Adaptive wide angle PWM control strategy of BLDC motor drive for efficiency optimization and wide speed control range

To reduce the torque pulsation of BLDC motors caused by conventional 120° commutation conduction control, this paper proposes an adaptive wide angle control scheme with adjustable modulation waveform to achieve wide speed control range with efficiency optimization. The proposed adaptive soft commutation PWM modulation scheme is based on an adjustable modulation waveform with wide angle conduction period (more than 120° but less than 180°) and control the phase current with quasi-sinusoidal waveform to minimize the pulsation torque due to commutation. By using the adaptive PWM modulation scheme, the RMS value of phase current is lower than conventional 120° conduction mode under the same testing condition. Compared with the traditional control method, torque ripple of the BLDC motor can be reduced significantly by using the proposed control method. Simulation and experimental verification have been given to illustrate the performance of the proposed PWM strategy.