Multi-level Energy Management Strategy for Fuel Cell Vehicle Based on Battery Combined Efficiency and Identification of Vehicle Operation State

The design of energy management strategy is one of the main challenges in the development of fuel cell electric vehicles. The proposed strategy should be well responsive to provide demanded power of fuel cell vehicle for motion, acceleration, and different driving conditions, resulting in reduced fuel consumption, increased lifetime of power sources and increased overall fuel efficiency. The purpose of this paper is to precisely identify the different driving conditions, separate the battery state of charge regions based on combined efficiency and its mathematical calculations, determine the fuel value of each gram of hydrogen in generating electric power, classify the fuel cell output power, extract the required information quickly and distribute power optimally with regarding to efficiency and lifetime. This paper presents a new multi-level online energy management strategy that is based on operational mode control aiming to operate at minimum equivalent consumption. Battery charging is also done at the optimum point of the fuel cell so that not only total efficiency is increased, but also subsequent maximum instantaneous power is also satisfied. The simulation results of the proposed strategy indicate reduction in fuel consumption and increment in energy consumption efficiency compared to other energy management methods.