Rule-based Energy Management Strategies for Hybrid Vehicle Drivetrains: a Fundamental Approach in Reducing Computation Time

The hybrid vehicle control problem at the highest level is termed the Energy Management Strategy (EMS). This paper presents a new, and simple RuleBased (RB) EMS, whereby maximum power level of the electric machine during pure electric driving is the control design variable. This maximum power level determines the overall power -, and efficiency specifications of the electric machine. A RB EMS consist of a selection of driving modes. The RB EMS is compared with the strategy based on Dynamic Programming (DP), which is inherently optimal for a given cycle. The RB method proposed in this paper requires 3000 times less computation time with the same accuracy (±1%) as DP. The RB strategy in this paper is a semi-empirical EMS with which the generic component specifications for the secondary power source (battery, power electronics, electric machine), primary power source (engine) and transmission technology can be obtained. Provided these generic specifications, a technology designer can quickly specify the hybrid technologies. In this way, control, optimization and component design are merged in a single framework.