An electronic gear concept for optimized efficiency operation of automotive converters

In this article, the concept of an Adjustable Hybrid Switch (AHS) converter is proposed and its benefits in improving the energy efficiency of an electric vehicle (EV) over the whole range of the driving profile is investigated. The AHS transforms a standard electric vehicle (EV) inverter into an advanced “Electronic Gear (E-Gear)” system by introducing a Cross-Switch (XS) hybrid semiconductor. Replacing the single transistor in a conventional EV inverter with a unique combination of unipolar Silicon Carbide (SiC) MOSFETs and bipolar Silicon (Si) IGBTs in parallel, the AHS allows for varying ratios of SiC MOSFETs to Si IGBTs, adapting to the EVs shifting load profile. Specifically, the converter controller selectively activates each transistor using dedicated gate units allowing it to choose the most efficient area ratio of SiC MOSFETs to Si IGBTs in the specific operating point of the vehicle's real-time torque-speed profile. A detailed analysis of the AHS converter featuring the E-Gear mechanism is performed in this paper. A water-cooled power train prototype is designed to verify the advantages of the system studied.