Performance comparison of three-step and six-step PWM in average-current-controlled three-phase six-switch boost PFC rectifier

In this paper, a three-step PWM method for the average-current-controlled three-phase six-switch boost PFC rectifier is proposed. It is shown that the three-step PWM compared to the conventional six-step PWM exhibits a lower total harmonic distortion of input currents and higher power factor. However, the three-step PWM, unlike the six-step PWM, is adversely affected by duty-cycle limitations and has unbalanced conduction losses of the upper and lower switches of the three-phase rectifier bridge. The average-current control with three-step and six-step PWM is illustrated with Matlab/Simulink simulation waveforms and experimentally verified on a 3-kW prototype.