Adaptive generator-torque-driven energy management with state-of-charge regulation for power-split hybrid electric vehicles

Abstract

Power-split hybrid electric vehicles (PS-HEVs) have gained considerable atten-tion owing to their potential to improve fuel efficiency through the coordinated operation of the internal combustion engine, electric motor, generator, and battery. However, the cou-pling introduced by the planetary gear set complicates energy management. This paper pre-sents an adaptive energy management strategy (EMS) based on generator-torque control and battery state-of-charge (SOC) regulation. The proposed approach uses generator torque as a principal supervisory control variable alongside vehicle speed, traction power demand, and battery SOC to coordinate power distribution. The strategy is implemented in a MATLAB/Simulink-based PS-HEV model and compared with three benchmark energy management strategies. Under the UDDS drive cycle, the proposed Case 4 consumes 0.1249 kg of fuel, compared with 0.2206 kg for the fixed baseline, corresponding to a re-duction of 43.39%. Additional simulations under Federal Test Procedure (FTP-75) and US06 Supplemental Federal Test Procedure (US06) show fuel-consumption reductions of 38.85% and 1.20%, respectively, relative to the baseline. These results demonstrate the po-tential of adaptive generator-torque modulation to reduce fuel consumption, although the magnitude of the benefit varies with driving conditions. These results demonstrate the po-tential of adaptive generator-torque modulation to reduce fuel consumption while regulat-ing battery SOC within the prescribed operating range, with the magnitude of fuel savings varying across driving cycles.