Paul & Sabrina's cheap DIY 144v motor controller

[Crossdan]

Originally Posted by jedsmd

Dan
Are you measuring the 12volts between the yellow wire and the red wire before the 8 seconds? after the 8 seconds? or both?
Jerald

I was measuring 12 volts after 8 seconds. So the pre-timer worked but on the wrong leads. However I found my problem. When I was desoldering the Mosfet I found a scorch mark under it, so now I'm sure the magic smoke got out and I need to replace it. When I checked my circuit in the car I found a short that sent 12v TO the contactor. That'll teach me not to triple check my work.
So while I wait for the Mosfet to arrive I put a 96v pack of old 17 AH UPS batteries in the car to see how the controller worked. With the car on jacks it seemed to work pretty good. Was able to control the speed but do need to adjust the throttle some. When I took it off the jacks and tried moving up my driveway it was a real dog. Would only go about 10 feet. Thought I killed the batteries but they still had 75% when I put them on the charger.
I'll save the controller data when I do my next test and post.
Dan

[jedsmd]

Originally Posted by Crossdan

I was measuring 12 volts after 8 seconds. So the pre-timer worked but on the wrong leads. However I found my problem. When I was desoldering the Mosfet I found a scorch mark under it, so now I'm sure the magic smoke got out and I need to replace it. When I checked my circuit in the car I found a short that sent 12v TO the contactor. That'll teach me not to triple check my work.
So while I wait for the Mosfet to arrive I put a 96v pack of old 17 AH UPS batteries in the car to see how the controller worked. With the car on jacks it seemed to work pretty good. Was able to control the speed but do need to adjust the throttle some. When I took it off the jacks and tried moving up my driveway it was a real dog. Would only go about 10 feet. Thought I killed the batteries but they still had 75% when I put them on the charger.
I'll save the controller data when I do my next test and post.
Dan

Glad to hear you found the problem with the contactor control!

It takes a lot of amps to move a car, not surprising that the used UPS batteries were not up to the job. Important thing is the controller works in the car.

[raszpel]

[QUOTE=MPaulHolmes;331068]I had put a controller together for a guy over a year ago for the 24 hours of LeMons (lemons, like junky cars). It's the first ever electric that they have ever done. It's on a real life racetrack with people in the stands and everything! He just took it for a maiden voyage tonight. Nothing blew up!



Thanks I also am looking for a design for a 72 volt regulator for my 300 amp alternator. I will follow their thread plus racing always makes me smile. You work helps a lot thanks.

[MPaulHolmes]

They have a blog entry about it here:
Car and Driver Blog (at the top)

Here's a direct link to it...
LeMons Texas Day 1: 280ZX Leads, Audi Quattro Likes Rain, LeMons EV Makes Debut

You can see the controller zip-tied inside the engine compartment.

[toledi]

Here is my EV Peugeot:
Denis' 1996 Peugeot 306 XR

How can I fine tune Kp and Ki ?

[MPaulHolmes]

It's a challenge to tune the PI loop. It can lead to very severe and wild behavior. To get snappier throttle, it's probably better to adjust t-pwm-gain and t-pos-gain. But if you must, I would start ki at 0, and gradually increase kp until "overshoot is observed", and then back off a bit on kp, and then gradually increase ki until the convergence is nice and fast, but no overshoot.

Check out post 239!
http://forums.24hoursoflemons.com/vi...p?id=8920&p=10

[MPaulHolmes]

New controller update...
I had ordered 2 new mosfets/diodes for testing the controller with the mosfets/diodes' backs soldered to the bus bars. I'm having a bit of trouble figuring out the cause of the ringing:

http://www.youtube.com/watch?v=Nmyu6XmF96Y

There's a monetary prize for anyone to solves the problem. But it isn't very much... It's only a penny.

[isaac_alaska]

have you tried using a second channel measuring the signal at the ground probe of the oscilloscope to make sure it's not just a stray signal getting picked up in the scope leads?

[MPaulHolmes]

I hooked up a scope to the same point on M+ and it had a repetitive nugget of jaggedy noise, but not very big. I'll check that on B- and B+ too, but I don't think it's the cause, but I have no idea, hence the rather large monetary award I'm offering.

[SakkeP]

This is the one that has +/- supplies for the gate driver split with resistor/zener from one voltage ?
Do you have enough low-ESR capacitance for both sides directly in the supply pins of the driver ic ?
I couldn't find the schematics and BOM for this.

Edit: Other proposal: Measure the capacitance across gate power isolation.