Hybrid Si/SiC Switch Modulation with Minimum SiC MOSFET Conduction in Grid Connected Voltage Source Converters

Abstract

In this article, a hybrid Si/Si carbide (SiC) switch (HyS) modulation with minimum SiC MOSFET conduction (mcHyS) is experimentally characterized, so as to derive its conduction and switching performance. These are later used to derive a silicon (Si) area analytical model for the HyS configuration. The chip area model is used to benchmark the mcHyS modulation concepts against single-technology switches and typical HyS modulation when considering the implementation of a 100-kW two-level voltage-source converter (VSC) deployed for three industrial applications: photovoltaic inverter, electric vehicle fast-charging station, and battery storage systems for grid ancillary service. The two additional switching events of the SiC MOSFET, which differentiate the mcHyS modulation from the typical HyS one, are proven to happen in soft switching; therefore, the mcHyS switching performances are not penalized. Furthermore, the analysis presented shows how the studied mcHyS modulation performs against the single semiconductor technology and the typical HyS solution in terms of cost and power conversion efficiency. More specifically, it is shown that the HyS solutions are particularly competitive versus the full Si-based VSCs when the application at hand often operates at low partial loads. Finally, a 10-kW two-level VSC assembled with mcHyS is tested, so as to compare its efficiency versus single-technology switches.