Investigation of influence of sensor positioning on PM BLDC motor with trapezoid control operation

Synchronous motors excited with permanent magnets (BLDC) require rotor position sensors in order to operate properly. Usually Hall sensors are used. A serious problem is posed here: how to place the sensors so that their operation might not be disrupted by coil end windings field. One possible way to minimise the interference is to place the sensors in slots cut in pole pieces teeth. Still, the accuracy of this solution is limited by slot pitch length. Influence of sensor position deviation on motor operation is presented in the paper. The conducted measurements show that motor may operate if deviation from the correct sensor position is less than 15 deg el