Hybrid Commutation-Based Active Loss-Balancing Control Scheme for Si/SiC Hybrid Three-Level ANPC Inverters

The hybrid utilization of silicon (Si) and silicon carbide (SiC) devices is an effective way to improve the efficiency and power density of three-level active neutral-point-clamped (3L-ANPC) inverters while the hardware cost is not significantly increased. However, the unbalanced power loss between SiC devices reduces the inverter lifespan and increases the complexity of the cooling system design. A hybrid commutation-based active loss-balancing control (HC-ALBC) scheme is proposed for Si/SiC hybrid 3L-ANPC inverters. First, the loss distribution of different commutation processes in the 4SiC-III hybrid 3L-ANPC inverter is analyzed. Then, three different commutation processes are utilized with an optimized usage ratio to actively control the power loss difference between SiC devices. As a result, the balanced power loss is achieved under different output power and modulation indices. Finally, a 6-kW Si/SiC hybrid inverter prototype is built, and experimental results show that the proposed HC-ALBC scheme achieves balanced power loss between SiC devices. Besides, both high efficiency and excellent harmonic performance are achieved.