EmbDev.net

Forum: Analog Circuits Active PFC in a 24V (Truck/Bus) network?


Author: Kayham (Guest)
Posted on:

Rate this post
0 useful
not useful
Hello,

when I was seaching for infos on how to use a standard Computer
in a truck or bus, I came across the "active PFC" and read,
that I should use it in DC/DC converters to, to avoid the high
switching frequencies on the bordnet.

Can someone tell me, which PFC chip I should use for it and
maybe some links to application notes and schematics?

Thanks Kayham

Author: Martin (Guest)
Posted on:

Rate this post
0 useful
not useful
I think that makes no sense. PFC means power factor correction, and for 
a power factor you need alternating current. But in a 24V net, you have 
DC current.
To reduce high switching currents, you just need a good filtering, so 
input capacitors and inductors must be well chosen.

Regards,

Martin Antoni

Author: Kayham (Guest)
Posted on:

Rate this post
0 useful
not useful
This is one of the source where I found the thing with the DC PFC:

http://www.smps.us/power-supply.html

The PFC is AFTER the rectifier, hence on the DC side.

Can someone enlight me please?

Thanks

Author: Esko (Guest)
Posted on:

Rate this post
0 useful
not useful
> I think that makes no sense. PFC means power factor correction,
> and for  power factor you need alternating current.
He is right.

Author: Martin (Guest)
Posted on:

Rate this post
0 useful
not useful
After the rectifier, you have also a alternating current, but only with 
positive sign. And then, the current is drawn sinusodial, to match it 
with the input voltage. This current is then stored in a 'big' 
capacitor, which is in input to the next switching converter.

In this picture, you see the current, which matches in average a sinus

http://cr4.globalspec.com/PostImages/200911/PFC_cu...

Author: Kayham (Guest)
Posted on:

Rate this post
0 useful
not useful
Ah OK, makes sense.

Greetings Kayham

Reply

Entering an e-mail address is optional. If you want to receive reply notifications by e-mail, please log in.

Rules — please read before posting

  • Post long source code as attachment, not in the text
  • Posting advertisements is forbidden.

Formatting options

  • [c]C code[/c]
  • [avrasm]AVR assembler code[/avrasm]
  • [code]code in other languages, ASCII drawings[/code]
  • [math]formula (LaTeX syntax)[/math]




Bild automatisch verkleinern, falls nötig
Note: the original post is older than 6 months. Please don't ask any new questions in this thread, but start a new one.