A High-Efficiency Three-Level ANPC Inverter Based on Hybrid SiC and Si Devices

Abstract

Silicon carbide (SiC) devices have excellent performance, such as higher switching frequency and lower switching loss compared with traditional silicon (Si) devices. The application of SiC devices in inverters can achieve higher efficiency and power density. In recent years, the production process of SiC devices has become more mature, but the cost is still several times that of traditional Si devices. In order to balance cost and efficiency, replacing only some of the Si devices with SiC devices in a topology is a better choice. This paper proposed a high-efficiency hybrid active neutral point clamped (ANPC) three-level inverter which has only two SiC devices and the other devices are Si devices. A specific modulation strategy was applied to concentrate switching losses on the SiC devices and reduce the on-state loss through parallel operation during freewheeling intervals. Theoretical efficiency curves and experimental verification of the proposed hybrid scheme with Si-only and SiC-only schemes were carried out.