A Megawatt-Scale Medium-Voltage High Efficiency High Power Density 'SiC+Si' Hybrid Three-Level ANPC Inverter for Aircraft Hybrid-Electric Propulsion Systems

Hybrid-electric propulsion system is an enabling technology to make the aircrafts more fuel-saving, quieter, and lower carbide emission. In this paper, a megawatt-scale power inverter based on a three-level active neutral-point-clamped (3L-ANPC) topology will be developed. To achieve high efficiency, the switching devices operating at carrier frequency in the power converter are configured by the emerging Silicon Carbide (SiC) Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs), while the conventional Silicon (Si) Insulated-Gate Bipolar Transistors (IGBTs) are selected for switches operating at the fundamental output frequency. To reduce system cable weight, the dc-bus voltage is increased to 2.4 kV. Unlike the conventional 400 Hz aircraft electric systems, the rated fundamental output frequency here is boosted to 1.4 kHz to drive the high-speed motor, which can also reduce system weight. Main hardware development and control modulation strategies are presented. Experimental results are presented to verify the performance of this MW-scale medium-voltage 'SiC+Si' hybrid three-level ANPC inverter. It is shown that the 1-MW 3L-ANPC inverter can achieve a high efficiency of 99% and high power density of 12 kVA/kg.