Holistic Design and Development of a 100-kW SiC-Based Six-Phase Traction Inverter for an Electric Vehicle Application

Six-phase drives are gaining popularity in electric vehicle (EV) applications owing to their superior fault-tolerance capability, modularity, and improved current handling. However, a thorough design of a six-phase traction inverter has not been investigated. As a result, the inherent advantages of six-phase inverters are not exploited. This article presents a holistic design methodology for a six-phase traction inverter. At the power device level, discrete silicon carbide (SiC) MOSFETs are utilized, and their electrothermal model is used to effectively size a liquid-cooled heat sink. At the dc-capacitor level, a multiobjective optimization algorithm is proposed to find the most suitable capacitor bank in terms of volume, impedance, and current capability. At the system level, coreless Hall-effect current sensor integrated circuits (ICs) are proposed to mitigate the higher count of sensors in six-phase systems. At the mechanical design level, design constraints are considered to deliver housing with an integrated coolant channel. The resultant inverter design is prototyped and experimentally tested. The proposed design demonstrates a 7% reduction in dc-capacitor volume and a 21% reduction in cabling cost when compared to conventional three-phase inverters of the same volt–ampere rating. The peak power density of the prototype inverter is 70 kW/L, demonstrating a compact design.