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Old 03-29-2009, 07:26 PM   #697 (permalink)
MPaulHolmes
PaulH
 
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Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
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Quote:
Originally Posted by Roger Heuckeroth View Post
Also, Paul, I have been following your thread on EVTech DL about the current sensor. I think the noise is normal for a PWM current. You definitely have to filter the LEM output to smooth it out, otherwise the output will be a scaled distorted version of the PWM current going through the sensor.

Holy Cow!!! You are right Roger! I forgot that the current going through the aperture isn't nice and perfectly smooth. I'm such a whippersnapper sometimes, I forget things! Thank! Now, I need to smooth that LEM output.

Since I couldn't figure out the right P and I, I just changed the code to have throttle be directly proportional to current by incrementing pwm if current is less than throttle, and decrementing pwm if current is greater than throttle. I think I could barely feel a hint of the variation in the current sensor, and I do mean BARELY. It could have been in my imagination, actually.

Am I missing something: Like 2 lines of code to get perfectly smooth driving. OR... Like 200 lines of code and an endless search for P and I IN THE DANG RAIN, WORKING WITH HIGH VOLTAGE!!! just to get the same result! Man, that makes me mad. But surely the ghetto increment, decrement way wouldn't work on a larger motor??????

Well, Ian of Zero Emissions Vehicles Australia uses that method, and he has an 11 inch Direct Drive monstrosity! It works great for him... I feel some rebellion coming on... hmm.....

Power to the people Marty. Power to the People, Coz... (Sneakers. 10th Best movie ever).

Also, for the first time, I could detect the 16 KHz tone, since the car is dead silent, and the controller is in the back seat, and the ceiling acts like a parabolic dish, with my head at the focus. hehe. Also, I was really scared again (always after changing code to drive the car), so my senses were heightened like a puma.

MOSFETS AND DIODES:
STTH6002C
IRFP4668pbF

STTH6002C's can be gotten cheap from Nu Horizons.com if those bozos ever order more! I emailed them, and they won't write me back. They ran out, and don't want to order the minimum 390 to replenish their supply. I need a business name! No respect! Geeze.

Both can be gotten from Digikey.com or Mouser.com.
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Last edited by MPaulHolmes; 03-29-2009 at 07:31 PM..
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