Paul & Sabrina's cheap DIY 144v motor controller

[KUSAW]

hi Paul,
thank you very much the PCB and components were arrived today. I am going to populate and solder them this week end, hope everything goes well....
thanks again,
Kukuh
JAKARTA

[jackbauer]

Well , spent most of the day playing about with resistor values and configs. Hit on one that gave the best compromise between ringing , overshoot and transition time.

Tests pefromed:

1)With coolant temp at 25C , took the controller to 510amps for 60 seconds. Coolant at 29C at end of test. No air flow through radiator. Simulate hill climb.

2)With modest (estimate 20mph) airflow through 3/4 of the radiator. Throttle locked at 210 amps for one hour. Heatsink temp leveled off at 49C after 40 minutes. At one hour temp difference between front and rear of heatsink at 3C. One minute power excursion to 510amps. Temp at 52C at end of test.

So i figure enough testing. Gonna install it in the car tomorrow.

[dave koller]

Jack
This may be off base, but have you tried small ferrite beads on the base end. It works for my bigger robots that run at 15khz. - quenches the ringing.

[jackbauer]

Dave, you mean beads on the gate drive leads or the power leads?

[dave koller]

Originally Posted by jackbauer

Dave, you mean beads on the gate drive leads or the power leads?

Gate Jack.

[jackbauer]

hmmmm.........interesting. Thanks Dave

[squiggles]

That would be an interesting test. In theory it should not work as you are adding inductance, it would smooth off spikes but possibly induce ringing. Still there is nothing like a bit of live testing.

[dave koller]

Originally Posted by squiggles

That would be an interesting test. In theory it should not work as you are adding inductance, it would smooth off spikes but possibly induce ringing. Still there is nothing like a bit of live testing.

It seems to suppress the ringing (med and high frequency) and snub the oscillation from longer lead inductance up to the resistors. Like I said, just a hunch. I have some longer traces from my opto drivers and I place the beads as close to the base of the inputs on my H-Bridge as I can get them. Without them I get ring and oscillation and messed up PWM signal.

[jackbauer]

Controller is in. Still have to hookup the coolant. Got the rad , pump and bottle installed then realised i didnt have one piece of hose. 'course the auto store was closed. Did a little test drive with no coolant. No probs so far. Fingers crossed.

http://www.youtube.com/watch?v=P5E3EgG0MrQ

[zekthecat]

Paul great work I cannot wait to keep reading about it.