Power management of PEM fuel cell hybrid systems

In this paper, a power management algorithm of PEM fuel cell hybrid system is proposed. Since the PEM fuel cell cannot response to fast load change, a rechargeable lithium-ion battery pack and two DC/DC converters are added to build a PEM fuel cell hybrid system to solve this problem. By utilizing a virtual potential field approach, a power coordinating algorithm is proposed to manage the power demand for the PEM fuel cell and the lithium-ion battery to respond to the dynamically changed power load while maintaining the lithium-ion battery´s state of charge (SOC). As the SOC of the battery cannot be measured directly, a nonlinear observer based on an inclusive battery model is utilized for the SOC estimation. Simulation results are provided to illustrate the performance of the power management method.