Development of an Energy Management Strategy for an All-Wheel Drive Electric Vehicle

Abstract

As part of the EcoCAR EV challenge, a energy management strategy was developed for a 2023 Cadillac Lyriq. To assist in testing the proposed strategy, a forward propagating model was developed in MATLAB and Simulink using virtual vehicle components. To validate the model, output data from simulation was compared with output data from the vehicle obtained on an all-wheel drive dynamometer under the same drive cycle. For this study, a power minimization equation with a torque split algorithm was used to find the optimal torque split across all torque-speed domains. This searches for the front and rear drive unit split ratios that minimizes power loss. Using driver demand and vehicle speed as inputs, a fuzzy logic controller was used to improve vehicle drivability by reducing jerk in high oscillating torque split regions. In depth simulations of UDDS, HWFET, and competition specified trapezoidal drive cycles were conducted to validate this method. The results show that the proposed strategy reduces energy consumption by 3.28% for UDDS, 1.46% for HWFET, and 2.41% for the trapezoidal drive cycles when compared to a baseline capability split.