SiC Impact On Grid Power Electronics Converters

The emerging medium voltage (MV) silicon carbide (SiC) devices (e.g. 10 kV SiC MOSFET) have higher voltage ratings, higher switching speed, lower switching loss, and higher temperature capability than mature MV silicon (Si) devices. Using MV SiC devices in grid power electronics converters may reduce the converter size leading reduced converter and system cost; and it may also improve the grid control and support functions provided by converters as a result of faster switching and control bandwidth. It is important to systematically assess the impact of using MV SiC devices on grid power electronics from both the converter and system standpoint side. This paper focuses on evaluating converter level benefits of SiC through Si- and SiC-based converter benchmark design. Converter size is used as the metric, and size comparison is conducted for different applications, voltage levels, and power ratings. It is found that SiC-based converters' sizes are reduced because of the simplification of topologies and smaller passives. In most topologies, SiC-based converters need smaller capacitors and smaller magnetics than Si-based converters because of higher switching frequency. The impact is a strong function of topology, voltage and power rating. The size reduction of one topology may even change for different applications because of different operating conditions.