Simulation-based investigation of energy management concepts for fuel cell – battery – hybrid energy storage systems in mobile applications

Abstract This paper presents the results of investigation of energy management concepts for fuel cell – battery – hybrid energy storage systems in mobile applications. The energy management has to control the power spilt between fuel cell and battery to guarantee the coverage of the power demand of the vehicle. First of all, the simulation tool is introduced, which enables the evaluation and comparisons of the energy management concepts. Therefore, the PEM fuel cell and the lithium-ion battery are modelled and dimensioned adequately. Performance-criteria are defined to evaluate the energy management concepts. The usage of hydrogen, the efficiency of the hybrid energy storage system and the operating conditions with regard to the life time of the components are especially considered. Three energy management concepts are implemented and analysed: a hysteresis controller, a stiffness-coefficient-model and a fuzzy-logic-controller. The two latter concepts are determining the fuel cell power according to the power demand. The main result, presuming realistic designs of fuel cell and battery, is that the general performance of the stiffness-coefficient-model and the fuzzy-logic-controller is significantly superior to the one of the hysteresis controller. An active limitation of the fuel cell power is recommended to further improve the performance of the energy management concepts.