Efficiency Improvement Evaluation and Loss Modeling of a Hybrid Switch-Based T-NPC Inverter

摘要

Si-IGBT and SiC-MOSFET based hybrid switch is an emerging technology which combines the advantages of the two types of devices and introduces SiC benefits at significantly lower cost compared to state-of-the-art SiC inverter technology. In this paper, a 1200V/50A Si/SiC hybrid switch is proposed. The switching characteristics and the steady-state current sharing model are analyzed. The analysis indicates that the switching loss of the hybrid switch can be reduced significantly due to the zero-voltage switching (ZVS) of Si-IGBT. Furthermore, a hybrid switch-based T-type neutral-point-clamped (T-NPC) inverter and its loss model are proposed. A 2.5kW hybrid switch-based T-NPC inverter prototype is designed and implemented to evaluate the efficiency improvement over a pure Si-IGBT-based inverter. The experimental results demonstrate that the inverter efficiency is improved by 4.75% at the switching frequency of 40kHz. The results also validate the proposed device loss model provides a good efficiency estimation of the hybrid devices-based T-NPC inverter.