Sorry if i'm getting carried away posting here, it was not really a question as such but more of a theory and a bit of a discussion based around a few curiosities that sprang to mind.Well Weather or not 4 controllers have more or less loss than one 4x their size is hard to say. But i guess my point was that there is always some loss in a speed controller and that they are probably made to be more efficient at nominal speeds (depending on the application).
I really think there could be a significant amount of power saved by eliminating the controller at top speeds which could work with a brushed motor especially if you were maxed out on a freeway for example.
I was just wondering if there might be a way to do something similar with three phase in order to get the best efficiency possible at top speeds. Since you need some sort of controller for three phase the only other option i could think of is to have multiple controllers that are designed to give better efficiency at different speeds. So for town driving the car would switch to the controller that was made to be most efficient at lower rpm. When on the freeway the controller best suited to high speeds would kick in and the other/s would switch out and turn off.
The difference might not be much but who knows it might be as much as a 5% increase in range or it could potentially decrease the battery size by 5% which could result in a saving of weight (depending on the weight of the extra/modified controller).
I should probably start a discussion in a new thread.