Efficiency increase of SiC-BJT inverter by driver loss reduction with one-step commutation

Silicon carbide bipolar junction transistors (SiC-BJT) are promising power semiconductor devices for high efficient motor drive inverters. Especially with the very low on-state voltage drop and high switching speed it challenges the state of the art device - the silicon IGBT. The main disadvantage is the high driver loss in on-state compared to its voltage driven competitors, though. With the one-step commutation in voltage source inverters (VSI) a new approach on decreasing driver losses is presented. An “all-SiC” inverter with DC-link consisting of SiC-BJTs and SiC-diodes has been designed and assembled. Measurements confirm that by using one-step commutation instead of the conventional one driver losses can be cut in half. This has a positive impact on total SiC-BJT-inverter efficiency.