Power split control strategy for a series Hybrid Electric Vehicle using fuzzy logic

Hybrid electric vehicle (HEV) is considered as the most promising solution to energy crisis and urban air pollution. However, it is a complex electro-mechanical system which is difficult to construct an accurate mathematical model. Fuzzy logic seems to be appropriate for the HEV control problem. In this paper, a fuzzy logic control strategy (FLCS) is developed for a series hybrid electric vehicle designed for campus and gymnasium. Based on the state-of-charge (SOC) of the batteries and the power information, the power required by the vehicle is split between the engine/generator set and the batteries instantaneously by the FLCS. The SOC of the batteries can be maintained always at a high level and the engine can steadily work in its high efficiency area. A forward simulation model for the vehicle is established, and both off-line and real-time simulations are performed. Simulation results show that the FLCS can realize constant SOC control, and fuel consumption and emissions are also considered by the FLCS.