Power management based on sliding control applied to fuel cell systems: A further step towards the hybrid control concept

This paper proposes a novel solution to power management based on sliding control techniques. Most of solutions to power management over fuel cell systems are based on traditional constant frequency control techniques like peak, valley and average current or voltage control or other kind of control techniques like PID controllers which act over switching devices on power conditioning stages (DC/DC converters). However, variable frequency control techniques like sliding control are widely used to control the hydrogen and oxidant supply (Balance of Plant, BOP) on PEM fuel cell stacks, but not on power management. In this paper, authors give a further step, and they join constant and variable frequency control techniques to establish the power management in fuel cell hybrid systems. That is, the power supplied by sources in a hybrid system is regulated applying hybrid control based on combining peak, valley or average current control (traditionally associated with fixed frequency), and sliding control techniques (variable frequency technique). Features like stability, precision, easy to implement and speed derive from this hybrid control concept. Simulation results of real system will show different power management solutions based on hybrid control applied to different topologies of fuel cell based systems.