Switching Performance Evaluation and Loss Analysis of SiC-based Neutral Point Clamped Bidirectional AC/DC Converter

This paper presents a comprehensive switching performance evaluation and the loss breakdown analysis of a 3-level Neutral Point Clamped (NPC) bidirectional AC/DC converter with SiC MOSFETs. The switching transient of SiC devices in different 3-level commutation loops is characterized and compared for design optimization. The loss analysis for the NPC converter at various operating modes is carried out, based on a detailed loss model for both power switch and filter inductor. Based on the evaluation, a 15-kW 3-level NPC bidirectional AC/DC converter is implemented with SiC devices to operate at various conditions for design verification.