A Three-Phase Si & SiC Hybrid Three-Level Hybrid Legs (Hybrid2) Inverter with Optimal Power Quality and Low Cost

Wide-bandgap (WBG) power semiconductors represented by silicon carbide (SiC) offer a higher switching frequency and lower switching loss than silicon (Si) semiconductors but face a notably elevated expenditure on components. In this paper, we propose a three-phase SiC & Si hybrid three-level (3L) hybrid legs (hybrid
²
) inverter, which combines the high frequency performance of WBG with the low cost of Si to achieve a better compromise between efficiency, power quality and cost. With the proposed coordinated current compensating control strategy, the Si leg switches with low-frequency (LF) and handles major power, while the SiC leg operates at high-frequency (HF) to compensate for the current ripple and handle minor power. On one hand, compared to all-SiC and existing hybrid inverters, this proposed inverter has less cost due to the use of low-current-rating SiC devices. On the other hand, because of high equivalent switching frequency, the optimal power quality and small filter size can be realized. The proposed topology and control strategy are verified by simulation.