Comprehensive Efficiency, Weight, and Volume Comparison of SiC- and Si-Based Bidirectional DC-DC Converters for Hybrid Electric Vehicles

Silicon carbide (SiC)-based switching devices provide significant performance improvements in many aspects, including lower power dissipation, higher operating temperatures, and faster switching, compared with conventional Si devices. However, tradeoffs in efficiency, size, and weight between Si-and SiC-based converters are still unclear in the literature. In this paper, a bidirectional dc-dc converter that is suitable for hybrid or electric vehicle application is studied based on three sets of device combinations, e. g., all-silicon [conventional silicon insulated-gate bipolar transistors (IGBTs) and silicon PN diodes], hybrid (silicon IGBTs with SiC Schottky diodes), and all-SiC (SiC metal-oxide-semiconductor field-effect transistors with SiC Schottky diodes). At the switching frequency of 20 kHz, comparative analyses regarding the power loss reduction of power devices and efficiency improvements are carried out for the converters. Possible size and weight reduction is also investigated by increasing the operating frequencies of hybrid and all-SiC converters while reducing the capacitance and inductance values.