Elimination of low-frequency harmonics caused by PWM in a three-phase soft-switched boost rectifier

This paper presents three major causes of low-frequency harmonics in a high-frequency soft-switched three-phase pulsewidth modulation (PWM) boost rectifier: pulsewidth limits; an improper space-vector modulation scheme; and dead time. Among these, the pulsewidth limits are related to soft-switching techniques. To eliminate undesirable low-frequency harmonics, each cause is illustrated and a solution is provided. Both simulation and experimental results prove the effectiveness of the proposed solutions. Due to the similarities between boost rectifiers and voltage-source inverters, the conclusions of this paper are also applicable to high-frequency PWM voltage-source inverters.