Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control

[WindyDrew]

Why don't you just use the factory resolver?

Originally Posted by arber333

Here in Slovenia at firm RLS they offered me an encoder replacement for my Leaf motor resolver sensor. Huh! I like to think out of the box...
I went on and took the back of the motor apart. Pictures show what i got.
There was a lot of bolts to loose. I even had to borrow a torx key to unscrew a bolt that doesnt have an edge to hold. I replaced it with normal bolt the instant it was loose .

I got resolver out and checked crevice. Well i could mount a rotating magnet inside aluminum fitting on the end of the shaft. I could fasten that as M12 nut with extension.
Then if you look closely the cover is made of two parts. First is just a final cover, but second has two holes on the left that are threaded and currently of no use. I would use this as my anchor for mounting encoder PCB. It is magnetic encoder with open collector NPN output pulse. I would use a pullup to 5V with it.
Rotary magnetic module on metal flange RMF44

Not so much expensive... I would use current connector and after cover is on you couldnt tell the difference.

Now the question to whom it may concern:
What encoder sensor would be best for our inverter/motor combination? Either 9bit (512ppr) or 10bit (1024ppr). I can get either one, there is no price difference. I just want to know if something is better than other?

tnx

A

[MPaulHolmes]

Arber is a mad scientist... I would say 512 ticks is plenty. The dspic can change that into 2048 ticks if you count every time A goes high/low and B goes high/low.

[MPaulHolmes]

encoder-ticks is one of the variables you can set, so it's not a big deal no matter what you pick. I think 256 ticks is plenty. That would turn into 1024 ticks per revolution after the dspic got a hold of it. And with an open collector, wouldn't it take a little time to get pulled up or down? I would err on the side of fewer ticks. I would go with 256 or 512 rather than 1024 or 2048. I'm just thinking about at 10,000 RPM. That's a lot of dang ticks. haha. That's more ticks than my old dog had. Hmm... pwm output based on RPM? I don't think that would be very hard under certain constraints (if it was in the 10KHZ loop). Just as an example, if the RPM was 1Hz, it could be a duty of 10/10000, and 100Hz would be 10000/10000 duty, or whatever. Then, it's just a matter of toggling the port. It's always 5-10 times harder than you would think, but I think this time it would only be 2 times harder. haha

[CoopL]

Hello guys, I'm Cooper, I'm 16 and I've started a conversion of an '88 VW Cabbie. My grandfather gave me an older AC motor (15KW / 50KW peak), but we're having a hard time finding a controller. My dad is an EE, so we're thinking of building one of Paul&Sabrina's but wondering how hard it will be to interface it to the motor and how "turnkey" the system will be once built? We're very comfortable with the physical build and soldering, but concerned about the software integration.

Any advice/recommendations? Any help is very much appreciated!

Thanks in advance!

Cooper

[mora]

Hello Cooper.

Is your motor old industrial motor? It might not be up to task unless you rewind it. I can tell that rewinding old AC motors can be rewarding and it is not hard or expensive at all. You need an encoder for that motor. What could be better than telling doubting people that you've rewound your motor and even built a controller for it. You could wind it for lower voltages and use safer DC voltages, say 90-150VDC.

I'd say, from reading recent posts, that this AC controller will be as good as P&S DC controller. I've drooled after this controller since this thread got started! Now I'm starting to build mine. I've already rewound some motors and I need another controller for smaller project. No doubt it will be downscaled P&S AC controller.

I can also advise not to buy any Kelly controller at all. They might look tempting (or price tag looks tempting) but they offer you zero support after you get one, promises about performance are way off and they even lie you about what their controllers actually are meant for.

[CoopL]

Thanks for getting back so fast! My grandfather says the motor was used by dominion power in some s-10 pickup truck conversions. Dominion power used them in the early 2000's so its not too old. We haven't been able to find too much about the motor but its made by Hughes power control systems and on the motor itself it says it is 60 kw peak. I know that it is oil cooled as well.
It looks like you are converting a similar car. How far have you gotten? what motor/controller are you using? Do you have Batteries? Where did you find them or do you have a plan to get them from somewhere? What voltage are you going for?
Thanks so much for the help!
Cooper

[MPaulHolmes]

Originally Posted by arber333

On the R to E board i see also the GND pin on the input. Do you use it at all?

And on the output, how do we use DOS, DIR and LOT pins? Can i just use A, B and I pins besides 5V and GND? I would like to install 5Pin connector.

A

Yes, just ignore the ground pin on the resolver side. I dont' think it's necessary. It was in case there was noise, but the lines are so low impedance (like 16 Ohms DC resistance) that I don't think it's worth using a shielded cable, and grounding the drain wire. At least I've never had any trouble getting it to work. Also, ignore the DOS/DIR/LOT pins. Just use a 5 pin connector for +5v, ground, A,B,INDEX.

[MPaulHolmes]

Originally Posted by CoopL

Hello guys, I'm Cooper, I'm 16 and I've started a conversion of an '88 VW Cabbie. My grandfather gave me an older AC motor (15KW / 50KW peak), but we're having a hard time finding a controller. My dad is an EE, so we're thinking of building one of Paul&Sabrina's but wondering how hard it will be to interface it to the motor and how "turnkey" the system will be once built? We're very comfortable with the physical build and soldering, but concerned about the software integration.

Any advice/recommendations? Any help is very much appreciated!

Thanks in advance!

Cooper

If you can include an encoder, it's a snap getting the motor to work. You can just run an autotuning command so that it automatically finds the rotor time constant as well as the PI constants. Then, you save those values and forget it. It's not a big deal.

Here are the commands:

run-pi-test
run-rotor-test
save

hurray, done! haha

-Paul

[mora]

Originally Posted by CoopL

Thanks for getting back so fast! My grandfather says the motor was used by dominion power in some s-10 pickup truck conversions. Dominion power used them in the early 2000's so its not too old. We haven't been able to find too much about the motor but its made by Hughes power control systems and on the motor itself it says it is 60 kw peak. I know that it is oil cooled as well.
It looks like you are converting a similar car. How far have you gotten? what motor/controller are you using? Do you have Batteries? Where did you find them or do you have a plan to get them from somewhere? What voltage are you going for?
Thanks so much for the help!
Cooper

My conversion was finished back in 2010. I drove it 4,5 years and then rust became too big issue. It was DC motor at 144V and of course P&S DC controller. Now I'd like to start similar conversion but with rewound AC motor and P&S controller! 140-160V. For batteries I'd use 18650 cells as they are pretty cheap right now. You should consider finding a wreck Nissan Leaf or Chevy Volt or anything similar for batteries. Disassemble, sell controller, motor and keep batteries. Even if you only bought a battery from wreckage it will be cheaper than getting brand new cells.

Then back to controller topic

[MPaulHolmes]

It is 8 pole (4 pole pairs). Here's a video I just finished with testing it on our go-kart. I don't think it would spin if the pole pairs were wrong:

https://www.youtube.com/watch?v=6FUEo_TXSDg