Performance Evaluation of Si/SiC Hybrid Switch-Based Three-Level Active NPC Converter

The configuration of a high current-rated silicon (Si) IGBT connected with a low current-rated silicon carbide (SiC) MOSFET has been proposed to be used as one basic switching unit. Benefiting from the combined advantages, this Si/SiC hybrid switch (Si/SiC HyS) is expected to present superior performance on semiconductor losses, overload capability, and device cost. Two types of Si/SiC HyS-based three-level active neutral point clamped (3L-ANPC) topologies, including 2-Si/SiC HyS and 4-Si/SiC HyS-based 3L-ANPC, are proposed in this paper to achieve higher inverter efficiency and lower device cost. A universal 4.4kW 3L-ANPC prototype has been developed for three evaluated topologies, including the 2-Si/SiC HyS-based 3L-ANPC inverter, 4-Si/SiC HyS-based 3L-ANPC inverter, and full Si IGBT-based 3L-ANPC inverter. The experimental results demonstrate that the Si/SiC HyS-based 3L-ANPC inverters can achieve 2% and 1.8% efficiency improvement at light load and heavy load respectively compared with the conventional full Si IGBT-based 3L-ANPC inverter. Compared with the full SiC MOSFET solution, the two types of Si/SiC HyS-based 3L-ANPC inverter both can achieve more than 80% cost reduction on the semiconductor devices. Among the two proposed Si/SiC HyS-based 3L-ANPC inverters, the 2-Si/SiC HyS-based 3L-ANPC inverter further reduces the semiconductor device cost and achieves a better balanced junction temperature and higher power output capacity for high power density applications.