I've created a BLDC ESC that has been working fairly well. One thing that has been bothering me, though, is the theory behind the BEMF zero-crossing for triggering commutations.
I understand BEMF is a function of how fast the magnetic and electromagnetic field lines are crossing each other as the motor spins. But why does the zero-crossing correspond to the "best" time to commutate the motor? If the BEMF is a function of angular rate, how does it predict a positional relationship?
Thanks,
Dan
I understand BEMF is a function of how fast the magnetic and electromagnetic field lines are crossing each other as the motor spins. But why does the zero-crossing correspond to the "best" time to commutate the motor? If the BEMF is a function of angular rate, how does it predict a positional relationship?
Thanks,
Dan