Modeling and Evaluation of SiC Inverters for EV Applications

In this paper, the efficiency benefits of adopting Silicon–Carbide devices for electric vehicle applications are studied. A hybrid time and frequency domain-based simulation tool is developed for the Silicon–Carbide (SiC) traction inverter modeling. The tool provides steady-state results with comparable accuracy to standard time domain methods and achieves a factor of thousand reductions in time when simulating a large number of operating points. Especially, the impact of temperature-dependent device losses has been considered to ensure the simulation precision. Next, a vehicle-level modeling is developed to evaluate the impact of the inverter efficiency on the endurance mileage increase of vehicles. It is found that, by applying Silicon–Carbide devices, the energy consumption of the inverter can be greatly reduced by 3/4 under WLTC (World light light-duty vehicle test cycle) profile. It can be transformed into a mileage endurance increase of 3–5%. The impact of the drive cycle profile and the vehicle’s drag coefficient on the endurance mileage are evaluated as well. In addition, an economic/cost model is developed for selecting the “optimal” chip paralleling number for Silicon–Carbide power modules. Interestingly, the results indicate that this number should be slightly overdesigned to achieve the most cost saving from the system point of view.