Comprehensive Comparison between Two-Level, Three-Level, and Hybrid Three-Level SiC Inverter for High Power High Speed Drive System

High speed drive system desires power converters with higher switching frequency to minimize the torque ripple and obtain a faster control capability. Silicon carbide (SiC) devices based converters have gained increasing attention in such applications due to their extraordinary switching performance. Possible solutions including two-level converters, three-level converters and hybrid converters comprising both Si and SiC device. In this paper, a comprehensive comparison of possible high density solutions is given. Simple calculations show that an outstanding efficiency can be achieved with the SiC based threelevel topologies in the medium switching frequency range. However, the cost of SiC based three-level topologies are still unacceptable. As an alternative, the hybrid three-level inverter can dramatically reduce costs with a little sacrifice on efficiency, which is a more promising choice at this stage.