Characterization and Mitigation of Conducted Emissions in a SiC Based Three-Level T-Type Motor Drive for Aircraft Propulsion

This paper presents the full-scale high power inverter design considerations that are needed for minimum conducted noise propagation throughout the system. Specifically, system design issues pertaining to high current and high altitude, high switching transients during commutation process, ribbon cables for high-speed signal transmission, strict conducted emissions requirements and motor side bearing/leakage currents are discussed. Based on the underlying deficits for high power motor drives, layout and circuit design methodologies are proposed to tackle such problems, while keeping costs at a bare minimum. Subsequently, modeling and prediction of common-mode (CM) and differential-mode (DM) noise is made possible using accurate lumped inverter and filter models, allowing for a better understanding of the sensitive components contributing to peak CM-DM noise. A high power (211 kW) rated three level T-type inverter prototype is used to demonstrate the viability of the proposed design techniques for reliable system operation and conducted electromagnetic interference (EMI) emissions mitigation.