Cheap 3 Phase Controller

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EVLearner
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Cheap 3 Phase Controller

Post by EVLearner »

A few weeks ago while web searching about microprocessor 3 phase controllers, one article was talking about a washing machine, and then it struck me that our home washing machine has autoprogrammable speeds, and has a 3 phase motor.

"> http://www.freescale.com/files/microcon ... AN3234.pdf

And here is a patent on this:
http://www.freepatentsonline.com/6442979.pdf
">
http://www.freepatentsonline.com/6442979.pdf

And gain another article
http://www.appliancemagazine.com/editor ... =1&first=1
">
http://www.appliancemagazine.com/editor ... =1&first=1

Now, putting a little of this together, it can make sense to follow this line as the microprocessor will be dirt cheap, as will the associated board - as they are made in the millions. The output may be a little weak or poorly engineered to drive IGBTs, but this is not that bad, and a little bit of insight into how this system works could be an insight into using cheap and highly available microprocessors already mounted in boards and pre-programmed to a large degree.

The only problem that I see is the ideal analogue interface from the Go and Stop pedals to drive the AC motor speed.

Seems to me that one missing link would ba an a/d converter, with the word being transferred into the speed control on a very regular (consistent) basis. All this would need iss a little bit of eligant analogue interfcing to the potentiometers/ variable resistors - variable lights etc, and this could be a path to cheap and highly reliable 3 phase motor drives...

Has anybody played with these washing machine 3 phase AC motor controllers??


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Johny
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Cheap 3 Phase Controller

Post by Johny »

Just take care when it goes into the spin cycle Image

Seriously. I saw these a few months ago while browsing too.
I would be surprised if it wasn't so integrated that you can not get at anything - but worth a look if you have one kicking around. They would be using a single micro to handle EVERYTHING. User interface, wash cycle timing, inverter control etc.
I think by the time you reverse engineer it, add bits, remove bits - it may be easier to start from scratch.

Sorry to be a bit negative.
If you want a jump start for a DIY inverter, google a device called an MC3PHAC. Add a few resistors, gate drivers and IGBTs and bingo (or is it Blam!)

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Cheap 3 Phase Controller

Post by bga »

The only problem withthe MC3PHAC is that it is specific market device for the likes of washing machines and airconditioners. I'm not sure how well it would work in an EV with torque overloads and field weakening. It's interesting that the device is 32bits.

I would think that the motorola DSP approach would work just as well.

The real problem is the scale-up needed to run big motors [at high voltages].
I'm going the DSPIC30F-6010A route. Microchip has a lot of info on motor control using the DSPIC devices. The ACIM application seems to compile OK, I'll eventually be able to say if it produces credible control signals. There is a 100KW AC Inverter project that has done a lot of trailblazing:

100kW AC Inverter Project (Opensource)

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Johny
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Cheap 3 Phase Controller

Post by Johny »

Yes, I understand that you are going that route. I was suggesting this device (again) for a simpler approach for someone who didn't want to write too much (or any) code.

Based on my experience now with the Lenze, although not yet in a vehicle, the MC3PHAC could do a credible job with a small PIC driving the speed control input. Feeding the accelerator and a speed reference into the PIC and having it control the speed real speed input to the MC3PHAC (demanding more slip) it would be possible to get good motor control from it.

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