An Improved Modulation Scheme for “Si&SiC” Hybrid 3L-Active NPC Rectifiers with Low Conduction Losses

Wide-bandgap devices such as SiC devices have good switching characteristics, the application of wide-bandgap devices can improve the efficiency and power density effectively because of the fast switching speed. However, it has not been widely used due to its high price. Therefore, the hybrid applications of Si&SiC devices attracted more attention, but few attentions are paid to the reduction of conduction losses. This paper proposes an improved modulation scheme based on the Si&SiC hybrid 3L-ANPC rectifier. It can not only make full use of the good switching characteristics of SiC devices, but also lower the conduction losses by decreasing the conduction resistance. However, the improved modulation scheme is not suitable for 4-SiC hybrid inverter. A 3kW prototype is built to verify the effectiveness and advantages of the proposed modulation scheme.