keywords Asymmetric back electromotive force (back EMF) BACK-EMF BRUSHLESS DC MOTOR COMMUTATION ERROR COMPENSATION CONTROL STRATEGY DIRECT TORQUE CONTROL EXTENDED KALMAN FILTER Engineering Engineering, Electrical & Electronic Inverters Motor drives Motors PERMANENT-MAGNET MOTOR POSITION DETECTION SLIDING-MODE OBSERVER Science & Technology Sensorless control Technology Transportation Transportation Science & Technology Voltage Voltage measurement ZERO-CROSSING DETECTION brushless dc (BLDC) motor nonideal back EMF sensorless control