Fuzzy logic controller for energy management of power split hybrid electrical vehicle transmission

This paper investigates energy management strategies for a power split hybrid electric transmissions using a fuzzy design method. Hybrid Electric Vehicles (HEV) is one of the most promising research topics for developing efficient and environmentally-friendly transportation solutions. A power split hybrid combines the advantages of both series and parallel hybrid configurations by providing a higher degree of freedom to fulfill the demand of the driver while improving overall fuel efficiency at the cost of higher complexity and non-linearity in the control system design. There are two issues that should be addressed for energy management: torque distribution and battery charge sustenance. The fuzzy controller controls the torque request for the internal combustion engine by taking into consideration the vehicle speed, battery state-of-charge, and the normalized torque request from either the driver or an automated driving controller. The controller has several rules to control the internal combustion engine (ICE) torque request. We show that our rule base provides greater control over the ICE operation over a wide range of conditions for optimum fuel consumption. The controller was tested by integrating with a vehicle model and simulated by running it for multiple United States Environmental Protection Agency drive-cycles and then compared to a controller based on a commercially available HEV system.