Three-phase high power factor rectifier with two NPC legs

A current-controlled switching mode rectifier with a reduced switch count is presented. The proposed rectifier is based on the neutral-point-clamped topology. Only eight power switches with voltage stress of half DC-link voltage and four clamped diodes are employed in the proposed rectifier instead of 12 power switches and six clamped diodes used in the conventional neutral-point-clamped rectifier. The purposes of the proposed control strategy are to keep the factor correction at unity, to reduce current harmonics and to regulate DC bus voltage. The analysis and mathematical model of the rectifier is derived and the control strategy is provided. The effectiveness of the proposed control scheme is verified by the experimental results.