A comparative study on topologies of two novel four-leg converters for three-phase DC-RM

This paper conducts a comparative study on two novel four-leg converters for three-phase dc-biased sinusoidal current reluctance machine (DC-RM). Compared with the traditional open-end winding topology, the two four-leg topologies have obvious advantages in cost, volume, and power loss. However, due to the different structures, there are differences in modulation performance, cost and power loss between these two topologies. These differences are compared experimentally. The three-phase four-leg topology is more suitable for low-power applications, such as home appliances, which focus on the cost and integration. The three-phase series-end winding topology is more suitable in high-performance applications, such as aerospace, which focus on the power density and DC voltage utilization. In addition, due to the advantages in DC voltage utilization, number of power devices, and fault tolerance, the series-end winding topology can replace the open-end winding topology to drive the multi-phase motors or traditional AC machine which doesn't require the DC current injection.