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High Power Density Medium-Voltage Megawatt-Scale Power Converter for Aviation Hybrid-Electric Propulsion Applications

Hybrid-electric propulsion is an enabling technology to make aircraft more fuel-efficient, quieter, and create lower carbon emissions. This paper presents a high power density medium-voltage (MV) megawatt-scale power converter based on a hybrid three-level active neutral-point-clamped (3L-ANPC) topology. To achieve high efficiency, the switching devices that operate at the carrier frequency are Silicon Carbide (SiC) Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs). Conventional Silicon (Si) Insulated-Gate Bipolar Transistors (IGBTs) switches operate at the fundamental output frequency. 2.4kV dc bus voltage was chosen to reduce system cable weight. The fundamental output frequency of the converter is 1.4kHz to drive a high speed motor The large fundamental frequency helps reduce system weight. Filters are designed to meet dv/dt limits on ac side and EMI specifications on dc side. Main hardware development and control modulation strategies are presented. Experimental results are included to verify the performance of this MW-scale power converter. The converter achieves a high efficiency of 99.1%, specific power density of higher than 18kVA/kg and high power density of 10MVA/m3.