Paul & Sabrina's cheap DIY 144v motor controller

[squiggles]

Sounds like you would be better off driving a pre loved coffin!

[xtian999]

And what's wrong w/ Luvin'?

[MPaulHolmes]

you guys are funny!

[xtian999]

To me, the Citi is a getting-off point for something new, like the tin lizzie is for the t-bucket, or the 49 merc for a lead sled. Only this one is electric. Say, an E-bucket?

Anyway, the controller is the heart of the beast, and the motor size should not be the thing that holds it back.

If a 9" is just right, then an 11" or a 13" should leave room for future improvements in the power supply. Or maybe up the ante with a pair of 9's.

[jackbauer]

Started building the new power section. Copper bars are 20mm x 10mm flat. igbt ratings of 1000amps at tj=25c and 800amps at tj=125c. Aliuminium heatsink it 300mm square x 12mm thick. Using a piece of fr4 copper clad board to carry the bus caps bolted down to the b+ and b- bars.

[MPaulHolmes]

That is looking beautiful. The LEM can handle up to 900 amps, so you should be OK. The software is really easy to change the current limit. It's like 1 line basically. Then you just need to adjust the pot on the control board. all the way to the right clockwise is 775 amps. You can change some resistor values if you want the current to be higher than that. It's not hard.

[jackbauer]

500amps is plenty for now. I just prefer to have some overhead and I like the igbts as they have big power handling capability. Hopefully get it finished and do a few tests tomorrow.

[jackbauer]

Well did some tests on the new hardware and it worked great. Oh and the lem seems to be working!

http://www.youtube.com/watch?v=TmhHjoEMbiE

[mike_lera]

Hello
i am requesting some help with the controler board. I have completed it and would like to test it without blowing it up. LOL. at this point i do not have a power board but I think I should be able to see the "pwm out" will it be seen with a meter at gate resistor to ground? do i have to look at it with a scope? the green power led and a flashing idle light are boring to watch. when i put my meter from grd to a gate resistor i get a progresive voltage and then it drops out and starts over. what hapend to HARPO (oprah) no new jokes
Mike

[MPaulHolmes]

Hi Jack! Jack Bauer ain't got nothing on you!!! The PI loop is set to a very gentle setting. If you want snappier response, you can increase the throttle ramp rate. It's one of the variables. Also, you can try larger values of Kp or Ki for more aggressive chasing of throttle. In fact, you could tune to your motor if you are feeling really bored. Start with Ki = 0. Start Kp = 1. Jerk throttle from 0 to whatever really fast and observe the step response. This process works best with a locked rotor on the motor, but I think it would be fine without a locked rotor. If there is no major overshoot by the current feedback, then increase Kp. Keep doing this until Current has some overshoot. Now decrease Kp just a bit, and gradually increase Ki. Stop when you get the results you like the best for your motor. hehe. By the way, is it raining over there right now? I thought I heard the rain. It rains over here all the dang time.

Hi Mike! Well, you might see something interesting on the pwm output, since the code you have is throttle proportional to current and speed together. It would be better to get a new chip with the new software on it. Then you should be able to see a PWM output on some of the settings. I'll get that programmed and mailed out to you. Don't worry. Were you able to change the orientation of L1?

No more oprah jokes because my wife told me it might hurt people's feelings. haha. And plus, she's so thin and beautiful, so How could I make fun of her? hahaha. On a completely separate note, not relating to Oprah at all, I had a delicious dessert last night. It was chocolate moose. (this is OK to say since my wife is black. That's the rules. I didn't write them. I just apply them.)