A Three-phase 450 kVA SiC-MOSFET Based Inverter With High Efficiency and High Power Density By Using 3L-TNPC

This paper presents a prototype of a 450 kVA inverter system by using 3-level T-type neutral-point-clamped converter (3L-TNPC). The prototype features high-power density and high-efficiency design. The design highlights an improved busbar structure, which achieves lower stray inductance than published literature of 3-level converters with limited temperature rise. The improved power-loop design provides sufficient room for accelerating switching speed. Over 67.7% of switching loss reduction is achieved by choosing optimal gate resistance (1 Ω). The paper also focuses on compact integration of signal sensing, conditioning circuits, and controller circuits to improve power density. The design strategy for the sensing system is discussed to optimize the trade-off between compact sensing and noise distortion. As a result, the converter reaches the power density of 26.6 kW/L. The peak efficiency of 99.47% is measured at 266 kVA under 70 kHz switching frequency.