Paul & Sabrina's cheap DIY 144v motor controller

[flores]

Originally Posted by MPaulHolmes

So, in summary, Do you guys want to just try the controllers by mounting it to your own finned heatsink? Or do you want me to try water cooling?

Paul, I say we should just try it.

[Astro]

Originally Posted by MPaulHolmes

...
So, in summary, Do you guys want to just try the controllers by mounting it to your own finned heatsink? Or do you want me to try water cooling?

Couldn't we just add a second thicker plate to it with channels milled in it and the milled side facing the IGBT's plate.
That would allow deeper channels as well as more width to add threaded inlet and outlets.
As long as we avoid having channels lining up with the IGBT mounting bolts etc.

That would mean the guys (and gals) that aren't pushing the envelope power wise could attach a finned heat sink and those that needed more cooling could add the water cooled plate.

Have to use all those failed gearbox adaptor plate attempts for something. (i haven't made my adaptor plate yet but i am predicting some "wastage")

[MPaulHolmes]

The IGBTs Otmar was using were back in 1994 too. Maybe they had a larger power loss than now. I'm not sure, but it's probably not a bad idea to just see how it goes with a finned heatsink. I can always make changes later if necessary. No big deal unbolting things and doing something different if it comes to that.

[jedsmd]

Originally Posted by MPaulHolmes

The IGBTs Otmar was using were back in 1994 too. Maybe they had a larger power loss than now. I'm not sure, but it's probably not a bad idea to just see how it goes with a finned heatsink. I can always make changes later if necessary. No big deal unbolting things and doing something different if it comes to that.

I am using a finned heatsink on my current controller and do not have any heating issues. Even though your controller is twice the beast I don't think I will be pushing it much harder. So I think I will test the air cooled version.

I do plan to have a dashed mounted temp gauge for the aluminum plate, so I will see in real time if the temperature is rising.

That said, if I did go to fluid cooling I would prefer to make my own cold plate anyway, so that I would have control of the nozzle locations and hose routing.

[MPaulHolmes]

Man, I got me some serious DIY beta testers! That sounds great to me. I'm going to just leave the base plate as it is then.

-Paul

[duncan]

Sorry to be dense
Where about on the base plate should I concentrate any cooling?

I don't think I am going to be able to use my "Copper flower in the airflow" heat sink so I will be looking at alternatives
Preferably air cooling

[MPaulHolmes]

The 3 igbts are just in a relatively small spot in the upper center. Ill post a pic later.

[Astro]

I was thinking, would it be easy to add a cruise control feature to the controller?
The controller will have an encoder to tell it precise motor rpm and full control of the power to the motor.
It should have all the information required to hold a fixed RPM on command.
So not the sort of cruise control where you select a speed but the type where you accelerate up to your cruising speed and then press a button to have that speed (rpm) held. Then a another press of the button to cancel or any brake input cancel also.

Maybe something for after the working prototypes have a few kilometers under their belt.
But as there would need to be an additional input i thought i would mention it as adding another input would be easier at prototype stage rather than later.

[duncan]

On the subject of extra features

I would like - Launch Control!!!

I currently measure motor speed (magnetic pick-up on motor shaft)
I intend to measure the front wheel speed

The intention is to compare both speeds and then reduce current until the rear wheels are doing 110% of the front wheel speeds

(110% is my first guess for an optimum launch)

I was going to do this crudely
have found a circuit that compares speeds - I now need to be able to reduce the throttle demand if the speed difference is too great

[flores]

Originally Posted by duncan

on the subject of extra features :d

i would like - launch control!!!

yeah!!!!!!!!