Topology Comparison and Sensitivity Analysis of Fuel Cell Hybrid Systems for Electric Vehicles

The hybrid system containing the fuel cell and energy storage sources contributes to realizing hydrogen energy in road traffic applications. It is meaningful to evaluate the different forms of system topology. In this work, the quantitative comparison of topologies and sensitivity analysis of system parameters are conducted. First, the output characteristics of the fuel cell, battery, and ultracapacitor (UC) are modeled by experimental data. Second, the dimensions of four hybrid topologies are determined by an iterative constraint method. An energy management strategy based on dynamic programming (DP) is conducted for all topologies. Then the overall economic cost is used as an indicator for quantitative evaluation, considering the initial acquisition, hydrogen consumption, and component aging. The base-case results illustrate that the fuel/cell battery semi-active topology is the least costly one. Finally, seven parameters are analyzed to determine the system cost's key factors. The relationship between costs and driving conditions is further studied. The rankings of the normalized parameter analysis results inspire us on how to further reduce the cost of fuel cell hybrid vehicles.