Aiming at the problem that torque ripple happens during the commutation of BLDCM, which brings bad effect to the system, this paper presents a three-phase pulse width modulation (PWM) technique to reduce the commutation torque ripple of brushless dc motor (BLDCM). Compared with existing approaches, the proposed technique does not require any torque observer and calculating commutation interval that is sensitive to motor parameters and requires much calculation time. Back-EMF zero-crossing method is used to determine the rotor position of the BLDCM and then the motor rotation speed is obtained....
