Thanks for reply FvM
alright! so, is Zmotor = R + XL(motor inductive impedance)?
Also, in my case, im measuring the period of back emf waveform and adjusting the commutation speed. So, as u said, i also have to measure the emf voltage value and subtract it from Vdd supply to find the back emf? And if i measure the Iphase and calculate the drop in motor and subtract it from Vdd, will the result be back emf?
im not much of a guru in motor control, so that may sound little novice. sorry for that.