choosing a topology for power supply

[yyoungengineers]

Hi everyone,

I want design a 5 KW converter with input voltage of 600 v and output voltage varying between 0-500V.
Up til now, i have dived into the literature to look which topologies are possible.
It seems like for high power applications ,the full bridge converter is widely used, but the reason for that particular choice is not stated explicitly.
So my question is : Why not use a simple buck converter ?or a buck-boost converter? if isolation is not required.
What are the limits of these converter, is there a particular reason why they are not employed for high power applications.

Thanks for your input!

 

[yyoungengineers]

i forgot to mention i want to design a dc-dc converter.

 

[MacGyverS2000]

Start designing a buck-boost that will cover 0-500V... you'll soon see why you don't find them on the shelf.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[yyoungengineers]

well, i know thast i will obtain problems with the duty cycle but if we suppose the output would have been fixed to 500 V .In that case it would be possible to use a buck or buck-boost right?

 

[DHambley]

If isolation is not required, your simplest topology would be a buck converter.

Darrell Hambley P.E.
SENTEK Engineering, LLC

 

[IRstuff]

Why do you think you need a boost?

TTFN
faq731-376

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Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

 

[yyoungengineers]

Thank you Dhambley, does a full-bridge converter have any advantages besides providing isolation and a higher power rating ? Because, I want to compare a few topologies instead of just focusing on only a buck-converter.

And IRstuff: I meant buck-boost since it can also step down the voltage, `but i found that the disadvantage is that the voltage stress over the switch is much greater compared to the buck (Vin+ Vout). So I won't be considering that as a option anymore.

 

[IRstuff]

A buck converter alone should be sufficient to step down. You only want a buck-boost if you need to go up and down, or you have insufficient voltage to step down from.

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

 

[MacGyverS2000]

You have 600 volts coming in, and you only want a max of 500 volts going out... at what point in this design would you ever increase (i.e., boost) the incoming voltage?

Dan - Owner

http://www.Hi-TecDesigns.com