I don't know at what point one controller makes sense though, maybe if you have a lead on 2 or 4 small motors that are just enough power for your needs (leads have to be the same length) and are on a tight budget. But if you have 4 regular motors, you are going to need so much battery that the extra power sections aren't gonna be noticed in the budget (and your controllers might need a controller, conceptually anyway, if you are trying to do stuff like traction control).
Quote:
Originally Posted by thingstodo
.. They are measuring back-EMF from the motor and determining rotor position with some space vector math.
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You have multiple rotor positions here (using current sensors), if you want FOC on multiple motors, you need multiple switches (IGBTs) and signals at a minimum so that the stator coils fire at just the right angle for each motor (though you still need some slip with FOC, I think it is mostly when changing speeds that it targets the highest torque vector). But a slip algorithm can also set slip for max torque, just not on the very first pulse.