I. INTRODTICTION
Permanent magnet brushless machines are extensively used for servo derives, ship propulsion systems and traction drives. The back-EMF wave form of brushless AC (BLAC) drive is sinusoidal and is supplied with SPWM voltage source inverter, while the Brushless DC (BLDC) stator phase currents are rectangular and its back-EMF is trapezoidal due to concentrated winding. BLDC motor has better efficiency, higher torque density, lower cost and simpler structure, comparing to BLAC motors. Furthermore, while BLAC drive requires an accurate encoder sensor, BLDC drive needs to discrete position sensor such as Hall Effect device.