Optimal Power Control of Hybrid Fuel Cell Systems for an Accelerated System Warm-Up

Key technical challenges in hybrid fuel cell power system applications are the power management and the thermal control. In this paper, a charge-sustaining supervisory power controller is developed, which minimizes the warm-up duration of a fuel cell/battery hybrid power system by optimally controlling the power split between the fuel cell system and the battery, as well as the operation of an auxiliary heater. The controller is implemented as a model-predictive feedback law. First, a control-oriented, mathematical model of the system is established and partially validated with experimental data. An optimal control problem is then stated, and from the necessary conditions of Pontryagin's minimum principle a solution is derived. The operation of the controller is demonstrated in the simulation, and the controller's functionality is analyzed in detail. As the controller has a feedback structure and as it requires only low computing power, it is adequate for an on-board, real-time application