> > vacuum and mechanically related. The power supply is another story
however.
> >
> > The journal articles I have ordered and read clearly label all
components
> > with specifications and values with the exception of the "HVDC portion"
> > (highlighted in red on the link). The only advice I have received to
date
> > regarding this is that it would follow a switching scheme as outlined at
the
> > link.
> >
> > Being mechanically inclined, and not electrically, is there something
that
> > I'm missing? How would I go about determining the required output
> > characteristics of the HVDC portion of the supply? Any help will be
GREATLY
> > appreciated. I'm still in the research phase and hope to have the
design
> > finalized for fall 2005.
> >
> > Thanks,
> > Bob Wolcott
> >
> > http://oregonstate.edu/~wolcottr/Switching%20supply%20outline.jpg
>
> The answer is in the jpeg.
>
> It says 'rectified and *filtered*' AC Line.
>
> 240V A.C. fullwave rectified into a capacitor input 'filter' a.k.a.
storage caps
> will indeed give around the 339V DC mentioned.
>
> It might be wise to transformer isolate the power though for safety
reasons.
>
> You'll likely need a 'surge protection device' too, such as an NTC
thermisitor.
> The 'inrush current' from directly recifying mains into a capacitor bank
will
> blow fuses quite happily. Google Rhopoint and Surge-Gard
>
>
> Graham
>

The required output of the HVDC is quite obvious... the block in red is
described by the graphics at the top. Its output is an 11,000 volt pulse,
swtiched at 50kHz. However, it's unclear whether the pulse is rectified
before being fed to the pulse forming network. I suspect that the final
output of the HVDC supply should be +11,000 VDC, at (according to the
transformer power requirement) 1500 watts. That translates into +11,000
volts at 140 ma. 

-- 
Dave M
MasonDG44 at comcast dot net  (Just subsitute the appropriate characters in
the address)
Never take a laxative and a sleeping pill at the same time!!
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