Selective Gate Driver in SiC Inverter to Improve Fuel Economy of Electric Vehicles

This paper proposes a selective gate driver (SGD) strategy that can adjust gate resistance based on estimations of relatively slow operating variables for each switching cycle (tens of $\mu\mathrm{s}$ ) to improve the fuel economy of electric vehicles and maintain the system reliability. With a conventional gate driver (CGD), switching energy loss, drain-source voltage changing rate, and drain-source voltage overshoot are fixed and constrained. The proposed SGD with multi-level gate resistance selection, which uses a single digital channel to match various inverter operating conditions, such as various dc-link voltage and varying output load currents, is developed. The proposed SGD can reduce switching energy loss while maintaining the drain-source voltage overshoot within the requirement with no need for ultra-fast dynamic control. An inverter simulation model with SGD incorporated in an electric vehicle system model for energy analysis is presented. The comparison of CGD and the proposed SGD shows that up to 1.24% improvement in energy saving for an HWFET driving cycle with the Tesla Model 3 electric vehicle is achieved. Furthermore, the SGD overcomes the implementation challenges due to the inherent feedback delay in the existing adaptive gate driver (AGD) method, which requires adjusting the gate drive strength in the nanoseconds range.