A Supervisory Control Algorithm for a Series Hybrid Vehicle With Multiple Energy Sources

This paper presents a new power distribution strategy (PDS) for a series electric hybrid vehicle (SHEV) in the sense of minimizing fuel usage. The target vehicle has three energy sources, i.e., an engine and generator set (EGS), a battery, and an ultracapacitor, and two traction motors for the front and rear wheels. A two-step PDS based on the real-time optimization technique is proposed to distribute the demand power among three energy sources. Several existing PDSs, such as the thermostat strategy and the power-follower strategy, are modified and applied to be compared with the proposed strategy. An optimal torque distribution strategy between front and rear traction motors is also proposed to minimize the electric energy consumption and to further improve fuel economy. Simulation results demonstrate the feasibility and effectiveness of the proposed strategies.