Looking for dead MC Card

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heathyoung
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Joined: 07/27/2011
Points: 60

Well, it turns out that the MC card I have is deader than expected - there has been some interaction between the high voltage output of the IGBT and the low voltage section. This is a bad thing

So, I'm chasing one with a dead IGBT - and a board that isn't charred through a few tracks, to make up a Mosfet replacement board (hopefully).

I'm sure that there are a few out there in the wild...

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antiscab
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Joined: 07/07/2007
Points: 1598
Re: Looking for dead MC Card

heathyoung wrote:

So, I'm chasing one with a dead IGBT - and a board that isn't charred through a few tracks, to make up a Mosfet replacement board (hopefully).

I may have one, it just depends upon how hard it would be for me to repair....

out of curiosity, which mosfets are you planning to use?

The vectrix motor at 110kmh has a back-emf of 141vac (or 200vdc if it were allowed to rectify out).

The motor controller uses field weakening to still be able to drive the motor when motor voltage exceeds battery voltage.

I haven't come across to many fets that are rated much above 200v (the original IGBT is a 600V module IIRC).

Matt

__________________

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah
Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst replacement TC Charger
conversion
Spent so far: $5800 + $7000 + $1720 + $960 + $320 + $720 + $140 + $600
Cost to do it again: $2500 + $5600 + $1720 + $960 + $320 + $720 + $140 + $600
Cost for a Petrol bike:$6000 + + $1440 + $6000 + $800 + $1400 + $3200 servicing
Total spent: $17260
Total to do again: $12560
Total to have used a petrol bike: $18840
Total distance travelled so far: 79'120km

heathyoung
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Joined: 07/27/2011
Points: 60
Re: Looking for dead MC Card

Well, I was looking at 200V Fets for the job, but looking to limit the speed to a maximum of 80Kph - since this will be a commuter bike, and there is little need to go any faster than this. There are some 250V ones, but the Rds gets ugly at this point. Speed limiting will be achieved with a CA (cycle analyst - I don't have a real one, its a homemade clone that I built by reverse engineering) using the single pulse per revolution output from the encoder as a speed signal/6 (either by using a 4017 or the inbuilt pulse divider) and interfacing to the throttle prior to the ICM. The throttle looks to be just a standard hall throttle, with a centre position (2.5V at rest) Need to look into this more - the CA uses the CCP (capture, compare, pwm) port of the PIC to modulate the throttle.

You seem to know a LOT about these bikes! I've only just started to scratch the surface at the moment, but have some pretty big plans for it.
One of the projects is to interface the CA to the dashboard - (hint there is a serial output, capture it with a PIC and manipulate the strings to produce a CANBUS string) - so it shows the correct battery capacity, and to modify the charger so it can be used as a bulk charger, with proper interfacing to the shunts on the lipoly cells, so when the shunts start working, the current is not cut off, but dropped to a level that the shunts can dissipate, which allows a proper balance charge every time. The charger could be even something as simple as 3 48V 400W meanwell power supplies slighty modified, which cost a whole $50 each. Its a darn sight cheaper than the alternatives.

The IGBT has a VCE of 2V and a VEC of 3V - so at 100A, the worst case Vf losses are ugly - 2-300W of heat, no wonder those poor fans have to run so hard.

The FETs I am looking at is IRFP4668 - 200V, 130A, 0.008Ohm (so @ 100A drop 1W in heat - technically) and the base of that aluminium battery tray is looking mighty tempting as a nice big heatsink.

I still maintain that the original design of the motor controller board (especially with respect to the output terminals = FAIL. The PCB should have been drilled out so that the hex terminals could connect directly to the IGBT - and have the correct style of washer so they didn't creep, and use brass (not steel!) hex terminals.

But I digress (as usual) - Trying to get that bloody IGBT off the board without damaging anything will be a challenge. I've got the right gear to do the job but - hmmm. Not confident. At least the bits I need can be interfaced with flyleads to the individual components on the PCB (those tracks are small, and easy to lift)

heathyoung
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Joined: 07/27/2011
Points: 60
Re: Looking for dead MC Card

antiscab wrote:
heathyoung wrote:

So, I'm chasing one with a dead IGBT - and a board that isn't charred through a few tracks, to make up a Mosfet replacement board (hopefully).

I may have one, it just depends upon how hard it would be for me to repair....

out of curiosity, which mosfets are you planning to use?

The vectrix motor at 110kmh has a back-emf of 141vac (or 200vdc if it were allowed to rectify out).

The motor controller uses field weakening to still be able to drive the motor when motor voltage exceeds battery voltage.

I haven't come across to many fets that are rated much above 200v (the original IGBT is a 600V module IIRC).

Matt

Do you still have this? I powered the bike up yesterday with a 112V power supply (two 48V meanwell SMPS'es in series, maxed out) and it 'sort of' booted, but kept crashing once I turned the bike off again - ie. would power up once, needed a power reset every time to get it to do it again. I had to remove about a 25mm hole around one of the IGBT pins, and a 15mm on the other, and it toasted the 4 tracks running past the IGBT as well.

It was good seeing the dash lit up, and the lights and indicators working, and the Klms (58.1) on the bike. It would be great to get it working...

heathyoung
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Joined: 07/27/2011
Points: 60
Re: Looking for dead MC Card

Update - looks like even though the 'go' light works, there is no signal going to the pins of the IGBT on this board. This reinforces the idea that it the damage did occur from high voltage going where it shoudn't.

The lights are on, but nobody is home :(

Not even the encoder test routine or twisting the throttle got any life out of it. Sigh.

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