Fuzzy control strategy for a tri-energy hybrid bus

摘要

Hybridization is recently a tendency of the vehicle development since it can relieve the stress of energy problem. Therefore, a hybrid powertrain, which is called thermal-electric-hydraulic (i.e.tri-energy) hybrid powertrain, is studied in this paper for the mutual complement between hydraulic hybrid vehicle and hybrid electric vehicle. The three types of power sources coupled in this configuration are regulated by the 2-DOF planetary gear sets for the accurate shifting between several driving conditions. The fuzzy logic control strategy with the benefit of good adaptability, robustness and real-time, is adopted in the paper in order to improve the fuel economy effectively. The fuzzy torque distribution controller with a two-layer structure is designed based on the selection of membership functions and the determination of a set of fuzzy rules. The simulation under the Chinese Urban Bus Cycle (CUBC) is built on the Matlab/Simulink/Driveline platform, whose following speed error is less than 1km/h. The results, which are analyzed under urban condition, suburb condition and high-speed condition, show an overall improvement of composite fuel consumption compared to deterministic rule based method, which indicates that the proposed fuzzy control strategy is quite suitable to be applied on the tri-energy bus.