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Old 03-31-2009, 12:22 AM   #712 (permalink)
MPaulHolmes's Avatar
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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I got the car "drivable" with a PI loop, but it was really crappy and rough. It would take a very long time to discuss all the things that happened, and all the stuff I tried, so I'll skip it all, and just say that I found a nice, no PI (gasp) super smooth (smoother than my PREVIOUS Curtis controller. it sold. ya! $432!) It's sort of hard to explain, but I basically came full circle. It doesn't have to respond super fast because of the hardware current limiting, although I haven't been able to get the hardware current limiting to come on with normal to hard driving, because I just don't use 500 amps for goodness sakes! Call me a conservative driver if you want to, but only if you want a Karate Chop Sandwich!

I'm going to make up a new box out of Lexan, because the Plexiglass cracked, and the Lexan is AWESOME and unbreakable. I'll ship it to Ben before the end of the week. I just hope it runs as smooth on Ben's bigger motor. It will be fun to find out.

On version 2, I'll really spend some time making the current sensor output really smooth, with greater resolution. I only have 0.6v of resolution this time that spans 0 to 500 amps, and the noise is like 0.12v! That's bad! So using that current with the best PI loop in the world is still crap.

I'm going to spend some serious breadboard time next on version 2 finding the right layout. Also, anyone that wants to make it better, feel free. I know basically nothing about electronics. I know that sounds like false humility, but it's true. I'm just winging it and trying to follow people's advice.

We were going to go to the Lacey Alternative Energy Fair, but they charge money this year! Man, that's messed up. $25 for a bike? Maybe I'll ride my electric bike there, or the electric car (come on, controller version 1a!) and just look at all the alternative energy vehicles. hehe. Wow... An "electric car", I didn't know they had those!
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