20Amp H-Bridge driving with AVR

I'm an electonic amateur enthusiast and  I want to drive 20Amp 12-24v DC 
motors with a H-bridge controlled with an AVR.

Basicly AVR will receive speed commands from RS232, and it will count 
quadrature encoder signals (I do not now how to do it fast yet) from an 
encoder attacehed to the motor shaft and it will  generate ON-OFF signals 
for the H-bridge.

Do you know any open source, open schematics project with the above 
functionality?

<Huaci> wrote:

> I'm an electonic amateur enthusiast and  I want to drive 20Amp 12-24v DC
> motors with a H-bridge controlled with an AVR.
> 
> Basicly AVR will receive speed commands from RS232, and it will count
> quadrature encoder signals (I do not now how to do it fast yet) from an
> encoder attacehed to the motor shaft and it will  generate ON-OFF signals
> for the H-bridge.
> 
> Do you know any open source, open schematics project with the above
> functionality?

This sort of thing I have done many times over for different projects 
(AC/DC/Stepper). You know the form of the output and you should know the 
form of the quadrature encoder input. Don't shy away from using hardware 
portions to the solution as this can often be less expensive and easier to 
accomplish than trying to do it all in software.

I would advise you to really read the specs of the IGBT's or PowerFETs you 
use and ensure that you drive them properly (quite simple when you set up 
the right drive voltages). Look at isolation issues within the bridge.

I won't post my schematics here as I earn my keep by knowing this stuff 
very thoroughly. But the above should be enough of a clue.

I will, however, reference a good book on the topic:-

  "Electric Drives and Their Controls" by Richard M. Crowder; OUP 
  ISBN 0-19-856565-8

-- 
********************************************************************
Paul E. Bennett ....................<email://peb@amleth.demon.co.uk>
Forth based HIDECS Consultancy .....<http://www.amleth.demon.co.uk/>
Mob: +44 (0)7811-639972
Tel: +44 (0)1235-811095
Going Forth Safely ....EBA. http://www.electric-boat-association.org.uk/
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Get thee over to
www.avrfreaks.net
There's a whole bunch of articles in the forums and academy section
well worth (free) registration

Good luck

Tom

On Sun, 13 Mar 2005 23:48:40 +1100, <Huaci> wrote:

>I'm an electonic amateur enthusiast and  I want to drive 20Amp 12-24v DC 
>motors with a H-bridge controlled with an AVR.
>
>Basicly AVR will receive speed commands from RS232, and it will count 
>quadrature encoder signals (I do not now how to do it fast yet) from an 
>encoder attacehed to the motor shaft and it will  generate ON-OFF signals 
>for the H-bridge.
>
>Do you know any open source, open schematics project with the above 
>functionality?
>

Check out 
http://www.4qd.co.uk 

<Huaci> wrote in message 
news:423436a9$0$22218$afc38c87@news.optusnet.com.au...
> I'm an electonic amateur enthusiast and  I want to drive 20Amp 12-24v DC 
> motors with a H-bridge controlled with an AVR.
>
> Basicly AVR will receive speed commands from RS232, and it will count 
> quadrature encoder signals (I do not now how to do it fast yet) from an 
> encoder attacehed to the motor shaft and it will  generate ON-OFF signals 
> for the H-bridge.
>
> Do you know any open source, open schematics project with the above 
> functionality?
>

Hi!

I'm about to finish a project with almost the same specification (I spec'ed 
it for 6..18V DC). SCH and PCB is available, but they contain some bugs I've 
found after publishing it. Firmware with I2C and RS232 support and a 
corrected SCH/PCB will soon follow. Note, that though the HW has support for 
quadrature encoders, I'm using back-EMF at the moment to measure the speed: 
easier and precise enough for my needs. Anyway, take a look:

http://h-storm.tantos.homedns.org/h-bridge.htm

Regards,
Andras Tantos