Multi-pole 48V motors

[johu]

Anyone heard of this: https://volabo.com/technology/ ?

It's a motor where the copper windings are replaced by aluminum bars. Each bar apparently has it's own set of mosfets spatially close by. So they can change the number of pole pairs on the go. They also state to not use "rare earth magnets" so it must be an asynchronous motor.

Essentially I guess it's a 3-phase induction motor with variable pole pairs, bus bars instead of windings and integrated power electronics. The low operating voltage then hardly comes as a surprise: 48V.

And of course its very innovative and disruptive and future cars should all run at 48V in their opinion. What do you think?

[celeron55]

Well, at 48 volts you need like 2000 peak amps from a battery to make a car have enough power. So, no. Unless they've also come up with a cheap room temperature superconductor, of course.

[johu]

Yes, John Metric kind of currents
In 3MW solar inverters they are running 3kA continuous with bus bars that could easily serve as a structural element of a car.
That said a car hardly ever needs continuous power (average WLTP is 11kW)

There is a Finish company, too (Toroidion) that claim to reach 1MW with 4 motors and 48V

[johnspark]

There used to be multipole induction motors that people used to buy for industrial processes. This was before the days of variable speed drives. Multipole motors are not as efficient as say 2 pole motors. And motors designed to have multipole switching lose a little bit more efficiency again, they are also slightly larger in dimensions. That said, it would be possible to use the multipole arrangement instead of a gearbox.
(Finnish)
48 volts at 1MW = 20,8333 amps. HV switchboards are often rated for 20kA for 1 second. For this 1MW supply, expect fault level to be ~20x this, or 416kA. I don't know of any HRC fuses that can carry this sort of fault level.
There is also the problem of stray magnetic fields, pacemaker problems, levitating toolboxes sticking to the side of the car. Unless the 48 volt circuits
are geometrically designed using FEA.

Just for interest, I have seen rectiformers that produce this kind of current, 20kA for depositing copper solution onto stainless steel plates, these copper bus bars are like 60cm by 30cm. They don't break the 20kA circuit, they break the upstream transformer that runs at 33kV instead.

I think it is better to go to a higher voltage.

[johnspark]

Maybe Volabo have lots of parallel 48 volt circuits then if one circuit short circuits, it doesn't effect the others, so lower fault level...

[celeron55]

Lots of parallel circuits will of course work, but you end up adding up silly amounts of weight and cost in conductors and stuff.

[johnspark]

Johu i really like the concept. Could they lengthen it so it runs on 144v instead of 48 volts?, would make large reduction in fault currents, smaller wires etc. I also like one conductor per semiconductor, helps with switching poles. Note, the single conductor could be litz wire, either bought or made to reduce losses (easy to make).