Paul & Sabrina's cheap DIY 144v motor controller

[jackbauer]

Paul could we just use an non isolated dc dc and send the desat signal to the overcurrent pin?

[MPaulHolmes]

Well shoot! I suppose we could, IF you wanted it to be simpler and more inexpensive! hahaha.

[sawickm]

Originally Posted by flores

Hi,

I've been searching the wiki for the PCB layout files and it seems like the links that are there are broken:

Full archives from MCUDOGS inc schematics, pcb files and software:

Power board V1d altium files --mcudogs 15 Sep 2009 (EDT)
Controller board V2d altium files --mcudogs 15 Sep 2009 (EDT)


Is there an alternative location, or can someone attach the pdf's with the pcb layout?

Thanks.

The file links were corrected by MCUDOGS on 1-12-2011:

The Australian Electric Vehicle Asn: Open source controller

Also check out the ReVolt "OZ" Cougar on top of a Netgain motor .....

The Australian Electric Vehicle Asn: Open source controller

-Mark

[twotires]

I've connected my thermistor and a pot, and faked the current sensor signal. I put a voltage divider across pins 3 and 4, and tapped about 2.5 V to pin 2. Apparently, the controller board likes all this as the yellow LED is now steady!

So, I should be able to look at the PWM signal at any of the G1 - G10 resistor connections, right? I'm having trouble finding it with my scope. What is the frequency there?

thanks,
Michael

[MPaulHolmes]

around 15.5 kHz. It will go from 0 pwm to 100% of pwm very quickly (maybe 1 or 2 seconds?) because it will try to make the current match the throttle. Like 5% throttle will try to command 5% of 500 amps, but no amps will be there, so it will ramp pwm all the way up to 100%. By the way, you tricked it! You are one sneaky little bugger...

By the way, I should probably change that. 100% duty and no current means there's a problem under normal circumstances.

[mrbigh]

Originally Posted by adamj12b

Good job Mark!

Looks like they have 15 in stock!

We can easily get 5 modules grouped. I will add another section to my site and people can get them from there. I will order then and then ship the out.

I just have to figure in a small amount for shipping from Richardson Electronics to me.

If this all sounds good I will set it up.

-Adam

Shipping is $5.20 inside the US and $13.95 International.

I'm on the purchase with 2 pieces....

[mrbigh]

Originally Posted by adamj12b

Good job Mark!

Looks like they have 15 in stock!

We can easily get 5 modules grouped. I will add another section to my site and people can get them from there. I will order then and then ship the out.

I just have to figure in a small amount for shipping from Richardson Electronics to me.

If this all sounds good I will set it up.

-Adam

Shipping is $5.20 inside the US and $13.95 International.

As soon as you make the nitche for the IGBT drivers with the Paypal collection logo, we'll be able to reach the minimum order; and I will be able to release de IGBT's driver boards with the parts kit.

[MPaulHolmes]

We are just so dang blasted cooperative! It makes me so happy inside! I'm almost done with a 1000amp power section, control section, and driver board for the mosfet version. It's non-SR, since I just found some much improved freewheel diodes that are 150amps per device instead of the 60amp ones I've been using. So, the plan is to use 14 of the standard irfp4668pbf mosfets, rated at 130amp, and 14 of the new freewheel diodes, and then calibrate the little surface mount current sensor to sit on top of the M- bar. I've already calibrated one type, that had a mTesla range up to 7, but I have some other ones that are up to 21mTesla, so are less sensitive, so they don't have to be 3/4" away from the bus bar. It should be closer by quite a bit. The SR version of the control board is about 2 days worth of work from being done.

[DJBecker]

What motivated the choice of the IRFP4668, vs the higher power and lower on resistance of the IXFX230N20T? The lower gate charge?

Have you considered using the a dedicated SR driver chip such as the IR11672AS or ZXGD3101T8CT? They sense the gate-drain voltage to emulate a diode, even tracking the PWM frequency to anticipate the transition. There are many similar chips out there, but the two above have a good combination of few external components, handling the full voltage without a voltage divider or input clamp, and having strong gate drivers. I haven't found ones in a through-hole package -- these are at least big enough to hand solder.

The gate drives for SR controllers might initially seem a little weak, but remember that the Miller charge is actually helping rather than hurting. And the intrinsic/body diode is still working, even if the gate is slow to turn on. The only performance critical region is the turn-off: an early turn-off lets the full body diode capacitance build, while a late turn-off allows shoot-through current. A perfect turn-off has the gate region narrow with a short carrier lifetime.

The neat thing is that you can add this circuit with only connections to SR MOSFET pins and a "bootstrap" diode connection to the low-side gate driver power supply. Note that you want the power supply V- to come from close to the low-side MOSFET drain, and SR MOSFET 'source sense' connected to the high side source pin. They are opposite ends of the same wire, but that wire carries a lot of current.

[jimphelps]

Maybe we're looking at alot more pep out of a 1000 amp controller? It's great to watch the progress, keep up the good work you guys!