Alternator modifications

[Josh8loop]

Originally Posted by t vago

Kia is still using a standard alternator. The only thing they're doing differently, WRT other late model cars, is that they're automatically varying alternator output based on whether the car is accelerating or decelerating.

ConnClark is trying to increase the efficiency of the alternator itself.

Totally get where he's going with increaseing the alternators efficiency. My point was that a smart control scheme for the alternator could be an added benefit. Chances are that he has probably incorporated this type of control scheme or something better in his plans already however. Thanks for the gut check. Still like the idea of having a PLC based control. It would allow the user to control the ultimate destiny of the charging system, and it's draw on the engine. User could also change charging voltages and charging cycles to maximize battery life. It could also allow for creating a PLC controlled smart charging system to use on board solar panels to help trickle charge the battery to further reduce alternator demand.


















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[Josh8loop]

Also the point of me mentioning the smart alternator was to make mention that it was in fact a standard alternator, except it incorporates a simple external smart controller to reduce drag under certain conditions. There isn't a reason that someone here couldn't come up with a simple circuit(or PLC topology) that could be added to most cars in use right now to reduce alternator draw in a similar and perhaps more beneficial way.














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[ConnClark]

Originally Posted by Josh8loop

Chances are that he has probably incorporated this type of control scheme or something better in his plans already however.

Nope I don't have a PLC in my plans. The part that controls voltage and charge rate is a separate system. It controls the rotor coil current. I would like to keep it out of this circuit. The reason why is it is different for different cars and designing in that flexibility would complicate things too much.

[George Tyler]

Originally Posted by ConnClark

I am. I had to have some diodes though. FETs won't work very well on their own. They can act like a diode for start up but they have a limit on the amount of current you can pass through them. I still need some diodes in parallel to the FETs. Also the diodes will serve as a back up if the FETs get fried.

The diodes can be used, they used to be slow on old FETs but the newer ones are fast too, and can usually handle similar currents, that fet you are using has a diode current peak rating of 400A, continuos of 89A at 25 deg C, not sure what it is at 100 C. It would still do it. Also, the FETs will die short curcuit, though it could fuse the bonding wire I suppose. there may be better FETs for this puspose, I also don't like driving them with an opamp for a number of resons. a driver IC would do a much better job, and you could use a comparitor instead of a opamp.

[ConnClark]

Status update,

George and I have been collaborating off forum on this. We each have our own designs. George's design is cheaper and simpler. My design is slightly more efficient and is possibly extendable for a secret feature.

cheap, simple, efficient, expandable pick any two


I have some dead time coming up at work. My manager says I can shop around for funding to build it with my secret feature. ( Note: If I get funding the secret part will probably stay secret for at least a year maybe more. )

[Daox]

I remember reading one of the papers you posted earlier. However, I didn't think there was a huge boost to efficiency. What kind of efficiency boost is your and/or george's systems looking to provide?

[ConnClark]

Simulations show about 20% less input energy to get the same energy out. In reality it may save slightly more because less rotor current will be required and the rotor and stator coils will be kept cooler.

Edit: The cooler temps will reduce copper losses. The lower rotor current besides reducing demands itself will reduce eddy current losses.

[t vago]

Any updates on this?

[ConnClark]

Originally Posted by t vago

Any updates on this?

I am creeping forward. Work got in the way. I have been refining my version of the design to work out some shortcomings foremost of which is the ability to drive enough mosfets to handle the current. I think I have this last problem fixed. I also got my hands on two alternators as test subjects.

With some dead time at work I hope to get more done soon.

[Josh8loop]

Any updates on this project? I have an VW Jetta TDI alternator torn apart on my bench now and I'm trying to see what if any modifications I could make to it to increase efficiency. The Low forward voltage drop diodes were my first thought as I posted quite some time ago. Active rectification sounds very promising and could add quite a bit more efficiency. Time for me to go back out in the garage to see if there is any room for me to sandwich a thin but wide diameter magnet into my rotor between the claws to magnetically "bias" the rotor field coil which should reduce it's energy requirements.