Energy management of fuel cell vehicles - Using prediction of power demand

The advantage of hybridization of fuel cell vehicles is the significant lessening of the dynamic load requirements for the fuel 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 or by using GPS data, 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 its solution is obtained and uptadted 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.