Sizing of a fuel cell stack and battery system for a fuel cell hybrid vehicle using dynamic programming and Pareto analysis.

Abstract

In this study we analyzed fuel cell hybrid electric vehicle models to identify the optimal size combination of fuel cells and batterie. This was in order to attain the lowest hydrogen consumption per trip. To achieve this goal, we used a tunnel dynamic programming technique to perform the optimal energy management strategy for each size combination. Battery selection is done based on different parameters in order to attain the most appropriate type. Two driving modes – charge sustaining and charge depleting - are obtained by adding a weight to battery cost in the optimization function. PARETO analysis is considered to find the best solution that secures the most appropriate battery and fuel cell sizes as well as the least operational cost for three specific driving cycles. Drivability constraints -gradeability, maximum speed and maximum acceleration - were taken into consideration during the sizing process. Different sizing combinations were obtained for the two driving modes over the three different driving cycles.