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Old 08-04-2009, 09:35 AM   #2142 (permalink)
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H-bridge - getting rid of the transmission and still having reverse.

First post after spending a couple of days reading all the posts. I am excited to build my controller and have had e few ideas for features that would really make this a full feature unit.

Since the idea of using a Atmega16 is being kicked around how about lets think about putting an H-Bridge into this so we can go in reverse without a transmission. Not everyone would need to build that part of the circuit if they only wanted forward rotation.

The following old diagram that I have found many times over the years uses N and P channel Mosfets for simplicity.

The Using MOSFETS Website: H-bridge using P and N channel FETs

Here is an excellent simple explanation of how an H-bridge works.

Even on a light weight Metro that would allow us to remove the transmission and just keep the differential and re-case it. That would shave about 30 pounds off the package. For heavier Units this could be a very significant gain.

An added benefit to this setup is the possibility to regen during breaking. Want to slow down? throw on the P- channel at a low rate. Kinda like a a Jake brake on a semi-tractor. Not full braking just a couple of hundred amps at the most.

Just some thoughts on some features I would like to see. I think all the work that had been done on here is fantastic and I can see how this could be a really great controller when completely finished.
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