I am controlling a 3-phase motor with 3 120° phase-shifted currents, which is done blindly, i.e without any sensor feedback, at the moment.
I have a Magnetic rotary position sensor which i communicate via SPI and want to integrate it to my control scheme. I already checked the related decomposition techniques, namely Clarke transformation, to find the corresponding values for the optimal driving (rotor angle + 90 °).
My question is: The sensor has 14 bit resolution and i tried and validated that it works properly. The confusing part is, 14 bit resolution apparently stands for 1 mechanical revolution (360° mechanical degrees) and since i have a 7 pole-pair motor, the resolution for 1 electrical cycle drops to (2^14 / 7) and as far as i have understood it is the electrical degrees that i should apply the inverse-clark transform on.
This resolution is still pretty acceptable but i am not really sure if my way of thinking is correct. It didnt make sense to me that the sensor resolution depends on the number of poles. Any clarification is much appreciated.
Link to the mentioned sensor: http://ams.com/eng/Products/Magnetic-Position-Sensors/Angle-Position-On-Axis/AS5147