An Improved Si/SiC Hybrid Three-Level ANPC Inverter with Optimized Thermal Distribution-Based Modulation Scheme

The utilization of silicon (Si) insulated gate bipolar transistors (IGBTs) and silicon carbide (SiC) MOSFETs in hybrid three-level active neutral-point-clamped (3L-ANPC) inverter inherits the advantages of traditional 3L-ANPC inverter, which has the capacity of balanced loss distribution and fault-tolerant operation. In addition, the improvement of short-circuit withstanding capacity and the tradeoff between cost and efficiency can be achieved in hybrid 3L-ANPC inverter. In this paper, an improved Si/SiC hybrid 3L-ANPC inverter is proposed to achieve balanced thermal distribution among power devices. A snubber branch is added in the topology to minimize parasitic inductance and address resonant issues. Based on available commutation types, two modulation schemes are analyzed to regulate current paths and power loss distribution. Furthermore, a simulation based on a hybrid 3L-ANPC inverter is provided to validate the effectiveness of the theoretical analysis and compare thermal distributions of different modulation schemes. Simulation results show that appropriate selection of modulation strategies helps improve system reliability.