Crazy enough to work? Controller in reverse??

[todayican2]

Ok, just had a weird idea for my hybrid trike.

Its a highway speed affair, and it is to be a hybrid. Originally I was thinking serial and use 2 large 72v (possibly 96v motors one for the gen, and one for the drive.

But I had an idea, since the engine's, a 10hp diesel, main job is to provide volts and amps to move the car with 20 or 30% left over to charge the pack. why not do a series / parallel and drive the rear wheel directly (more efficient) and run a smaller 72 or 96v gen to charge with, say 2kw.

My question is this then: If the diesel will be driving at somewhat varying speeds the volts / amps will vary so I will need to find a way to "stabilize" the volt output from the gen.

(admittedly, I am better with a welder then with a controller, and I may be way off base,) but could a 72v x 30a ebike controller take the varying v&a and output a steady voltage?

 

[FMB42]

Quote:
"My question is this then: If the diesel will be driving at somewhat varying speeds the volts / amps will vary so I will need to find a way to "stabilize" the volt output from the gen."

You might be able to use a "vintage" (pre-sixties) automotive generator voltage regulator...

 

[todayican2]

I would have thought they would only be good for regulating to 14v or so?

 

[John in CR]

How about making it a serial hybrid instead or what sounds like a series/parallel hybrid? Then instead of the weight of the tranny the diesel will need, replace that weight with a generator head to charge the batteries. 10hp isn't much, and you can use it only at it's most efficient rpm as a generator and charge your batteries on the go or while parked. That simplification will save weight and space, as well as increase durability while reducing complexity. The motor that is the generator can be smaller than the drive motor, because it runs continuous and doesn't have the same peak torque or power requirements of the drive motor. Your battery pack can't handle the same charge rate as it can discharge anyway.

To answer the original question, yes a controller works in reverse as a charger. That's exactly what happens during regen braking.

Since you're after highway speeds with enough range to need ICE aboard, I suggest a significant investment of time and effort toward aerodynamics. That will pay huge dividends in terms of speed and the power requirements at high speed.

Please share your project here as it progresses. I'm sure I'm not the only one who also would like a highway capable electric trike.

John

 

[todayican2]

Thanks for the input John, I beleive I posted this elsewhere, but here is a pic or two:

I think I have aero fairly well addressed, and im closing in on the final design for the hybrid setup. One idea posed to me was, during highway driving (The diesel would not have a tranny, other then a centrifugal clutch and would only be engaged at speeds over 50mph up to 70 or 75) The diesel would have about 2kw "left over" after driving the car by my math.

There may be 2 ways to go, 1) use a smaller gen with an ebike controller running off the diesel or 2) use a measured amount of regen off the main drive motor.

Wondering how efficient the main motor would be if I diverted, say 30% of the diesels output (about 2kw) back to the batts via regen?

 

[FMB42]

Quote:
"I would have thought they would only be good for regulating to 14v or so?"

They can, in some cases, be adjusted to output much higher voltages.

Otherwise, consider an industrial (heavy equipment) type DC VR.