Research On Fuel Cell Hybrid Locomotive Modeling And Energy Management Strategy

The power system of the fuel cell hybrid locomotive consists of fuel cell stack and auxiliary energy unit, such as battery or super capacitor. For the features of high efficiency and environmental protection, the fuel cell hybrid locomotive is considered as a new rail transit tool with tremendous potential, receiving extensive attention and in-depth research in the world.Energy management strategy is one of the key technologies for the fuel cell hybrid locomotive, and its core is optimizing the performance of each energy unit and improving the vehicle fuel economy at the same time ensuring the locomotive power demand, which is achieved through the reasonable allocation of the output power for the fuel cell stack and auxiliary energy unit.The fuel cell hybrid locomotive modeling and the optimal design of the energy management are researched in this paper, and the main achievements are summarized as follows:(1) The fuel cell hybrid locomotive system model is established based on MATLAB/SIMULINK simulation environment, including the fuel cell model, the battery model, the locomotive load model and the DC/DC converter model, so as to provide a simulation platform for studying the correctness and validity of the energy management strategy. Based on a assumed driving cycle of the fuel cell hybrid locomotive, the simulation analysis of the various components’performance is implemented under the power following energy management strategy, and the main technical parameters are taken as the baseline for comparison.(2) The fuzzy logic energy management strategy is designed according to the fuzzy logic control theory, with the locomotive power demand and the state of charge of the battery as the input and the DC/DC converter reference power as the output. The designed fuzzy logic energy management strategy is verified based on the system model. The simulation results show that compared with the power following energy management strategy, the designed fuzzy logic energy management strategy is able to reduce the dynamic load of the fuel cell stack effectively, maintain the state of charge (SOC) of the battery within the desired range, and improve the vehicle fuel economy,.(3) Through introducing the concept of the equivalent hydrogen consumption of the battery and regarding the minimum of the total hydrogen consumption of the locomotive as the objective function, the membership function parameters of the designed fuzzy logic energy management strategy is optimized base on the Particle Swarm Optimization algorithm. The optimized fuzzy logic energy management is verified based on the system model. The simulation results show that the optimized fuzzy logic energy management strategy is able to further improve the vehicle fuel economy while reducing the dynamic load of the fuel cell stack effectively and maintaining the state of charge (SOC) of the battery within the desired range.