Global Optimized Design of an Electric Variable Transmission for HEVs

A way to improve existing hybrid vehicles is by globally optimizing the design of their components in relation to their actual use. This paper proposes a global optimal design method for power-split hybrid electric vehicles (PS-HEVs) equipped with an electric variable transmission (EVT). A genetic algorithm is used to optimize system parameters. The process includes discrete dynamic programming (DDP) for optimal energy management. The optimization focuses on minimizing fuel consumption and the number of battery cells. Pareto fronts are depicted and compared for different drive cycles, and they show the existence of a possible tradeoff between fuel consumption and battery size.