Split phases and run dual controllers?

On my new build I will run the new QS 180 90h mid drive IPM motor.
The problem is to find any good, powerful controller and then fit it on the bike..

So I am considering splitting the motor phases by mesuring strand by strand in to 6 equal phases and run dual controllers.
The strands will then be paralell on the same tooths, but electrical isolated from each other.

Would there be potential problems? Like the magnetic fields interfearing with each other and things like that.

I havent decided on controllers, but I am looking at BESC g2, the new Powervelocity vesc based, nucular 24fet etc.

Nope, just do it. Doesn’t matter at what distance the wires are from the steel, especially not since they’ll anyway be bundled.

Using same set of sensors will activate them at the same time.

I’d take care that the phase wires are the same length and routed symmetrical from the motor to each controller. I don’t think it’s super critical, just as a way to decrease possible resistance and inductance differences.

This’ll be interesting!

Most likely it'll work fine; there are a few motors already built this way, and people using them with dual controllers (John in CR probably has the longest experience that way, here on ES).

This thread is old, but discusses the issue some:
https://endless-sphere.com/forums/viewtopic.php?f=30&t=64001

I've considered it with my MXUS 450x hubmotors on the SB Cruiser trike, when I was using cheap generic controllers that couldnt' take advantage of the power / torque those could have made, but then I started the HI-Lebowski controller project to just go ahead and be able to supply them with the power they need without modifying them...and then other stuff happened, so *that* project hasn't happened yet either. :/

But...I might still try it someday.


The hard thing about many motors is there is barely enough room for the existing phase/etc wires, much less another three phase wires, to go thru the wire exit to the outside, and not really any good way to make that exit bigger. So the thing that had really stopped me doing it on my motors was that I'd need to make a new sidecover for one side of each, with a larger bearing hole that has a larger ID bearing in it, big enough to use a spacer ring between that bearing ID and the axle, and the spacer ring would have holes in it for all the wires to pass thru, so they no longer go thru the axle at all.

Don't know how the motor you're going to use does it's wire-exit, but might be something to consider.

Thanks guys.
It is not a hub, so I dont think finding room for the extra set of wires will be a big problem.
I dont think it is really comparable to John:s "hubmonsters" as those are wired with different phases at different slots.
I dont plan to rewind the motor, only split up the existing wiring. (I hope it is an even number of strands..)

What worries me most is when running FOC controllers they seem to only use the hall sensors at low rpm, then switch to sensing the back emf on the phase wires? That is when I worry that the controllers might interfere with each other.

Thanks for the thread, it seems like it worked for lebowski to run double foc sensorless on a motor with split phases

I am thinking about another possibility that would be very simple if it would work..
How about just connecting 2 controllers paralell?

As long as they are somewhat in sync I guess it would be ok?
If they for some reason is not in sync it might end bad I suppose..

Anyone with thoughts or experiance?

If I get this right he rode a motor with dual winds and dual controllers.
Still one blew when there was a sync issue?
https://endless-sphere.com/forums/viewtopic.php?f=30&t=22091#p321635

I dont really understand why, if it looses sync it just turn off the output right?
Does it die from back emf?

An interesting thread on the subject of paralleling 2 controllers on the same windings:
https://endless-sphere.com/forums/viewtopic.php?f=30&t=91515

And another, there is a link in the first one:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=75186

I should probably read those threads but isn’t it simply that an out of sync will allow one controller to short circuit through the other controllers fets?

Means that it can never work as a concept other than by stroke of luck, for some time..

larsb said:

I should probably read those threads but isn’t it simply that an out of sync will allow one controller to short circuit through the other controllers fets?

Means that it can never work as a concept other than by stroke of luck, for some time..

Click to expand...

Well, that kind of sums it up. But it seems to be a lot to it, and there is an example of it working.
But probably a risky way of doing it, splitting the phases are probably a better idea.

And then there are the possible problems with sharing throttle:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=18108

It should be possible. I have a dual stator motor which I will be doing the same thing with.