Simulation and Measurement-Based Analysis of Efficiency Improvement of SiC MOSFETs in a Series-Production Ready 300 kW / 400 V Automotive Traction Inverter

As experienced for most power electronic applications in the past, efficiency is also becoming one of the key characteristic for automotive applications, affecting the design of future high-voltage components for electric vehicles. In case of traction inverters, mainly semiconductor losses deteriorate system efficiency and thus, upgrading the switches in hard-switched PWM-controlled 2-level inverters is a direct measure to significantly reduce system losses. For this task, SiC MOSFETs are a promising class of power semiconductors with superior device characteristics. With SiC high power modules becoming available on a broader basis, proper design-in approaches are necessary in order to obtain robust and cost-effective system solutions. Addressing this topic, a new full-SiC power module suited for direct replacement of existing Si-based solutions is described in this paper. A simulation and measurement-based analysis of the efficiency benefits of such a retrofit solution for a 400 V based drivetrain with up to 300 kW of output power is presented. Simulation results predict a loss reduction on inverter level of around 50 % compared to the Si IGBT based solution with respect to steady-state part load operation. The simulation results are verified by drivetrain test bench measurements showing a very high accuracy of the simulation model. Drive cycle simulations indicate an advantage in terms of energy consumption of up to 6.6 % for the drivetrain equipped with SiC MOSFETs over its counterpart equipped with Si IGBTs.