Energy management of fuel cell vehicles operating in fixed-route service

The davantage of hybridization of fuel cell vehicles is the significant lessening of the dynamic load requirements for the ful cell system and as a major consequence the extension of the fuel cell system's lifetime and reliability. Moreover, hybridization potentially allows downsizing of the fuel cell and consequently a substantial reduction of the costs of the drive system is achieved. The energy management strategy , which controls the flow of electrical power between the components of the drive system depending on the required mechanical power, is a crucial point of hybrid power drives. If predictions about the power demand of the drive are available, e.g.,in fixed-route service, advanced model-based predictive control schemes can be applied to determine the electrical power flow in such a way that the dynamic load of the fuel cell system and the fuel consumption as well are minimized. The paper shows how information about the parameters of the vehicle dynamics, the hybrid drive components and the given route and schedule is combined into an optimization problem. Moreover, we describe how is solution is obtained and updated in real time. For the latter influencing factors that cannot be predicted in advance are taken into account. The new control strategy shall be implemented into the onboard controller of the test vehicle at Fraunhofer IVI, Dresden (Germany), and is by now verified by simulation using real life data.