A new current control algorithm for torque ripple reduction of BLDC motors

The BLDC (brushless DC) motor is characterized by linear torque to current and speed to voltage. It has low acoustic noise and fast dynamic response. Moreover, it has high power density with a high proportion of torque to inertia in spite of a small size drive. However, when armature current is commutated, the current ripple is generated by the motor inductance components in stator windings and back-EMF This current ripple caused torque ripple. Therefore, it is difficult to apply the BLDC motor to a precision servo drive system. In this paper, a new current control algorithm using Fourier series coefficients is proposed. This proposed algorithm can minimize torque ripple due to the phase current commutation of a BLDC motor. Simulation and experimental results prove the effectiveness at the proposed algorithm through comparison with the conventional unipolar PWM method.