Paul & Sabrina's cheap DIY 144v motor controller

[duncan]

It's funny that the exact same hardware can be a 3 phase AC controller, a solar inverter, and a DC controller (with extra clean near-DC output, just how the motor likes it).

Is this new controller the 1000amp DC ?
I will have to go back and do some reading - I have just been ignoring AC stuff as irrelevant!

[MPaulHolmes]

haha, It could be 1000amp if I could get the frequency high enough to fit the inductors. I've put the "1000 amp" TO-247 version on the back burner at the moment.

Tomorrow is Thursday!! That marks the 2 week point for notifying TIAA-CREF about my change of address! That means I can get my retirement money soon! haha. The solar panels are on sale (50 cents per watt, 20 year warranty) until Friday, which means I won't have the money in time. HURRAY!!!

[Dwffy]

Hi there Jack,
I seem to have lost touch with what's going on around here. Could you let me know where I can glean some info on this new controller. It sounds as though it will be awesome.
Thanks, Doug

[duncan]

Hi Paul

I have put 300km on my car - including a sprint - great fun,- I was not last (almost though)
Anyway I had better get onto fixing my controller,

I have been looking at using GiGamos MOSFETS as you suggested - IXFK170N20T
These are 170 amps rather than 130 amps
The gate charge is higher - 265nC rather than 241nC - only 10% more

I was thinking of using the same diodes and capacitors (new ones)

With these higher current MOSFETS I hope to be able to turn the motor current up to about 700 amps

I will also replace the MIC4451 - I hope I don't damage the control board!

Will I be able to use the current sensor or will I have to upgrade that as well

Or am I barking up the wrong tree altogether?

[adamj12b]

Originally Posted by duncan

Hi Paul

I have put 300km on my car - including a sprint - great fun,- I was not last (almost though)
Anyway I had better get onto fixing my controller,

I have been looking at using GiGamos MOSFETS as you suggested - IXFK170N20T
These are 170 amps rather than 130 amps
The gate charge is higher - 265nC rather than 241nC - only 10% more

I was thinking of using the same diodes and capacitors (new ones)

With these higher current MOSFETS I hope to be able to turn the motor current up to about 700 amps

I will also replace the MIC4451 - I hope I don't damage the control board!

Will I be able to use the current sensor or will I have to upgrade that as well

Or am I barking up the wrong tree altogether?

IIRC, the limiting factor in the 500A controller is more the diodes then the fets. I would say upgrade the diodes and you can probably push it to 700A as long as the controller stays cool.

-Adam

[duncan]

Thanks Adam,
I am starting from an empty board so-
I am thinking of
MOSFETS - Gigamos - IXFK140N25T -
140amps, 255nC, 250volts - slightly more current but 50 more volts

Diodes - SBR60A300PT-ND -
60amps, - 300volts - the reverse recovery is not as good 55nS as opposed to 27nS
Is that a killer???

Capacitors - EET-ED2E681CA
680uF - 250volts,

This would enable me to increase the voltage - ~ 180v??

I would like to increase the voltage as I am sagging a lot - I only have a small pack

2P - 44S of 16Ah Headway cells

I do intend increasing my pack size as soon as I can afford it

[adamj12b]

Im not sure exactly, but 250V parts are probably still cutting it a little close. Also, 60A diodes will never get you to 700A total.

-Adam

[duncan]

Originally Posted by adamj12b

Im not sure exactly, but 250V parts are probably still cutting it a little close. Also, 60A diodes will never get you to 700A total.

-Adam

Hi Adam
the standard 500amp board diodes are 30A - STTH6002CW - I had assumed that the switching was done by the MOSFETS and the diodes were there to allow the stored energy to go away before the next cycle

[adamj12b]

Whoops, Sorry about that. I forgot they were a dual package diode. They still share one leg so keep that in mind.

-Adam

[duncan]

Originally Posted by adamj12b

Whoops, Sorry about that. I forgot they were a dual package diode. They still share one leg so keep that in mind.

-Adam

Sorry to be a numpty but I still don't understand - ??