Analysis of the commutation torque ripple effect for BLDCM fed by HCRPWM-VSI [brushless DC motors]

The authors present an analytical study of the torque ripple due to the phase commutation in a BLDCM (brushless DC motor) fed by HCRPWM-VSI (hysteresis current regulated pulse width modulation voltage source inverter). In order to show the duration of the phase commutation and the torque ripple during the phase commutation, the instantaneous trapezoidal waveform of the back EMF and the amplitude of the phase current are considered. Simulation and experimental results indicate that the duration of the phase commutation and the current ripple during the phase commutation vary with speed and depend on the amplitude of the phase current. Also, the effect on the motor speed due to the torque ripple during the phase commutation is studied